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OF THE 


CARBON COMPOUNDS 


ORGANIC CHEMISTRY 


BY 


PROF. VICTOR: von RICHTER, 


UNIVERSITY OF pandenen 


AUTHORIZED TRANSLATION  — G 
BY 


EDGAR F, SMITH, 


PROFESSOR OF CHEMISTRY, UNIVERSITY OF PENNSYLVANIA. 


SECOND AMERICAN EDITION 


FROM THE 


SIXTH GERMAN EDITION. 


(ONLY ERSITY 
‘ SCALIFORNI 
fy PHILADELPHIA : 


'. BLA KIS TON:-SON & CO: 


No. 1012 WALNUT STREET. 
1892. 







WITH ILLUSTRATIONS. 








& Co. 


‘Son 


N, 


; 


P. 











TAREE OF CONPENTS. 





INTRODUCTION. 


Organic Chemistry Defined, 17. Elementary Organic Analysis, 18. Determina- 
tion of Nitrogen, 22. Determination of the Molecular Formula, (1) from the 

Vapor Density, 29; (2) from the Behavior of Solutions, 33. 
Chemical Structure of the Carbon Compounds, 37. Radicals and Formulas, 45. 
i Early Theories upon .the Constitution of Carbon Compounds, 47. Stereo- 
“a Chemical Theories, 50. Tautomerism,54. Physical Properties, 55. Specific 
Gravity, 55. Melting Points—Boiling Points, 58. Optical Properties, 60. 

i Electric Conductivity, 65. 





a SPECIAL PART. 
CLASS I.—FATTY BODIES OR METHANE DERIVATIVES. 
a iE ydrocarbons, 69. 

Hydrocarbons C,H ,+,, 70. Petroleum, 71. Paraffins, 73. Unsaturated 
Hydrocarbons C,H,,, 79. Hydrocarbons C,H,,—,—Acetylene Series, 86, 
Halogen Derivatives of Hydrocarbons, go. _ 

Compounds C,Hyn+, X — Alkylogens, 93. Compounds C,H,,—, X, 96. 

by Allyl Iodide, 98. 

| : Compounds C,H,,X,, 99. Chloroform, 102. 

_ Nitro-derivatives, 105. 

Nitro-paraffins, 107. . Nitrolic Acids, 109. 
Pseudo-nitrols, 109. Nitrosates, 111. Nitroform, 112. 


Alcohols, Acids and their Derivatives, 114. 





! Monovalent Compounds, 116. 

Monovalent Alcohols, 116. 

” Structure of Monovalent Alcohols, 117. Formation of Alcohols, 118, Prop- 
erties and transpositions, 123. 

Alcohols C,H,,+,.OH. Methy! Alcohol, 124. Ethyl Alcohol, 125. Propyl 
Alcohols, 127. Butyl Alcohols, 128. Amyl Alcohols, 129. 

Unsaturated Alcohols, 1 34. Allyl Alcohol, 134. Propargyl Alcohol, 135. 
Ethers, simple and mixed, 136. Ethyl Ether, 139. 

S Vil 


a. BAe 





Vill : TABLE OF CONTENTS. 


Mercaptans and Thio-ethers, 140. Alkyl Sulphines, 144. 


Esters of Minerals Acids, 146. Esters of Nitric Acid, 147. Esters of Sul. 

phuric Acids, 148. Esters of Sulphurous Acid, 150. Sulpho-Acids, 152. 

Sulphinic Acids, 154. Esters of the Phosphoric Acids, 155. Esters of the 
Arsenic Acids, 156. Esters of Silicic Acids, 156. 


Amines, 157. 
Primary, 162. Secondary, 163. Tertiary, 164. Nitroso-amines, 164. Nitro- 
amines, 164. Ammonium Bases, 165. Hydroxylamine Derivatives, 166. 


Hydrazines, 166. Diazo-compounds, 167. 
Phosphines or Phosphorus Bases, 168. 


Arsenic Bases, 170. Cacodyl Compounds, 172. 
Antimony Compounds, 174. Boron Compounds, 175. Silicon Compounds, 
176. ? 


Metallo-Organic Compounds, 177. 
Compounds of the Alkali Metals, 178. Zinc Compounds, 179. Mercury 
Compounds, 181. Aluminium Compounds, 182. Tin Compounds, 183. 
Lead Compounds, 185. Bismuth Compounds, 185. 


Aldehydes and Ketones, 186. 

Aldehydes, 187. Aldoximes, 191. Aldehydes of Paraffin Series—Methyl 
Aldehyde, 191. Acetaldehyde, 193. Condensation of Aldehydes, 194. 
Chloral, 196. Thialdehyde, 197. Amy] Aldehydes, 198. 

Unsaturated Aldehydes, 198. Acrylaldehyde, 199. Crotonaldehyde, 199. 

Ketones, 200. Acetone, 203. Acetoximes,-205. Glyoximes, 207. Conden- 
sation of Acetone, 207. Phorone, 208. Acetone Bases, 208. Acetone 
Homologues, 209. 


Monobasic Acids, 211. 

Fatty Acids C,H,,O,, 215. Formic Acid, 216. Acetic Acid, 219. Sub- 
stituted Acetic Acids, 221. Propionic Acid, 222. Butyric Acids, 226. 
Valeric Acids, 228. Hexoic Acids, 229. Heptoic Acids, 230. . Higher 
Fatty Acids, 230. - Soaps, 231. Stearic Acid, 232. 

Unsaturated Acids C,Hyn—.0,, 233. Acrylic Acid, 236. Crotonic Acids, 238. 

2 Angelic Acid, 240. Oleic Acid, 242. Linoleic Acid, 243. 

Acids C,H,,—,O,:. Propiolic Acid, 244. Sorbie Acid, 245. 

The Acid Haloids, 246. Acetyl Chloride, 247. 

Cyanides of Acid Radicals, 247. 

Acid Anhydrides, 248. Thio-acids and Thio-anhydrides, 250. 

Esters of the Fatty Acids, 251. Spermaceti, Beeswax, 255. 

Acid Amides, 255. Amide-chlorides, 258. Thio-amides, 260. 

Cyan-, sulpho-, and Amido-derivatives of Acids, 261. 





TABLE OF CONTENTS. ix 


Cyanogen Compounds, 263, 

Dicyanogen, 263. Hydrocyanic acid, 265. Halogen Compounds of Cya- 
nogen, 267. Metallic Cyanides, 268. Nitroprussides, 270. 

Cyanic Acids, 271. Cyanuric Acids, 272. Esters of Cyanic Acids or Cyan- 
etholins, 273. Isocyanic Esters, 274. Esters of Cyanuric Acids, 275. Thio- 
cyanic Acids, 277. Esters of Thio- and iso-thiocyanic Acids, 278. Allyl 
Mustard Oil, 281. 

Cyanides of Alcohol Radicals, Nitriles, 282. 

Acetonitrile, 283. Mercury Fulminate, 285. Fulminuric Acid, 286. Iso- 
cyanides or Carbylamines, 287. 

Amide Derivatives of Cyanogen, 288. Amides of Dicyanic Acids, 289. 
Melamine, 290. Imido-ethers, 292. Amidines, 292. Oxamidines, 292. 
Guanidines, 294. 


Divalent Compounds, 296. 

Divalent (dihydric) Alcohols or Glycols, 296. Methylene Derivatives, 301. 
Ethylene Glycol, 301. Ethylene Oxide, 303. Polyethylene Glycols, 304, 
Ethidene Compounds, 305. Propylene Glycols, 308. Butylene Glycols, 309. 
Amines of Divalent Radicals, 311. Imines, 312. “Oxy-ethyl Bases, 314. 
Alkines, alkeines, 315. Choline, 315. Ptomaines, 316. Betaine, 316. Sul- 
phonic Acids of Divalent Radicals, 317. Isethionic Acid, 318. Taurine, 
319. Ethidene Sulphonic Acids, 320. : 

Aldehyde Alcohols, 320. Aldol, 321. Ketone Alcohols, 321. Keton-Alde- 
hydes, 323. Acetyl Aldehyde, 323. Dialdehydes, 324:—Glyoxal, 324. 

_ Glyoxime, 324. Diketones: a- Diketones, 325. $- Diketones, 327. y- Dike- 
tones, 328. Aldehyde Acts, 329. Glyoxylic Acid, 330. Formyl Acetic 
Acid, 331. 

Ketonic Acids, 331. a- Ketonic Acids, 332. Pyroracemic Acid, 332. (- Ke- 
tonic Acids, 333. Acetoacetic Ester, 338. y- Ketonic Acids, 343. Lzvu- 
linic Acid, 343. 

Unsaturated Ketonic Acids, 344. Aceto-acrylic Acid, 344. 


Divalent Monobasic Acids, 345. a-, 3 and y-oxy-acids, 348. Their Decom- 

position, 350. Anhydrides of Oxy-acids, 351. Lactones, 351. 

Oxy-Fatty Acids C,H 105, 353. Glycollic Acid, 354. Glycolide, 356. Lactic 
Acids, 356. Chloralides, 360. Hydraerylic Acid, 361. Oxybutyric Acids, 
362. Butyrolactone, 362. Oxyvaleric Acids, 363. 

Amides of Dihydric Acids, 363. Amido-acids, 366. ” 

Glycocoll, 369. Alanine, 371. Leucine, 373. Diazo-acids, 373. Diazo-acetic 
Acid, 374. Triazo-acids, 375. Carbonic Acid and Derivatives, 375. Cyan- 
carbonic Acid, 377. Esters of Carbonic Acid, 377. Trithio-carbonic Acid, 
379. Dithio-carbonic Acid, 380. Xanthic Acids, 380. Monothiocarbonic 
Acids, 381. Amide Derivatives, 382. Urethanes, 382. Chlorimido-carbonic 
Ethers, 384. Dithio-urethanes, 385. Thiourethanes, 385. 


x TABLE OF CONTENTS. 


Urea, 386. Compound Ureas, 388. Ureides, 391. Hydantoin, 391. Allo- 
phanic Acid, 393. Thiourea, 394. Sulpho-hydantoin, 396. 
Guanidine Derivatives, 397. Creatine, 398. 


Dibasic Acids, 399. Anhydrides, 4or. 

Oxalic Acid, 403. Amides of Oxalic Acid, 406. Malonic Acid, 408. Succinic 
Acids, 410. Succinimide, 412. Pyrotartaric Acids, 416. Adipic Acid, 419. 
Suberic Acid, 422. 

Unsaturated Dibasic Acids, 423. : i 

Fumaric and Maleic Acids, 425. Itaconic Acid, 429. Teraconic Acid, 431: 
Xeronic Acid, 431. 

Acetylene Dicarboxylic Acids, 431. Muconic Acid, 432. Ketone Dicarboxylic 
Acids, 432. Mesoxalic Acid, 434. Oxalo-acetic Acid, 435. Acetone Dicar- 
boxylic Acid, 435. Oxal-diacetic Acid, 437. Diaceto-succinic Acid, 437. 

Carbamides of Dibasic Acids, 438. Parabanic Acid, 439. Barbituric Acid, 
441. Alloxan, 443. Uric Acid, 445. Guanine, 448. Caffeine, 449. 


Trivalent Compounds, 450. 


Trivalent Alcohols, 451. Orthoformic Ester, Ortho-acetic Ester, 452. Gly- 
cerol, 452. Haloid Esters of Glycerol, 454. Glycide Compounds, 456. Alcohol 
Ethers of Glycerol, 457. Acid Esters of Glycerol, 458. 
Fats and Oils, 459. 
Polyglycerols, 459. Butyl Glycerol, 460. 


Trivalent Monabasic Acids. Glyceric Acid, 460. 


Dibasic Mono-oxy-Acids. ‘Tartronic Acid, 463. Malic Acid, 464. Amides 
of Malic Acid, 465. Asparagine, 466. 
Oxy-pyrotartaric Acids, 467. Paraconic Acid, 468. 
Terebic Acid, 469. 


Tribasic Acids. Formyl Tricarboxylic Acid, 471. Tricarballylic Acid, 472. 
Aconitic Acid, 472. 
Tetravalent Compounds. 
Tetrahydtic Alcohols, 473. Erythrol, 474. 


Monobasic Acid. Erythritic Acid, 474. 4 
Dibasic Acids. Tartaric Acid, 475. Racemic Acid, 478. 


Tribasic Acids. Carboxytartronic Acid, 480. Citric Acid, 480. 


Tetrabasic Acids. Acetylene Tetracarboxylic Acid, 481. Dicarbon-tetracar- 
boxylic Acid, 482. . ; 
-Pentavalent Compounds. 
Arabite, 483. Arabinose, Xylose, Isodulcite, 483. Saccharin, 484. Aposorbic 
Acid, 485. Desoxalic Acid, 485. 


TABLE OF CONTENTS. xi 


Hexavalent Compounds. 

Manitol, 487. Dulcitol, 488. Gluconic Acid, 489. Mannonic Acid, 490. 
Dioxytartaric Acid, 491. Saccharic Acid, 492. Mucic Acid, 493. 

Heptavalent (Heptahydric) Compounds, 494. 
Perseite, 494. Glucose Carboxylic Acid, 495. 
Butane Heptacarboxylic Acid, 496. 
Manno-octite, 496. 
Manno-nonite, 496. 


Carbohydrates, 497. Hexoses, 497. Osazones, 501. Mannoses, 503. 
Glucoses, 503. Fructoses, 505. Heptoses and Octoses, 507. Désaccharides :— 
Cane Sugar, 508. Maltose, 510. Raffinose, 511, Polysaccharides -—Starch, 
512. Dextrine, 513. Cellulose, 514. 

Derivatives of Closed Chains. Polymethylene Derivatives, 515. Trimethylene 
Carboxylic Acid, 516. 


Tetramethylene Derivatives, 519. 
Tetramethylene Carboxylic Acid, 519. 
Pentamethylene Derivatives, 520. 
Hexamethylene, 521. 


Furfurane, Thiophene and Pyrrol Derivatives. 


Furfurane Group, 523. 
Furfurane, 523. Furfurol, 524. Furfurane Carboxylic Acid, 526. Furfur- 
acrylic Acid, 527. Methionic Acid, 528. 


Thiophene Group, 528. 
Thiophene, 529. Thiotolene, 531. Thioxene, §31. Thiophenin, 533. Thio- 
phenaldehyde, 534. Thiophene Carboxylic Acid, 535. Dithiényl, 536. Pen- 
thiophene Derivatives, 537. _Methylpenthiophene, 537. 


Pyrrol Group, 538. 
Pyrrol, 539. Iodol, 541. Pyrrol Homologues, 542. Pyrrol Ketones, 544. 
Pyrrol-Carboxylic Acid, 546. Pyrocoll, 547. Pyrrol Dicarboxylic Acid, 548. 
Pyrroline, Pyrrolidine, 549. 
Azole Compounds or Diazoles, 551. Pyrazole, 551. Glyoxalines, 552.  Tri- 
azoles, 553. Thiazoles, 554. Oxazoles, 555. 


CLASS II, BENZENE DERIVATIVES. 


Benzene Nucleus, 556. Isomerism of Benzene Derivatives, 559. Structure of 
Same, 559. Constitution of Benzene Nucleus, 563. Formation of Benzene 
Derivatives, 565. Addition Products, 567. 


Hydrocarbons, C, Hyn—s, 568. 
Benzene, 571. Toluene, 572. Xylenes, 573. Mesitylene, 574. Cumene, 
575. Durene, 576. _Cymene, 577. Hexamethyl Benzene, 579. 


XIV TABLE OF CONTENTS... 


Tetrabasic Acids: Pyromellitic Acid, 798. Quinone Tetracarboxylic Ester 

798. Mellophanic Acid, 799. 

Hexabasic Acids: Mellitic Acid, 799. Euchroic Acid, 799. 
Unsaturated Compounds. 

Styrolene, 800. Phenyl Acetylene, 802. Allyl Phenols, 803, Safrol, Asarone, 
804. Styryl Alcohol, 804. Benzylidene Acetone, 805. Cinnamic Acid, 
808. Isocinnamic Acid, 812. Atropic Acid, 813. Phenyl-propiolic Acid, 
814. Coumaric: Acid, 818. Coumarin, 819. Umbelliferon, 821. Piperic 
Acid, 822. Benzmalonic Acid, 823. Phthalyl-acetic Acid, 823. 


Derivatives with Closed Side-Chains. 
Benzofurfurane Group, 825, Coumarone, 825. 
Benzothiophene Group, Benzothiophene, 826. 

- Benzopyrrol, or Indol Group, 826. 

Indol, 827. Alkyl Indols, 828. Skatole, 830. Oxindol, 831. Indoxyl, 832. 
Indogenides, 833. Dioxindol, 834. Isatin, 834. Isatoxime, 837. Indigo- 
Blue, 837. Indigo-White, 840. 

Benzo-diazole Compounds: Indazole, 841. Isindazole, 841. 

‘Derivatives with Several Benzene Nuclei, 842. 


(1) Derivatives of Directly Combined Nuclei. Diphenyl Group. 
Diphenyl, 843. Ditolyls, 844. Benzidine, 844. Benzidine Dyes, 845. 
Carbazol, 847. Coeroulignone, 848. Diphenic Acid, 849. 

Diphenylene Derivatives, 850. Fluorene, 850. _Diphenylene Ketone Acids, 
oo 
Diphenyl Benzene, Triphenyl Benzene, 852. 


(2) Derivatives of Benzene Nuclei Joined by one Carbon-atom. 
Diphenyl Methane Derivatives, 352. 
Diphenyl Methane, 856. Benzophenone, 858. Auramine, 859. Diphenyl 
Ethanes, 861. Diphenyl Acetic Acid, 861. Benzilic Acid, 862. Phenyl- 
. tolyl Methanes, 862. Benzoyl-benzoic Acids, 863. 
Triphenyl Methane Derivatives, 864. 
Triphenyl Methane, 865. Diphenyltolyl Methane, 866. 
Amido-derivatives. Malachite-green, 867. Rosaniline, 871. . Alkylic Ro- 
sanilines, 873. Pararosaniline Derivatives, 874. 
Phenol Derivatives, 876. Benzeines, 877. Rosamines, 877. Aurines, 877. 
Rosolic Acid, 878. 
- Carboxyl Derivatives, 879. Phthalophenone, 880. Phthaleins, 381. Fluorescein, 
882. Fluorescin, 883. Coerulein, 883. Rhodamines, 884, 
(3) Derivatives of Benzene Nuclei Joined by two Carbon-atoms. 
Dibenzyl Group, 884. 
Dibenzyl, 884. Stilbene, 885. Hydrobenzoins, 886, Benzoin, 887. Benzil, 
888. Benzil Dioximes, 888. Pinacones and Pinacolines, 889. Carboxy] 
Derivatives, 889. Tetraphenyl Ethane, 891. Dibenzyl Ketone, 891, 


TABLE OF CONTENTS. ; XV 


Anthracene Group, 892. 
Anthracene, 894. Oxyanthracenes, 896. Phthalidins and Phthalideins, 896. 
Anthraquinone, 896. Oxyanthraquinones, 897. Dioxyanthraquinones: Ali- 
zarin, 898. Trioxyanthraquinones: Purpurin, goo. 
Alkylic Anthracenes, 960. Methyl Anthracene, goI. Chrysophanic Acid, 
go1. Anthracene Carboxylic Acids, 902. 
Indene and Hydrindene Group, 902. Hydrindone, 904. 


(4) With Condensed Benzene Nuclei. 

Naphthalene, 905. Homologous Naphthalenes, 909. Acenaphthene, 909. 
Amidonaphthalenes, 910, Hydronaphthylamines, 911. Naphthylene Dia- 
mines, 912. Naphthalene Red, 914. Naphthionic Acid, 915. Naphthols, 
915. Naphthoquinones, 918. Naphthalene-alizarin, 919. Naphthoic Acids, 
922. Naphtho-furfurane and Naphthindol, 923. Phenanthrene, 924. 
Phenanthraquinone, 925. Retene, 926. Fluoranthene, 927. Pyrene, 928. 
Chrysene, 928. Naphanthracene, 929. 


Derivatives of Nuclei containing Nitrogen. 


(1) Derivatives of five-membered Nuclei. 

Phenyl-pyrazoles, 930. Pyrazolons, 933. Antipyrine, 933. 

Phenol glyoxalines, 934. Phenyl-triazoles, 935. 

(2) Derivatives of six-membered Nuclei. 

(1) Pyridine Group, 937. Pyridine, 941. Alkyl Pyridines, 942. Oxypyri- 
dines, Pyridones, 945. Lutidones, 945. Pyridine Carboxylic Acids, 946. 
Pyridine Tricarboxylic Acids, 949. 

Hydropyridines: Piperidine, 950. 

Conine, 952. Piperideines, Tropine, 953. Nicotine, 953. 

Diazines or Azines: Pyrazines, 954. Pyrimidines, 955. Pyridazines, 957. 
Oxazines and Morpholines, 957. 

Pyrone Group, 958. 

(2) Quinoline Group, 960. Quinoline, 965. Oxyquinolines, Kairine, 967. 

Thallin, 967. Carbostyril, 968. Alkyl Quinolines, 969. Quinaldine, 969. 
Flavaniline, 971. Quinoline Carboxylic Acids, 972. Quinaldinic Acid, 972. 
Quininic Acid, 973. Naphtholquinoline, 974. Phenanthridine, 974. An- 
thraquinoline, 975. 


Isoquinoline Group, 975. 

Benzodiazines: Cinnolines,976. Quinazolines,977. Quinoxalines, 978. 
Benzotriazines, Beizemaniics, 981. 

Acridine Group, 981. Chrysaniline, 983. Phenoxazine, 983. 

Phenazine Group, 984. 


Eurhodines, 986. Toluylene Red, 988. Safranines, 989. Indulines, 990. 
Rosindulines, 991, 


Xvi TABLE OF CONTENTS. 


Alkaloids: 991. 
Opium Bases, 992. 
Cinchona Bases, 994. 
Strychnine Bases, 995. 
Atropine, 996.’ Cocaine, 996. 


Terpenes, 998. Pinene, 999. Camphenes, 1001. Citrene, 1001, Cinene, 1002. 
Sylvestrene, 1003. 


Camphor, 1004. Borneo-camphor, 1006. Mentha-camphor, 1006. Camphoric 
acid, 1007. 


Resins, 1008. 
Glucosides, 1008. _ 
Coloring Substances: Aloes, Iolo. 
- Biliary Substances, 1011. Gelatines, 1012. 
Albuminates: Albumen, 1014. Fibrin, 1015. Casein, 1015. Oxyhzmoglobin 
1015. Lecithin, 1016. 





ERRATA. 





Page 78.—13th line from top, read hexa-hydropseudo-cumene for mesitylene 
hexahydride. 


Page 313.—8th line from top, read ethylene imine identical with fiperazine 
(P- 955). 
Page 356.—Ist line, read pseudo-diketothiazole. 


Page 645.—2Ist line from bottom of page, read disazo-derivatives for diazo-deri- 
vatives. 


Page 657.—14th line from bottom, read a-methyl-phenyl-hydrazine, instead of 
a-methylhydrazine. 


Page 707.—8th line from bottom, read 


3 N.C,H,.N(CHs)., 
a °\N instead 
of 
N.C,H,.N(CH,),. 
Crolle | 


Page 788,.—23d line from top, read hydrogenized for hydrided. 
Page 874.—8th line from top, read zodine for iodide. 


Page 912.—Sth line from top, read alicyclic for alicylic. 











LEE SE S1BRG 
(EX OF THE , 
; UNIVERSITY 


CALIFORNIA 
A TEXT-BOOK 









OF 


ORGANIC CHEMISTRY. 





INTRODUCTION. 


The chemistry of the carbon compounds was formerly called 
Organic Chemistry. This designation originated in the time of 
Lavoisier (1743-1794), who announced the fundamental ideas of 
the nature of the chemical elements and compounds. He it was, 
too, who first recognized the true composition of the so-called 
organic substances occurring in the organism of plants and animals. 
He discovered that by their combustion, carbon dioxide and water 
were always formed, and showed that the component elements were 
generally carbon, hydrogen, and oxygen, to which sometimes— — 
especially in animal substances—nitrogen was added. Lavoisier 
further gave utterance to the opinion that peculiarly constituted 
atomic groups, or radicals, were to be accepted as present in organic 
substances; while the mineral substances were regarded by him as 
the direct combinations of single elements. 

In this way it was proved that the substances peculiar to the 
plant and animal kingdoms possess a composition different from 
that of mineral matter. As, however, it seemed impossible, for a 
long time, to prepare the former from the.elements synthetically, 
the opinion prevailed that there existed an- essential difference 
between the organic and inorganic substances; and this led to 
the distinction of the chemistry of the first as Organic Chemistry, 
and that of the second as Inorganic Chemistry. The prevalent — 
opinion was, that the chemical elements in the living bodies were 
subject to other laws than those in the so-called inanimate nature, 
and that the organic substances were formed only in the organism 
by the intervention of a peculiar vital force, and that they could 
not possibly be prepared in an artificial way. 

One fact sufficed to prove these rather restricted views to be 

2 17 


\ ‘ 


18 cee _ * ORGANIC: CHEMISTRY. 


unfounded, * The -first ‘argani¢. substance artificially prepared was 
urea (Wohler, 1828). By this synthesis chiefly, to which others 
were soon added, the idea of a peculiar force necessary to the 
formation of organic compounds, was contradicted. However, even 
as late as 1840, Gerhardt clung to the view that chemical forces only 
exercise a destroying action, and with Berzelius, defined organic 
substances as those produced by vital force. Numerous additional 
syntheses soon showed that such opinions were no longer tenable. 
All further attempts to separate organic substances from the inor- 
ganic were futile. At present we know that these do not differ 
essentially from each other ; that the peculiarities of organic com- 
pounds are dependent solely on the nature of their essential con- 
stituent, Carbon ; and that all substances belonging to plants and 
animals, can be artificially prepared from the elements. 

Organic Chemistry is, therefore, the chemistry of the carbon 
compounds. Its separation from general chemistry is demanded by 
practical considerations ; it is occasioned by the very great number 
of carbon compounds. 


We would here note the difference between the conceptions of organic and 
erganized bodies. Different carton compounds possess the power to assume in 
the living organisms an organized structure—to form cells. The causes and con- 
ditions of this power are as yet unknown to us. We know no more of them than 
of the cause of the union of molecules to form crystals, or of the atoms to form 
molecules. 

Further, notice that organic chemistry does not occupy itself with the investiga- 
tion of the chemical processes in vegetable and animal organisms. This is the 
_ office of Physiolegical Chemistry. 





COMPOSITION OF CARBON COMPOUNDS. 
ELEMENTARY ORGANIC ANALYSIS. 


Most carbon compounds occurring in vegetables and animals 
consist of carbon, hydrogen, and oxygen. Many, also, contain 
nitrogen, and on this account these elements are termed Organogens. 
Sulphur and phosphorus are present in some naturally occurring 
substances. Almost all the elements, metalloids and metals, may 
be artificially introduced as constituents of carbon compounds in 
direct union with carbon. The number of known carbon com- 
pounds is exceedingly great, while the possible ones are almost 
without limit. The general procedure, therefore, of isolating the 
several compounds of a mixture, as is done in mineral chemistry in 
the’separation of bases from acids, is impracticable. The mixtures 
occurring in vegetable and animal bodies, are only separated by 
special methods. The task of elementary organic analysis 1s to 


DETERMINATION OF CARBON AND HYDROGEN. 19 


determine, qualitatively and quantitatively, the elements of a carbon 
compound after it has been obtained ina pure state and charac- 
terized by definite properties. The analysis is generally limited to 
the determinations of carbon, hydrogen, and nitrogen. Simple 
practical methods for the direct determination of oxygen do not 
exist. Its quantity is usually calculated by difference, after the 
other constituents have been found. 


DETERMINATION OF CARBON AND HYDROGEN. 


The presence of carbon in a substance is shown by its charring 
when ignited away from air. Ordinarily its quantity, as also that 
of the hydrogen, is ascertained by combustion. The substance 1s 
mixed in a glass tube with copper oxide and heated. Carbon burns 
to carbon dioxide, the hydrogen to water. In quantitative analysis, 
these products are collected in separate vessels, and the increase in 
weight of the latter determined. Carbon and hydrogen are always 
simultaneously determined in one operation. ‘The details of the 
quantitative analysis are fully described in the text-books of analytical 


Fic. 1x. 





chemistry. It is only necessary here, therefore, to outline the 
methods employed. Asa usual thing, the combustion is effected 
by the aid of copper oxide in a tube of hard glass, fifty to sixty 
centimetres long, and drawn into a point at one end (Fig. 1). 

Dry, freshly ignited, granular copper oxide is first introduced 
into the tube (from @ to 4); then the mixture of the solid substance 
(about 0.2-0.3 gr.) with pulverized cupric oxide (4 to ¢), and 
afterwards granular copper oxide (to 2), upon which is placed a 
wad of asbestos. If the substance to be analyzed is a liquid, it is 
weighed out in a glass bulb drawn out to a point, and this placed 
in the combustion tube. When the latter has been filled, the 
open end is closed with a cork, carrying a straight or bent calcium 
chloride tube (Fig. 2). 

This is filled with dried granulated chloride of calcium, which 
absorbs the aqueous vapor produced in the combustion tube, while 
the carbon dioxide passes on unchanged. ‘To the calcium chlo- 
ride tube is attached, by means of rubber tubing, a Liebig bulb 
(Fig. 3), containing potassium hydroxide (of sp. gr. 1.27); the 
potash bulb of Geissler is better. The carbon dioxide formed in 


20 ORGANIC CHEMISTRY. 


the combustion is absorbed in this. To the potash bulb there 
is also attached a small tube; this is filled with stick potash. It 
serves to retain the slight quantity of aqueous vapor which might 
escape from the bulbs. Before the combustion takes place, the 
calcium chloride tube and the apparatus containing potassium 
hydroxide (also the small tube) are weighed separately. Their 


Fic. 2. Fic. 3. 





connection is then made, and the combustion tube placed in 
the furnace. The arrangement of the apparatus is illustrated in 
(Fig. 4). 

The front and back portions of the combustion tube are heated 
first. These parts contain only pure cupric oxide. Subsequently 
the middle portion, containing the substance, is gradually and 


Fic. 4. 





partially heated. ‘The heat should be so applied that the liberated 
carbon dioxide enters the potash bulbs in separate bubbles. When 
this no longer occurs the combustion is complete. ‘The flames are 
then extinguished, the draw-out end of the tube is connected, by 
means of rubber tubing, with a drying apparatus; the pomt of the 
tube is broken off and air drawn through, to remove all aqueous 


DETERMINATION OF CARBON AND HYDROGEN. 21 


vapor and carbon dioxide from the combustion tube, and to bring 
them into their proper absorption vessels (the drying apparatus 
removes moisture and carbon dioxide from the aspirated air). When 
the substance is difficult to burn, it is advisable finally to conduct 
a stream of oxygen through the combustion tube, in order that all 
the carbon may be converted into carbon dioxide. After complet- 
ing the operations just outlined, disconnect the apparatus and weigh 
the various pieces separately. The increase in weight of the cal- 
cium chloride tube represents the quantity of water produced ; that 
of the potash bulbs, the amount of carbon dioxide. From these we 
can readily calculate the quantity of carbon and hydrogen in the 
substance analyzed. 

Instead of mixing the substance with cupric oxide, it may be 
placed in a porcelain or platinum boat, then introduced into a tube 
open at both ends. The combustion in this case is carried out in 
a stream of air or oxygen—method of Glaser (Fig. 5). 

A layer of granular copper oxide fills the tube from @ to ¢ (enclosed 
by two asbestos wads). This is ignited in a current of air, then 
allowed tocool. Theend (/) is connected with the usual apparatus, 





previously weighed ; the boat containing the substance (¢) is intro- 
duced at the opposite end, and the latter joined either to an oxygen 
gasometer or some apparatus for purifying gases. The layer of 
cupric oxide is brought to a red heat, and the combustion executed 
in a slow current of air or oxygen. To avoid a diffusion of the 
gases backward in the tube, there is placed immediately behind the 
boat a wad (4) of asbestos or some copper; or a layer of mercury 
is introduced between the drying apparatus and the combustion 
tube. A second analysis may be commenced as soon as the first is 
ended. 


“3 


In this last method, platinum black (mixed with asbestos) may be substituted for 
cupric oxide :—method of Kopfer. A much shorter and more simple combus- 
tion furnace may then be employed. The method is adapted to the combustion 
of compounds containing the halogens (Zeitschrift fiir anal. Chemie, 1878, 
17,1). Dudley has found that a platinum tube, having a layer of granular man- 
ganic oxide in the anterior part, is of great service when substances are placed in 
boats and exposed to combustion (Ber., 21, 3172). 

When nitrogen is present in the substances burned, oxides of it are sometimes 
produced, and these are absorbed in the calcium chloride tube and potash bulbs. 
To avoid this source of error, the oxides must be reduced to nitrogen. This 
may be accomplished by conducting the gases of the combustion over a layer of 


22 ORGANIC CHEMISTRY. 


metallic copper filings, or a copper spiral, placed in the front portion of the combus- 
tion tube. The latter, in such cases, should be a little longer than usual. The 
copper is previously reduced in a current of hydrogen, then ignited, when it often 
includes hydrogen, which subsequently becomes water. To remedy this, the cop- 
per heated in a current of hydrogen is raised to a temperature of 200° in an air- 
bath, or better, in a current of carbon dioxide orin a vacuum. Its reduction by the 
vapors of formic acid or methyl alcohol is more advantageous; this may be done 
by pouring a small quantity of these liquids into a dry test tube and then suspend- 
ing in them the roll of copper heated to redness ; copper thus reduced is perfectly 
free from hydrogen. It is generally unnecessary to use a copper spiral when the 
combustions are executed in open tubes, because nitric oxide (NO) only is pro- 
duced, and this passes through the caustic potash unabsorbed (Ber., 22, 3066, 
LNVot.). 

a the presence of chlorine, bromine or iodine, halogen copper compounds 
(CuX) arise. These are somewhat volatile and pass over into the calcium 
chloride tube. The placing of a spiral of copper or silver foil in the front part of 
the tube will obviate this. When the organic compound contains sulphur a por- 
tion of the latter will be converted into sulphur dioxide, during the combustion 
with cupric oxide. This may be combined by introducing a layer of lead peroxide 
(Zeitschrift f. anal. Chemie, 17,1). Or lead chromate may be substituted for the 
cupric oxide. This would convert the sulphur into non-volatile lead sulphate. In 
the combustion of organic salts of the alkalies or earths, a portion of the carbon 
dioxide is retained by the base. To prevent this and to expel the CO,, the sub- 
stance in the boat is mixed with some potassium bichromate or chromic oxide 
(Berichte, 13, 1641). When carbon alone is to be determined this can be effected, 
in many instances, in the wet way, by oxidation with chromic acid and sulphuric 
acid (Messinger, Ber., 21, 2910). 


DETERMINATION OF NITROGEN. 


In many instances, the presence of nitrogen is disclosed by the 
odor of burnt feathers when heat is applied to the compounds 
under examination. Many nitrogenous substances yield ammonia 
when heated with alkalies (best with soda-lime). A simple and 
very delicate test for the detection of nitrogen is the following: 
Heat the substance under examination in a test tube with a 
small piece of sodium or potassium. When the substance is ex- 
plosive, add dry soda. Cyanide of potash, accompanied by slight 
detonation, is the product. Treat the residue with water; to the 
filtrate add ferrous sulphate, containing a ferric salt, and a few drops 
of potassium hydroxide, then apply heat and add an excess of hydro- 
chloric acid. An undissolved, blue-colored precipitate (Prussian 
blue), or a bluish-green coloration, indicates the presence of nitro- 
gen in the substance examined. 

Nitrogen is determined, quantitatively, either by volume, by’ 
burning the substance and collecting the liberated, free nitrogen, or 
as ammonia, by igniting the substance with soda-lime. The first 
method is applicable with all substances, while the second can only » 
be employed with the amide and cyanide compounds, not with those 
containing the nitro- and the azo- groups. 


DETERMINATION OF NITROGEN. 23 


1. Method of Dumas.—lIn a glass tube sealed at one end 
(length 70-80 cm.), place a layer (about 20 cm.) of dry, primary 
sodium carbonate or magnesite, then pure cupric oxide (6 cm.), , 
afterwards the mixture of the substance with oxide, then again pure 
granular cupric oxide (20-30 cm.), and finally fill the tube with 
pure copper turnings (page 22) (about 20cm.). In the open end of 
the tube is placed a rubber cork bearing a gas-delivery tube, which 
extends into a mercury bath. 

The back part of the combustion tube, containing the carbonate, 
is heated first; this causes the liberated carbon dioxide to expel 
the air from all parts. of the apparatus. We can be certain of this 
by placing a test tube filled with potassium hydroxide over the exit 
tube in the mercury trough. Complete absorption of the eliminated 
gas proves that air is no longer present. ‘This done, a graduated 


Fic. 6. 


gpey 0/0/0j0 fe u/o| 4 






























































cylinder filled with mercury is placed over the end of the exit tube 
and into the tube containing mercury is introduced, by means of 
a pipette, several cubic centimetres of concentrated potassium 
hydroxide. Proceed now with the combustion. First heat the 
metallic copper and the layer of cupric oxide in the anterior por-: 
tion of the tube, and afterwards gradually approach the mixture. 
When the combustion is ended, again apply heat to another part of 
the sodium carbonate layer, to insure the removal of all the nitrogen 
from the tube and itsentrance into the graduated tube. The potas- 
sium hydroxide absorbs all the disengaged carbon dioxide, and only 
pure nitrogen remains in the graduated vessel. The latter is then 
placed in a large cylinder of water, allowed to stand a short time 
until the temperature is equalized, when the volume of gas is read 
and the temperature of the surrounding air and the barometer. 


24 ORGANIC CHEMISTRY. 


height noted. With these data, the weight (G) of the nitrogen 
volume, in grams, may be calculated from the formula— 


eae V (A— w) 
760 (1 -++ 0.00367 #) 
in which V represents the observed volume in cubic centimetres, 
Ah the barometric pressure, and zw the tension of aqueous vapor at 
the temperature 4 ‘The number o.0012562 is the weight, in grams, 
of 1c. c. nitrogen at o° C, and 760 mm. pressure. 





X 0.0012562, 


Instead of reducing the observed gas volume V, from the observed barometric 
pressure and the temperature at the time of the experiment, to the normal pressure 
of 760mm. and the temperature of 0° (as recommended in the preceding formula), 
the reduction may be more readily effected by comparing the observed volume of gas 
or vapcr with the expansion of a normal gas-volume (100) measured at 760 mm. and 
100 


v 

the changed normal volume (100). The apparatus recommended by Kreusler 
(Ber., 17, 30) and Winkler (Zer., 18, 2534), or even the Lunge nitrometer will 
answer very well for this purpose. 

The nitrogen determinations, as a general thing, are a little high in result, be- 
cause it isalmost impossible to expel the air from the combustion tube, and the 
metallic copper sometimes contains H (page 22). It is, therefore, well to remove 
the air from the tube by a mercury air-pump (Zedtschrift f. analyt. Chemite, 17, 
409). Frankland conducts the combustion in a vacuum, and dispenses with the 
layer of metallic copper in the anterior portion of the tube. If any nitric oxide is 
formed it is collected together with the nitrogen, and is subsequently removed by 
absorption (Ber., 22, 3065). 5 

Instead of collecting the disengaged nitrogen in an ordinary graduated glass 
tube, peculiar “ azotometers’”? may be employed. Of these the apparatus of Schiff 
(Berichte, 13, 886), Zulkowsky (zbzd., 1099), Groves (7bzd., 1341), and Ilenski 
(2b¢d., 17, 1348), may be recommended. Consult the Zettschrift fiir analyt. 
Chemie, 17, 409, and Ber., 19, Ref. 710, for methods by which carbon, hydrogen, 
and nitrogen are determined simultaneously. 

See Gehrenbeck (er., 22, 1694) when a method is desired for the simultaneous 
estimation of nitrogen and hydrogen in cases where the carbon was determined in 
the wet way. 

We can determine the nitrogen of nitro- and nitroso-compounds indirectly with 
a titrated solution of stannous chloride. The latter converts the groups NO, and 
NO into the amide group, with production of stannic chloride; the quantity of 
the latter is learned by the titration of the excess of stannous salt with an iodine 
solution. Method of Limpricht (erichie, 11, 40). 


o°. For this purpose employ the equation V, = V. , in which v represents 





2. Method of Will and Varrentrap.—When most nitro- 
genous organic compounds (nitro-derivatives excepted) are ignited 
with alkalies, all the nitrogen is eliminated in the form of ammo- 
nia gas. The so-called soda-lime is best adapted for this decompo- 
sition ; it is prepared by adding 2 parts lime hydrate to the aqueous 
solution of pure sodium hydroxide (1 part), then evaporating the 
mixture and gently igniting it. Mix the weighed, finely pulver- 
ized substance with soda-lime (about ro parts), place the mixture 


DETERMINATION OF NITROGEN. 25 


in a combustion tube about 30 cm. in length, and fill in with soda- 
lime. In the open end of the tube there is placed a rubber cork 
bearing a bulb apparatus (Fig. 7), in which there is dilute hydro- 
chloric acid. The anterior portion of the tube is first heated in the 
furnace, then that containing the mixture. To carry all the am- 
monia into the bulb, conduct air through the tube, after breaking 
off the point. The ammonium chloride in the hydrochloric acid is 
precipitated With platinic chloride, as ammonio-platinum chloride 
(PtCl,. 2NH,Cl), the precipitate ignited, and the residual Pt 
weighed ; 1 atom of Pt corresponds to 2 molecules of NH; or 2 
atoms of nitrogen. 


Generally, tco little nitrogen is obtained by this method. A portion of the 
ammonia suffers decomposition. This is avoided by adding sugar to the mixture 
of substance and soda-lime, and by not heating the tube too intensely (Zez/schrift, 
19,91). It isalso advisable to fill up the tube with soda-lime as far as is possible 
(Zett. fiir analyt. Chemie, 22, 280). A more rapid volumetric method may be 
substituted for the gravimetric method in determining the ammonia. A definite 


Fic. 7. 











volume of acid is placed in the bulb apparatus, and its excess after combustion 
ascertained by residual titration, employing fluorescein or methyl orange as in- 
dicator. 

The method of Will and Varientrap is made more widely applicable by adding 
reducing substances to the soda-lime. Goldberg uses a mixture of soda-lime (100 
parts), stannous sulphide (100 parts), and sulphur (20 parts); this he considers 
especially advantageous in estimating the nitrogen of nitro- and azo-compounds 
(Ber., 16, 2549). For nitrates, C, Arnold (Ber., 18, 806) employs a mixture of 
soda-lime (2 parts), sodium hyposulphite (1 part), and sodium formate (1 part). 


3. Method of Kjeldahl.—The substance is dissolved by heating it with con- 
centrated sulphuric acid. Potassium permanganate (pulverized, or its solution in 
sulphuric acid) is then added until a distinct green color appears. This treatment 
decomposes the organic matter; its nitrogen is converted into ammonia. After 
the liquid has been diluted with water the ammonia is expelled from it by boiling 
with sodium hydroxide (Zet/. f. a. Chem., 22, 366). This method is well adapted 
for the determination of the nitrogen of plants (compare Ber., 18, Ref. 199). 

When estimating the nitrogen of nitro- and cyanogen compounds it will be 
found decidedly advantageous to add sugar, and with nitrates, benzoic acid. The 
addition of potassium permanganate will be unnecessary. Pyridine and quinoline 
cannot be analyzed by this method (Ber., 19, Ref. 367, 368). 


26 ORGANIC CHEMISTRY. 


DETERMINATION OF THE HALOGENS. 


Substances containing chlorine and bromine yield, when burned, 
a flame having a green-tinged border. The following reaction is 
exceedingly delicate. A little cupric oxide is placed on a platinum 
wire, ignited in a flame until it appears colorless, when a little of 
the substance under examination is put on the cupric oxide and 
this heated in the non-luminous gas flame. The latter is colored 
an intense greenish-blue in the presence of chlorine or bromine. 
More decisive is to ignite the substance in a test tube with burnt 
lime, dissolve the mass in nitric acid, and then add silver nitrate. 

The following guantitative methods for estimating halogens are 
in use :— 


1. A hard glass tube, closed at one end, and about 30 cm. in 
length, is partly filled with calcium oxide, thea the mixture of the 
substance with lime, followed by a layer of calcium oxide. The 
latter should be free of chlorine. Heat the tub2 in a combustion 
furnace ; after cooling shake its contents into dilute nitric acid, 
filter, add silver nitrate and weigh the precipitated silver haloid. 

The decomposition is easier, if we substitute for lime a mixture of lime with 
part sodium carbonate, or I part sodium carbonate, with 2 parts potassium nitrate, 
and in the case of substances volatilizing with difficulty, a platinum or porcelain 
crucible, heated over a gas lamp, may be used (Amz., 195, 295 and 190,40). With 
compounds containing iodine, iodic acid is apt t» form; but after solu.ion of the 
mass this may be reduced by sulphurous acid. The volumetric method of Volhard 
(Ann. 190, 1) for estimating ha'ogens by means of ammonium sulphocyanide may 
be employed instead of the customary gravimetric course. 

The same decomposition can also be effected by ignition with ferric oxide 
(Berichte, 10, 290). 


2. Method of Carius.—The substance, weighed out in a small 
glass tube, is heated together with, concentrated HNO, and silver 
nitrate to 150-300° C., in a sealed tube, and the quantity of the 
resulting silver haloid determined. The furnace of Babo (Bevzchie, 
13, 1219) is especially adapted for the heating of tubes. 


In some cases the substance may also be oxidized by the method proposed by 
P, Klason (p. 27). 


3. In many instances, especially when the substances are soluble 
in water, the halogens may be separated by the action of sodium 
amalgam, and converted into salts, the quantity of which is deter- 
mined in the filtered liquid. 


DETERMINATION OF SULPHUR AND PHOSPHORUS. 


The presence of sulphur is often shown by fusing the substance 
examined with potassium hydroxide ; potassium sulphide results, and 
produces a black stain of silver sulphide on a clean piece of silver. 


DETERMINATION OF THE MOLECULAR FORMULA. 27 


Heating the substance with metallic sodium is more accurate and 
always succeeds (even when sulphur is combined with oxygen): 
the aqueous filtrate is tested for sodium sulphide with sodium 
nitro-prusside. 

In estimating sulphur and phosphorus ignite the weighed sub- 
stance with a mixture of saltpetre and potassium carbonate; or, 
according to Carius, oxidize it by heating with nitric acid in a 
sealed tube (see Ber., 20, 2928). The resulting sulphuric and 
phosphoric-acids are estimated by the usual methods. 


Briigelmann employs a method not only applicable in the case of sulphur and 
phosphorus, but also adapted for the halogens. He burns the substances in an - 
open combustion tube in a current of oxygen, conducting the products through 
a layer of pure granular lime (or soda-lime), which is placed in the same tube, 
and raised to a red heat. Later, the lime is dissolved in nitric acid, the halogens 
precipitated by silver nitrate, the sulphuric acid by barium chloride and the phos- 
phoric acid (after removal of the excess of silver by HCl) by uranium acetate. 
Arsenic may be determined similarly (Zezts. f. anal. Chemie, 15,1 and 16, 1), 
Sauer recommends collecting the sulphur dioxide, arising in the combustion of the 
substance, in hydrochloric acid containing bromine (/é7d., 12, 178). To deter- 
mine sulphur and the halogens by the method suggested by P. Klason (4er., 19, 
1910), the substance is oxidized in a current of oxygen charged with nitroso- 
vapors. The products of combustion are conducted over rolls of platinum foil. 
Consult Th. Poleck (Zezt. fa. Chem., 22, 17) upon a method which is applicable 
for the estimation of the sulphur contained in coal gas. 

Sulphur and phosphorus can often be estimated by the wet method. The oxida- 
tion is effected by means of potassium permanganate and caustic alkali, or with 
potassium bichromate and hydrochloric acid (Messinger, Ber., 21, 2914). 





DETERMINATION OF THE MOLECULAR FORMULA. 


The elementary analysis affords the percentage composition of 
the analyzed substance. ‘There remains, however, the deduction 
of the atomic-molecular formula. : 

We arrive at the simplest ratio in the number of elementary 
atoms contained in a compound, by dividing the percentage 
numbers by the respective atomic weights of the elements. Thus, 
the analysis of lactic acid gave the following percentage com- 
position :— 


CAFUND s ccc ore cansvdtanvekes sFaeees 40.0 per cent. 

FL RCNORES ayia); cavecdessacincess <x eRe 

825. See eee wiioiedes bvinenaden 53-4 a (by difference.) 
100.0 


Dividing these numbers by the corresponding weights (C = 12, 
H = 1, O = 16), the following quotients are obtained :— 
40.0 6.6 53-4 


12 =_ 3-3 aos = 6.6 ba 16 —_— 3.3 


28 ; ORGANIC CHEMISTRY. 


Therefore, the ratio of the number of atoms of C, H and O; in 
the lactic acid, isas 1: 2: 1. The simplest atomic formula, then, 
would be CH,O; however, it remains undetermined what multiple 
of this formula expresses the true composition. Indeed, we are 
acquainted with different substances having the empirical formula 
CH.O, for example oxymethylene, CH,O, acetic acid, C,H,O,, lactic 
acid, C;H,O;, grape sugar, C,H,,O,, etc. With compounds of com- 
plicated structure, the derivation of the simplest formula is, indeed, 
unreliable, because various formulas may be deduced from the 
percentage numbers by giving due regard to the possible sources of 
error in observation. ‘The true molecular formula, therefore, can 
only be ascertained by some other means. ‘Three courses of pro- 
cedure are open to us. First, the study of the chemical reactions, 
and the derivatives of the substance under consideration ; this is 
common to all cases. Second, the determination of the vapor 
density of volatile substances. Third, determining certain pro- 
perties of the solutions of soluble substances. 


(1) Determination of the Molecular Weight by the Chemical 
Method. 


This is applicable to all substances. It is generally very compli- 
cated, and does not invariably lead to definite conclusions. It 
consists in preparing derivatives, analyzing them and comparing 
their formulas with the supposed formula of the original compound. 
The problem becomes simpler when the substance is either a base 
or an acid. ‘Then it is only necessary to prepare a salt, determine 
the quantity of metal combined with the acid, or of the mineral 
acid in union with the base, and from this calculate the equivalent 
formula. A few examples will serve to illustrate this. 

Prepare the silver salt of lactic acid (the silver salts are easily 
obtained pure, and generally crystallize without water) and deter- 
mine the quantity of silver in it. We find 54.8 percent. Ag. As 
the atomic weight of silver = 107.7, the amount of the other con- 
stituent combined with one atom of Ag in silver lactate, may be 
calculated from the proportion— © 


54.8 : (100 — 54.8) :: 107.7: x . 
x == 80.0, 
Granting that lactic acid is monobasic, that in the silver salt one 
atom of H is replaced by silver, it follows that the molecular weight 
of the free (lactic) acid must = 89 + 1 = 90. Consequently, the 
simplest empirical formula of the acid, CH,O = 30, must be tripled. 
Hence, the molecular formula of the free acid is C;H,O; = go: 


DETERMINATION OF THE MOLECULAR FORMULA. 29 


When we are studying a base, the platinum double salt is usually 
prepared. The constitution of these double salts is analogous to 
that of ammonio-platinum chloride—PtCl,.2(.NH;HCl)—the am- 
monia being replaced by the base. ‘The quantity of Pt in the 
double salt is determined by ignition, and calculating the quantity: 
of the constituent combined with one atom of Pt (198 parts). 
From the number found, subtract six atoms of Cl and two atoms of 
'H, then divide by two; the result will be the equivalent or mole- 
cular weight of the base. 


(2) Determination of the. Molecular Weight from the Vapor 
Density. 


This method is much simpler than the first. The results are per- 
fectly reliable. It is, however, limited to only those substances 
which can be gasified and volatilized without suffering decomposi- 
tion. ‘The method is based upon the law of Avogadro, according 
to which equal volumes of all gases and vapors at like temperature 
and like pressure, contain an equal number of molecules (see v. 
Richter’s Inorganic Chemistry). The molecular weights are, there- 
fore, the same as the specific gravities. As the specific gravity is 
compared with H = 1, but the molecular weights with H, = 2, we 
ascertain the molecular weights by multiplying the specific gravity 
by two. Should the specific gravity be referred to air = 1, then the - 
molecular weight is equal to the specific gravity multiplied by 28.86 
(since air is 14.43 times heavier than hydrogen). 


Molecular Weight. Specific Gravity. 

Ait ae — — 14.43 I 
Hydrogen ........... H, 2 2° I 0.0693 
OSIPES sc iccon mowers O, << 81.92 15.96 1.1060 
Chlorine. .,....0...¥es Cl, a= FO. 74 28.397 2.4550 
Nitrogen ©. .cseseeu0 N, =2 2S 14 ‘0.970 
Hydrogen Chloride Het 36.37. 18.18 1.260 . 
MV MGES. ocucsccibieas BO} Se 38 9 0.622 
Ammonia.,,.......... Nit, == 17.06 8.98 0.589 
Methane ss gic otaxe CH, $4507 7.98 0553 
Ethane, ccanssresae Coit... ==-29.04 14.97 1.037 
Pentane’ ics ievedie Cathss 5 75-05 35.92 2.489 
Ethylene... ca82.3; Cy == 27-904 13.97 0.964 
Anrylene 0 ike Ja5 CH, = 69.85 34-92 2.430 


The results arrived at by the chemical method, by transpositions, 
and those obtained by the physical method, by the vapor density— 
are always identical. Experience teaches this. If a deviation 
should occur, it is invariably in consequence of the substance 
suffering decomposition, or dissociation, in its conversion into 
vapor. 


30 ORGANIC CHEMISTRY. 


DETERMINATION OF THE VAPOR DENSITY. 


‘Two essentially different principles underlie the methods employed 
in determining the vapor density. According to one, by weighing 
a vessel of known capacity filled with vapor, we ascertain the weight 
_ of the latter—method of Dumas. Or, in accordance with the 
other principle, a weighed quantity of substance is vaporized and 
the volume of the resulting vapor determined. In this case the 
vapor volume may be directly measured—methods of Gay-Lussac 
and A. W. Hofmann—or it may be calculated from the equivalent 
quantity of a liquid expelled by the vapor—displacement methods. 
The first three methods, of which a fuller description may be found 
in more extended text-books,* are seldom employed at present in 

| se Aa laboratories, because the recently 
Fic. 8. published method of V. Meyer, 
characterized by simplicity in exe- 
| -  cution, affords sufficiently accurate 
E | results for all ordinary purposes. 
Consult Berichte, 15,2777,21,2018, 
upon the applicability of the various 
methods. 

Method of Victor Meyer.— 
Vapor density determination by azr 
displacement. According to this 
a weighed quantity of substance is 
vaporized in an enclosed space, 
when it displaces an equal volume 
of air, which is measured. Fig. 8 
represents the apparatus constructed 
for this purpose. It consists of a 
narrow glass tube about 60 mm. 
long, to which is fused the cylin- 
d “ drical vessel, 4, of 100 c.cm. ca- 
a pacity. . The upper, somewhat en- 
oe larged opening, BZ, is closed with a 
caoutchouc stopper. There is also 
a short capillary gas-delivery tube, 
C, intended to conduct out the dis- 
placed air. It terminates in the 
water bath, DY. ‘The substance is 
weighed out in asmall glass tube 
provided with a stopper, and va- 
porized in A. The escaping air is 


AUNTY TITTY TT Rae OTTO MTT Np 














* Consult Handwéorterbuch der Chemie, Ladenburg, Bd. 3, 244. 
+ Ber., 11, 1867 and 2253. 








DETERMINATION OF THE VAPOR DENSITY. 31 


collected in the eudiometer, &. The vapor-bath, used in heating, 
consists of a wide glass cylinder, /,* whose lower, somewhat enlarged 
end, is closed and filled with a liquid of known boiling point. 
The liquid employed is determined by the substance under examina- 
tion; its boiling point must be above that of the latter. Some of 
the liquids in use are water (100°), xylene (about 140°), aniline 
(184°), ethyl benzoate (213°), amyl benzoate (261°), and dipheny- 
lamine (310°). 


The air-baths, suggested by Lothar Meyer (Ber., 16, 1091) can be used for heating 
purposes; they may be substituted for the vapor-baths. 


The method of operation is as follows: First clean and dry the 
apparatus, A £&, by drawing air through it by means of a long, 
thin, glass tube, and, for safety, cover the bottom of A with ignited 
asbestos, or thin platinum spirals. Next place it in the heating cylin- 
der, /, containing about 200 c.cm. of the heating liquid, close 
£ and dip the end of C into the water-bath, YD. With a lamp 
bring the contents of / to boiling, and wholly encircle 4 with 
vapor, which condenses somewhat higher and flows regularly back. 
The air in 4 is thus heated, expands, and in part escapes from the 
side delivery tube through the water-bath. The non-evolution of 
air bubbles indicates a constand temperature in A B, which is now 
prepared to receive the substance. The cork at B is rapidly 
removed, and the substance (0.05-0.1 gr.) weighed out in a small 
glass vessel, permitted to drop into A, the opening is again closed, 
and the end of the delivery tube, C, placed under the graduated 
tube filled with water. An improved method for the introduction 
of the substance is described below. When the substance vaporizes 
_ it displaces an equal volume of air which collects in the graduated 
tube. The quantity of material taken for each determination is 
always small, because it is desirable that the volume of its vapor 
should not exceed % of the volume of 4. As soon as bubbles are 
no longer emitted, the determination is finished. The graduated 
tube is placed to one side, the cork at B eased, to admit air and 
thus avoid the entrance of water when the apparatus cools. The 
volume of vapor formed is represented in the eudiometer by an 
equal volume of air, reduced to the temperature of the water-bath 
and given air pressure. Read off its volume and note the tempera- 
ture and barometric pressure. 

The calculation of the vapor density, S, from the volume of gas 
found and the quantity of substance employed is simple. It equals 
the weight of the vapor, P (afforded by the weight of the sub- 





* See Ber., 19, 1862, for another form of vapor mantle. 


32 ORGANIC CHEMISTRY. 


stance employed), divided by the “weight of an equal volume of 
air, P— 
P 

rs Pp 
I c.cm. air at o° and 760 mm. pressure weighs 0.001293 gram. 
The air volume found at the observed temperature is under the 
pressure H—vw, in which H indicates the barometric pressure 
and w the tension of the aqueous vapor at temperature t. The 
weight then would be— 

I EL ome. WE 

I ee 0.00367 Zz 760 





F’ = 0.001203. V. 


Consequently, the vapor density sought is— 


P (1 + 0.00367 2.) 760 F. 


wre 0.001293. V. H—w 





V. Meyer’s method yields results that are perfectly satisfactory practically, al- 
though not without some slight errorin principle. However, they answer, because 
in deducing the molecular weight from the vapor density, relatively large numbers 
are considered and the little differences discarded. A greater inaccuracy may arise 
in the method in filling in the substances as described, because air is apt to enter 
the vessel. L. Meyer (Ber. 13, 991), Piccard (z2z¢., 13, 1080), Mahlmann (7d2d., 
18, 1624), and V. Meyer and Bilz (zd7¢., 21, 688) have suggested different devices 
to avoid this source of error. To test the decomposability of the substance at the 
temperature of the experiment, heat a small portion of it in a glass bulb provided 
with a long point (see Berichte, 14, 1466). 

Substances boiling above 300° are heated in a lead-bath (Berichte, 11, 2255). 
Porcelain vessels are used when the temperature required is so high as to melt 
glass, and the heating is conducted in gas-ovens (Berichte, 12,1112). Where air 
affects the substances in vapor form, the apparatus is filled with pure nitrogen. 
(Compare Zer., 18, 2809; 21, 688). When the substances under investigation 
attack the porcelain, tubes of platinum are substituted for the latter. These are 
enclosed in glazed porcelain tubes, and heated in furnaces (Ber., 12, 2204; Zeit. © 
phys. Chem., 1, 146; Ber., 21, 688). This form of apparatus allows of the simul- 
taneous determination of temperature. The air or nitrogen which may be in them 
can be displaced by carbon dioxide or hydrochloric acid gas (Ber., 15, 141. Zeit. 
phys. Chem., 1, 153). 

For modifications in methods of determining the density of gases, consult V. 
Meyer, Berichte,.15, 137, 1161 and 771; Langer and V. Meyer, Pyrotechnische 
Untersuchungen, 1885; Crafts, Berichte, 13, 851, 14, 356, and 16, 457. Forair- 
baths and regulators, see L. Meyer, Berichte, 16, 1087; 17, 478; 18, 2838. 

Modifications of the displacement method, adapted .for work under reduced 
pressure, have been proposed by La Coste (Ber., 18, 2122), Schall (Ber., 20, 1827 
and 2127; 21, 100), Malfatti (Zeit. phys. Chem., 1, 159), and Eyckmann (Zer., 
22, 2754). For the method of Nilson and Petterson, see Ber., 17, 987 and 19, 
Ref. 88; also Jour. pr. Chem., 33,1. See Ber., 21, 2767, for the method of Bilz. 





* It is simpler to make the reduction to 760 mm. and 0° by comparison with a 
normal volume (p. 24). 

+ The calculation of the molecular weight can be —_ directly and more 
readily by using the equation given on p. 34. 


DETERMINATION OF MOLECULAR WEIGHT. 33 


(3) Determination of the ‘Molecular Weight of Substances when in 
Solution. 


1. By means of Osmotic Becnwee Receiaty Van’t. Hoff 
has developed an exceedingly important theory in regard to solu- 
tions.* According to this new idea chemical substances, when in 
dilute solution, exhibit a deportment similar to that observed when 
in a gaseous or vapor-form ; therefore, the laws applicable to gases 
(Boyle, Gay-Lussac and Avogadro) possess the same value for solu- 
tions. We know that the gas-particles exert pressure, and it is also 
true that the’particles of compounds, when dissolved, exert a pres- 
sure, which is directly expressed or shown by the osmotic phe- 
nomena, and hence it is termed osmotic pressure. ‘This pressure is 
equal to that which would be exerted by an equal amount of the 
substance, if it were converted into gas, and occupied the same 
volume, at the same temperature, as the solution. Solutions con- 
taining molecular quantities of different substances exert the same 
osmotic pressure. It is, therefore, possible, as in the case of gas- 
pressure, to directly deduce the molecular weight of the substances 
in solution from this osmotic pressure. The methods thus far 
employed for the determination of this pressure have been too 
complicated and time-consuming to permit of their application in 
practical work. ‘The determination of the vapor pressure, or the 
freezing point of solutions is more suitable; these are Bani 
related to osmotic pressure (p. 35). 


Pfeffer determines osmotic pressure by means of artificial cells, having semi- 
permeable walls. These are produced by saturating porous earthenware cells with 
solutions of copper sulphate, and potassium ferrocyanide. A sheet of copper 
ferrocyanide is formed in the wall of the cell, through which water can circulate, - 
but not sugar or other substances which may be held in solution. The pressure 
exerted on the membranous cell, by the dissolved substances, is. measured by the 
osmotic elevation, or by a manometer. If suitably modified this method promises 
to be of wide applicability (Ladenburg, Aer., 22, 1225). 

The plasmolytic method of de Vries (Zeit. phys. Chem., 2, 415), employed in 
determining osmotic pressure, is based upon the use of living plant cells; the proto- 
plasma of the latter is clothed with a thin pellicle (the protoblast), which is semi- 
permeable (see above). When such cells are introduced into aqueous solutions of 
_ definite concentration their membranes contract, if the external osmotic pressure 
exceeds that of the cell-contents (Zez?¢. phys. Chem., 2, 415). 

To calculate the molecular weight, make use. of the general formula for gases: 
pv = RT, in which R represent a constant, and T the absolute temperature, 
caculated from — 273° forward. 

If this equation is also to include the law of Avogadro (that the molecular 
weights of gases or dissolved substances occupy the same volume at like tempera- 
ture and pressure), then molecular quantities of the substances must always he 





* Van’t Hoff, Zezt. phys. Chem. -» I, 481; 3, 198. ‘“ Ein elementare Darstellung 
der Theorie der Lésungen,” see Ostwald’s “ Grundriss der allgemeinen Chemie,” 
1889. 


3 


34 ORGANIC CHEMISTRY. 


taken into consideration. The constant equals 84800 for gram molecular weights 
(2 grams hydrogen, or 31.92 grams oxygen) at the temperature 0° (or 273°), and 
the pressure (gas or osmotic pressure) of 76 cm. of mercury. 


Pp i. ¥ = S4500:, T*. 
v represents the volume corresponding to the gram molecular weight 


SB 





ci , in which a is the weight in grams of 1 c.cm. of the gas, or dissolved 
a ; 


substance, contained in I c.cm. of the solution). Substituting figures the formula | 
would read: p . 13.59 X Te 84500 (273 -+-t), with the four variables p, M, | 
“a 


aandt. Ifthree of these be given the fourth can be calculated. Consequently, the 
molecular weight AZ is found from the formula :— 


At es 84500 (273 +t) _ a. 6218 (273+ t) 
p- 13-59 P 
2. From the Lowering of the Vapor Pressure.—The lowering of the 
vapor pressure of solutions is closely allied to osmotic pressure. It is a known 
fact that solutions at the same temperature have a lower vapor pressure (f”) than 
the pure solvent (f), and consequently boil at a more elevated temperature than 
the latter. The lowering in pressure (f —f’) is in proportion to the quantity 


of the substance dissolved (Wiillner). This harmonizes with the equation 
f—f’ 











= k. g, in which k represents the “ relative lowering of the vapor pressure ”’ 


f 
— f/ ‘ AY 
Cc} for I per cent. so'utions, and ¢ their percentage content. 


If the lowering be referred not to equal quantities, but rather to molecular 
quantities of the substances dissolved, it will be discovered that equi-molecular 
solutions (thos: containing molecular quantities of the different suistances in equal 
amounts in the same solvent) show equal lowering—the molecular vapor pressure 
lowering is constant :— 

Me ta G. 
f 


Again, on comparing the relative lowering of vapor pressure in different solvents, 
it will be found also that they are equal, if equal amounts of the substances are 
dissolved in molecular quantities of the solvent. In its broadest sense the law 
would read: ‘The lowering of vapor-pressure is to the vapor-pressure of the solvent 
(f) as the number of molecules of the dissolved body (n) is to the total number of 
molecules (n + N):— 


ff “= 'n 


fe ie an 





Substituting the quotients 8 and = (g and G represent the weight quanti- 
m } 


ties of the substance and the solvent; m and M are their molecular weights), for 
n and N, it will be easy to calculate the molecular weights. \ 
F, M. Raoult (1887) developed these rules empirically. Soon thereafter van’t 











* R= PY ; p = 1033 = 76 X 13.59 (sp. gr. of mercury); v = 22330 = 
ay 1033 X 22320 
ag 273 





31.92,40.091430 (wt. of I c.cm. of oxygen). R 





DETERMINATION OF MOLECULAR WEIGHT. 35 


Hoff (Zeit. phys. Chem., 3, 115), deduced them theoretically from the osmotic 
pressure. They are only of value for non-volatile (as compared with the solvent) 
substances, or such as volatilize with difficulty. -The same abnormalities observed 
with osmotic pressure and depression in the freezing point also appear here. 

The methods for the determination of vapor-pressure are yet too little known 
and primitive in their nature to be applied in the practical determination of mo- 
lecular weights (4e7., 22, 1084). It is easier to determine the rise in the boiling 
points; this is also more reliable (Beckmann, Zezt. physs Chem., 4, 5). 


3. From the Depression of the Freezing Point.—The 
molecular weights of dissolved substances are more accurately and 
readily deduced from the depression of the freezing points of their 
solutions. Blagden in 1788, and Riidorff in 1861, found that the 
depression of the freezing points of crystallizable solvents, or sub- 
stances (as water, benzene and glacial acetic acid) is proportional 
to the quantity of substance dissolved by them. ‘The later re- 
searches of Coppet (1871), and especially those of Raoult (1882), 
have established the fact that when molecular quantities of different 
substances are dissolved in the same amount of a solvent they show 
the same depression in their freezing points (Law of Raoult). If z 
represents the depression produced by ~ grams of substance in roo 


grams of the solvent, the co efficient of depression ! will be the 


depression for 1 gram of substance in 100 grams of the solution.* 
The molecular depression is the product obtained by multiplying 
the depression co-efficient and the molecular weight of the dissolved 


substances. ‘.his is a constant for all substances having the same — 
solvent :— ; 
M.t=C 
P 


Raoult’s experiments show the constant to have the following 
values: for benzene 4.9; for glacial acetic acid 39; for water 19. 
When the constant is known the molecular weight is calculated as 
follows :— 


wo GPs 
t 


A comparison of the constants found for different solvents will disclose the fact 
that they bear the same ratio to each other as the molecular weights—that conse- 
quently the quotient obtained from the molecular depressions and molecular weights 
is a constant value (about 0.62). It means, expressed differently, that the molecule 
of any one substance dissolved in loo molecules of a liquid lowers the point of 
_ $dliditication very nearly 0.62. 

Guldberg (1870) and van’t Hoff (1886), have since made a theoretical deduc- 
tion, of these laws from the lowering of the vapor peu, and from the osmotic 





* Raoult (Zeit. phys. Chem., 2, 353). Arrhenius expresses the content of solu- 
_ tions by the weight in Seeee of the substances contained in 100 c.c. of the solution. 


° 


36 ORGANIC CHEMISTRY, 


pressure. The constant C is obtained, for the various solvents, from the formula 
r 2 . 


r 
0, 02 w Here T indicates the temperature of solidification of the solvent calcu- 


lated from the absolute zero-point forward. W is its latent heat of fusion. In this 
way van’t Hoff calculated the constants for benzene (53), acetic acid (38.8), and 
water 18.9 (see above). 


The laws just described possess a direct value for indifferent sub- 
stances, having but slight chemical activity. Salts, strong acids and 
bases (all electrolytes) constitute the exceptions. The depressions 
in freezing point are greater for these than their calculated values 
(they also have greater osmotic pressure, and greater lowering of the 
vapor pressure). ‘The electrolytic dissociation theory of Arrhenius * 
would account for this by the assumption that the electrolytes have 
separated into their free ions. However even the indifferent bodies 
exhibit many abnormalities—generally the very opposite of the 

ordinary. These seem to be due to the fact 

Fic. 9. that the substances held in solution had not 

completely broken up into their individual 

molecules. ‘The most accurate results are ob- 

tained by operating with very dilute solutions, 

sl and by employing glacial acetic acid as solvent. 
This dissociates solids most readily. 


DETERMINATION OF THE DEPRESSION OF THE 
FREEZING POINT. 

A weighed quantity of the solvent, is.placed in a wide 
test-tube of hard glass, and its freezing point determined. 
In the mouth of the tube is a large cork through which a 
thermometer and astirring rod pass. A weighed quantity 
of substance is now added to the solvent, and dissolved 
in it. The freezing point is again determined (Holle- 
mann, Ler., 21, 860). 

Various forms of apparatus suitable for the above pur- 
pose, and methods of working have been proposed by 
Auwers, t Hentschel, { Beckmann, 3 Eykmann, || and 
Klobukow. § 

Beckmann’s Method.—A hard glass tube A, 2-3 
cm., in width, with a side projection E (Fig. 9), is filled 

. with 15-20 grams of the solvent (weighed out accurately 
in centigrams), and closed with a cork, in. which are 
placed an accurate thermometer (Walferdin), and a stout 
platinum wire serving as a stirring rod. The lower part 
of the tube is attached by means of a cork to a somewhat 
‘larger, wider tube. The Jatter serves as an air-jacket. 
The entire apparatus projects into a beaker glass filled with a freezing mixture. 



































* Zett. phys. Chett., r, 631; 1, 5773 2, 491. 
{ Ber., 21,711; © } Zeit. phys. Chem., 2,307; 3 Lbid., 2, 638; || 2, 966; 
{ /bid., 4, 66. ee : oe 





CHEMICAL STRUCTURE OF CARBON COMPOUNDS. 29 


Cold water will answer for glacial acetic acid (congealing at 16°), and ice-water 
for benzene (about 5°). Fiist determine the congealing point of the solvent by 
cooling it 1-2° below its freezing point, and then by agitation with the platinum 
rod (after addition of platinum clippings), induce the formation of crystals. 
During this operation the thermometer rises, and when the mercury is stationary 
it indicates the freezing point of the solvent. Allow the mass to melt, and intro- 
duce an accurately weighed amount of substance through E. When this has 
dissolved the freezing point is re-determined as before. 

Eykmann (Zeit. phys. Chem., 2, 966) has designed a method by which it is 
possible to use smaller amounts of solution (6-8 grams) andsubstance. Thisis done 
by using phenol (m. p. about 38°), as the solvent. Its molecular depression has 
been theoretically deduced; it is about 76 (see above). 

Paterno’s investigations show, contrary to earlier observations, that the carbon 
derivatives mostly yield normal results; the exceptions being the alcohols, phenols, 
acids and oximes.* 

Naphthalene may also be used for determinations of thiskind. Van’t Hoff gives 
its depression constant as equal to about 70 (Ber., 22, 2501; and Eykmann, Ser., 
23, Ref. 1). 





CHEMICAL STRUCTURE OF THE CARBON COMPOUNDS. 


The molecular weight of a given substance and the absolute 
number of atoms contained in the latter, are ascertained by elemen- 
tary analysis, and the study of the chemical transpositions, or by the 
determination of the vapor density. ~The problem of establishing 
the chemical formula of a compound would soon be solved, did 
not experience show that very often entirely different substances 
are possessed of the same molecular composition. Jsomerides 
(from tcopepys, consisting of equal parts), is the name given these. 
In 4 more extended sense, isomerism includes all bodies of like per- 
centage composition. When the isomerism depends upon a differ- 
ence in molecular weight (p. 28), it is termed polymerism ; a special 
case of the latter is the allotropy of the elements (see Richter’s 
Inorganic Chemistry). 

Real isomerism, 2. ¢., the phenomenon of bodies of like compo- 
sition and like number of atoms, being different, is interpreted only 
by granting a different grouping or arrangement of the atoms in> 
the molecule. That this, indeed, occurs, follows. from the investi- 
gation of chemical reactions, as it is easy to split off from isomeric 
bodies entirely different atomic groups and- atoms, or even to 
replace them by others. Hence, the atoms in such compounds are 
differently distributed or linked to one another. To investigate 
this different chemical union of the atoms, the chemical constitution 
of compounds—as an expression for their entire chemical deport- 
ment—is the task presented us. Since, however, the nature of 
chemical affinity and the manner of the union of atoms to mole- 


* Ber., 22, 1431, and Zezt. phy, 
; SE LIBRASS 
= Vat JERR 





38 ORGANIC CHEMISTRY. 


cules are absolutely unknown to us, the expression of chemical 
constitution can only be hypothetical—a mere formulation of the 
actually known regularities in the chemical transpositions of 
compounds. 

The various attempts to formulate the chemical constitution 
of compounds belong to the history of chemistry (p. 47). At 
present, the problem, especially in its relation to the derivatives of 
carbon, is largely solved by the doctrine or theory of chemical 
structure. ‘This is based upon the ideas of differences in valence 
in the elementary atoms, and upon their capability of combining by 
single affinity units (see Richter’s Inorganic Chemistry). 

Although the number of cases of. isomerism is but limited in 
inorganic chemistry, and there being consequently but little import- 
ance attached to the presentation of structural formulas, the phe- 
nomena of this kind are exceedingly abundant with the carbon 
compounds, so that constitutional or structural formulas, represent- 
ing the entire chemical deportmént, are absolutely mecessary. 
Frequently, very complicated relations occur, yet the structure of 
all investigated carbon derivatives may be deduced from the 
following principles :— 

1. The carbon atoms, in their hydrogen combinations, are 
constantly quadrivalent. The position of carbon in the periodic 
system gives expression to this fact. The only derivative in which 
carbon apparently figures as a bivalent element is carbon monoxide, 
CO (see below). 

2. The four affinity units of carbon are, as generally represented, 
equal and similar, 7. ¢., no differences can be discovered in them 
when they form compounds. If these four affinities be attached to 
different elements or groups, the order of their combination is 
entirely immaterial. The compounds— 


CH,Cl CH,.NH, CH,.COOII CH,CH, 
Methyl . Methyl Acetic Di-methyl. 
Chloride. Amine. Acid. 
/CH, /OCH, /0.C,H,O 
CHC, COCGH COCGEH, CH CHC ea'o 
f Methyl Methyl- Methyl- Ethylidene 
Dichloride. ethyl Acetone. ethyl Carbonate, Aceto-propionate. 


are known in but one modification each; their isomerides have 
never been prepared. 

3. The carbon atoms can unite in a chain-like series, by com- 
_bining with each other by one or more units. This they can do, 
also, with other elementary atoms. 

These principles express the relations really known at present All investi- 


gated compounds prove carbon to be quadrivalent. Carbon monoxide, CO, is not 
a contradiction, as valence is a relative function of the atoms (compare Richter’s 


Inorganic Chemistry), and its existence is affected in the same way by the nature — 


| 





CHEMICAL STRUCTURE OF CARBON COMPOUNDS. 39 


of oxygen, as by carbon; we can, with equal correctness, represent O in CO as 
quadrivalent and C as bivalent. Because CO does exist, it in no manner follows 
that carbon can figure as a dyad in the hydrogen derivatives. Repeated efforts 
to prepare compounds containing bivalent carbon were unsuccessful (page 42). 

The equi-valence of the four carbon affinities, in the sense above illustrated, 
has likewise been positively confirmed. By the early type or substitution theory, 
it appeared possible that compounds like ; 


CH,Cl and CCIH, or CH,NH, and NH,CH,, etc., 


were isomeric. All experiments instituted proved that the succession of substitu- 
tion or the replacement of the substituting atoms again were without effect; 


identical bodies resulted in all analogous cases. 


It may be added, in regard to the capability of union of the carbon atoms with 
each other and with other elements, that all the imaginable combinations are 
really not possible. Certain groupings can in no way be realized, and the union 
of two atoms is very often influenced by the atoms present with them in the mole- 
cule. The related phenomena, which are of such great interest as regards the 
constitution, will be developed later, in special cases. 


The different manner, in the linking of the carbon atoms, shows 
itself most plainly in their hydrogen compounds—in the so-called 
hydrocarbons. By removing one atom of hydrogen from the 
simplest hydrocarbon, methane, CH,, the remaining univalent 
group, CH;, can combine with another, yielding CH,;—CHs, or 
C,H,, ethane or dimethyl. Here, again, a hydrogen atom may 
be replaced by the group CH,, resulting in the compound CH,;— 
CH,—CH,; propane. ‘The structure of these derivatives may be 
more clearly represented graphically :— 

H H H HoH 


| aa ae 
H—C_H- AAC Cr ae 


| ee ae 
H HH ~t bd 


CH, - CH, | C,H, 
By continuing this chain-like union of the carbon atoms, there 
arises an entire series of hydrocarbons :— | 
ie --CH, = CH,—CH, — CHy—CH,'—-CH, CH; + CHgete. 
C, Hy 5 Hy, 
having the common formula C, H,,,., in which each member 
differs from the one immediately preceding and the one following, 
by CH,. 
The compounds constituting such a series are said to be homolo- 
gous. In addition to the hydrocarbons forming such a series, many 
Others exist, ¢. g., the monohydric alcohols and monobasic acids :— 


CH, CH,O CH,O, 

C,H, C,H,O C,H, O, 
C,H, C,H,O C,H, O, 
C,Ayo ors re C,H, O, 
C5), C;H),0 CH, 


40 ORGANIC CHEMISTRY. 


The compounds belonging to such an homologous series, because — 
of their similarity in chemical structure, exhibit great analogy in — 


their entire chemical character. 


The manner of union just considered, that of a simple, open 3 
chain, is designated normad/ structure. In this we distinguish inter- 
mediate and terminal carbon atoms; the first are connected with — 
two other carbon atems and have two valence units which may be | 
saturated by two hydrogen atoms (or other elements). The ter- — 


minal carbon atoms of the chain are combined with three hydro- 


gen atoms. Usually, the normal structure may be expressed by the | 


following formulas :— 


OH. (Ci ja —~ CH, of (CH aco 


\ CH, 


Carbon atoms can unite with even three or four other carbon 
atoms, then Zertiary or guaternary union or structure arises : 


CH; 3 CH, 
| | 
H—C—CH, H—C—CH,—CH, 
| | 
CH, CH, 
CH C,H, 
Tertiary fi ealary 
Butane. Pentane. 
CH, CH, 
| | 
H,C—C—CH, HC -CCH ACH, 
| 
CH, CH, 
C.H CH 
Ouaeerenes Ciatiieaty 
Pentane. Hexane. 


This varying union of the carbon atoms explains the numberless 
isomerides possible for the higher series. ‘This will be especially 
observed in case of the hydrocarbons. | 

In all the structural cases introduced here, the two carbon 


atoms are in simple combination with each other. The number 
of valence units (hydrogen atoms) with which the carbon nuclei 


consisting of # atoms can directly combine equals 2n + 2 (p. 39). 


This cannot be exceeded without the consequent destruction of the - 
carbon nucleus. Therefore, compounds constituted according to- 


the general formula C,X,,,. (in which X represents the valences 
directly joined to C), are termed sa¢urated compounds or paraffins. 


Besides the hydrocarbons C,H,, 4», there exists another homolo-— 


gous series (p. 39) of the form C,H,,:—— 


C,H, Ethylene. 
H, Propylene. 
I, Butylene. 
H,, Amylene, etc., etc. 


SIE A ere IN gg ey an oy ee 


CHEMICAL STRUCTURE OF CARBON COMPOUNDS. 41 


Their existence is accounted for by assuming that in them two 
carbon atoms are united by two valences—a doudle or bivalent 
union. The following structural formulas indicate this :— 


CH, = CH; CH, —CH = CH, 
Ethylene. Propylene. . 


For the formula C,H, three structures are possible :— 


CH, — CH, —CH=CH, CH, — CH = CH — CH, 
and CN a 
CH” = Ol 


As only a simple union is required for the linking of the carbon 
atoms, such compounds as the last are yet capable of saturating two 
valence units; they are, therefore termed unsaturated compounds. 
By the addition of two hydrogen atoms, they pass into C,H,,,9.: 
The double changes to single union :— 

CH, CH, 
I po Ags iS be 
CH, CH, 

The acceptance of this double union of the carbon atoms in no manner indi- 
cates (as sometimes erroneously supposed) a close, stronger combination. It 
has long been known, ‘that the unsaturated compounds could be much more 
readily broken up than the saturated; and that they possess, too, a greater spe- 
cific volume; hence, the double union is /ess intimate than the simple. (Com- 
pare Ist Ed. of this book, p. 40.) The useof the double lines represents the 
fact that only two directly combined carbon atoms are capable of saturation 


(Pp. 39). 

_ That the unsaturated compounds do possess a greater heat of combustion is an 
argument in favor of the view that the union of the carbon atoms is less intimate. 
A. Baeyer (Zer., 18, 2277) has published an experimental prvof of this deportment. 


A third series of hydrocarbons arises when a triple union of two 
carbon atoms occurs. ‘Their composition corresponds to the com- 
mon formula C,H,,-.:— 

C,H, Acetylene. 
C,H, Allylene. 
C,H, Crotonylene, etc. 


Their structural formulas are— 
CH=CH bel cn. oe ce eee 


We can view these as unsaturated hydrocarbons of the second 
degree. They are capable of combining directly with two and 
‘four valences, passing into the compounds C,H,, or C,H,, +1 

Compounds containing a like number of carbon atoms, with a 
gradually decreasing number of hydrogen atoms, are designated 
tsologous compounds. ‘The following ate examples :— 

C,H, Ethane. C,H, Propane. C,H,O  Propyl alcohol. 
C,H, Ethylene. C,H, Propylene. C,H,O Allyl alcohol. 
_ C,H, Acetylene. C,H, Allylene. C,H,O  Propargylic alcohol. 
4 


42 ORGANIC CHEMISTRY. 


Finally, there is a large series of carbon compounds bearing the 
name aromatic. ‘They all originate from a nucleus composed of 
‘ six carbon atoms. Benzene, C,H,, represents their simplest com- 
bination. The simplest structure of this nucleus is probably one 
in-which the six carbon atoms form a closed ring, with alternating 
single and double union, as represented by the following :— 


CH = CH 
oe Ss 
HC=CH—CH = CH—CH=CH or CH CH 


ny ae Be a 


The innumerable aromatic or benzene compounds resulting from 
the replacement of H in benzene by other atoms or groups, consti- 
tute a distinct class. 

The ring-shaped compounds trimethylene, C,;H,, tetramethylene, 
C,H,, and pentamethylene, C;H,,, recently described, are forerun- 
ners of the stable, closed benzene ring :— 





/CH, CH,— CH, /CH,— CH, 
CH, | | | CH, 
\.CH, CH, — CH, \CH,— CH, 
Trimethylene. Tetramethylene. Pentamethylene. 


A series of compounds is likewise derived by the replacement of 
hydrogen in the preceding hydrocarbons. 


Formerly, another view prevailed relative to the unsaturated carbon com- 
pounds. It was assumed that bivalent carbon atoms could occur in the hydrogen 
ccmpounds, just as well as.in carbon monoxide. The other two affinities re- 
mained unsaturated or free. This view would allow the existence of innumerable 


“a 
isc meric derivatives. Thus two bodies, CH, = CH, and CH,— CH, could corres- 
pond to the formula C,H,, but only the first, ethylene, really exists. In addition 


Ms 
to the true propylene, CH, -CH —CH,, two other bodies, CH, —-CH,— CH 


and CH, EE wt could correspond to the formula C,H,. The preparation of 
such isomerides has been fruitless. The compound CH,, methylene (see this), 
cannot bemade. Inthe case of all sufficiently well-studied unsaturated compounds, 
it is established that the two free valences izvariably belong to two different car- 
bon atoms. By adding two atoms of chlorine to ethylene, CH,=—CH,, there 


“4 
arises the compound CH,C] — CH,Cl; the isomeride CH,CH, should yield CH, 
—CHCl,. Inversely, we get ethylene, CH,—=CH,, from its chloride, CH,Cl 


— CH,Cl, while the isomeric, so-called ethylidene, CH,CH, cannot be obtained 
from ethylidene chloride, CH,— CHCl,. If really, as above supposed, the free 
affinities of the two carbon atoms are combined with each other—if double union 
occur—it cannot be asserted with certainty, and it is entirely irrelevant, as we 
possess no representation as to the nature of the union. ‘It is doubtless certain that 


CHEMICAL STRUCTURE OF CARBON COMPOUNDS. 43 


the possibility of the so-called free valence of a carbon atom is influenced by the free 
valence of another atom, which is in @zrec¢ union with the first. It is very likely there 


“d 
exists CH, — CH = CH, (propylene), but not the forms CH,—CH,—CH or 
CH,— C—CH,. This knowledge accords with the actual facts, and considerably 
limits the number of possible isomerides. It finds expression in the supposition of 
the constant tetravalenceof carbon. Ifnew isomerides are discovered in the future, 
the assumption of the divalence of carbon can be admitted. So long, however, as 
convincing reasons are not present, we must refrain from introducing a new, funda- 
mental, and far-reaching hypothesis, which would remove the existing regularities. 


In the preceding pages we have discussed the different ways in 
which the carbon atoms are bound to each other in their hydrogen 
derivatives. We meet these in all other carbon compounds that 
may be regarded as derivatives of the hydrocarbons, resulting from 
the replacement of hydrogen by other elements or groups. 

Since all the facts go to prove that the four valences of the car- 
bon atom are similar (p. 38), isomerisms in similar carbon nuclei can 
take place only when the entering elements or groups attach them- 
selves to carbon atoms with different functions; or, as ordinarily 
expressed, when they occupy different chemical positions. The fol- 
lowing examples serve to illustrate :— 

According to the formula C,H;Cl, there can be but one body 
of the structure CH; — CH,Cl, because, in the original substance 
CH; — CH;, dimethyl, both carbon atoms act alike. On the other 
hand, two isomeric bodies of the structure— 


CH, — CH, — CH,Cl and CH, — CHCl — CH,, 


correspond to the formula C,H,Cl, because, in propane, CH, — 
CH, — CH,, from which they originate, the carbon atoms are not 
similarly united, consequently, the entering halogen atoms can 
occupy relatively different positions. ‘Thus, too, four isomerides 
correspond to the formula C,H,Cl, two springing from normal 
butane, CH, — CH, — CH, — CH, and two from isobutane— 


CH,\ 


CH’ >CH — CH,, ete. 


The number of isomerides is further increased by the entrance of 
‘two or several similar or dissimilar atoms or groups. For the 
formula C,H,Cl, we have two isomerides:—CH,Cl — CH,Cl and , 
CH; — CHCl,. 
For the formula C;H,Cl, four structural cases are possible :— 


: ss CH, CH, -CH,Cl 
| | | 
CH, CCl, CHCl bus, 
| | 
CHCl, CH, CH,Cl CH,Cl. 


44 ORGANIC CHEMISTRY. 


All other possible isomerides are derived in the same manner. 
The nature of the atoms or groups entering is immaterial as far as 
the isomeric relations (p. 38) are concerned. 

Compounds obtained from the hydrogen derivatives by the re- 
placement of hydrogen by halogens or the nitro group, NO,, are 
usually designated substitution products; generally they retain the 
chemical character of the parent substance. In a broader sense, 
one can consider all carbon compounds as substitution derivatives 
of the hydrocarbons, or of methane, CH,. 

Two bivalent elements like S and O can unite with C with either 
one or two valences. In the first case, they may be combined with 
one or two carbon atoms :— 


CH, — CH =O CH, CH, — O — CH, 
; Shier yde | O Methyl Oxide, or 
Ethylidene Oxide. CH, / imethy! Ether. 
Ethylene 
Oxide. 


If the bivalent element unite with but one affinity to carbon, the 
other must be saturated by some other element :— 
CH, — CH, — OH CH, — CH, — SH. 
‘Ethyl Rieohiol. Ethyl Mercaptan. 
Likewise, the trivalent elements, like nitrogen and phosphorus, 
may unite with carbon with all or with one affinity—either with one 
carbon atom— 


CH NCE CO = NH CH=N 
Ethylamine. Carbimide. Hydrogen 
= Cyanide. 
or with two or three carbon atoms :— 
CH, 
o\NH CH,—N 
Ch 
CH, 
Dimethylamine. Trimethylamine. 


In this way two or more carbon atoms may be united to a mole- 
- cule through the agency of an element of higher valence. 

Those isomeric bodies (of like composition) containing several 
different carbon groups, held in combination by an atom of higher 
valence, are termed metameric. Examples are— 


chy. 
C,H, pO and CHO Paes, also 
Methy!- Diethyl 
propyl Ether. Ether. 
CH, CH, C,H, 
cH, }N CH,}N and HIN 
CH, H H 


Trimethylamine. Methylethylamine. Propylamine. 


CHEMICAL STRUCTURE OF CARBON COMPOUNDS, 45 

These can be resolved by various reactions into their component 
carbon groups (or their derivatives), and inversely be synthesized 
from these groups or their derivatives. 

Law of Even Numbers.—In every carbon compound, the sum of 
the elements of uneven valence (of the monads and triads), like 
H, Cl, Br, and N, P, As, is an even number. Thus, in cyanuric 
acid, C;H;N;O;, the sum of the hydrogen and nitrogen atoms — 6; 
in ammonium trichloracetate, C,Cl, (NH,)O,, the sum of the atoms 
of Cl, N and H = 8. This law, established empirically at first, 
and of importance in the deduction of chemical formulas, finds, at 
present, as observed in preceding lines, a simple explanation in the 
quadrivalent nature of carbon and the property of the elements to 
unite themselves by single affinities. 

Radicals and Formulas.—Radicals or residues are atomic 
groups remaining after the removal of one or more atoms from 
saturated molecules. Ordinarily, radicals are groups containing 
carbon, while all others, like O, SH, NH,, NO,, are residues or 
groups. By the successive removal of hydrogen from the hydro- 
carbons of the formula C,H,, ,., radicals of different, increasing 
valence result. These may combine with other elements or groups 
until the form C,H,, , . is attained :— 


Molecules. CH, CA OF Ci 
Methane Ethane, _ Propane Butane 
. { univalent. CH, C,H, C,H, C,H, 
i, Methyl Ethyl. Propyl Butyl. 
2 | bivalent. CH, Ce ee CH, 
oO 1 : Methylene, Ethylene. Propylene. Butylene. 
O | trivalent. CH C,H, CH, C,H, 
=< ‘ Methine. Vinyl. Glyceryl, Crotenyl: 
% | quadrivalent. C CH, atl, 
L Carbon, Acetylene. Allylene. Creponyless 





It may be observed from the preceding pages, that radicals are 
not capable of existing free. When the univalent radicals eaees 
from their compounds they double themselves :— 


CH,I CH, 
+ 2Na= | + 2Nal. 
CH,I CH, : 
2 mols. Methyl Boccssads 
Iodide. 


The bivalent and quadrivalent radicals can only be isolated from 
their compounds when the affinities that are liberated belong to 
two adjacent carbon atoms—that is, those mutually uniting each 
other :— 


CH,Cl CH, 

| + 2Na = 2NaCl + = 
CH,Cl 

Ethylene one 


Chloride. 


46 ORGANIC CHEMISTRY. 


The radical CH, -- CH = cannot be isolated from CH, — CHCl, 
(comp. p. 42). 

As in the examples just given, acetylene may be obtained from 
dichlorethylene :— 


CHCl CH 

i 4+2Na= |i} + 2NaCl. 

CHCl CH 
Dichlorethylene. Acetylene. 


The acceptance of radicals leads to a special nomenclature of 
the compounds. MMonochlorethane, C,H;Cl, derived by substitution 
from the molecule of ethane, C,H,, may be viewed as a compound 
of the group ethyl with chlorine, hence, called ZEthylchloride. 


. C,H,Cl, is called dichlormethane or methylene chloride ; C,H;NH, is 


known as amidoethane or ethylamine, etc. For this reason it is 
customary to ascribe especial names to the simpler and more fre- 
quently occurring radicals or atomic groups (see above). <Alco- 
holic radicals or alky/s is the name applied to the univalent radicals 
C,H,,,,, from their most important compounds—the alcohols, 
C,H,,,, OH. Those groups that are bivalent are called a/kylens, 
etc. 

The univalent radicals are again distinguished as primary, second- 
ary and fertiary, according as the unsaturated carbon atom is 
attached to one, two or three carbon atoms :— 


Pe CH, — CH, —. Ci? CH =k (CIE3C ne 
Primary Propyl. Secondary Propyl. Tertiary Butyl. 


These correspond to the primary, secondary and tertiary alcohols 
(see these). 

Structural formulas are those indicating the complete grouping 
of all the atoms :— 


CH, — Gi, «CHO ace — OH 
3 
Primary Propyl Alcohol. Secondary, or Isopropyl Alcohol. 


They are a representation of the whole chemical deportment of 
a given compound. The rational or constitutional formulas only 
indicate the union of individual atoms—such as are especially 
characteristic of the compound. Thus, the formula C,H,.OH indi- 
cates that the body is an alcohol; has properties common to all 
alcohols; it leaves undetermined, however, whether it is a primary 
or a secondary alcohol. For simplicity we employ such formulas 
and assign special names to the isomeric radicals. The empiric or 
unitary formula C,;H,O affords no hint as to the character of the 
compound, since it belongs to an entire series of bodies that are 
isomeric, yet wholly different. 


CONSTITUTION OF CARBON COMPOUNDS. 47 


EARLY THEORIES RELATING TO THE CONSTITUTION OF THE CARBON 
COMPOUNDS. 

The opinion that the cause of chemical affinity resided in electrical forces, 
came to light in the commencement of this century, when the remarkable decompo- 
sitions of chemical bodies, through the agency of the electric current, were dis- 
covered. It was assumed that the elementary atoms possessed different electrical 
polarities, and the elements were arranged in a series according to their electrical 
deportment. Chemical union depended on the obliteration of different electri- 
cities. The dualistic idea of the constitution of compounds was a necessary 
consequence of this hypothesis. According to it, every chemical compound was 
composed of two groups, electrically different, and these were further made up of 
two different groups or elements. Thus, salts were viewed as combinations of elec- 
tro-positive bases (metallic oxides), with electro-negative acids (acid anhydrides), 
and these, in turn, were held to be binary compounds of oxygen with metals and 
metalloids. (See Richter’s Inorganic Chemistry.) With this basis, there was 
constructed the electro-chemical, dualistic theory of Berzelius. This prevailed 
almost exclusively in Germany, until about 1860. 

The principles predominating in inorganic: chemistry were also applied to 
organic substances. It was thought that in the latter complex groups (radicals) 
pre-existed, and played the same réle that the elements did in mineral matter. 
Organic chemistry was defined as the chemistry of the compound radicals (Liebig, 
1832), and led to the chemical-radical theory, which flourished in Germany 
simultaneously with the e/ectro-chemical theory. According to this view, the. 
object of organic chemistry was the investigation and isolation of radicals, in the 
sense of the dualistic idea, as the more intimate components of the organic com- 
pounds, and by this means they sought to explain the constitution of the latter. 

In the meantime, about 1830, France contributed facts not in harmony with 
the electro-chemical, dualistic theory. It had been found that the hydrogen 
in organic compounds, could be replaced (substituted) by chlorine and bromine, 
without any apparent change in the character of the compounds. To the electro- 
negative halogens was ascribed a chemical function similar to electro-positive 
hydrogen. This showed the electro-chemical hypothesis to be erroneous. The 
_ dualistic idea was superseded by a uitary theory. Laying aside all the primitive 
speculations on the nature of chemical affinity, the chemical compounds began to 
be looked upon as constituted in accordance with definite mechanical ground-forms 
—types—in which the individual elements could be replaced by others (early-type | 
theory of Dumas, nucleus theory of Laurent). At the same time the dualistic view 
on the pre-existence of radicals was refuted. The correct establishment of the ideas, 
equivalent, atom and molecule (Laurent and Gerhardt), was an important conse- 
quence of the typical unitary idea of chemical compounds. By means of it a cor- 
rect foundation was laid for further generalization. The molecule having been 
determined a chemical unit, the study of the grouping of atoms in the molecule be- 
came possible, and chemical constitution could again be more closely examined. 
The investigation of the reactions of double decomposition, whereby single atomic 
groups (radicals or residues) were preserved and could be exchanged (Gerhardt) ; 
the important discoveries of the amines or substituted ammonias by Wiirtz (1849), 
and Hofmann (1850); the epoch-making researches of Williamson, upon the 
composition of ethers, and the discovery of acid-forming oxides by Gerhardt— 
these all contributed to the announcement of the type theory of Gerhardt (1853), 
which was nothing more than an amalgamation of the early type or substitution 
theory of Dumas and Laurent with the radical theory of Berzelius and Liebig. 
The molecule was its basis—and to it there was attached a more extended grouping 
of the atoms in the molecule. The conception of radicals became different. They 
were no longer regarded as atomic groups that could be isolated and compared 


48 ORGANIC CHEMISTRY. 


with elements, but as molecular residues which remained unaltered in certain 
reactions. 

Comparing the carbon compounds with the simplest inorganic derivatives, 
Gerhardt referred them to the following principal fundamental forms or type:— 


H Cl H O H 
H H H \ H\N 

Hydrogen. Hydrogen Water. H 
Chloride. Ammonia. 


From these they could be obtained by substituting the compound radicals for 
hydrogen atoms. All compounds that could be viewed as consisting of two 
directly combined groups were referred to the hydrogen and hydrogen chloride 
types, ¢. 2. -— 


CH C,H CN C,H, C,H,O \ 
H ci H CN Cl 
Ethyl Ethyl Cyanogen Ethyl Acetyl 
Hydride. Chloride. Hydride. Cyanide. Chloride. 


It is customary to refer all those bodies derivable from water by the replace- 


ment of hydrogen, to the water type; 7. ¢., those in which two groups are united 
by oxygen :— 


C,H C,H BS Be = | C,H,O 
O Bite, nell, & & atts 2i?3 
ait} HS? CH {? Coat” 
Alcohol. Acetic Acid. Ethyl Ether. Acetic Anhydride. 


The compounds containing three groups united by nitrogen are considered 
ammonia derivatives :— 


CH, CH C,H,O 
Hin cut Ly : hy Ete 
H CH, H 


These types no longer possessed their early restricted meaning. Sometimes a 
compound was referred to different types, according to the transpositions the 
formula was intended to express. Thus aldehyde was referred to the hydrogen or 
water type; cyanic acid to the water or ammonia type :— 


nrg and GH Lo, ae \o and oa \n 


The development of the idea of polyatomic radicals, the knowledge that the 
hydrogen of carbon radicals could be replaced by the groups OH and NH,, etc., 
contributed to the further establishment of mz/¢iple and mixed types -— 


Compound Types :— 


H 
Ht Hy \ O H, \N 
H, H, 2 H, 2 
e. £.— ‘ 
_ H Lo H, \ N 
CH ‘ C,H,” CO” 

Ethylene Chloride. H \ 0 ,s% 
Ethylene Carbamide. 


Glycol. 


THEORIES RELATING TO STRUCTURE. 49 


Mixed Types :-— 


H 
ie \ H N 

H 

A, \ O { H 
H, f 72 i \ O 

Cl js Ree H 
C,H,’ 0 cot N C,H,O” \ N 
H, }O2 H}O O 

Chlorhydrin. Oxamic Amido-acetic Acid. 


The manner of arrangement finding expression in these multiple and mixed 
types was this: two or more groups were united into one whole—a molecule—by 
the univalent radicals. Upon comparing these typical with the structural formulas 
employed at present, we observe that the first constitute the transitional state from 
the empirical to the unitary formulas of the present day. The latter aim to express 
the perfect grouping of the atoms in the molecule. By granting a particular 
function to the atoms—their atomicity or valence—Kekulé (1858) indicated the 
idea of types; the existence and combining valence of radicals was explained 
by the tetravalence of the carbon atoms, and their tendency to mutually combine 
with each other, according to definite affinity units (Kekulé and Cooper). The 
type theory, consequently, is not, as sometimes declared, laid aside as erroneous; 
but it has only found generalization and amplification in a broader principle—just 
as the present structural theory will, at some future time, find wider importance in 
a more general hypothesis which-encompasses the nature of chemical affinity. 


RECENT VIEWS RELATING TO THE THEORY OF STRUC- 
TURE. 


The theories now extant, relating to the manner in which the 
atoms are connected, do explain in a great measure the isomerisms 
and the behavior of carbon derivatives, yet they fail to give a com- 
plete picture, inasmuch as they do not touch, or even attempt to 
convey any idea as to the spatial relations of the atoms, Nor do 
they include any explanation of the nature of chemical affinity 
(p. 38). The instances, in which the ordinary structural formulas 
do not satisfy the actual relations, have become so numerous, that 
additions must be made to our structural theory, and many parts of 
it wholly recast. This cannot be deferred any longer. Two series 
of phenomena demand it. 

The one series comprises all cases in which one and the same struc- 
tural formula must be assigned two or more different compounds. 
Heretofore, such derivatives were regarded as physical tsomerides. 
They were explained by assuming them to be different aggregations 
of molecules which were chemically similar. At present many © 
different compounds are known to which one and the same struc- 
tural formula must be assigned. For example, the two oxy-pro- 
pionic acids, CH;. CH(OH). CO,H (lactic acid, and sarco-lactic 


50 ORGANIC CHEMISTRY. 


acid), the two acetylene dicarboxylic acids (fumaric and maleic 
acids), the three dioxy-succinic acids (dextro-, laevo- and inactive 
tartaric acid), etc. Isomerides of this kind, different from the 
ordinary, may be formulated as al/otsomeric bodies ; the phenomenon 
is termed al/otsomerism (Michael, Ber., 19, 1384). An explanation, 
for these phenomena, has been sought in the spatial relations of the 
atoms, hence we speak of a spatial or geometrical tsomerism, and of 
stereochemical formulas. For the term constitution or structure is 
substituted the phrase configuration of the molecules. The word 
position corresponds to the old term wzzon (linking) (J. Wislicenus, 

Pp. 54): 

oo the second series of phenomena are included all compounds to 
which two different structural formulas may be rightly attributed. 
Such formulas are fautomeric. Tautomerism is explained by the 
assumption of motion of atoms between two positions (points) in 
equilibrio (Laar, p- 54). 


STEREOCHEMICAL THEORIES. 


As the assumption that the four atoms or groups, combined with 
one carbon atom, are arranged or lie in the same plane, leads to a 
far greater number of isomerides than are known, and as isomerides 
corresponding, ¢. g., to the two planimetric and different atomic 
arrangements 


have not been proved to exist, the structural theory makes no attempt 
to interpret spatial relations, but confines itself to the union of 
atoms in definite successive series. Le Bel and van’t Hoff (1874)* 
were the first to demonstrate in what manner the actual relations 
might be made to harmonize with these representations. Their 
assumptions are embodied in the three following propositions :— 
(1) The four affinities of the carbon atom, while separated in 
space, are arranged like the summits of the tetrahedron. The union 
of other atoms consists in the attachment of the same to these sum- 
mits (tetrahedral angles). Hence, isomerides can only occur when 
the carbon atom is combined with four different monovolent groups. 
In such instances two isomeric derivatives C a b c d are possible. 
This is evident from an inspection of the tetrahedron model, and 
stands proved by the existence of, for example, two @-oxypropionic 





*van’t Hoff-Herrmann: “ Die Lagerung der Atome in Raum,’ 1877. van't 
Hoff: “ Dix Années dans V/histoire d’une theorie.”’ 1887. ; 


STEREOCHEMICAL THEORIES. 51 


acids, CH;.CH(OH). CO,H. Carbon atoms of this kind, linked 
to four different groups, are called asymmetric (represented by an 
italic C). This representation is chiefly employed by Le Bel and 
van’t Hoff* to explain the optical rotatory power of the derivatives 
of carbon (p. 63). : 

(2) Single linking (union) between two carbon atoms occurs when 
two tetrahedra unite and have a pair of summits in common. The 
resulting form is a double pyramid, with six solid angles, to which 
the remaining six groups of the general formula, abcC — Cdef, 
attach themselves. This representation gives rise to a series of iso- 
merides, greater in number than is known, or even probable ; there- 
fore van’t Hoff assumes that the two tetrahedra, united with each 
other, rotate about a common axis, and that isomerism can only 
occur when the rotating systems are different. Compounds, with 
six different groups, abcC — Cdef, could then occur in four different 
forms. By doubling each of the three different groups—in accord- 
ance with the formula, abcC — Cabc, as in dioxy-succinic acid (tar- 
taric acid) and dimethylsuccinic acid, three isomerides are possible 
for each. Compounds of the formula aabC — Cabc, as oxysuc- 
cinic or malic acid, can exist in two isomeric modifications each, 

CH,. COOH 
etc., while succinic acid, | (on rotating the octahedron), 
| CH,. COOH 
cannot possibly have any isomerides. 

(3) The double linking (union) of two carbon atoms is repre- 
sented by two tetrahedra having two summits in common (by an 
edge each.) The two previously rotating tetrahedra are now ar- 
rested, and isomerjsms are therefore possible, where they could not 
formerly occur when they were united by single bonds. Thus, the 
compounds abC = Cab (or abC = Cac) must exist in two isomeric 
modifications each, the one in which similar groups are arranged 
upon the same side (maleic acid), or that in which they are on oppo- 
site sides (fumaric acid) :— 








7C0,H H 





COH HOC 
The same idea is expressed in a simpler way, as follows :— 
i ee Co ' (2) HO,C. CH 
| and | 
HG; CO, He: HC. CO,H. 


* [bid. 





52 ORGANIC CHEMISTRY. 


The first formula allows maleic acid to form an anhydride. Fumaric 
acid is not adapted thereto, because of the distance between the 
two carboxyls. 

Triple union of two, carbon atoms is represented by two tetra- 
hedra, with three pairs of common summits (according to van’t 
Hoff )—that is, each tetrahedron presents one of its plane surfaces. 
Geometrical isomerides are not possible for the compounds aC = Cb. 
This is also the case with the structural formulas. 

These ideas, first employed by Le Bel and van’t Hoff almost 
exclusively for the purpose of explaining the optical activity of the 
carbon compounds (p. 63), have been given more recently a 
broader development, through the labors of J. Wislicenus*; they 
have been especially applied in the interpretation of chemical rela- 
tions. ‘This has been achieved by the introduction of two new 
theories bearing upon the manner (kind) of the additive-reactions 
of the unsaturated carbon compounds, and also upon the mutual 
influence of the groups in union with carbon. 

C.. COW 

For example, begin with acetylene dicarboxylic acid, || 

C.20,8. 
In this, the two carbon tetrahedra have three summits in common. 
When addition products are formed, the groups added must be 
attached upon the same sides of the tetrahedra (just as is the case 
with the two carboxyls). The addition of two hydrogen atoms, 
therefore, to the acetylene dicarboxylic acid would produce maleic 
and not fumaric acid. In the stereochemical formulas corresponding 
to these acids (see above), the position of similarly named groups in 
formula 1 is designated A/ane-symmetric, in formula 2 (that of fuma- 
ric acid) it is called central or axially-symmetric. ‘The positions on 
the same sides of the tetrahedra are also termed corresponding. 

Additions occur with the ‘‘ double linking’’ of carbon atoms, just 
the same as in the case of “ triple linking.’’ The added groups 
occupy corresponding positions. The addition of hydrogen to maleic 
and fumaric acids gives rise to two different configurations :— 

(1) H.CH.CO,H ; (2) HO,C.H.CH 
an 
HoCcH, CO,H H. der CO,H. 


corresponding to two isomeric succinic acids. When, however, the 
*¢ double linking ’’ is broken, the tetrahedra which, previously, were 
stationary, become movable and revolve about their common axis, 
and for this reason isomerism is impossible (according to van’t Hoff ). 
Wislicenus maintains, however, that singly-linked tetrahedra can 
become fixed in position, and that in consequence there will result 





* J. Wislicenus, Ueber die réumliche Anordnung der Atome, 1887. 


STEREOCHEMICAL THEORIES. 53 


a partial rotation (about 120°) of the same. This is induced by the 
mutual action or influence of the elements or groups in union with 
the carbon atoms, in which case like-named groups (positive or 
negative) repel, and those that are unlike, strive to approach one 
another. In the plane-symmetric formula (1) given above, the 
two carboxyls and the hydrogen atoms, occupying corresponding 
positions, repel each other and produce a rotation of the system, 
which reaches to the axially-symmetric position (formula 2). The 
latter configuration is the preferad/e one ; therefore, the more stable, 
or the only one that really exists. 

K. Auwers and V. Meyer* have made perfectly similar observa- 
tions upon the “‘ fixation’”’ of two ‘‘ singly-linked’’ tetrahedra. At 
the same time they call attention to the fact that compounds of the 
general formula aabC — Caab (¢. g. benzil dioxime) can occur in 
three isomeric configurations. 

By means of the representations just described, it is possible to 
interpret and explain the facts which, in many cases, fall far short 
of meeting satisfactory explanation from the structural theory. 
However, many and great difficulties yet remain ;f so that, in ap- 
plying the stereochemical views, reserve and caution should be used. 

It should not be forgotten that even the new doctrine includes no 
explanation for, or representation of, the nature of chemical affinity ; 
hence, like the structural formulas, it gives but an imperfect 
formulation of actual facts. The basis of this theory, that the 
‘¢ double ’’ and ‘‘ triple linking ’’ is dependent upon a more inti- 
mate, therefore more stable position or arrangement of the atoms, 
is rather questionable, as it is well established that the unsaturated 
compounds possess greater specific volume, greater heat of combus- 
tion, less stability, etc., than those that aresaturated (p. 57). There- 
fore, the stereochemical doctrine can only be regarded as an empiri- 
cal amplification of the theory of atomic linking. Like the Ptolemaic 
epicycles, it can have but a restricted, temporary value. 

V. Meyer and E. Riecke have also developed a hypothesis upon 
the linking of atoms (Ber., 21, 946) ; it, however, leaves the nature 
of chemical affinity undisturbed, and for that reason further deduc- 
tions do not follow from it. A. Baeyer seeks to evolve a mechanical 
representation upon the polyvalent and ring-shaped union of the 
carbon tetrahedra by assuming the deviation of the points of attrac- 
tion. The tensions thus induced correspond approximately to the 
variable stability and heat of combustion of these compounds (Ber., 
18, 2278). 





* Ber., 21, 790, 948, 3511. 

+ Aronstein, Ber., 21, 2831; Hell, Ber., 22, 57; v. Miller, 22, 1713; Michael, 
Jour. pr. Chem., 38, ‘; Compare Annalen, 248, 3425 Anschiitz, ‘Ann. 254, 170; 
L. Meyer, Anzn., 247, 251. 


54 ORGANIC CHEMISTRY. 


THE TAUTOMERIC THEORY. 


Those cases in which, according to the structural theory, two 
formulas are possible, while but one corresponding compound is 
known, contradict the idea of alloisomerism. If we build up the 
compound corresponding to the formulas by means of synthetic re- 
actions, two different products are not obtained. On the contrary, 
but one results. Conversely, such bodies frequently react, in different 
reactions, in two different directions as indicated by the formulas. 
Therefore, such formulas seem to be identical—éautomeric—and in 
tautomeric compounds the atoms appear to hold an alterable position 
(Laar, Ber., 18, 730; Rathke, Ber., 20, 1057). Examples of this 
class are :— 


N NH N NH 
4 y, Y Y 
CG ‘and ¢ CG "and C 
\ \ 
\ouH bee \nH, NH 
Cyanic Acid, Isocyanic Acid. - Cyanamide. Carbdi-imide. 
—CH CH, —NH it 
ee and | | and H 
—C.0H —CO —CO —C.OH 
Hydroxylform. Ketoneform. Lactam. Lactim. 
/NO ZN.OH C,.H,.N: N C,H;. NH. N 
Co; and C,H | and | 
\ OH o4\N : | 
wl, OH C,pHg=O 
Nitrosophenol. Quinone-oxime. Phenyl-azonaphthol. §Naphtho-quinone- 
phenylhydrazone. 


From their formulas, these compounds are apparently different ; 
in reality, they are identical. Laar assumes that the cause of this 
is to be ascribed to a mobile- (hydrogen) atom oscillating between 
two points in equilibrio, and thereby rendering the entire aggrega- 
tion movable. This phenomenon Laar styles ¢automerism, while 
others designate it desmotropy (Ber., 21, 2228). The replacement of 
this hydrogen atom of tautomeric bodies by less mobile alkyls 
gives rise to the isomerides of the tautomeric compounds. 

A. Baeyer opposes the preceding idea by maintaining that there 
is but one definite formula for each compound (er. ,16, 2188), and 
of the tautomeric forms but one will be stable while the other is 
unstable and can only exist in its derivatives. The latter form or 
modification is designated pseudomeric (see lactams and lactims). 
Hantzsch (4er., 20, 2801, 21, 1754), too, holds that every com- 
pound has but one definite structural formula. Tautomeric bodies 
(reacting in two directions) can exist in two ‘‘ phenomenon-forms,”’ 
corresponding to the tautomeric formulas; these are distinguished 
by physical characteristics, and are designated desmotropic conditions 





SPECIFIC GRAVITY. 55. 


(see the ester of hydroquinone dicarboxylic acid). However, it is fre- 
quently impossible to fix upon any particular formula for a compound 
(see nitrosophenol), or to prove that it exists in two modifications. 
Tautomerism, therefore, appears to be the limit, and its desmotro- 
pism constitutes the gradual transition to isomerism (Zer., 21, 1857). 
In determining questions pertaining to tautomerism, those reactions 
only are applicable, from which electrolytic dissociation is excluded 
(Goldschmidt, Ber., 23, 253). 


PHYSICAL PROPERTIES OF THE CARBON COMPOUNDS. 


Usually we can foresee that the physical, as well as the chemical, 
properties of the derivatives of carbon must be conditioned by 
their composition and constitution. Such a regular connection, 
however, has been as yet only approximately established for a few 
properties. Those meriting consideration here, serving, therefore, 
chiefly for the external characterization of carbon derivatives, 
are the specific gravity in the gaseous and liquid condition, 
the melting and boiling temperatures, the behavior towards light, 
and electric conductivity. 


SPECIFIC GRAVITY. 


By this term is understood the relation of the absolute weights 
of equal volumes of bodies, in which case we take as conventional 
- units of comparison, water for solids and liquids, and dir or hydro- 
gen for gaseous bodies (see p. 29). 

For the latter, as we have already seen, the ratio of the specific 
gravity (gas density) to the chemical composition is very simple. 
Since, according to Avogadro’s law, an equal number of. molecules 
are present in equal volumes, the gas densities stand in the same 
ratio as the molecular weights. Therefore, the specific volume, t. ¢., 
the quotient of the molecular weight and specific gravity, is a con- 
stant quantity for all gases (at like pressure and temperature). The 
relations are different in the cases of liquid and solid bodies. 
Since in the solid and liquid states the molecules are considerably 
nearer each other than when in the gaseous condition, the specific 
gravities cannot be, as with gases, proportional to the molecular 
weight, and are also modified by the size of the molecules and their 
distance from each other. The size and distance are unknown to 
us; the latter increases, too, with the temperature, therefore, the 
theoretical groundwork for deduction of specific gravities is far 
removed from us. However, some regularities have been empirically 
established for the specific gravity of Zguéd bodies. ‘These appear, 
upon comparing the specific volumes or molecular volumes. 


56 ORGANIC CHEMISTRY. 


In determining the specific gravity of liquid compounds, a small bottle—a_pyk- 
nometer—is used. Its contracted portion is provided with a mark; more compli- 
cated apparatus is employed where greater accuracy is sought (Azma/len, 203, 4). 
Descriptions of modified pyknometers will be found in the Handwéorterbuch v. 
Ladenburg, 3, 238. To get comparable numbers, it is recommended to make 
all determinations at a temperature of 20° C., and refer these to water at 4°, anda 
vacuum. Letting m represent the weight of substance, v that of an equal volume 
of water at 20°, then the specific gravity at 20° referred to water at 4°, and a vacuum 
(with an accuracy of four decimals), may be ascertained by the following equation 
(Annalen, 203, 8) :— 


4 Vv 


To find the specific volumes at the boiling temperature, the specific gravity at 
any temperature, the coefficient of expansion and the boiling point must be ascer- 
tained; with these data the specific gravity at the boiling point is calculated, and 
by dividing the molecular weight by this, there results the specific or molecular vol- 
ume. Kopp’s dilatometer (Anmalen, 94,257, compare Thorpe, Journal Chem. Soc., 
1880, 141, and Weger, Azmadlen, 221, 64), is employed in obtaining the expansion 
of liquids. For a method of getting the direct specific gravity at the boiling point, 
consult Ramsay, Ber., 12, 1024; Schiff, dzz., 220, 78, and Ber., 14, 2761; also 
Schall, Ber., 17, 2201, and Neubeck, Zeit. phys. Chem., 1, 651. 


H. Kopp ascertained that the following relations existed between 
the composition of carbon compounds and their molecular volumes 
at the boiling temperature :— 


I. Isomeric compounds possess approximately like specific volumes. 

_ 2. Like differences in specific volume correspond to like differences in compo- 
sition. 

From these data arose the following law: the specific volume of a liquid com- 
pound (mol. volume), at its boiling point, is equal to the sum of the specific volumes 
of its constituents (of the atomic volumes), This gives to every element a definite 
atomic volume in its compounds. 

_ In homologous compounds the difference, CH,, corresponds to a difference of 
22 in specific volume, for example :— 


Molecular Specific 
Weight. Volume. Difference. 


Formic Acid.......... weve CHAO 46 $24, 22 
ooete Acie oii. C,H,O, 60 64 22 
Propionic Acid............ C,H,O, 74 86 j 

Butyric Acid....... sections CHO, 88 108 i 22 


The replacement of a carbon atom by two hydrogen atoms, does not cause any 
alteration in specific gravity, ¢. ¢.,— 
Molecular Specific 
Weight. Volume. 


Cymene..,...... biiisaneis eared Ot: 134 187 
TICEADE tseckisiarasciorindis . CH 114 187 


As the specific volume of the group CH, equals 22, and the specific volume of one 
atom of C is equal to that of two hydrogen atoms, it follows that the specific volume 
of one carbon atom (its atomic volume) is 11, and that of one hydrogen atom 5.5. 
In a similar manner Kopp deduced two different atomic volumes for oxygen. If 


' SPECIFIC GRAVITY. 57 


oxygen be in union with both affinities to one carbon atom (intra-radical), its ato- 
mic volume is equal to 7.8; but if it be combined (extra-radical) with two different 
atoms (as in (C,H,) ,O and C,H,OH), its atomic volume is equal to 12.2. Hence, 
the specific volume of a compound of the formula C,H,O,O0’q (O represents intra- 
and O/ extra-radical oxygen) may be calculated from the equation :— 


Molecular Volume= II .a+5.5.b+12.2.c+ 78.4. 


The other elements exhibit similar definite specific volumes in their compounds, 
é. g., chlorine = 22.8, bromine = 27.8, iodine = 37.5. Sulphur, like oxygen, 
has two values: the atomic volume of the intra-radical sulphur (in CS) equals 
28.6; that of the extra-radical, 22.6. In ammonia and its derivatives, nitrogen has 
the specific volume 2.3, in the CN group 17, in NO,, 8.6. 

With such data the molecular volumes, and, of course, the specific gravities, can 
be obtained with approximate accuracy. 

The most recent researches,* based upon an abundance of material, and at the 
same time giving due consideration to the structural relations of the carbon com- 
pounds, prove conclusively that the supposed regularities, mentioned above, are un- 
founded. The fact is, isomeric compounds in no manner have equal molecular 
volumes, and their atomic volumes are not constant (Lossen, Anz., 213, 316). 
The volume for the difference CH, (see above) is not constant in the different 
homologous series, but varies, for example, in the esters of the fatty acids, from 19-28, 
and constantly increases with the higher members. Further, the hydrogen volume 
is not always 5.5, but it varies according to the manner in which it is derived (see 
Ann., 233, 318; Ber., 20,767). The atomic volume of O is exceedingly variable 
(Ann., 233, 322); at times the entrance of oxygen into compounds causes a de- 
crease in volume (er., 19, 1594) :-— 


Vol. : Vol. 
Toluene, C,Hyg. ...:..0+s000020103.8 | Propyl Alcohol, C,H,O.......+. 73-4 
Benzyl Alcohol, C,H,O...... 102.1 | Propyl Glycol, C,H,O,.......... 72.1 


Another point to be considered is that the comparability of the sp. volumes of 
liquid bodies is not fixed by the boiling temperature, because the boiling points are 
dependent upon external pressure, and vary very widely in accordance with pressure. 
Consequently at temperatures other than that of boiling, similar but varying regular- 
ities were observed (Horstmann, Ber., 19, 1579; Lossen, Aum., 243,101). Hence 
it is (1) that the molecular volumes in nowise represent the sums of the atomic 
volumes, (2) that the latter are scarcely determinable, (3) that the specific gravities 
and molecular volumes depend less upon the volume of the atoms, than upon their 
manner of linkage, and upon the structure of the molecules. Therefore to deduce 
regularities in the specific volumes it is first necessary to carefully consider the 
chemical structure of the compounds. For an exhaustive treatment of these rela- 
tions, see Kopp, 4zz., 230, 1-117; Zer., 22, Ref., 190, In this connection the 
influence of the double union of the C- atoms in the unsaturated compounds and 
the ring-form linking in the benzene derivatives, is significant. It has long been 
known (Buff) that the molecular volumes of the unsaturated compounds of the 
paraffin series were from 1.5-3 greater than those calculated by Kopp. Later 
research made them 4.4 (Azm., 220, 298 and 221, 104), which has been confirmed 
by Horstmann’s most recent investigations (Ber., 19, 1591 and 20,779). The 
divalent union is therefore less intimate (p. 41) and the unsaturated compounds 
consequently show a greater heat of combustion (Aum., 220, 320). 





* Lossen and others ; Am.,214, 81,138: 221, 61; 224, 56; 225, 109; 233, 249, 316; R. Schiff, 
Ann., 220, 113, 278; Horstmann, Ber., 19, 1579; 20, 766 and 21, 2211. Lossen, Axnaden, 243, 


1-103. 
5 


58 ORGANIC CHEMISTRY. 


In the conversion of benzene hydrocarbons into their hydrides there is an increase 
in volume which is three times as great as in the conversion of the olefines into their 
corresponding paraffins. This would emphasize the theory that in the benzene 
nucleus there are three doubly combined carbon atoms (Amz., 225, 119 and Ler., 
20,771). The specific gravities of the benzene hydrides is notably greater (conse- 
quently the molecular volumes are smaller) than their corresponding olefines, and 
that accounts for the fact that in the ring-linking of the C- atoms in the benzene 
nucleus there is an appreciable contraction in volume (472., 225, 114 and Ber., 20, 
773). For further investigations relating to the benzene derivatives see Horstmann, 
Ber., 21, 2211, and Neubeck, Zezt. phys. Chem., 1, 649. 


MELTING POINTS—BOILING POINTS. 


Every pure carbon compound, if at all fusible or volatile, exhibits 
a definite melting and boiling temperature. It is customary to 
determine these for the characterization of the substance. 

Boiling Points. ‘These are determined in a so-called boiling 
flask, z. ¢., a small flask with wide neck, and provided on the side 
with an exit tube. The thermometer is fixed in the opening of 
the neck by means of a-cork. It should not be allowed to dip into 
the liquid; it must only be surrounded by the vapors. 


In accurate determinations it is necessary to apply corrections to the indicated 
temperatures. If a thermometer is not wholly immersed in vapor, but as ordi- 
narily happens, is partly extended into the air beyond the distillation vessel, the 
external mercury column will not be heated the same as that on the interior, 
hence the recorded temperature will be less than the real. The necessary cor- 
rection will be reached with sufficient accuracy by adding to the observed temper- 
ature the quantity n(T —t). 0.000154. Here x indicates the length of the mer- 
curial column without the vessel, in degrees of the thermometer, T the observed 
temperature, t the medium temperature of the air about the external column 
of mercury (this is approximately ascertained by holding a second thermometer 
about the middle of the exposed part); 0.000154 is the apparent coefficient of 
expansion of mercury in glass. The correction is best avoided by having the 
entire mercurial column played upon by the vapors of the liquid. Pawlewski 
has presented a simple device to effect this (Berichie, 14, 88). It is also appli- 
cable in cases where but small quantities of liquid are employed. 

If the barometric column did not indicate a normal pressure of 760 mm. during 
the distillation a second correction in the observed boiling temperature is neces- 
sitated. This is ordinarily accomplished by either adding to or deducting from 
the observed temperature 0.1° C. fora difference of every 2.7 mm. between the 
observed and normal barometric height (760 mm). This correction is, however, 
very inaccurate, because the differences between pressure and boiling point vary 
widely for each body (Ber., 20, 709). To avoid this correction it is advisable to 
reduce the pressure in the apparatus to the normal. The pressure regulators of 
Bunte (Azn., 168, 139) and Lothar Meyer (Azm., 165, 303) are adapted to this 
purpose. In distilling under any pressure the forms of apparatus devised by Stae- 
del and Schuhmann (Azm., 195, 218 and Ser., 13, 839) will be found very ser- 
viceable. For a method, applicable in determining the boiling points of very small 
amounts of liquids, see Ber., 19, 794. 

Liquids of different boiling points are separated by fractional distillation, an 
operation performed in almost every distillation. The portions passing over 


1 


MELTING POINTS—BOILING POINTS. 59 


between definite temperature intervals (from I—10°, etc.) are caught apart and 
subjected to repeated distillation, the portions boiling alike being united. To 
attain a more rapid separation of the rising vapors, these should be passed through 
a verticaltube. In this the vapors of the higher boiling compound will be con- 
densed and flow back, as in the apparatus employed in the rectification of spirit. 
To this end there is placed on the boiling flask a so-called fractional tube of 
Wiirtz. Excellent modifications of this have been described by Linnemann, Le 
Bel, Hempel and others. For the action of these boiling tubes see Anm., 224, 
259; Ber., 18, Ref. 101, and Ann., 247, 3. It is often required to perform the 
distillation in vacuo; and this is best effected by exhausting the boiling cham- 
ber. An apparatus answering this purpose is mentioned in Berichte, 9, 1870. A 
very simple contrivance, regulating the pressure at the same time, is that de- 
scribed by F. Krafft (Berichte, 15, 1693; 22, 829). Also consult Thorne and 
Godefroy, Ber., 16, 1327, and 17, Ref. 159; as well as Anschiitz, ‘“ Distillation 
under reduced pressure,” 1887. Vessels designed for the collection of the distil- 
lates have been described by L. Meyer, Ber., 20, 1833, and Briihl, Ber., 21, 3339. 


The connection between the boiling points and chemical consti- 
tution of compounds will be discussed later in the several homolo- 
gous groups. Generally the boiling point rises with the complica- 
tion of the molecule. The unsaturated compounds boil at a higher 
temperature than those that are saturated. With isomerides having 
an equally large carbon nucleus those of normal structure possess 
the highest boiling points. These fall with the accumulation of 
methyl groups. 

It may also be noted that the lower boiling isomerides possess 
a greater specific volume (Ber., 15, 2570). 

Melting Points. To determine these, introduce the substance 
into a thin, drawn-out tube, sealed at one end. This is attached 
to a thermometer and allowed to dip into a small beaker containing 
water, or a high boiling compound—paraffin. The beaker is warmed 
upon a sand bath until the substance in the little tube melts, and 
the temperature noted. For convenient apparatus for this purpose, 
see Berichte, 10, 1800. 

The greater partof the mercury column of the thermometer extends beyond 
the heated bath, and therefore receives less heat. In all accurate determinations, 
a correction for this is consequently necessary. This is done as described with the 
boiling temperature. Correction for barometric pressure is not required, because 
the melting points are but slightly affected by pressure. 

See Ber., 19, 1970, for a device intended for the direct determination of the 
corrected melting point. The melting point is generally rather high if the 
melting tube is very narrow. The most accurate results are obtained when larger 
quantities of material are used in the determination (er., 21, Ref. 638). 


Very often slight admixtures, which can hardly be excluded, 
even by fractional crystallization, will materially lower the melting 
point. 

The relation between the melting point and the chemical consti- 
tution will be more fully considered under the different homologous 
groups of bodies. 


60 ORGANIC CHEMISTRY. 


OPTICAL PROPERTIES. 


Refraction. ‘The carbon compounds (like all transparent sub- 
stances) possess a variable light refracting power. In this case, as 
in other cases, the quotient of the sine of the angle of refraction (7) 
into the sine of the angle of incidence (7) is a constant quantity for 
each substance. This number is termed the coefficient of refraction, 
or refractive index (n):— 


The refractive index of liquids is mostly determined by two methods. In the one 
the deviation of a ray of light is noted when it passes through a cylinder filled with 
the liquid under examination. The spectrometer of Meyerstein is especially adapted 
to this purpose. The second method (that of Wollaston) is less accurate, but much 
simpler than the first. It is also applicable to small amounts of substance. It is 

_based on the total refraction caused by a layer of liquids. This is determined by 
means of the refractometer of Pulfrich and Abbé. 


The coefficient of refraction (n) varies with the temperature, con- 
sequently also with the specific gravity of the liquid. 
Their relation was formerly assumed to correspond to the formula 


ew: ft 


;~’ in which d represented the sp. gr. of the liquid for a given 


temperature. It is an almost constant quantity for all temperatures, 
and is called the specific refractive power. However, later re- 


search has proved that the theoretically deduced equation, aad 
(the so-called n’-formula), more nearly represents the actual facts 
(Ber., 19, 2760). It is therefore, at present, applied almost 
exclusively.* 
On comparing the refractive constants (using the n —1 or n?— 
formula) of a mixture of several liquids with those of the con- 
stituents, it will be discovered that the first equals the sum of 
the refractive constants of the latter, and corresponds to their 








* For a more accurate representation of these relations, see Landolt, Pogg. Ann., 
123, 595; Ber., 15, 1031; Briihl, Ber., 19, 2746 and 2821; Ann., 235, 1, and 236, 
233; Ber., 20, 2288, and Zeit. phys. Chem., 1, 307; Wiegmann, Zeit. phys. Chem., 
1, 218 and 257; Ketteler, zdzd., 2, 905. 

The refractive index (n) can be referred to any wave-length that may be desired. 
Since, however, different substances have different dispersive power, such indices 
are not directly comparable, and they were, therefore, referred to rays of infinite 
wave-length (according to Cauchy’s dispersion formula). The indices supposed to 
be freed from the influence of dispersion were represented by the letter A, and the 
OE aya ore» 

d (A? + 2)d 
have shown that these assumptions possess neither theoretical nor empirical value, 
and on that account it is necessary to come back to the refraction of one definite 
ray. ‘Therefore, either the yellow sodium line (D of the sun’s spectrum) or the 
red line of hydrogen Ha (C of the sun’s spectrum) may be used. 





refractive constants by The most careful investigations 


OPTICAL PROPERTIES. 61 


percentage content in the mixture. A similar relation exists for 
chemical compounds. Designating the product of the specific re- 
fractive power of a compound R (according to n—or n?— for- 
mula), the molecular weight M as the molecular refraction, and the 
product of the refractive index of the elements and their atomic 
weights, the atomic refraction, the proposition would read: ‘‘ The 
molecular refraction of a liquid carbon compound is equal to the 
sum of the atomic refractions,’’ corresponding to the equation :— 


MR = amr + bm/r’ + cm//r’/, 


in which a, b, c, represent the number of elementary atoms in the 
compound. The atomic refractions of the elements are deduced 
from the molecular refractions of the compounds obtained empiri- 
cally, in the same manner as the atomic volumes are obtained from 
the molecular volumes (see p. 57). 

While it was formerly assumed that but one atomic refraction 
existed for each element in its compounds, later researches have 
proved that the atomic refraction of the polyvalent elements is in- 
fluenced by their manner of union. The following atomic refrac- 
tions have been calculated for the red hydrogen ray, Ha, and the 


formula went a (Briihl, Ann. , 235, 35, and Conrady, Ber., 32, Ref. 
224) ; ceaininky linked ’’ carbon has the atomic refraction* (r,) equal _ 
to 2.48, hydrogen 1.04. chlorine 6.02, bromine 8.95. Oxygen has 
two ‘‘atomic refractions.’’ When it is united by one bond tocar- 
bon (as hydroxyl, and in ethers), the constant is 1.58 (1.52 and 1.68 
for the line D), while in its double union (in C =O) it is 2.34. 
Similarly, sulphur exhibits two different values (Ber., 15, 2878). 

The deportment of double- and treble-linked carbon atoms is 
worthy of note. ‘The double union (C, =), according to Briihl, is 
1.78 (for r,), that of the triple union (C, == ., 1f two car- 
bon atoms are ‘‘ doubly linked,’’ their atomic refraction equals 
2X 2.48 + 1.78 = 6.74,while in triple union it is4.96-+ 2.18 7.14. 

These relations have met with frequent application in the decision 
of questions pertaining to chemical constitution. Thus the greater 
molecular refraction (by 31.78 = 5.34 units) of the benzene bodies, 
confirms the view previously deduced from chemical facts, that 
there is present in the benzene nucleus three ‘‘ double-linked ’’ car- 
bon atoms (Ser., 20, 2288). However, the regularities noted above 
only hold good for bodies with slight dispersive power (the fatty 
bodies). In the case of substances possessing a greater dispersive 
power than cinnamyl alcohol, the molecular refraction is valueless 
for the determination of chemical structure (Ber., 19, 2746). 











* The molécular refraction of a ray of indefinite wave-length (index A) is 
designated by R,, the atomic refraction by ry. 


62 ORGANIC CHEMISTRY. 


Rotation of the Plane of Polarization.*—Many carbon 
compounds, liquid and solid, are capable of rotating the plane of 
polarized light. These are chiefly naturally occurring substances, 
like the various vegetable acids, amyl alcohol, the sugars, carbo- 
hydrates and glucosides, the terpenes and camphors, alkaloids and 
albuminoids; they are said to be optically active. The rotation 
(of the angle a) is proportional to the length 1 of the rotating plane, 


hence, the expression + is a constant quantity. To compare sub- 


stances of different density, in which very unequal masses fall upon 
the same plane, these must be referred to like density, and hence, 
the rotation must be divided by the sp. gr. of the substance at a 


definite temperature. The expression ma == [a], in which the 


length of the rotating plane is given in decimeters, is called the 
specific rotatory power of a substance at a definite temperature and is 
designated by [a], or [a];, according as the rotation is referred to 
the yellow sodium line D or the transitional color j.. For solid, 
active substances, with an indifferent solvent, the expression 
fat Tq will answer; in this p represents the quantity of 
pl: 

substance in too parts by weight of the solution, and d represents 
_ the specific gravity of the latter. © 


The specific rotatory power is constant for every substance at a definite tem- 
perature; it varies, however, with the latter, and is also influenced more or 
less by the nature and quantity of the solvent. Therefore, in the statement of 
the specific rotatory power of a substance, the temperature and the percentage 
amount of the solution must be included. By investigating a number of solu- 
tions of different concentration, the influence of the solvent may be established and 
the true specific rotation or the true rotatory constant of the pure substance, 
designated by A,, may then be calculated. The product of the specific rotatory 
power and the molecular weight » divided by 100 is designated the molecular 
rotatory power :— 


Consult Ber., 21, 91,2586, 2599, upon the influence of inactive substances on 
the rotatory power. 


In crystalline substances, the rotatory power is connected with 
the crystalline form, and is usually conditioned by the existence of 
hemihedral planes (see Tartaric Acids). As the activity of most of 
them is retained by solution, or is then first perceptible, it is sup- 
posed that crystal molecules exist in the solution, and that these 
consist of a union of several chemical molecules. Since, further, 





* Compare Landolt, “ Das optische Drehungsvermégen,” 1879. 


t 
} 


OPTICAL PROPERTIES. 63 


numerous solids and liquids are known in dextro- and levo-rotatory 
and inactive modifications, in which we can detect no difference in 
chemical structure, besides the active modifications mostly con- 
vertible into inactive, it was concluded that the activity was caused 
not by single chemical molecules, but by groups of physical mole- 
cules. These were termed physical tsomerides. Since we have as- 
certained that turpentine oil and camphor, in the form of vapor, 
possess the same specific rotatory power as when they are in the 
liquid or solid state, and inasmuch as optically different substances, 
having the same structural formula, possess the same molecular 
weight, it can no longer be doubted that the activity is induced by 
a peculiar, chemical atomic-grouping, which finds no expression in 
the structural formulas usually offered. Le Bel and van’t Hoff * 
deserve the credit of having advanced a theory, based on the spatial 
relations of atoms, that succeeds in bringing the latter and the 
optical rotatory power into full harmony. 


According to this theory, the activity of the carbon compounds is dependent upon 
the presence of asymmetric carbon atoms, 7. ¢., such as are combined with different 
atoms or atomic groups. 

In all cases of this nature, every compound C a b ed, having its four groups 
arranged like the four solid angles (summits) of a tetrahedron, can have two possible 
configurations, the one being nothing more than the reflected image of the other. 
These forms are not superposable. There are two corresponding isomerides for 
each of these forms. These all agree perfectly in their chemical behavior, and 
differ from each other only in their opposite rotatory power, and opposite 
hemihedral (enantiomorphous) crystalline forms (see Tartaric Acids). 

The following are examples of those compounds in which ome asymmetric 
carbon atom is present :— 


CH;. CH(OH)CO,H ~—C,H,. CH(CH,)CO,H_ _—C,,H,. CH(CH,). CH,OH 


Ord. Lactic Acid. Active Valeric Acid. Active Amyl Alcohol. 
CH(OH), CO,H CH(NH,). CO,H CH(NH,) . CO,H 
CH,. CO,H CH,. CO. NH,. CH,.CO,H, ete. 

Malic Acid. Asparagine. Aspartic Acid.f 


Each of these compounds can occur in adextro- and /evo- rotatory modification. 
What is more, the oppositely active forms can combine in equal quantities with 
each other, and produce an zzactive double form, capable of re-solution into two 
active varieties (p. 64). Therefore, compounds containing ove asymmetric carbon 
atom can give rise to ¢kree isomerides—two of which are active, and the third 
inactive, but capable of further division. 

When two asymmetric carbon atoms are present in a compound, the number of 
possible isomerides is correspondingly greater. If the entire six groups in union 
with the two carbon atoms are different, corresponding to the general formula 
abecC—Cde f, then four different configurations (p. 51) can exist, two of 





* van’t Hoff, “* Dix années dans l’historie d’une théorie,”’ 1887. 
ft The asymmetric carbon atoms are indicated by an italic C. 


64 ORGANIC CHEMISTRY. 


which will be opposite and active. If each of the two carbon atoms are in union 
with three similar groups, as in tartaric acid— 


CH(OH). CO,H 


CH(OH). CO,H 


three configurations are possible for each: a dextro- and Jevo- form, as well as an 
inactive modification not capable of division. This is known as the avitt-modifica- 
tion ; init the three groups are diametrically opposed to each other, and there re- 
sults an inner compensation. Besides these there is also the active or para-form, 
resulting from the union of the two active varieties; this can be separated again 
into its components. Hence, tartaric acid may occur in fowr isomeric modifica- 
tions, while malic acid yields but three isomerides (see above). The inactive form, 
capable of further division, is not possible in this instance. 

Further research has fully confirmed the deductions of Le Bel and van’t Hoff, 
so that at present it is an established fact that all known active substances contain 
asymmetric carbon atoms; conversely, it has repeatedly occurred that asymmetric 
compounds, previously known only in their active form, have been split up into 
their components (see tartaric acid, lactic acid, mandelic acid), while compounds, 
not asymmetric, have never yet undergone such a separation (47z., 239, 164). 

On converting active substances into other derivatives, the activity is retained, 
providing asymmetric carbon atoms are present; when they disappear the deriva- 
tives are inactive. Thus, from the two active tartaric acids are derived the two 
corresponding active malic acids; whereas, the symmetrical succinic acid, ob- 
tained from the latter by further reduction, is inactive. Again, active amyl iodide 
affords an active ethylamyl and diamyl; on the other hand, an inactive amyl 
hydride (see Active Amy] Alcohol). 

The asymmetric compounds, prepared by artificial means from inactive sub- 
stances, are almost always inactive. This is explained by the fact that both 
modifications are found simultaneously and in like amounts; further, they also 
have the tendency to combine into inactive conglomerates. To this must be 
added that energetic reactions, or heat, tend to change the active into the inactive, 
decomposable variety (¢. g., dextro-tartaric acid changes at 175° into racemic 
acid); consequently the active variety formed is eventually changed to the inac- 
tive. Thus, when the albuminates are decomposed on heating them with baryta, 
the products are inactive leucine, tyrosine and glutamine, whereas at a lower tem- 
perature hydrochloric acid produces the active modifications (Ber., 18, 358). 

Artificially inactive, asymmetric compounds can be split into the two active forms. 
This splitting-up may sometimes be effected by the crystallization of salts, as was 
first demonstrated by Pasteur (1848) in the case of racemic acid. (See above.) 
This decomposition occurs at a fixed temperature, known as the conversion tempera- 
ture ; it is also dependent upon the solubility of the salts (Ber.,19, 2148 and 2975). 

The decomposition of inactive substances takes place more readily by the inter- 
vention of other active substances (especially cinchonine and quinine). This, too, 
was first observed by Pasteur with racemic acid. It seems to be due to the ten- 
dency of the active substance to unite itself exclusively with an active form of the 
inactive compound. By the employment of cinchonine not only racemic acid, 
but also malic, mandelic and tropaic acids have been thus split up. The splitting- 
up of inactive a-propyl piperidine into active conine, and that of methyl- and 
ethy]-piperidine, was effected through the use of active tartaric acid (Ber., 20, 339). 

A third procedure for the splitting-up of these derivatives is noteworthy ; it de- 
pends upon the action of ferments—especially Peniciliium glaucum—which re- 
sults in the destruction of one of the active modifications. Under this treatment, 
racemic acid yields lzvo-tartaric acid (Pasteur), inactive amyl alcohol passes into 


ELECTRIC CONDUCTIVITY. 65 


dextro-amyl alcohol, and methyl-propyl carbinol and propylene glycol yield their 
lzevo-rotatory modifications. Penicillium glaucum or Bacterium termo converts the 
synthetic, inactive mandelic acid into its dextro-rotatory form, while Saccharomyces 
ellipsoideus or Schizomycetes-fermentation produces the lzvo-acid (Ber., 16, 1568). 
Glyceric acid and ordinary lactic acid (Ber., 16, 2721), as well as leucine and 
glutaminic acid, have sustained similar decomposition. 

All these observations confirm the proposition of Le Bel and van’t Hoff, that the 
asymmetrically constituted inactive carbon derivatives can be broken up into two 
oppositely active modifications. 


ELECTRIC CONDUCTIVITY. 


It is well known that substances capable of conducting electricity 
arrange themselves into two widely-separated groups: conductors 
of the first class, or those which conduct electricity without sus- 
taining any change, and conductors of the second class, or those 
which constitute the electrolytes, and conduct only with their simul- 
taneous separation into two zeus. Conductivity can also be con- 
sidered as a resistance, which the conductor opposes to the passage 
of the electricity. The customary measure of conductivity or resist- 
ance is the mercury unit, This is a column of mercury of one sq. 
mm. cross section, and one meter in length, at the temperature 0° 

Ostwald’s investigations have demonstrated that the conductivity 
of electrolytes is intimately related to chemical affinity. It.is a 
direct measure of the chemical affinity of acids and bases. There- 
fore, the determination of the conductivity of electrolytes (in aque- 
ous solution), to which all organic acids and their salts belong, is of 
great interest and importance for all carbon derivatives. 

Kohlrausch* has suggested a very simple and accurate means of 
determining the conductivity of electrolytes, which has been exten- 
sively applied by Ostwald.+ 

It is dependent upon the application of alternating currents, pro- 
duced by an induction spiral, so that the disturbing influence of 
galvanic polarization is obviated. 

The conductivity of electrolytes is not referred to the percentage 
content of their aqueous solutions, but (as the conductivity is ascer- 
tained by the equivalent ions) to solutions containing a molecule, 
or an equivalent of substance in grams, This value is the molecular 
(or equivalent) conductivity of the substance (Zeit. phys. Chem., 2, 


567). Uns 
The strong acids have the Srentest molecular conductivity, then the 
fixed alkalies and alkali salts. Most organic acids, on the contrary 





* Wiedemann, Anz., 11, 653. 
+ Journ. pr. Chem., 32, 300, and 33, 353; Zezt. phys. Chem., 2, 561. 
6 


X 


66. ORGANIC CHEMISTRY. 


(e.g. acetic acid) are poor conductors in a free condition, while 
their alkali salts approach those of the strong acids in conductivity. 
The molecular conductivity increases by about 2 per cent. per 
degree of temperature. It also increases with increasing dilution, 
and in the case of the poor conductors it is far more rapid than with 
the good conductors; in both instances it approximates a maxi- 
mum (limiting) value. With good conductors this is attained at a 
dilution of 1000 litres to the gram-molecule ; while with those poor 
in conducting power it is only reached when the dilution is indefi- 
nitely large. In fact, in such cases the conductivity is practically 
indeterminable. 

An interesting observation in connection with the alkali salts of 
all acids is the variable increase of the molecular conductivity with 
increasing dilution. ‘This is true both in the case of the strong and 
the weak acids (most organic acids belong to the latter class), and it 
varies according to their basicity. With sodium salts of monobasic 
acids, this increase equals from 10-13 units, by dilution of 32-1024 
litres for the equivalent of substance, for the salts of dibasic acids 
from 20-25 units, for those of the tribasic 28-31, for those of the 
tetrabasic about 4o, and those of the pentabasic about 50 units. 
Thus it may be seen that the increase in conductivity of acids, in 
their sodium salts, offers a means of determining the basicity and, 
consequently, the molecular magnitude of acids (Ostwald, Zeit. 
phys. Chem., 1, 74and 97; 2, 901; Walden, Jdid., 1, 530, and 
2, 49). Me ; 

Molecular eSidactivity has acquired still greater importance by 
its application to the measurement of the dissociation of the elec- 
trolytes ; it is at the same time the measure of the reactivity or 
chemical affinity, first, of acids, then bases, and, finally, of salts. 

Arrhenius’s electrolytic dissociation theory maintains that in 
- aqueous solution the electrolytes are more or less separated into 
their ions; this would give a simple explanation for the variations 
of solutions from the common laws (under osmotic pressure, under 
the depression at the freezing point, etc.). (The dissociation is also 
manifest in the molecular conductivity, for the latter is dependent 
upon the degree of dissociation and the speed of migration of the 
free ions; it is directly proportional to the quantity of the latter. 
Molecular conductivity increases with dilution and dissociation. 
When the latter is complete, it attains its maximum (py, ). The 
degree of dissociation (m) (or the fraction of the electrolyte split 
up into ions) for any dilution is found from the ratio of the molec- 
ular conductivity at this dilution (w) to the maximum conductivity 
(for an indefinite dilution) :— 


Wee 
i 


ELECTRIC CONDUCTIVITY. 67 


The latter cannot be directly measured in the case of free organic 
acids, because most of them are poor conductors. But it can be 
obtained from the molecular conductivity of their sodium salts, by 
deducting from their maximum values the speed of migration of the 
sodium-ions (41.1), and adding those of the hydrogen-ions (285.8). 

Since the molecular conductivity depends upon the dissociation 
of the electrolytes into their ions, their alteration by dilution of so- 
lution must proceed by the same laws as those prevailing in the dis- 
sociation of gases. This influence of dilution or volume (v) upon 
the molecular conductivity, or the degree of dissociation (m) is, 
therefore, expressed in the equation :— 


2 
v(I —m) 


which represents the law of dilution advanced by Ostwald (Zet¢. phys: 
Chem., 2, 36 and 270). This law has been fully confirmed by the 
perfect agreement of the calculated and observed values (van’t Hoff, 
Lett. phys. Chem., 2, 777): 

The value, k, is the same at all dilutions for every monobasic acid ; 
hence, it is a characteristic value for each acid, and is the measure 
of its chemical affinity. The determination of these chemical 
affinity-constants by Ostwald for more than 240 acids, has proved 
that they are closely related to the structure and constitution of 
organic acids (Zett. phys. Chem., 3, 170, 241, 371). 


SrPBUIAL PART. 





The carbon derivatives may be arranged in two classes—the 
fatty and aromatic compounds. The name of the first class is 
borrowed from the fats and fatty acids comprising it. These 
were the first derivatives accurately studied. It would be better to 
name them marsh gas or methane derivatives, inasmuch as they all 
can be obtained from methane, CH, They are further classified 
into saturated and unsaturated compounds. In the first of these, 
called also paraffins, the directly united tetravalent carbon atoms 
are linked to each other by a single affinity. 

The number of z carbon atoms possessing affinities capable of 
further saturation, therefore, equals 2n + 2 (see p. 40). Their 
general formula is C,X,,,,. Here X represents the affinities of the 
elements or groups directly combined with carbon. The unsatu- 
rated compounds result from the saturated by the exit of.an even 
number of affinities in union with carbon. According to the 
number of affinities yet capable of saturation, the series are dis- 
tinguished as C,X,,, C,X,, 2, etc. (See p. 41.) 

All the aromatic or denzene compounds contain a group consist- 
ing of six carbon atoms. The simplest derivative of this series is 
_ benzene, C,H, (see p.. 42). This accounts for the great similarity 
in their entire character. Their direct synthesis from the methane 
derivatives is only possible in exceptional cases; as a usual thing 
they cannot be converted into the series C,H... Their relatively 
great stability distinguishes them from the fatty bodies. They are 
generally more reactive, yielding, for instance, nitro-substitution | 
products very readily, and forming various derivatives which the 
fatty compounds cannot possibly yield. 

The recently investigated trimethylene and tetramethylene de- 
rivatives (see p. 42), with which may be included those of furfurol, 
thiophene and pyrrol, may be viewed as the transition stage: from 
the methane compounds containing the open carbon chain, to those 
of benzene. 


68 


HYDROCARBONS. ee 


CLASS I. 


FATTY BODIES, OR METHANE DERIVATIVES. 


HYDROCARBONS. 


The hydrocarbons show most clearly and simply the different 
manner in which the carbon atoms are bound to each other. We 
may regard them as the parent substances from which all other 
carbon compounds arise by the replacement of the hydrogen atoms 
by differents elements or groups. 

The outlines of the linking of carbon atoms were presented in the 
Introduction. In consequence of the equivalence (confirmed by 
facts) of the four affinities of carbon (see p. 38) no isomerides are 
possible for the first three members of the series C,H,, . »:— 


CH, CH, — CH; CH, — CH, — CH, Aion 
Methane. Ethane. Propane. rh 


Two structural cases exist for the fourth member, CHe:— 


. ACH, C/ 2 
CH, ~ CH, CH: =F. and CH—CH, 
Normal Butane.- \.CH, 


T rinethyimenans 
(Isobutane. ) 


For the fifth member, pentane, C;H,,, three isomerides are 
possible :— . 


/CH, 
CH, — CH, — CH, — CH, — CH, CH—CH, 
Noemi Pentabé: \ CH, . CH, 
CH, Dimethyl-ethyl Methane. and 
ae ie Tetramethyl Methane. 
CH,” “cH, 


Hexane, C,H,,, the sixth member, has five isomerides (see p. 75). 
With reference to the different formulation of these hydrocarbons 
seep. 72. 

Formation of Hydrocarbons.—The higher paraffins can be grad- 
ually built up synthetically from methane, CH,, yet not produced 
directly from their elements. Methane itself can be synthesized 
from carbon disulphide, CS, (produced by direct union of carbon 
and sulphur on application of heat) by passing the latter, in form 
of gas, together with hydrogen sulphide, over red-hot copper :— 


CS, + 2H,S + 8Cu = CH, + 4Cu,S, 


or by heating with phosphonium iodide, PH,I; further, by the 
action of chlorine, carban disulphide may be changed to carbon 


7° ORGANIC CHEMISTRY. 


tetrachloride, CCl,, and this reduced, by means of nascent hydrogen 
(sodium amalgam and water), to methane :— 


CCl, + 4H, = CH, + 4HCl. 


The direct union of carbon and hydrogen has only been observed 
in passing the electric spark between carbon points in a hydrogen 
atmosphere ; the product is acetylene, C,H,, which, with additional 
hydrogen (in presence of platinum black), becomes ethylene, C,H,, 
and then ethane, C,Hg. 

A universal method of producing the hydrocarbons consists in 
the dry distillation of complex carbon compounds, like wood, 
lignite and bituminous coal. At higher temperatures, ¢. ¢., when 
their vapors are conducted through red-hot tubes, the hydro- 
carbons can condense to more complicated bodies, hydrogen 
separating. Thus, the compounds C,H,, C,H,, C,H, (benzene), 
C,H, (naphthalene), and others, are obtained from CHy,, methane. 

A noteworthy formation of the hydrocarbons, especially the 
paraffins, ‘is that of the action of hydrochloric acid or dilute sulphuric 
acid, and even steam, upon iron carbide. 





(1) PARAFFINS OR ETHANES. 


4 Ca Hon + 2" 
CH, Methane. C,H,, Hexane. 
C,H, Ethane. C,H,, Heptane. 
C,H, Propane. C,H, Octane. 
C,H,) Butane. C,H, Nonane. 
C;H,, Pentane. CG, H.. Decane, etc. (see p. 76). 


There is no known limit to these hydrocarbons, or the number of 
carbon atoms attaching themselves to each other. 
_ Formerly these hydrocarbons were designated as the hydrides of 
the corresponding monovalent radicals or alkyls: CH, (methyl), 
C,H, (ethyl), C,H, (propyl), etc. (see p. 45), because they were 
first obtained from compounds of these with other elements or 
groups. Hence the names methyl hydride for methane, ethyl hy- 
dride for ethane, etc. ‘Fhe most accessible and first known deriva-" 
tives of the alkyls, C,H,, 4,1, were their hydroxides or alcohols as 
C,H;:OH, ethyl alcohol, and the halogen ethers of the latter. : 

The following are the most important methods serving to con- 
vert the alkyl, C,H,,4,, derivatives into the corresponding hydro- 
carbons :— 

1. Treat the alkylogens, C,H, +4 Cl (readily produced from the 
alcohols, C,H,, +, OH), with nascent hydrogen. This may be done 


PARAFFINS OR ETHANES. 71 


by allowing zinc and hydrochloric acid, or sodium amalgam, to act 
upon the substance dissolved in alcohol :— 


C,H,Cl + H, = C,H, + HCl. 


Ethyl Eth ane 
Chloride. Ethyl 
Hydride. 


2. Decompose the zinc alkyl compounds with water or the mer- 
cury derivatives with hydrochloric acid (compare metallic com- 
pounds of the alcohol radicals) :— 


an OH 2H; 41 2,0 —2C,H, + Zn(OH),. 
Zinc Ethyl. Ethyl Hydride. 


A more convenient mode of preparation is a combination of both methods: 
heat the iodides of the radicals with zinc and water, in sealed tubes, to 120°—180°. 


3. A mixture of the salts of fatty acids (the carboxyl deriva- 
tives of the alkyls) and sodium or potassium hydroxide is sub- 
jected to dry distillation. Soda-lime is preferable to the last 
reagents :— 

CH,CO,Na + NaOH =CH, + Na,CO,. 


Sodium Acetate. : Methane 
Methylhydride. 


When the higher fatty acids are subjected to this treatm2nt the usual products 
are the ketones; hydrocarbons, however, are produced when sodium methylate is 
used (Ber., 22, 2133). 


The dibasic acids are similarly decomposed : — 
CO,Na 
Hi + 2NaOH = C,H, + 2CO,Na,. 
\CcO,Na 
The hydrides of the radicals obtained by the preceding methods 
were distinguished from the so-called free alcohol radicals. These 
were prepared syntheticaily, as follows :— 

. By the action of sodium (or reduced silver or copper) upon 
the ‘bromides or iodides of the alcohol radicals in ethereal solu- 
tion :— C,H; 
2C,H,I + Na, = ° + 2Nal. 

Diethyl. 
The iodides react in the same manner with the zinc alkyls :— 


C,ASN C,H; 
2C,H,I + Zn=2 | + Znl,. 
H,/ CH, 
2. By the electrolysis of the alkali salts of the fatty acids in 
concentrated aqueous solution: here, as in the decomposition of 


72 ORGANIC CHEMISTRY. 


inorganic salts, the metal separates at the negative pole, decompos- 
ing water with liberation of hydrogen, while the hydrocarbons and 
carbon dioxide appear at the positive pole :— 


CH, 
2CH,.CO,K = = | +300, + XK. 
Potassium CH, 
Acetate. Dimethyl. 


Both synthetic methods proceed in an analogous manner, if a mixture of the 
iodides of two different alcohol radicals, or the salts of different acids, be em- 
ployed :— 


CH, 
CH,I+C,H,I+Na, = |  +2Nal 
C,H, 
Propy! Methyl 
C,H, 
CHs.CO.K + GHCK = | + 200, +K, 


3 
Propyl! Ethyl. 


It is known that the hydrocarbons obtained by these different 
methods are of similar composition and similar structure. Di- 
methyl is identical with ethyl hydride (ethane) ; diethyl with methyl 
propyl or butyl hydride (butane). This is evident from a con- 
sideration of the structural formulas. Thus, normal butane, 
CH,— CH,— CH,—CH;, may be viewed as butyl hydride, 

CH. 


C,H,H, or as diethyl, | a or propyl methyl, | 
C,H, CH,.CH,CH,. 
CH 
Isobutane, ae , can be regarded as isobutyl hydride, 


CH, j CH, 


H.CH, — CH¢ or as isopropyl methyl, | , or tri- 
CH,, CH(CH,), 

methyl methane, CH(CH;);, etc. Thus, the various syntheses of a 
given hydrocarbon may be deduced from its structural formula. 

Of other synthetic methods we will yet mention the one employed 
in the preparation of quaternary hydrocarbons (p. 40). It consists 
‘in the action of the zinc alkyls upon acetone chloride and bodies 
- similarly constituted :-— 


CH CH CH CH 
mi a eat ie A age SNR «0/7 + ZnCl, 
CH?” NCH, CH,” CH, 
Acetone Zinc Tetramethyl 
Chloride. Methyl. Methane. 





The ethanes arise in the dry distillation of wood, turf, bitumi- 
nous shales, lignite and bituminous coal, and especially Boghead 


PARAFFINS OR ETHANES. 73 


and cannel coal, rich in hydrogen; hence they are also present 
in illuminating gas and the light tar oils. Petroleum contains 
them already formed. They are, from methane to the highest 
hydrocarbon, almost the sole constituents of this compound. 

~The lowest members, up to butane, are gases, at ordinary temper- 
atures, soluble in alcohol and ether. The intermediate members 
form colorless liquids of faint, characteristic odor, insoluble in 
water, but miscible with alcohol and ether. The higher members, 
finally, are crystalline solids (paraffins), soluble in alcohol, more 
readily in ether. The specific gravities of the liquid and solid — 
hydrocarbons increase with the molecular weights, but are always - 
less than that of water. The boiling points, too, rise with the 
molecular weights, and, indeed, the difference for CH, in case of 
similar structure of homologues, equals 30°, subsequently, with 
higher members it varies from 25°—13° (see p. 76). The isomer- 
ides of normal structure (p. 40) possess the highest boiling points ; 
the lowest are those of the quaternary hydrocarbons. The general 
rule is—the boiling point of isomeric compounds falls with the 
accumulation of methyl groups in the molecule. 

The paraffins are not capable of saturating any additional affini- 
ties; hence, they are not absorbed by bromine or sulphuric acid, 
being in this way readily distinguished and separated from the 
unsaturated hydrocarbons. They are slightly reactive and are 
very stable, hence, their designation as paraffins (from parum 
afinis). Fuming sulphuric acid and even chromic acid are with- 
out much effect upon them in the cold; when heated, however, 
they generally burn directly to carbon dioxide and water. When 
acted upon by chlorine and’ bromine they yield substitution pro- 
ducts :— 

CH,+ Cl, =CH,Cl + HCl, 
CH, + 4Cl,= CCl, + 4HCl. 


Other derivatives may be easily obtained by employing these 
products. 





(1) Methane, CH, (Methyl hydride), is produced in the decay 
of organic substances, therefore disengaged in swamps (marsh 
gas) and mines, in which, mixed with air, it forms fire damp. 

In certain regions, like Baku in the Caucasus, and the petro- 
léum districts of America, it escapes, in great quantities, from 
the earth. It is also present, in appreciable amount, in illu- 
minating gas. 

The synthesis of methane from CS, and CCl, was noticed upon 
page 69. It is most conveniently prepared by heating sodium 


74 ORGANIC CHEMISTRY. . py oe 
acetate, in a glass retort, with 2 parts of soda- lime : CH, CO,Na 
+ NaOH = CH, + CO,Na,. 

Methane is a colorless, odorless gas, compressible under great 
pressure and at alow temperature; its critical temperature is —82°, 
and its critical pressure 55 atm. Its density equals 8 (H —1) (or 
0.5598, air==1). It is slightly soluble in water, but more readily 
in alcohol. It burns with a faintly luminous, yellowish flame, and 
forms an explosive mixture with air :— 

CH, + 20, = CO, + 2H,0. 
rvol. 2vols. t1vol. 2 vols. 

It is decomposed into carbon and hydrogen by the continued 
passage of the electric spark. When mixed with two volumes of 
chlorine it explodes in direct sunlight, carbon separating (CH, + 
2Cl, = C + 4HCl); in diffused sunlight the substitution products 
CH,Cl, CH,Cl,, CHCl, and CCl, are produced. 

(2) Ethane, C,H, (Ethyl Hydride, Dimethyl), is a coforless and 
odorless gas, condensable at 4° and a pressure of 46 atmospheres. 
Its formation from C,H,;I, (C,H;).Zn, CH;I and CH;.CO,K cor- 
responds to the general methods. 


To prepare ethane, decompose zinc ethyl with water. It is obtained more 
conveniently by heating acetic anhydride with barium peroxide :— 


2(C,H;0),0 + BaO, = C,H, + (C,H;0,), Ba + 2C0,. 


The identity of the ethanes prepared by the various methods is ascertained. from 
their derivatives, and confirmed by their similar heat of combustion (Berichée, 14, 


501). 


Ethane is almost insoluble in water ; alcohol dissolves upwards 
of 1.5 vols. Mixed with an equal volume of chlorine it yields 
ethyl chloride, C,H;Cl, in dispersed sunlight; higher substitution 
products arise with excess of chlorine. 


(3) Propane, C,H,, ethyl methyl, occurs dissolved in crude petroleum, and 
is most conveniently formed by the action of zinc and hydrochloric acid upon the 
two propyl iodides, C,H,I. It is a gas, but becomes a liquid below 17°. Alcohol 
dissolves upwards of six volumes of it. 

(4) Butanes, C,H, (Tetranes). According to the rulesof chemical structure, 
two isomerides correspond to this formula :— 


© 
1). CH,— CH, —CH, —CH, CHL CHZ: 
(1) 3 
Norinal Biche, \cH 

Trimethyl Methane. 


1. Mormail butane (or diethyl, or propyl methyl, p. 72) occurs in crude petro- 
leum, and is obtained synthetically by the action of zinc or. sodium upon ethyl 
iodide, C,H,;I. It condenses below 0° to a liquid, boiling at + 1°. 

2. Trimethyl methane or isopropyl methyl, also termed isobutane, i is prepared 
from the iodide of tertiary butyl alcohol, (CH,),CI, by the action of zinc and 
hydrochloric acid. It condenses to a liquid at —17°. 


S-v 


PARAFFINS OR ETHANES. 75 


(5) Pentanes, C;H,,. There are three possible isomerides :— 


CH 
(1) CH, — CH; CH CH, CH,” GO) CH, ea ne 
Normal Pentane. NCH, 
B,-P. 38°: Dimethyl Ethyl Methane, 
B. P. 30°. 
(3) CH, CH, 
SC 
CH,” \cu, 
Tetramethyl Methane. 
. 20°; 


1. Normal pentane exists in petroleum and the light tar oils of cannel coal, but 
has not been obtained by synthesis, It is a liquid, boiling at 37-39°, and having 
a specific gravity of 0.626 at 17°. 

2. Lsopentane is also present in petroleum, and is obtained from the iodide of 
the amyl alcohol of fermentation. It is a liquid, boiling at’ 30°; specific gravity 
= 0.638 at 14°. 

3. Tetramethyl methane (quaternary pentane) is made by acting upon the 
iodide, (CH,),CI, of tertiary butyl.alcohol, or upon so-called acetone chloride, 


3 
Sec, with zinc methyl (comp. p. 71). It is a liquid, boiling at 9.5°, and 

CH, 

solidifying to a white mass at—-20°. The addition of methyl groups constantly 

lowers the boiling point, but facilitates the transition to the solid state—raises the 

melting point. 


(6) Hexanes, C,H,,. Five isomerides are possible :— 


Jos 
(1) CH,—CH,—CH,—CH,—CH,—CH, (2) CH,—CH;€H,—CH 


Normal Hexane. Propyl-dimethyl-methane. \cH Pe 
Dipropyl, B. P. 71°. Propyl-isopropyl, B. P. 62°. 
CH CH CH,—CH, 
(3). Once. * (4) CHeCHS 
CH ,% \CH "2 SC aaa 
Di-isopropyl, B. P. 58°. . Diethyl-methyl-methane. 
CH CH..cn: 
(Pca Sane 
CH,” CH 


3 3 
Tri-methyl-ethyl-methane, B. P. 43°-48°. 


Four of these are known. Mormal hexane, occurring in petroleum, may be 
obtained artificially by the action of sodium upon normal propyl iodide, CHj. 
CH,.CH,I; by the distillation of suberic acid with barium oxide (p. 71); and 
further when nascent hydrogen acts on hexyl iodide, C,H,,I (from mannitol). 
It boils at 71.5°, and has the specific gravity 0.663 at 17°. 

(7) Heptanes, C,H,,. Four of the nine possible isomerides are known. 

Normal heptane, CH,.—(CH,),—CH,, is contained in petroleum and the tar 
oil from cannel coal. Together with octane it constitutes the chief ingredient 
of commercial ligroine (p. 77). It is produced in the distillation of azelaic 
acid, C,H,,O,, with barium oxide. It boils at 99°. Its specific gravity at 
19° = 0.6967. ee 

(8) Octanes, C,H,,. Of the eighteen possible isomerides, two are known. 
Normal octane is present in petroleum and is obtgined from normal butyl iodide, 


76 ORGANIC CHEMISTRY. 


C,H,I, by action of sodium (hence dibutyl), also from sebacylic acid, 
C,,H,,0,, and from octyl iodide, C,H,,I. It boils at 125°, and its specific 
gravity at o° = 0.718. 

The higher homologues occur in petroleum and tar oils, but cannot be 
isolated perfectly pure by fractional distillation. The different isomerides are 
obtained according to the methods already indicated. A series of normal 
paraffins in pure condition has been prepared by the reduction of the corres- 
ponding acids, Cn HenO,, acetones, Cn HeanO, and alcohols, Cn Han + 20 (of 
normal structure). The reduction of acids to paraffins ensues when the former 
are directly heated to 200-250° with concentrated HI and amorphous phos- 
phorus; the acetones (ketones) must first be converted into the chlorides, 
Cn HenCl,, through the agency of PCl,;, and the alcohols also into chlorides, 
Cn Hon +, Cl, and alkylens, Cn Hon. ‘The higher paraffins can be readily pre- 
pared by the action of sodium upon the methyl iodides. In this way the following 
normal paraffins have been obtained (F. Krafft, Berichte, 15, 1687 and 1711; 
17, 2218). 


Melting Point. Bee. Sp. Gr.* 
MORNE So ciceisssssa Galle —5I1° 149.5° 0.7330 
ie aay a c. 0 H 22 —32° ea EM 0.7456 
Undecane............0+ toe Oe ——26,6° E | 194.5° 0.7745 
Dodecane.............-. 1 ms Oa —I12° % 214° 0.773 : 
Tridecane .......:...... Ce aeics —6,2° a. | 234° 0.775 
Tetradecane ..........- OR; Sa +4.5° g | 252.5° 0.775 
Pentadecane..,......... es Thee +10° & | 270.5° 0.775 
Piexdecane.......i..... C etisa +18° 8 | 287.5° 0.775 
Heptdecane............ gre” Ge +22.5° & | 303° 0.776 
Oetdecane...0...6i204. Ci tHe. +28° = | 317° 0.776 
Nondecane ......-..... Colao +32° — t $30" 0.777 
WAGOPRNG i560 ss cb gases ee Cogthes +36.7° 3 { 205° 0.777 
Heneicosane..........- Ci,H,, +40.4° 3 | 215° 0.778 
TIOCMRR SS id ies SPE: +44.4° & | 224.5° 0.778 
Tricosane......:...... asta +47-7° o 1) 236° 0.778 
Tetracosane...<........ ag. +-51.1° E + 243° 0.778 
Heptacosane ec cccsccecs 27 H 56 +59.5° holy 270° 0.779 
Hentriacontane........ CREF AP +68.1° = | 302° 0.780 
Dotriacontane......... C,,H¢, +70.0° | 310° 0.781 
Pentatriacontane...... Pe +74.7° gare 0.781 





The higher normal paraffins, from hexdecane, C,,H,,, forward, are solids at 
ordinary temperatures, and crystallize readily from alcohol or ether. It is very 
remarkable that the specific gravities of the higher members are almost equal at 
their melting points, consequently the molecular volumes are nearly proportional 
to the molecular weights (Berich/e, 15, 1719). Compare dzn., 223, 268. 

The highest paraffin that has yet been obtained is Hexacontane, C,,H,5., oF 
Dimyricyi. tis produced when potassium or sodium acts upon myricyl iodide, 
C,,H,,1 (from myricyl alcohol). It dissolves with difficulty in alcohol and 
ether, and separates in the form of a white powder from benzene and chloroform. 
It melts at 102°, and when distilled, even in vacuo, sustains a partial decom- 
position (Ber., 22, 502). 


The higher members of this series are contained in petroleum 
and the tar oils produced in the distillation of turf, lignite and 





* The specific gravities correspond to the temperatures at which the bodies melt (for nonane 
and decane at 0°). ‘ 


PARAFFINS OR ETHANES. 77 


bituminous coal. To isolate them in a pure condition, crude petro- 
-leum or the light tar oils are treated with concentrated sulphuric 
acid, which dissolves the non-saturated hydrocarbons, e. g., C,H», 
and those of the benzene series (in tar oil) and destroys other 
organic substances. The separated oil is further treated with fuming 
nitric acid and sodium hydroxide, washed’ with water, dried, and 
fractionated over metallic sodium. In this way a whole series of 
hydrocarbons is obtained. Two series of hydrocarbons have been 
isolated from that fraction of American petroleum that boils from 
0°-130°. The members of the first series possess normal struc- 
ture :~ 








C,H 0° 

C;Hy, 38° C5Hi2 30° 
Cove 43° Civ 61° 
C,H, 99° C,Hy, gi° 
C,H, 125° C,H. 118° 


The members, C,H. to C,,H,, (boiling at 270°), separated from 
the higher fractions, have not been obtained perfectly pure. 

Petroleum or rock-oil (naphtha) was probably produced by the 
dry distillation of coal beds, caused by the earth’s heat, or more 
probably by that of the fatty constituents of fossil animals (see 
Engler, Ber., 21, 1816). It occurs widely distributed in the upper 
strata of the earth—in Italy, Hungary, Gallicia, and in very con- 
siderable quantities in the Crimea and the Caucasus (on the shore 
of the Caspian). Its occurrence in Alsace and Hanover is not very - 
extensive. It is obtained in remarkably large quantities in North 
America (in Pennsylvania and Canada) by boring. In a crude 
condition, it is a thick, oily liquid, of brownish color, with greenish 
lustre. Its more volatile constituents are lost upon exposure to the 
air; it then thickens and eventually passes into asphaltum. The 
greatest differences prevail in the various kinds of petroleum ; it is 
only of late years that their thorough study has been commenced. 

American petroleum consists almost exclusively of normal paraf- 
fins; yet minute quantities of some of the benzene hydrocarbons 
(cumene and mesitylene) appear to be present. In a crude form. it 
has a specific gravity of o.8—-o.92, and distils over from 30—360° 
and beyond this. Various products, of technical value, have been 
obtained from it by fractional distillation: Petroleum ether, specific 
gravity 0.665-0.67, distilling about 50-60°, consists of pentane and 
hexane ; petroleum benzine, not to be confounded with the benzene 
of coal tar, has a specific gravity of 0.68—0:72, distils at 70-90%, 
and is composed of hexane and heptane; ligroine, boiling from 
go°-120°, consists principally of heptane and octane; refined 
petroleum, called also kerosene, boils from 150-300° and has a 
specific gravity of o.78-o.82. The portions boiling at higher tem- 


78 ' ORGANIC CHEMISTRY. 


peratures are applied as lubricants ; small amounts of vaseline and 
paraffins (see below) are obtained from them. 


Caucasian petroleum (from Baku) has a higher specific gravity than the Ameri- 
can; it contains far less of the light volatile constituents, and distils about 150°. 
Upwards of 10 per cent. benzene hydrocarbons (C,H, to cymene C,,H,,) may be 
extracted by shaking it with concentrated sulphuric acid; and in addition less 
saturated hydrocarbons, C, Hon_., etc., (Ber., 19, Ref. 672). These latter are also 
present in the German oils (Naphthenes, Bev., 20, 605). That portion of the 
Caucasian petroleum insoluble in sulphuric acid consists almost exclusively of 
C, Hon hydrocarbons, of peculiar constitution. They are designated naphthenes, 
octonaphthene, C,H,,, nononaphthene, C,H,, (Zer., 16, 1873; 18, Ref. 186). 

( At present they are considered identical with the benzene hexa¢hydrides (octonaph- 

~—~thene is xylene-hexahydride, nononaphthene is mesitylene hexahydride (Zer., 20, 
1850, Ref. 570). From its composition, Gallician petroleum occupies a position 
intermediate between the American and that from Baku (Azna/en, 220, 188). 

German petroleum also contains benzene hydrocarbons (extracted by sulphuric 
acid), but consists chiefly of the saturated hydrocarbons and naphthenes (Kraemer, 
Ber., 20, 545). The so-called petrolic acids are present in all varieties of petro- 
leum (see oleic acids). 


Products similar to those afforded by American petroleum, are 
yielded by the tar resulting from the dry distillation of cannel coal 
(in Scotland) and a variety of coal found in Saxony. The com- 
bustible oils obtained from the latter usually bear the names, phofo- 
gene and solar otf. Large quantities of solid paraffins are also 
present in these tar oils. 

. By paraffins, we ordinarily understand the high-boiling (beyond 
300°) solid hydrocarbons, arising from the distillation of the tar 
obtained from turf, lignite and bituminous shales. They are more 
abundant in the petroleum from Baku than in that from America. 
Mineral wax, ozokerite (in Gallicia and Roumania) and neftigil (in 
Baku), are examples existing in a free solid condition... For their 
purification, the crude paraffins are treated with concentrated sul- 
phuric acid, to destroy the resinous constituents, and then re-distilled. 
Ozokerite that has been directly bleached, without distillation, bears 
the name ceresine, and is used as a substitute for beeswax. Paraffins 
that liquefy readily and fuse between 30—40°, are known as vaselines ; 
‘they find application as salves. 

When pure, the paraffins form a white, translucent, leafy, crys- 
talline mass, soluble in ether and hot alcohol. They melt between 
45° and 70°, and are essentially a mixture of hydrocarbons boiling 
above 300°, but. appear to contain also those of the formula C, H,,. 
Chemically, paraffin is extremely stable, and is not attacked by 
fuming nitric acid. Substitution products are formed when chlo- 
rine acts upon paraffin in a molten state. 


The hydrocarbons, C,,H,,, C,,H;, and C,,H,,, were isolated from a com- 
mercial paraffin, melting at 52—54°, by fractional distillation and crystallization. 


ALKYLENS OR OLEFINES. 79 


They have been proved identical with the normal paraffins prepared artificially 
(see p. 76) 
Another paraffin, known as scaly paraffin, has been resolved into hydrocarbons 
ranging from heptdecane, C,,H,,, toC,,H,, (tricosane), Ber., 21, 2256). 
Caucasian ozokerite consists mainly of one hydrocarbon (called lekene) melting 
at 79°, and having the composition Cy Hop + , or Cp Hap (Berichte, 16, 1548). 


(2) UNSATURATED HYDROCARBONS C, Ha. 


ALKYLENS OR OLEFINES. 


C,H, Ethylene. C,H,, Hexylene. 
C,H, Propylene. C,H,, Heptylene. 
C,H, Butylene. CoH, :- Cetene. 
C;H,, Amylene. Cyotigo Melene. 


The hydrocarbons of this series contain two hydrogen atoms less 
than the first series. In their general structure, two adjacent car- 
bon atoms are united by two affinity units each—by double linking 
(see p. 42): 

CH, = CH, CH,—CH = CH, 
Ethylene. Propylene, 


Three structural cases are possible for the third member :— 


(1) CH,—CH,—CH = CH, (2) CH,—CH = CH—CH, 
Butylene. Isobutylene, 
oH, 
CH, 
Pseudobutylene. 


Five isomerides of the formula C;H,) are possible.* The most 
important general methods for the preparation of these hydro- 
carbons are :— 

(1) Distil the monohydric alcohols, C,H,,,,OH, with dehy- 
drating agents, ¢. g., sulphuric acid, chloride of zinc, and phos- 
phorus or boron trioxide. These remove one molecule of water :— 


C,H,O — H,O = C,H, 
Alcohol. Ethylene. 


The secondary and tertiary alcohols decompose with special readiness. The 
higher alcohols, not volatile without decomposition, suffer the above change when 
heat is applied to them; thus cetene, C,,H,,, is formed on distilling cetyl alcohol, 
C,H. ; 





* The ring-shaped atomic linkings, exemplified in trimethylene, C,H,, and 
tetramethylene, C,H, (see p. 42), are not included here. Their properties are 
different from those of the alkylens, and they at the same time form a transition to 
the closed ring of benzene. For this reason they will be considered after the 
fatty bodies. 


80 ORGANIC CHEMISTRY. 


When sulphuric acid acts upon the alcohols, acid esters of sulphuric acid (the 
so-called acid ethereal salts—see these) appear as intermediate products. When 
heated these break up into aca acid and Cp H,n hydrocarbons :— 


Pied C,H, 
SO 2\ OH = SO,H, + C,H, 
. Ethylene. 
Ae cies 
Acid. 


The higher olefines may be obtained from the corresponding 

alcohols by distilling the esters they form with the fatty acids. 

The products are an olefine and an acid (Berichte, 16, 3018) :— 
C,,H,,0.0.C,,H,,; =C,,H,;,0.OH+C,,H.,4 


Dodeewt Ether te Palmitic Acid. Dodecylene. 
Palmitic Acid. 


(2) The halogen derivatives, readily formed from the alcohols, are 


_ digested with alcoholic sodium or potassium hydroxide :— 


CH, CH, 
| -KOH= | + KBr 4- 1,0. 
»Br CH, 4 
Ethyl Bromide. Ethylene. 


In this reaction also, the haloid (especially the iodides) derivatives corresponding 
to the secondary and tertiary alcohols break up very readily. Heating with lead 
oxide effects the same result (Berichte, 11, 414). 


(3) Electrolyze the alkali salt of a dibasic acid (see p. 71) :— 
CH 00 nC: 
bu,-co,x CH, 


Potassium . 
Succinate. 
This reaction is perfectly analogous to the formation of the dialkyls 
from the monobasic fatty acids (see p. 72). 
(4) The olefines also result, on heating some of the dihalogen 
compounds, C,H,,X., with sodium :— 


CH,Cl CH, 
ie 4 Na, = 2NaCl + I 
H,Cl CH 
- Ethylene Chloride, Ethylene. 


The olefines can be prepared synthetically according to methods 
similar to those employed with the normal hydrocarbons (see p. 69). 


The formation of higher alkylens in the action of lower members with tertiary 
alcohols or alkyl-iodides is noteworthy. Thus, from tertiary butyl alcohol and 
isobutylene, with the assistance of zine chloride or sulphuric acid, we get 
isodibutylene, (Azzalen, 189, 65) :— 

(CH;),C - OH + CH, : C(CHg), = (CH,)3C . CH : C(CH;), + H,0. 


Isodibutylene, 


y ss 
ALKYLENS OR OLEFINES. 81 


Tetramethy] ethylene (Berichte, 16, 398) is singularly produced on heating 6-isoamy- 
lene (see p. 85) with methyl] iodide and lead oxide :— 


(CH,),C ¢ CH . CH, + CH,I = (CH,),C : C(CH,), + HI. 
In the dry distillation of many complicated carbon compounds, 


the olefines are produced along with the normal paraffins, hence 
their presence in illuminating gas and in tar oils. 





As far as physical properties are concerned the olefines resemble 
the normal hydrocarbons ; the lower members are gases, the inter- 
mediate ethereal liquids, while the higher (from C,H; up) are 
solids. Generally their boiling points are a few degrees higher than 
those of the corresponding paraffins. 

Being unsaturated, they can unite directly with two univalent 
atoms or groups; then the double binding becomes single. 
With chlorine, bromine and iodine they combine directly: 
CH, CH,Br 
|| + Br,=|]| , forming oily liquids; hence the designation 

; H.Br 

of ethylene as olefiant gas, and that of o/efines for the entire 
series. The liquid olefines react very energetically with bromine ; 
on this account they should be cooled and diluted with ether. 

Concentrated sulphuric acid absorbs them, forming ethereal 
salts :— 


C,H, -+ SO,H, = SO Mince 
2-4 4°°2 *\ OH - 


Very often the absorption takes place only at high temperatures. 


They combine, too, directly with HCl, HBr and with especial 
readiness with HI. 
They yield so-called chlorhydrins with aqueous hypochlorous 
acid :— 
CH, CH,Cl 


fh 4+ Clon = I 
CH H,OH. 


Nascent hydrogen (zinc and hydrochloric acid, or sodium amal- — 
gam) converts the olefines into the saturated hydrocarbons : 
C,H, aa Hy os Cis 

Concentrated hydriodic acid effects the same if aided by heat, 
and, especially, when phosphorus is present. The iodide formed 
_at first is reduced by a second molecule of HI :— 

CH, + HI = Gj and 
C,H,I ++ HI = C,H, +1,. 


82 ORGANIC CHEMISTRY. 


Oxidation of Olefines. It has been generally supposed that when 
the olefines were exposed to the action of oxidizing agents (e. g., 
potassium permanganate, and chromic acid), they were split up 
at the point of their double union (4mm., 197, 225). The most 
recent research, however, has demonstrated that two hydroxyl 
groups always result, thus giving rise to the formation of dihydric 
alcohols (see these) (Wagner, Ber., 21, 1230 and 3359) :— 


CH,.0OH 
C,.H,+0+0= b 
H,.OH. 


The unsaturated alcohols and acids are similarly oxidized. Potassium per- 
manganate is without action upon trimethylene. 


Polymerization of Olefines. When acted upon by dilute hydro- 
chloric acid, zinc chloride, boron fluoride and other substances, 
many olefines sustain, even at ordinary temperatures, a polymeri- 
zation, in consequence of the union of several molecules. Thus 
there result from isoamylene, C;H,,: di-isoamylene, C,H. ; tri- 
isoamylene, C,;H,, etc., etc. Butylene and propylene behave in 
the same way. Ethylene, on the other hand, is neither condensed 
by sulphuric acid nor by boron fluoride. The polymerides act like 
unsaturated compounds, and are capable of binding two affinities. 


The nature of the binding of the carbon atoms in polymerization is, in all 
probability, influenced by the different structure of the alkylens. The manner of 
formation and structure of the isodibutylene produced from isobutylene corres- 
pond to the formulas :-— 

(CH,),C + CH, +°CH, : C(CH,), =(CH,),C-CH : C(CH,),. 
2 Mols. Isobutylene. Isodibutylene. 

Tertiary butyl alcohol very probably figures as an intermediate product, and 
afterwards unites with a second molecule of isobutylene, and condenses to iso- 
dibutylene. 

Although ethylene suffers no alteration, yet its substitution products polymerize 
very readily. 

Methylene, CH,, the first member of the series C, Hn, does not exist. In 
all the reactions in which it might be expected to occur, for instance, when copper 
acts on methylene iodide, CH, I,, we obtain only polymerides; ethylene, C,H,, 
propylene, C,H,g, etc. 


(1) Ethylene, C,H, (olefiant gas), is formed in the dry distillation 
of many organic substances, and is, therefore, present in illuminating 
gas (6 per cent.). It is best prepared by the action of sulphuric 
acid upon ethyl alcohol. 


A mixture of I vol. 80 per cent. alcohol and 6 vols. sulphuric acid is permitted 
to stand for awhile, then heated, in a capacious vessel, upon a sand bath. The 
foaming may be prevented by the addition of sand. The liberated gas is conducted 
through a vessel containing potassium hydroxide, to remove CO, and SO,, and, 
finally, collected over water (Anma/len, 192, 244). 


ALKYLENS OR OLEFINES. 83 


Ethylene is a colorless gas, with a peculiar, sweetish odor. Its 
sp. gr. equals 14(H=r1). Water dissolves but small quantities 
of it, while alcohol and ether absorb about 2 volumes. It is lique- 
fied at o°, and a pressure of 42 atmospheres. At ordinary pressure 
it boils at —1o5°, and is suitable for the production of very low 
temperatures. It burns witha bright, luminous flame, decomposing 
into CH,and C. In chlorine gas the flame is very smoky; a mix- 
ture of ethylene and chlorine burns away slowly when ignited. It 
forms a very explosive mixture with oxygen (3 volumes). 

When in alcoholic solution ethylene combines readily with 
chlorine, bromine and iodine. Fuming hydriodic acid absorbs 
it with formation of C,H;I. Aided by platinum black it will 
combine with H, at ordinary temperatures, yielding C,H,. At the 
ordinary temperature it combines with sulphuric acid only after 
continued shaking; the absorption is, however, rapid and com- 
plete at 160-174°. By boiling the resulting ethylsulphuric acid 
with water we can get alcohol. Potassium permanganate oxidizes 
ethylene first to ethylene glycol, C,H,(OH), (p. 82), and then to 
oxalic and formic acids. 

(2) Propylene, C;H,—=CH;.CH : CH,, is obtained from many 
organic substances, ¢. g., amyl alcohol, when their vapors are 
conducted through red-hot tubes. Propyl and isopropyl iodide 
are converted into it when boiled with alcoholic potash :— 


C,H,I + KOH =C,H, + KI + H,0O. 


The same end is achieved by the action of nascent hydrogen 
(zinc and hydrochloric acid) or hydriodic acid upon allyl iodide :— 


C,H,I + HI =C,H, + I. 


Preparation.—\. Digest a mixture of 80 gr. isopropyl iodide, 50 gr., 95 per 
cent. alcohol, and 50 gr. KOH upon a water bath; at 40-50° a regular stream of 
propylene escapes. 2. A solution of allyl iodide in glacial acetic acid, or, better, 
one in alcohol, is allowed to drop upon granulated zine (Ber., 6, 1550). 


Propylene is a gas, liquefiable under great pressure. It combines 
directly with the halogens and their hydrides. Concentrated 
H,SO, dissolves it with formation of isopropyl sulphuric acid and 
polymeric propylenes (C;H,),. It dissolves in concentrated HI, 
yielding isopropyl iodide :— 


CH, — CH = CH, + HI = CH, — CHI — CH,. 


Trimethylene, C,H,, isomeric with propylene, is obtained from trimethylene 
bromide (see p. 102), by aid of sodium, Unlike propylene, it unites with difficulty © 
with bromine to trimethylene bromide, and with HI to normal propyl iedide. It 
appears to contain a closed carbon chain (see p. 42), and, with its derivatives, is 
considered after the fatty bodies. 


84 ORGANIC CHEMISTRY. 


(3) Butylenes, C,H,.—Theoretically, three isomerides are possible :— 


CH..CH,.CH;:CH, CH,.CH:CH.CH,;. “(CH,),C:CH,. 


a-Butylene B-Butylene Isobutylene. 


(1) a-Butylene (normal Butylene) is formed from normal butyl iodide, 
CH, . CH, . CH, . CH,I, by aid of alcoholic potash; and also from brom- 
ethylene and zinc-ethyl: 2CH, : CHBr + (C,H,),Zn = 2CH, : CH.C,H, 
+ ZnBr,. In the cold it condenses to a liquid, boiling at —5°. With HI, 
it forms secondary butyl iodide, CH, . CH, . CHI . CH;. Its bromide, 
C,H,Br,, boils at 66°. 

(2) B-Butylene (pseudo-butylene) results from secondary butyl iodide (see 
above) and alcoholic potash or mercuric cyanide; also (together with isobutylene) 
from isobutyl alcohol, in which case there occurs a molecular transposition. It 
boils at + 1° and solidifies on cooling. It yields secondary butyl] iodide with HI. 
Its bromide, C,H, Br,, boils at 159°, and is changed by alcoholic potash to crotony- 
lene, CH, .C: C.CH, (p. 89). See Ann., 250, 252, for the geometrical isomerides 
of pseudobutylene. 

(3) Zsobutylene is obtained from isobutyl iodide, (CH,), CH . CH,I, and ter- 
tiary butyl iodide, (CH,),Cl . CH,, when alcoholic potash acts upon them; 
further from isobutyl alcohol, (CH,), .CH . CH,OH, when heated with zinc 
chloride or sulphuric acid. Pseudo-butylene appears at the same time (Zerichée, 
13, 2395 and 2404, 16, 2284). For a method of separating these two butylenes, con- 
sult Ber., 19, Ref. 554. It boils at — 6° and dissolves in sulphuric acid (diluted 
one half with water), forming butyl-sulphuric acid. The latter yields trimethyl 
carbinol, when boiled with water. Concentrated HI absorbs isobutylene with 
formation of tertiary butyl iodide. Its dromide boils at 149°. Potassium perman- 
ganate oxidizes isobutylene to its glycol, (CH,), . C(OH) . CH,(OH) (p. 82). 

When isobutylene is digested with H,SO, and H,O (equal volumes) it becomes 
isodibutylene, (CH,),C . CH : C(CH,)., boiling at 130° (see p. 81). 

(4) Amylenes, C,H, ,.—Five isomerides are theoretically possible :— 


(1) CH, .CH, . CH, . CH: CH,. (2) CH, . CH, .CH: CH. CH. 


a-Amylene, Normal Propy! Ethylene. B-Amylene, Ethyl] Methyl Ethylene. 
(3) >CH . CH : CH, (4). DC: CH . CH, 
CH CH, 
Sctéoain viene, Isopropyl Ethylene. B-Isoamylene, Trimethy] Ethylene. 


CH 
(5). a : CH,. 


H 
: 2°" 5 
y-Amylene, Unsym. Ethyl Methylethylene. 


(1) a-Amylene, C,H, . CH: CH, (normal amylene, propylethylene), has not 
yet been prepared in a pure condition; it appears to be that part of ordinary 
amylene (see below) which is insoluble in sulphuric acid, boils about 37° and is 
oxidized by a KMnO, solution chiefly to butyric and formic acids (Annalen, 
197, 253). It unites with HI to the iodide, C,H, . CHI . CHa, boiling at 144°. 

(2) B Amylene, C,H, . CH : CH . CH, (sym. ethylmethyl-ethylene), is 
produced from the iodide of diethylcarbinol, C,H, .CHI.C,H,, boiling at 
145°. The boiling point of f-amylene is 36°; with HI it yielas the same 
iodide as a-amylene. Its bromide, C;H,,Br,, boils at 178°. 

(3) a-Lsoamylene, (CH,),CH.CH:CH, (isopropyl ethylene), is formed together 
with y-amylene, from the iodide of the amyl alcohol of fermentation (see this), by 
the action of alcoholic potash (duna/en, 190, 351). A mixture of these two 


ALKYLENS OR OLEFINES. 85 


amylenes results, and boils at 23-27°. On shaking with cold H,SO, (diluted one- 
half with water) the y-variety dissolves, leaving a-isoamylene unaltered (about 60 
per cent. of the mixture). Similarly, by action of HI (or H Br) upon the mixture 
at—z20°, y-amylene is changed to the iodide, while a-amylene is not affected. 
It yields propyl-ethylene glycol when oxidized with potassium permanganate. 
Isoamylene boils at 21.1°-21.3°. It does not unite in the cold (below 0°) with 
H,SO,, HI, or HBr. At ordinary temperatures it combines gradually with 
Hi, HBr, and HCl, yielding derivatives of methyl isopropyl carbinol, (CH,),. 
CH.CHX. CH. 

(4) B-Lsoamylene, (CH,)4.C:CH.CH, (trimethyl ethylene) produced from 
the iodides of methyl isopropyl carbinol, (CH,),CH.CHI.CH,, and dimethyl- 
ethyl carbinol, (CH,),.CI.CH,.CH,, boils at 36-38°. At ordinary temperatures 
it reunites with HI to the iodide, (CH,),.CI.CH,.CH,. It combines readily, 
in the cold, with sulphuric acid to the sulphuric ether, and the latter, when boiled 
with water, affords dimethyl-ethyl carbinol, (CH, ),.C(\OH).CH,CH,. 


8-Isoamylene is the chief ingredient of the ordinary amylene 
obtained from fermentation amyl alcohol by distillation with zinc 
chloride. (See Annalen, 190, 332.) The product, boiling about 
25-40°, is a mixture of f-isoamylene (50 per cent.) with pentane 
(boiling about 29°) and probably contains, in addition, y-amylene 
and also a-amylene. On shaking crude amylene in the cold 
(—20°) with sulphuric acid, diluted with %-1 vol. of H,O, the 
f-isoamylene dissolves (also any y-amylene that may be present) to 
amyl-sulphate, which yields dimethyl-ethyl carbinol, (CH,),. 
C(OH).CH,.CH;. The chief constituents of the undissolved oil 
are pentane and a-amylene, which are oxidized by KMnO, to 
butyric and formic acids (see above). 


On shaking ordinary crude amylene with H,SO, (diluted with % vol. water), 
without cooling, polymeric amylenes are produced: diamylene, C,,H,,, boiling 
at 156°, triamylene, C,H, ,, boiling at 240-250°, and tetramylene, boiling about 
360°. All these are oily liquids, which combine with bromine, 


H, \ 
2H” 
(40 per cent.) in crude amylene, obtained from the iodide of fermentation amyl 
alcohol (see above 3), hence, very probably also present in ordinary amylene. It 


(5) y-Amylene, C:CH,, (unsym. methyl-ethyl ethylene), is contained 


very likely comes from the‘active alcohol, " CH.CH 2-OH, present in the 


fermentation alcohol, although itself not active, It cannot be isolated because of its 
very ready union with H,SO, and HI, even in the cold. Both the sulphuric acid 
ether from it and the iodide yield tertiary amyl alcohol. The iodide of active amy] 
alcohol furnishes an amylene boiling at 31° (Le Bel). This is probably pure 


y-amylene. It gives the chloride,  CCLOHKgs with HCl. This boils at 


87°, and decomposes with alcoholic potash into 6-isoamylene. 


Various higher olefines have been prepared from the correspond- 
ing alcohols. The highest can be made by the distillation of the 


86 ORGANIC CHEMISTRY. 


esters derived. from the alcohols and the higher fatty acids (p. 80). 
In this way the following olefines of normal structure have been 
prepared : 


Melting Point. B.P.at15 mm. Sp. Gr. 
Dodecylene ..........0s0e« Be —31.5° 96° 0.7954 
Tetradecylene ...... ods aay: 28 —I2° 127° 0.7936 
Hexadecylene............ Citi +4° 154° 0.7917 
Octodecylene............4 Gi,8y, +18° 179° 0.7910 


Hexadecylene, C,,H;,, is sometimes called cetene; it was first ob- 
tained from cetyl alcohol, and at ordinary temperatures boils about 
‘240°. Cerotene, from Chinese wax, melts at 58°, while melene, 
C3>H 9, from ordinary wax, melts at 62°. 





(3) HYDROCARBONS C, Hon —2, 


ACETYLENE SERIES. 


C,H, Acetylene. C,H, Valerylene. 
C,H, Allylene. C,H,, Hexoylene. 
C,H, Crotonylene. 


The above hydrocarbons, differing from the normal C,H,, +, by 
four atoms of hydrogen, may be based upon two structurally differ- 
ent but possible formulas. In one case we assume a triple union of 
two neighboring carbon atoms— 


CH=CH CH,—C=CH 
Acetylene. Allylene. 


while in the second a double union occurs twice— 


CH,=—C=—CH, CH, = CH—CH,—CH,—CH = CH,, 
Isomeric Allylene. Diallyl. 


‘This structural difference is abundantly manifest in the varying 
chemical behavior, since only members of the first class (having 
the group =CH) that can be regarded as true acetylenes, possess the 
power of entering into combination with copper and silver, thereby 
yielding derivatives in which the H of the group =CH is replaced 
by metals. 


These compounds result from the action of acetylene upon ammoniacal silver 
nitrate and cupric chloride solutions (p. 87). The silver derivatives are obtained 
without difficulty by using an alcoholic solution of silver nitrate (Ber., 21, Ref. 


). Gu 
Diolefines, such as diallyl (see above), do not form copper and silver compounds, 
but produce precipitates with mercury sulphate and chloride in aqueous solution 
(Ber., 21, Ref. 185 and 717, and allylene, p. 89). 


ACETYLENE SERIES. 87 


The hydrocarbons of this series are produced according to the 
same methods as those of the ethylene series. They are formed on 
heating the haloids, C,H,, _, X (corresponding to the alcohols of 
the allyl series) and C,H,,X,, with alcoholic potash; in the latter 
case the reaction proceeds in two phases— 


CH,Br CHBr 
4+KOH=|| +KBr+H,0 
CH,Br CH, 

and CHBr CH 


| +KOH=|]| + KBr+4H,0. 
CH 


2 


If the heating with alcoholic potash be too violent the acetylene which has 
formed frequently sustains a ¢ransposition ; thus, ethyl acetylene, C,H;.C=CH, 
yields dimethyl acetylene, CH,. C=C. CH,, and propyl acetylene, C, i he * CCH, 
furnishes ethyl methyl acetylene, C,H;.C=C. CH,, etc. (Ber., 20, Ref. 781). 

The reverse transposition sometimes occurs on heating with metallic sodium : 
ethyl methyl acetylene passes into propyl acetylene, and dimethyl allene, (CHs), 
C = C=CH,, yields isopropyl! acetylene, etc. (Ber., 21, Ref. 177). 


Acetylenes also arise in the electrolysis of unsaturated dibasic 
acids (compare p. 80). 


CH.CO,H CH 
| =| + 2CO,+ H,. 
CH.CO,H CH 


Fumaric Acid. Acetylene. 


As unsaturated compounds of second degree, the hydrocarbons 
C,H,,. are capable of adding to themselves four affinity units. 
Hence they unite with one and two molecules of the halogens and 
their hydrides. ‘Thus acetylene forms C,H,Br, and C,H,Br, They 
are absorbed by concentrated sulphuric acid with the formation of 
sulphuric ethers ; condensation occurs at the same time. Nascent 
hydrogen converts them into the hydrocarbons C,H, and 


CH + 2° 


In the presence of HgBr, and other salts of mercury, the acetylenes can unite 
with water. In this way we get from acetylene, aldehyde, C,H,O, from allylene, 
C,H,, acetone, C, H,O, from valerylene, C,H,, a ketone, C -H,,0 (Berichte, 14, 
1542 and 17, 28). “Very often moderately dilute sulphuric acid will act in the 
same way (see Allylene). 


A characteristic of the true acetylenes is their power to yield 
solid crystalline compounds by the action of ammoniacal solutions 
of silver and copper salts. Hydrochloric acid will again liberate 
the acetylenes from these salts. This behavior affords a very con- 
venient method for separating the acetylenes from other gases, as 
well as obtaining them in a pure condition. 


eae ORGANIC CHEMISTRY. 


Like the alkylens (p. 82) the acetylenes condense, and in this manner we 
very frequently obtain bodies that belong to the benzene series. At a red heat 
benzene, C,H,, is obtained from acetylene, C,H,; mesitylene, C,H,, (trimethyl- 
benzene, C,H, (CH ada): from allylene, C,H,, by the action of sulphuric acid, and 
hexamethyl benzene, C,H), (see p. 89), from crotonylene, C,H,. 





Acetylene, C,H,, is formed when many carbon compounds, like 
alcohol, ether, marsh gas, methylene, etc., are exposed to intense 
heat (their vapors conducted through tubes heated to redness). 
Hence it is present in illuminating gas, to which it imparts a 
peculiar odor. Its direct synthesis from carbon and hydrogen is 
described on p. 70; acetylene results, too, in the decomposition of 
calcium carbide by water. Its formation in the electrolysis of the 
alkali salts of fumaric and maleic acids is significant :-— 


C,H,(CO,H), = C,H, + 2CO, + H,. 
It is produced when silver, copper or zinc dust acts upon iodoform. 


Preparation—1. Ethylene bromide, C,H,Br,, is heated with two parts of 
KOH and strong alcohol, in a flask provided with an upright condenser. The 
escaping gas is conducted through an ammoniacal silver solution, the precipitate 
washed with water and decomposed by hydrochloric acid (Annalen, 191, 368). 
2. Let the flame of a Bunsen burner strike back, 2. ¢., burn within the tube, and 
then aspirate the gases through a silver solution (Berthelot’s apparatus), 


Acetylene is a gas of peculiar, penetrating odor, and may be 
liquefied at + 1° and under a pressure of 48 atmospheres. It is 
slightly soluble in water; more readily in alcohol and ether. It 
burns with a verysmoky flame. The color of the copper compound, 
C,HCu.CuOH, is red, while that of the silver derivative, C,HAg.Ag 
OH, is white ; their composition is not definitely established. When 
heated, both explode very violently. When acetylene is conducted 
through ammoniacal silver chloride, a white, curdy precipitate, 
-C,HAg. AgCl, is thrown out of solution. Sodium heated in acety- 
lene gas disengages hydrogen, and we obtain the compounds C,H Na 
and C,Na,. 

Nascent hydrogen (zinc and ammonia) converts acetylene into 
C,H, and C,H,; and when hydrogen and acetylene are ona over 
platinum black, C,H,, is formed. 


Acetylene reacts very energetically with chlorine gas. It forms a crystalline 
compound with. SbCl,, but heat changes this to dichlor-ethylene, CHCl : CHCl 
and SbCl,. With bromine it forms C,H,Br, and C,H,Br,. 

Monochlor-acetylene, C,HCl, obtained from dichloracrylic acid, is an explo- 
sive gas. 


ACETYLENE SERIES. 89 


secetletaadein: C,HBr, obtained by boiling acetylene dibromide with 
alcoholic potash, is a gas that inflames in contact with air. Below 0° it condenses 
to a liquid, which on ¢xposure to the light polymerizes to a yellow powder. The 
latter contains symmetrical tri-brom-benzene, C,H,Brs. 

Mono-iodo-acetylene, C,HI, results on boiling iodopropargylate of barium 
with water. It is an gil with a very disagreeable odor. It solidifies on cooling. 
When preserved it polymerizes to tri-iodo-benzene, C,H,I, ( Ber., 18, 2274). 

Di-iodo-acetylene, C,I,, results from the action of iodine upon thé silver 
compound of acetylene, It melts at 78°. It is very readily decomposed when 
exposed to a higher heat. In the light it polymerizes to hexa-iodo-benzene, C,Ig. 


*Allylene, C,H,>¢CH;—C=CH. This is produced by the 
action of alcoholic potash upon monochlor-propylene, CH,. 
CCl: CH,, and by heating dichloracetone chloride, CH;.CC\,. 
CHCl, with sodium; further, in the electrolysis of the alkali salts 
of.mesaconic and citraconic acids. It is very similar to acetylene. 
Its copper compound is siskin green in color ; the silver derivative, 
C,;H;Ag, is white. Allylene forms the compound (C;H;),.Hg with 
mercuric oxide. This crystallizes from alcohol in brilliant needles ; 
acids decompose it into allylene and a mercury salt. With bromine 
we get the liquid bromides, C;,H,Br, and C,;H,Br,; and with two 
molecules of the halogen hydrides the compounds CH;.CX,.CH3. 

Allylene is soluble in concentrated sulphuric acid. A large 
quantity of acetone is produced by diluting this solution with. 
water ; but on distilling it the allylene condenses to mesitylene ; 
3C;H,= C,H,,, a benzene derivative, In the presence of mercury 
salts, allylene combines with water to form acetone (see p. 87). 





Isomeric Allylene, CH,:C:CH,. This does not unite with copper and silver. 
It is produced by the electrolysis of potassium itaconate; by the action of sodium 
upon dichlor-propylene, C,;H,Cl, (from dichlorhydrin, see glycerol), or of zinc 
dust and alcohol upon dibrom-propylene, C,H,Br, (from tribromhydrin) (Zer., 
21, Ref. 717). It forms precipitates in aqueous solutions of mercuric sulphate or 
chloride (p. 86). Sulphuric acid and water convert it into acetone, and when, 
heated with sodium to 100° it passes into allylene. With bromine it forms a tetra- 
bromide, C,H,Br,, crystallizing in leaflets and melting at 195°. 

Crotonylene, C,H,, Valerylene, C;H,, Hexoylene, C,H,,, or Butine, Pentine 
Hexine, etc., are the higher members of the series Cag Hon _ 

Crotonylene,CH ae : C.CH,—dimethyl acetylene (4mn.,250, 252), is a strong 
smelling liquid obtained from the bromide of pseudo-butylene, CH,.CH:CH.CH,, 
by the action of alcoholic potash. Its boiling point is 180°. When it is shaken 
with sulphuric acid (diluted 14 with water), it is converted into solid hexamethyl 
benzene, C,(CH,),, melting at 164° :— 


3C,H, = C,.Hig = Cy (CH). 


Diallyl, CH,:CH.CH,.CH,.CH:CH,, is produced when silver or sodium acts 
upon allyl iodide (see p. 98), and by distilling allyl mercury iodide, C,H, Hel, 
with potassium cyanide. It boils at 59°, and when oxidized with KMnQ, yields 
two isomeric diglycols, C,H,, (OH), (Ber., 21, 3344). It forms two tetrabromides, 
C,H,,Br,, the crystalline melting at 63°, and the other a liquid (4er., 22, 2497). 
As it does not contain the group =CH, it forms no metal derivatives. Higher 

8 “4 


go ORGANIC CHEMISTRY. 


members have been obtained from the dibromides of the higher alkylens (p. 86), 
Ber., 17, 1374 — 


M. P. Eppley Sp. gr. 
Dodecylidene,. ... . . . . CypHo —9° 105° 0.8097 
“OTRO ECVGENG, i253) 5. + oy Cio, +6.5° 134° 0.8064 
seexadecyndene, . oc, . .; 3 Gygllyn 20° 160° 0.8039 
Octadecylidene, ..... . Cities 30° 184° 0.8016 


(4) HYDROCARBONS C, Hons 


Various bodies of this series have been obtained from the tar oil (from cannel 
coal) boiling as high as 300°. In all probability they result from the polymeriza- 
tion of the hydrocarbons C, Hy» _ 2, contained in the coal tar, through the agency 
of sulphuric acid. 

The lowest member of this series would be vinyl acetylene, C,H, — CH,:CH.C 
: CH. It has not been isolated. Its homologue is 

Valylene, C,H,, with the structure CH,.CH:CH.C : CH or CH,:C (CH,). 
Ci CH. This is obtained from valerylene dibromide, C,H,Br, by the action of 
alcoholic potassium hydroxide. It boils at 50°, and has an alliaceous odor, It 
forms precipitates with ammoniacal copper and silver solutions, and yields the 
hexabromide C,H, Br,, with 6 atoms of bromine. 

_ The terpenes, C,,H,,, are hydrogen addition products of benzene compounds, 
and are homologues of the hydrocarbons just described. 


(5) HYDROCARBONS C, Hay - , 


_ Diacetylene, C,H, — HC : C.C : CH, is formed from diacetylene dicarbonic 
acid on heating its copper salt with potassium cyanide. It isa gas that yields a 
yellow precipitate with an ammoniacal silver solution. Jodine converts the silver 
compound into di-iodo-diacetylene, C,I,, a colorless, crystalline body, melting at 
1o1°. It has an odor like that of iodoform. It explodes when heated. 

- Dipropargyl, C,H, —CH :? C.CH,.CH,.C ? CH. This is isomeric with ben- 
zene, ‘but its properties are entirely different. On warming solid crystalline dially1- 
tetrabromide, C,H,,Br, (see above), with KOH, there is formed dibrom-diallyl, 
C,H,Br, (together with a little dipropargyl), a liquid boiling at 205-210°. - On 
treating the latter compound with alcoholic potash we obtain dipropargyl, C,H,. 
This is a very mobile liquid, of penetrating odor, and boiling at 85°; its specific 
gravity at 18° equals 0.81. 

The compound C,H,Cu, + 2H,O, which it forms with ammoniacal copper 
solutions is siskin yellow in color; that with silver, C,H,Ag, + 2H,0, is white, 
but blackens on exposure to the air. Acids again liberate dipropargyl from 
these, 

._ If dipropargyl be allowed to stand, or if heat be applied to it, it polymerizes 
and becomes thick and resinous. It unites energetically with bromine to C,H, 
Br, and C,H, Br, ; the latter melts at 140°. 

Dimethyl Di-acetylene, CH,.C=C.C=C.CH,, is the second isomeride of 
benzene. It has been obtained from the copper derivative of allylene, CH. 
C—C.Me. It melts at 64° and boils at 130° (Ber., 20, 564). 


HALOGEN DERIVATIVES OF THE HYDROCARBONS. 


_ The halogen substitution products result from the replacement of 
hydrogen in the hydrocarbons by the halogens. In general charac- 
ter they resemble the compounds from which they have their origin. 


ACETYLENE SERIES. gf 


The following are the most important methods for their prepara- 
tion :— 

(1) By direct action: of the halogens upon the hydrocarbons, 
when one or all the hydrogen atoms will suffer replacement, the 
hydrides of the halogens forming at the same time :— , 


Ca Hm -- xCl. = Ca Hm — x Clix + xHCl. 


The action of chlorine is accelerated, and very often also dependent upon direct 
sunlight, or the presence of small quantities of iodine. It is the IC1,, which arises in 
the latter case, that facilitates the reaction. SbCl, also plays the réle of a chlorine 
carrier, since upon heating it yields SbCl, and 2Cl. Ferric chloride serves as an 
excellent chlorine and bromine carrier (Auz., 225, 196 and 231, 132).. Whenthe 
chlorination is very energetic a rupture of the carbon linking takes place (Berichte, 
8, 1296, 10, 801). Heat hastens the action of bromine. Usually iodine does not 
replace well, inasmuch as the final iodine products sustain reduction through the 
hydriodic acid formed simultaneously with them :— 


C,H,1 +HI=C,H, + I,. 


‘In the presence of substances (like HIO, and HgO) capable of uniting or de- 
composing HI, iodine frequently effects substitution :— 


5C,H, + 21, + IO, H = 5C,H,I + 3H,0, 
2C,H, +21, + HgO =—2C,H,I+ H,0+ Hgl,. 
And in the presence of ferric chloride iodation occurs with the liberation of 
hydrogen chloride (Azz., 231, 195). 
In direct substitution a mixture of mono- and poly-substitution products gen- 
erally results, and these are separated by fractional distillation or crystallization. 


(2) By adding halogens to the unsaturated hydrocarbons :— 
CH, CH,Cl 
Cl, = 
ba * z dct 


At ordinary temperatures, chlorine and bromine react very vio- 
lently ; in the absence of light the action is more regular, and when 
it is present, substitution products also arise. Iodine (in-alcoholic 
solution) generally enters combination only upon application of 
heat. 

(3) Byadding halogen hydrides to the unsaturated hydrocarbons. 
In concentrated aqueous solution, HI reacts very readily :— 


CH,.CH:CH, ++ HI = CH,.CHLCH,. 


Here again we observe the common rule that the halogen atom almost invariably 
attaches itself to the least hydrogenized carbon atom (Anna/en, 179, 296 and 325). 
Sulphuric acid attaches itself similarly (p. 81). The reaction proceeds in accord- 
ance with the principle of the greatest heat evolution (Ber., 21, Ref. 179). 


(4) By replacing the hydroxyl groups of the alcohols C, H,, +; OH 
by halogens. This is the most convenient method of preparing the 


92 ORGANIC CHEMISTRY. 


mono-halogen products, as the alcohols are very readily obtained. 
The transposition is brought about by heating the alcohol pre- 
viously saturated with the halogen hydride :— 


: C,H,.0H + H Br =C,H,Br + H,0. 


This rearrangement between the two reacting compounds is, how- 
ever, not complete. It depends very much on the mass of the 
substances reacting, and upon the temperature (compare esters of 
mineral and fatty acids). The alteration is most speedy with HI; 
however, transpositions sometimes occur in this case, in the higher 
alcohols. See p. 95. 

The change is most —. when effected v8 the halogen pro- 
ducts of phosphorus :— 


C,H,.OH+PCl, =C,H,Cl + PCI,0+ HCl, 
3C,H,.OH + PCI,O — 3C,H,Cl + PO(OH),, 
3C,H,.OH + PCl, =3C,H,Cl-+ PO,H,. 


Even here the reaction is not. perfect. Phosphoric and phos- 
phorous acids are formed, and these convert a portion of the alcohol 
into ethereal salts, which constitute the residue after distilling off 
the halogen derivatives. 

(5) By the action of PCl, and PBr, upon the aldehydes and 
ketones, when an atom of oxygen is replaced by two halogen 
atoms :— 

CH,CHO + PCl, =CH,.CHCI, + PCI,0, 


‘Aldehyde, 
CH,\ CH > 
Wetolie. 





The halogen derivatives prepared according to these methods 
are partly identical, as will be seen further on, and partly isomeric. 
They are generally colorless, ethereal smelling liquids, zwsoludle 
in water. The iodides redden in sunlight, iodine separating. The 
chlorides and bromides burn witha green-edged flame. 

Nascent hydrogen (zinc and hydrochloric acid or glacial acetic 
acid, sodium amalgam and water) can reconvert all the halogen 
derivatives, by successive removal of the halogen atoms, into the 
corresponding hydrocarbons :— 


CHCl, + 3H, — CH, + 3HCL. 


When the mono-halogen compounds are heated with moist silver 
oxide, the corresponding alcohols are produced :— 


C,H,I + AgOH = C,H,.0H + Agl. 


HALOGEN COMPOUNDS. 93 


Alcoholic sodium and potassium hydroxides occasion the splitting 
off of a halogen hydride, and the production of unsaturated com- 
pounds: (pp. 80, 87) :— 


CH,.CH,.CH,Br + KOH = CH,.CH:CH, + KBr + H,0. 
Propyl Bromide. Propylene. 


In this reaction the halogen attracts to itself the hydrogen of the least hydro- 
genized adjacent carbon atom (compare p. 91). Such a splitting sometimes occurs 
on application of heat, and it appears that the primary alkylogens are more easily 
decomposed than the secondary and tertiary (see p. 94). 


(1) HALOGEN COMPOUNDS—Cy Hop + 1X. 


ALKYLOGENS. 


Because of their formation from the alcohols by the action of the 
halogen hydrides, the alkylogens are called haloid esters. They are 
perfectly analogous to the true esters produced by the action of 
alcohols and oxygen acids. 

Monochlormethane, CH;Cl, Methyl chloride, is obtained 
from methane or methyl alcohol. At ordinary temperatures it is a 
gas, that may be condensed to a liquid (by a freezing mixture of 
ice and calcium chloride). It boilsat —22°. Alcohol will dissolve 
35 volumes of it, and water 4 volumes. 


It is prepared by heating a mixture of 1 part methyl alcohol (wood spifit), 2 
parts sodium chloride, and 3 parts sulphuric acid. A better plan is to conduct 
HCl into boiling methyl alcohol in the presence of zinc chloride (% part). The 
disengaged gas is washed with KOH, and dried by means of sulphuric acid. 
Commercial methyl chloride usually occurs in a compressed condition. It finds 
application in the manufacture of the aniline dyes, and in producing cold. It is 
obtained by heating trimethylamine hydrochloride, N(CH,),.HCl. 


Monochlorethane, C,H;Cl, Ethyl chloride, is an ethereal 
liquid, boiling at 12.5°; specific gravity at o° —o.g21. It is 
miscible with alcohol, but is sparingly soluble in water. 


Preparation.—Heat a mixture of 1 part ethyl alcohol, 2 parts H,SO,, and 2 
parts NaCl. The gas is washed by passing through warm water and condensed in 
a strongly cooled receiver. Or HCl may be passed into 95 per cent. alcohol con- 
taining % part ZnCl,. Heat should be applied. 


If heated with water to roo®° (in a sealed tube), it changes to 
ethyl alcohol. The conversion is more rapid with potassium 
hydroxide. In dispersed sunlight, chlorine acts upon it to form 
ethylidene chloride, CH;.CHCl,, and substitution products. Of 
these C,HCI; was formerly employed as “ther anestheticus. 

Monochlorpropane, C;H,Cl. Two isomerides are possible :— 

Normal propyl chloride, CH; CH,.CH,.Cl, derived from normal 
propyl alcohol, boils at 46.5°." Its specifi vity.is 0.8898 at 0°. 


“ESE LIBRAB 
LEK Ry 


THE 


UNIVERSITY ; 





94 ORGANIC CHEMISTRY. 


Lsopropyl chloride, CH;.CHC1.CH,, obtained from the corres- 
ponding alcohol, and by the union of propylene with HCl, boils at 
37°; its specific gravity is 0.874 at 10°. 


Monochlor-Butanes, C,H,Cl, Butyl chlorides. Four isomerides ‘are possi- 
ble: two of these arise from the normal and two from the tertiary butane (see p. 
43). These (and also their homologues) will be mentioned under the correspond- 
ing alcohols. 

The alkyl fluorides are produced when the potassium salts of the alkyl sul- 
phates are heated with acid fluoride of potassium. The first four members, from 
Methyl Fluoride, CH,F1, to Butyl Fluoride, C,H,FI, are gases with an ethereal 
odor. 


For the preparation of the bromides from the alcohols, the al- 
ready made PBr; (or PC1,Br,) (see p. 92) isnot essential. Amorphous 
phosphorus is taken, alcohol poured over it, and while carefully 
cooling, bromine is gradually added. The mixture is subsequently 


distilled :— 
3C,H,.0H + P + 3Br = 3C,H,Br + PO,H,. 


The distillate is washed with H,O and dilute KOH, dried over 
CaCl,, and then fractionated. The bromides boil from 22-24° 
higher than their corresponding chlorides. 

The bromides may be obtained from the chlorides, by heating 
with aluminium bromide (Berichte, 14, 1709) :— 


3C,H,Cl + AlBr, = 3C,H,Br + AICI,. 


Conversely, the bromides are changed to chlorides through the 
agency of HgCl,. 

Methyl Bromide, CH,Br—Monobrommethane—boils at nk 
4.5°; its specific gravity is 1.73 at 0° 

Ethyl Bromide, C,H,Br, boils at 39°; its specific gravity is 
ag cat: 43°. Ethylidene Bromide, CHs;CHBr,, and ethylene 
bromide, CH,Br.CH,Br, are obtained from it by the action of 
bromine. 

Propyl Bromide, C,H,Br, from the normal alcohol, boils at 
71°; its specific gravity is 1.3520 at 20°. 

Isopropyl Bromide, C,H,Br, from its corresponding alcohol, 
boils at 60-63°; its specific gravity is 1.3097 at 20°. It is most 
conveniently obtained by the action of bromine upon isopropyl 
iodide (Berichte, 15,1904). 


Upon boiling with aluminium bromide, or by heating to 250°, normal propyl 
bromide passes over into the isopropyl bromide (not completely, however, 
Berichte, 16, 391). Such a transposition, due to displacement of the atoms in the 
molecule, occurs rather frequently, and is termed molecular transposition. In 
many instances it may be explained by the formation of intermediate products. 
Thus, it may be qgsumed that the normal propyl bromide, CH,.CH,.CH,.Br, at 
first breaks up into propylene, CH,.CH:CH, and HBr (see p. *93)s ‘which then, 


HALOGEN COMPOUNDS. : 95 


according to a common rule of addition (p. 92), unite with the propylene to isopro- 
pyl bromide, CH,.CHBr.CH,. Similarly, isobutyl bromide, (CH,),.CH.CH,.Br, 
changes at 240° to tertiary butyl bromide, (CH,),.CBr.CH,. ‘The transpositions 
occurring on heating the halogen hydrides with the alcohols may be explained in 
the same manner. 





The iodides are obtained just like the bromides, that is, by heat- 
ing a mixture of the alcohols, phosphorus (yellow or amorphous) 
and iodine. Concentrated HI converts the alcohols into iodides :— 


C,H,.0H + HI = C,H,I + H,0. 
Excess of HI, however, again reduces them. (Compare p. 91.) 


The polyhydric alcohols (containing several hydroxyl groups) also yield mono- 
iodides :— 

C,H, (OH), + 3HI 

C,H; (OH); + 5HI 


CHY 41. 4° sto 
C,H,I +21, + 3H,O 
C,H, (OH), + 7HI = CHI + 31, + 4H,0 
C,H, (OH), +11HI = C,H,I + 51, + 6H,0. 


The mechanism of the reaction will be more carefully studied when we reach 
allyl and isopropyl iodides. 


th 


Many iodides can be obtained from the chlorides by heating 
with All, (or Cal,) Berichte, 16, 392, and 19, Ref. 166): 


3C,H,Cl + All, = 3C,H,I + AICI. 


In some cases HI accomplishes the same result. Conversely the 
iodides can be changed to chlorides by heating with mercuric, 
cupric or stannic chlorides :— 


2C,H,I + HgCl, = 2C,H,Cl + Hgl,. 
Free chlorine and bromine can also replace iodine directly :— 
CH,I + C,=¢H,cl + ICL 
As to the action of various metallic haloids upon organic chlor-, brom-, and 


iodo- derivatives, see Ann., 225, 146, 171, and 231, 257. These transpositions are, 
in general, determined by the thermo-chemical deportment of the compounds. 


_On exposure to the air the iodides soon become discolored by 
deposition of iodine. The iodides of the secondary and tertiary 
alcohols are easily converted by heat into alkylens, C,H,, and HI. 
Their boiling points are about 33° higher than those of the corres- 
ponding bromides. 

Methyl Iodide, CH,I, is a heavy, sweet-smelling liquid, boil- 
ing at 45°, and hasasp. gr. = 2.19 at o°. In the cold it unites 
with H,O to form a crystalline hydrate, 2CH,I + H,O. 


96 ORGANIC CHEMISTRY. 


Ethyl Iodide, C,H,I, is a colorless, strongly refracting liquid, 
boiling at 72° and having.a sp. gr. of 1.975 at 0°. 


Preparation.—Pour 5 parts alcohol (90 per cent.) over I part amorphous 
phosphorus, then gradually add 10 parts iodine and distil. The distillate is 
poured back on the residue and redistilled. It is advisable to previously dissolve 
the iodine in alcohol or ethyl iodide, and add this to the alcohol containing 
phosphorus. In this case yellow phosphorus may be employed. 


Propyl Iodide, C,H,I, boils at ro2°, and has a specific gravity 
of 1.7427 at 20°. 

Isopropyl Iodide, C;H,1, is formed from isopropyl alcohol, 
propylene glycol, C;H,(OH),, or from propylene, and is most con- 
veniently prepared by distilling a mixture of glycerol, amorphous 
phosphorus and iodine :— 


C,H, (OH), + 5HI = C,H,I + 21, + 3H,0. 


Here we have allyl iodide produced first (see p. 98), and this is 
further changed to propylene and isopropyl iodide :— 
CH, = CH — CH,I + HI= CH, = CH — CH, + l,, 
Allyl Iodide. Propylene, © 
and 
CH, = CH — CH, + HI = CH, — CHI — CH,. 
Propylene. : Isopropyl Iodide. 


Preparation.—300 gr. iodine and 200 gr. glycerol (diluted with an equal 
volume of HO) are placed in a tubulated retort, and 55 gr. of yellow phosphorus 
added gradually, The portion passing over first is returned and redistilled. To 
remove admixed allyl iodide from the isopropyl iodide, conduct it into HI and let 
stand. (Annalen, 138, 364.) 


Isopropyl iodide boils at 89.9°, and has a specific gravity of 
1.7033 at 20°. | 

The higher alkyl iodides are mentioned under the corresponding 
alcohols. 


HALOGEN DERIVATIVES—CnpHon —_— >.< and CnHen mae? OY 


As a general thing, the halogen substitution products of the un- 
saturated hydrocarbons cannot be prepared by direct action of the 
halogens, since addition products are apt to result (p. 91). They 
are produced, however, by the moderated action of alcoholic potash, 
or Ag,O, upon the substituted hydrocarbons C,H,,X,. This re- 
action occurs very readily if we employ the addition products of 
the olefines :— 

C,H,Cl, + KOH = C,H,Cl+ KCl + H,0. 


Ethylene Monochlor- 
Chloride. ethylene. 


HALOGEN DERIVATIVES. 97 


When the alcoholic potash acts very energetically the hydro- 
carbons of the acetylene series are formed (p. 86). Being un- 
saturated compounds they unite directly with the halogens, and also 
the hydrides of the latter :— 


CH, CH,Br 
| + Br, = | 
CHBr CHBr,. 

Monochlorethylene, C,H,Cl—CH,:CHCl, or Vinyl chloride (the group 
CH,:CH is called Vinyl), derived from ethylene chloride, CH,Cl.CH,Cl, and 
(although with greater difficulty) from ethylidene chloride, CH,.CHCl,, is a gas 
with garlic-like smell, liquefying at —18° and polymerizing in the sunlight. 

Monobromethylene, C,H,Br, Vinyl bromide, is obtained by boiling ethy- 
lene bromide with aqueous potassium hydroxide. It possesses an odor similar to 
that of the chloride, boils at 16°, and has a specific gravity of 1.52. Under cer- 
tain conditions, in sunlight, for example, it is converted into a solid polymeric 
modification. It dissolves readily in concentrated sulphuric acid, and if the 
solution be boiled with water crotonaldehyde results (from acetaldehyde that is 
formed previously). Vinyl bromide does not react with CNAg or CNK, and, 
indeed, does not appear capable of double decompositions. (Berichte, 14, 1532.) 

Ethylene Mono-iodide, C,H,I, Vinyl iodide, is obtained from ethylene and 
ethylidene iodides, by the aid of alcoholic potash, and boils at 55°; its specific 
gravity is 1.98. 





Ethylene Dichlorides and Dibromides:— 


CH: = OCl, CHCl = CHC 
Ethylene a-dichloride. Ethylene [-dibromide, 


Ethylene a-Dichloride (unsymmetrical) is formed from ethylene chloride, 
CH,Cl. CHCl,, by the action of alcoholic potash, and boils at 37°. Ethylene 
f-dichloride (symmetrical) is formed by the union of acetylene, C,H,, with 
SbCl,. It boils at 55°. Ethylene a-Dibromide, from bromethylene bromide, 
CH,Br.CHBr,, boils at 91°. Ethylene §-dibromide, formed from acetylene 
by addition of Br,, and from acetylene tetrabromide, C,H,Br,, through the 
agency of zinc, boils at 110°, Ethylene a-dibromide, with benzene and AIC1,, 
yields ethylene diphenyl, CH,:C(C,H,),; but from ethylene /-dibromide 
dibenzyl is obtained C,H,.CH,.CH, C,H,. (Berichte, 16, 622.) 

The unsymmetrical products are inclined to polymerize. This is not the case 
with the symmetrical (Berichie, 12, 2076). The ethylene mono-haloids polymerize 
similarly, but ethylene itself does not change. It appears, too, that the power of 
direct union with oxygen, thereby yielding the chloranhydrides of substituted 
acetic acids, is only possessed by the unsymmetrical substitution products, CH,: 
CBr, + O= CH,. Br. COBr. (Berichte, 16, 2918.) For the course of the re- 
action see Ber., 21, 3356. 

Two isomeric Di-iodo-ethylenes, CH,I. CH,I, are said to form when acetylene 
unites with iodine in an alcoholic solution (Amm., 178, 118). 


98 ORGANIC CHEMISTRY. 


Three different mono-halogen products are derived from propylene, CH, — 
CH = CH, :— 


(1) CH, —CH =CHX (2) CH, —CX —CH, (3) CH,X — CH = CH,. 


a Disivations. 6- Derivatives. y-Derivatives, 


(1) The a-derivatives are obtained from the propylidene compounds, CH, 
CH,.CHX, (from propyl aldehyde), when the latter are heated with echads 
potassium hydroxide, while from the addition products of propylene, CH,.CHBr. 
CH,.Br, we obtain the -derivatives at the same time. Propylene a-chloride 
boils at 35° (see Ber., 20, 1040 for a geometrical, isomeric a-chlorpropylene). 
a-Brompropylene boils at 59-60° ; ; its specific gravity at 19° is 1.428. 

(z) The $-derivatives, CH,.CX:CH,, are prepared in pure condition from the 
halogen compounds derived from acetone. Propylene {-chloride boils at 23°; 
its sp. gr. at 9° is 0.918. Propylene 6-bromide boils at 48°; its sp. gr. at 19° is 
1.364. 

Continued heating with alcoholic potash causes both a- and (-varieties to 
pass into allylene. Propylene $-bromide combines in the cold with HBr to form 
acetal bromide, CH,.CBr,.CH,, while the alpha variety only unites with it at 
100°, and then yields a mixture of propylene and propylidene bromide (p. 101). 
Sulphuric acid and water, aided by heat, convert the #-chloride into acetone, 
CH,.CO.CH,. The a-products especially appear to react with far more difficulty 
(like ethylene monochloride) than the f-varieties (compare the chlorides of 
styrolene). 


(3) The ;-derivatives of propylene, CH,X — CH = CH,, are 
designated Allyl haloids, because they correspond to allyl alcohol, 
CH,;:CH.CH,OH. The allyl group (CH,:CH.CH,) occurs in 
some vegetable substances (mustard oil, oil of garlic). Heated 
with alcoholic potash the allyl haloids yield allyl ethyl ether, C;H;. 
O.C,H;. The ease with which they undergo transpositions is 
characteristic, and serves to distinguish them from the a- and 
8-products. 


_ Allyl chloride, C,H,Cl, is formed by the action of PCl, or HCl upon allyl 
alcohol, or by the transposition taking place between allyl iodide and HgCl, 
(p. 95). It is a liquid with an odor resembling that of leeks; boils at 46°, and 
has a specific gravity of 0.9379 at 20°. If heated to 100° with concentrated 
hydrochloric acid it yields propylene chloride, CH,.CHCI.CH,Cl (trimethylene 
chloride, CH,Cl.CH,.CH,Cl, is not produced). 

Allyl Bromide, G: H Br, ‘boils at 70-71°; its specific gravity at 0° equals 
1.461. Upon warming to 100° C., it combines with bonrentrsted HBr to form 
trimethylene bromide, CH, Br.CH, ‘CH 2 Br (see p. 102). 


Allyl Iodide, C,H,I, is obtained from allyl alcohol, or better, 
from glycerol, by the action of HI, or iodine and phosphorus (com- 


pare p. 95) :— 
CH,OH CH, 


| 
H.OH + 3HI = CH + 3H,O + I,. 
CH,.0H CHI 


DIHALOGEN COMPOUNDS. 99 


We may suppose that at first CH,I.CHI.CH,I forms, but is sub- 
sequently decomposed into CH,:CH.CH,I and I,. With excess 
of HI or phosphorus iodide, allyl iodide is further converted into 
propylene and isopropyl iodide (p. 96). 

Preparation.—150 parts of concentrated glycerol and 100 parts pulverized 
iodine are introduced into a tubulated retort, and 60 parts of yellow phosphorus 
gradually added to the mixture. When the first action has passed away, the allyl 
iodide is distilled off, and the distillate washed with dilute potassium hydroxide. 
When larger quantities are employed explosions sometimes occur; these may be 
obviated if the operation be carried out in a stream of CO, gas. (Compare 
Annalen, 185, 191 and 226, 206.) 


Allyl iodide is a colorless liquid, with a leek-like-odor, boiling 
at 101°. Its specific gravity equals 1.789 at 16°. By continued 
shaking of allyl iodide (in alcoholic solution) with mercury,C;H,HgI 
separates in colorless leaflets (see mercury ethyl). Iodine liberates 
pure allyl iodide from this :— | 

C,H,HglI + I, =C,H,I + Hel,. 





DIHALOGEN COMPOUNDS C, HonX2, 


These derivatives of the paraffins arise by direct substitution, 
by the addition of halogens to the alkylens, C, H.n, and the halogen 
hydrides to the substituted alkylens, Cy Hn», X; and by the action 
of the phosphorus haloids upon the aldehydes and ketones (p. 92). 
The products thus obtained are of like composition, and are partly 
identical, partly isomeric. The direct addition products, C, H.nX,, 
have the halogen atoms attached to two adjacent carbon atoms (see 
p. 86). In the compounds resulting from the replacement of the 
oxygen of aldehydes and ketones, both halogen atoms are in union 
with the same carbon atom :— 

CH CH ; 
L * yields | - "Sco yields etl,. 
HO CHCl, CH, CH, 
Aldehyde. : ' Acetone, 

Heated with alcoholic potash, the addition products pass into the compounds 
Cn Haon—1 Xand Cp Hon—2 (page 96). The alkylens result when the dihalogen 
compounds are heated with sodium : — 

CH,Cl CH, 
| + Na,= | + 2NaCl. 
CH,Cl CH, 


Those derivatives, in which the halogens are attached to er carbon atoms, 
are capable of forming glycols :— 


CH,Cl CH,OH 
L yields i 
H,Cl H,OH. 


100 ORGANIC CHEMISTRY. 


Methylene Chloride, Dichlormethane, CH ,Cl,, is produced in the chlorina- 
tion of CHCl, by the action of Cl upon CH,1, or CH,I, and by the reduction of 
chloroform ‘by means of zinc and ammonia. It is a ‘colorless liquid, boiling at 
41°, and having a specific gravity of 1.36 at 0°. 

Methylene Bromide, CH,Br,, results on heating CH,Br with bromine 
(together with CHBr,), and by the action of bromine upon methylene iodide. It 
boils at 81° (98.5°) and has a specific gravity of 2.493 at 0°. 

Methylene Iodide, CH,1,, is produced in the action of sodium alcoholate upon 
iodoform, CHI,, and is best prepared by heating CHCl, or CHI, with fuming 


HI to 130° :— 
CHCl, + 4HI = CH,I, + I, + 3HC1. 


It is a colorless liquid with a specific gravity of 3.34. It boils, with decomposi- 
tion, about 182°. At low temperatures it forms shining leaflets, melting at + 4°. 





The empirical formula C,H,X, has two possible structures :— 


CH,X CH, 
‘og a 
H,X HX, 
Ethylene Ethylidene 
Compounds, Compounds. 


The first originate from ethylene, the second from aldehyde 

CH;.COH. The former yield acetylene with alcoholic potash, the 
O.C,Hs. 

latter acetal, CH. CH ; the former yield glycol, the 

latter do not. ‘\0.C,H, 

Ethylene Chloride, C HCl, is obtained by the direct union 
of equal volumes of ethylene and chlorine gas, or by conducting 
ethylene through warm SbCI,. It is a colorless, pleasant-smelling 
liquid, of specific gravity 1.2521 at 20°, and boils at 84°. 

Ethylidene Chloride, CH;.CHCl,, is produced by the chlori- 
nation of ethyl chloride (both gases are conducted over animal 
charcoal heated to about 306°) and from aldehyde (better paralde- 
hyde) by the action of PCI,, or phosgene (Ber., 18, 578). Ona 
large scale it appears as a by-product in the preparation of chloral. 
It is a liquid, smelling like chloroform, with a specific gravity of 
1.1743 at 20°, boils at 57.7°, and is employed as an anesthetic. By 
further chlorination it yields CH;.CCl, together with a little 
CH,Cl.CHCl,. When AICI, is present, the latter is the only 
product. 

Ethylene Bromide, C,H,Br,, is formed by saturating bromine 
with ethylene gas (Anmmalen, 192, 244), and is an oily, pleasant- 
smelling liquid, boiling at 131° ; its specific gravity is 2.178 at 20°. 
At o° it solidifies to a crystalline mass, fusing at + 9°. 

‘Ethylidene Bromide, C,H,Br, — CH;.CHBr,, formed together 
with ethylene bromide by the bromination of C,H;.Br (in presence 


DIHALOGEN COMPOUNDS.;/ 2 stor 
of AlBr,, only ethylene bromide is produced), is obtained: by the ac- 
tion of PCl,Br, upon aldehyde. It boil§ at-z10.5°; and ‘has’a spe- 
cific gravity of 2.082 at 21°. 


The formation of ethylene and ethylidene bromides from monobromethylene is 
quite interesting. When the latter is heated with very concentrated HBr, ethy- 
lene bromide forms, while with more dilute acid ethylidene bromide results. 

Ethylene Iodide, C,H,I,, is produced in the union of iodine with ethylene, 
by conducting the latter into a solution of iodine in alcohol. It crystallizes from 
alcohol in brilliant needles, which rapidly become yellow on exposure to light. 
The compound melts at 81°, and at higher temperatures decomposes into C,H, 
andI,. It may be distilled in an atmosphere of ethylene gas without decom- 

sition. 

P" Bthylidene Iodide, CH,.CHI,, is obtained from ethylidene chloride by the 
action of aluminium iodide (p. 95). It boils at 178°, sustaining partial decompo- 
sition; its specific gravity is 2.84 at 0°. It is also formed by the addition of 2HI 
to acetylene. 





Four different di-halogen products are derived from. propane 
CF taser 


(1) CH,.CH,.CHX,. (2) CH,.CX,.CH,. (3) CH,.CHX.CH,X, and 
2 2 ee CHGS CH, CHS: 


(1) Derivatives of the first structure, called propylidene compounds, arise from 
propyl aldehyde, CH,.CH,.CHO, by the action of PCl,. 

Propylidene Chloride, C,H,Cl,, is a liquid, with an odor resembling that of 
leeks, and boiling at 84-87°. Its specific gravity at 10° is 1.443. The bromide, 
C,H,Br,, from propylene a-bromide, boils at 130°. 

(2) Derivatives of the formula CH,.CX,.CH, are obtained from acetone by 
the action of PCl; and PBr,:— 


CH CH 
“Sco yields te 
CH,” CH, 
Dimethyl Methylene Chloride, C,H,Cl, — CH,.CCl,.CH,, methyl chlor- 


acetol or acetone chloride, is formed by the addition of 2HCI to allylene (together 
with propylene chloride) :— 


a yes 


CH, CH, an. 
d 4+ 2HCl yields der, and CHCl; 
I 

CH Co CH,Cl 


and by the chlorination of isopropyl chloride, CH,.CHCI1.CH,. 

It is a colorless liquid, boiling at 69~70°, and having a specific gravity 1.827 at 
16°, £-Monochlorpropylene is obtained from it by the action of alcoholic potash 
(p. 98). Heated to 150° with water, it changes in part to acetone. 

Dimethyl Methylene Bromide, C,H,Br,, from acetone, and from allylene, 
by the addition of 2 HBr, boils at 113-116°; its specific gravity at 0° is 1.875. 


a 


102 *:*|* > {ORGANIC CHEMISTRY. ° 
: (a). We: gét : the <derivatives -of the structure CH;.CHX.CH,X 
by uniting propylene’ with thé-halogens :— 

CH, — CH=CH, affords CH,. CHX.CH,X. 


This class passes into propylene glycol when acted upon by moist 
silver oxide; with alcoholic potash they yield CH;.CX:CH,, and 
allylene. 

Propylene Chloride, C,H,Cl, = CH;.CHCI.CH,Cl, is pro- 
duced, together with acetone chloride, when chlorine acts in sun- 
light upon isopropyl-chloride (in presence of iodine the chlorina- 
tion extends only to propylene chloride). It boils at 97°, and has 
a specific gravity of 1.165 at 14°. 3 

Propylene Bromide, C;H,Br, — CH,;.CHBr.CH.Br, is a 
liquid boiling at 141°. It is formed in the bromination of propyl 
bromide and isopropyl bromide. Its specific gravity at 17° equals 
1.946. Propionic aldehyde and acetone result when propylene 
bromide or the chloride is heated, together with H,O, to 200°. 

Propylene Iodide, C,H,I, — CH;.CHI.CH.I, results by 
the union of iodine with propylene at 50°. It is a colorless oil, 
that cannot be distilled without suffering decomposition. 


(4) The products of the formula CH,X.CH,.CH,Cl are designated trime- 
thylene derivatives. 

Trimethylene Chloride, C,H,Cl, —CH,Cl.CH,.CH,Cl, is obtained by 
heating the corresponding bromide with, mercuric chloride to 160°, It is an 
agreeably smelling liquid, that boils at 119°, and at 15° has a sp. gr. == 1.201. 

Trimethylene Bromide, C,H,Cl,, results on heating allyl bromide, CH, : 
CH.CH, Br, with concentrated hydrobromic acid. Propylene bromide is pro- 
duced at the same time. This can be removed by fractional distillation. (With 
HCl the only product of allyl chloride is propylene chloride, CH,.CHCI.CH, 
Cl.) It is obtained in a purer form on saturating allyl bromide with HBr in the 
cold, and letting the whole stand some time (Azma/en, 197, 184). Trimethylene 
bromide is a colorless liquid, boiling at 164°, and has a specific gravity of 2.01 
at o°. When treated with alcoholic potash, it yields allyl bromide and allyl ethyl 
ether. Trimethylene is the product with sodium (p. 83). Continued boiling 
with water converts it into trimethylene glycol. 

Trimethylene Iodide, C,H,I,, obtained on heating trimethylene bromide 
with sodium iodide, is a colorless oil, boiling near 224°. 





THE HALOGEN COMPOUNDS C,Hon_,X3. 


Chloroform, CHCl,;, Trichlormethane, is formed: by the 
chlorination of CH, or CH;Cl; by the action of chloride of lime 
upon different carbon compounds, ¢.g., methyl or ethyl alcohol, 
acetone, acetic acid; and by heating chloral with aqueous 
potassium or sodium hydroxide :— 

CCl,.CHO + KOH = CCl,H + CHKO,, 


Chloral. Potassium 
i - Formate. 


4 


THE HALOGEN COMPOUNDS. 103 


In preparing chloroform a mixture of alcohol, bleaching lime, and water is dis- 
tilled from a capacious retort (Anna/en, 165, 349). It would be an advantage to 
substitute acetone for the alcohol. The chloroform produced is carried over with 
the steam and collects in the bottom of the receiver as a heavy oil. It is purified 
by shaking with H,SO, and repeated distillation. At present it is generally 
obtained from chloral. Pure chloroform should not color on the addition of con- 
centrated sulphuric acid. 


Chloroform is a colorless liquid of an agreeable ethereal odor and 
sweetish taste. It solidifies in the cold and meltsat— 71°. It boils 
at 61°, and its specific gravity at o° equals 1.526. Inhalation of its 
vapors causes unconsciousness, and at the same time has an anes- 
thetic effect. It is uninflammable. Chlorine changes it to CC]. 
Potassium formate is produced when chloroform is heated with 
alcoholic potash :— 


CHCl, + 4KOH = CHO.OK + 3KCl + 2H,0. 


The so-called tribasic formic acid ester, CH (O.C,H,);, is produced 
by treating chloroform with sodium alcoholate. When heated to 
180° with aqueous or alcoholic ammonia, it forms ammonium cyan- 
ate and chloride. When KOH is present, an energetic reaction 
takes place at ordinary temperatures. The equation is— 


CHCl, + NH, + 4KOH = CNK + 3KCl+4 4H,0. 


Bromoform, CHBr;, is produced in the same way as. chloro- 
form, by the action of bromine and KOH upon methyl and ethyl | 
alcohol. It is a colorless, agreeable-smelling liquid, solidifying at 
—9°. It boils at 151° and has a specific gravity 2.83 at 0°. 

Iodoform, CHI;. This compound results when iodine and 
potash act upon ethyl alcohol, or acetone, aldehyde and other sub- 
stances containing the methyl group. Pure methyl alcohol, how- 
ever, does not yield iodoform. (Berichte, 13, 1002). 


Preparation.—Dissolve 2 parts crystallized soda in 10 parts of water, add I 
part alcohol, bring the whole to 60—80°, and gradually introduce 1 part of iodine. 
The iodoform that separates is filtered off. By renewed warming of the filtrate 
with KOH and alcohol, followed by the sofa pak aem of chlorine, an additional 
quantity of iodoform may be obtained. 


Iodoform crystallizes in brilliant, yellow leaflets, soluble in 
alcohol and ether. Its odor issaffron-like. It evaporates at medium 
temperatures; fuses at 119° and distils over with the aqueous 
vapor. Digested with alcoholic KOH, or HI, it passes into 
methylene iodide, CH,I,. 


Two isomeric tri-halogen derivatives may be obtained from ethane C,H, :— 
CH, — CX, and CH,X —CHX,. 


a-Trichlor-Ethane, CH,.CCl,, is produced (together with CH,Cl.CHC1,) 
by the chlorination of ethyl ‘and ethylidene chloride in sunlight. It ‘is a liquid 


To4 ORGANIC CHEMISTRY. 


with chloroform-like odor, and boils at 74.1°. Its specific gravity at 0° is 1.346. 
If heated with KOH it yields potassium acetate :— 


CH,.CCl, + 4KOH = CH,.CO.OK 4+ 3KCl + 2H,0. 


Treated with sodium alcoholate it yields the tri-ethyl ester CH,.C(O.C,H,),. 
Further chlorination of trichlor-ethane produces CH,Cl.CCl,, boiling at 131°, 
CHCI,.CC1,, at 162°, and perchlor-ethane, CCl ,.CCl, (see p. 105). CHCl,.CHC1,, 
from dichlor-aldehyde, boils at 113.7° (Berichte, 15, 2563). 

8-Trichlor-Ethane, CH,Cl.CHCl,, monochlor-ethylene chloride, is pro- 
duced by the union of vinyl chloride, CH,.CHCI, with Cl,, and boils at 113.7°. 
Its specific gravity at 0° equals 1.422. 

a-Tribrom-Ethane, CH,CBr,, has not been formed. 

8-Tribrom-Ethane, CH,CHBr,, monobrom-ethylene bromide, forms upon 
brominating ethyl and ethylene bromides, also by addition of bromine to brom- 
ethylene, CH,.CHBr. It boils at 187°; its specific gravity at 21° equals 2.610. 





Trisubstituted propane, C;H;X;, can have five structural forms. 

The most important derivatives are those having the formula 
CH,X.CHX.CH,X. They correspond to glycerol, CH,(OH). 
CH(OH).CH,(OH). The trivalent group CH,.CH.CH,, present 
in them, is termed g/ycery/. They are produced by the addition of 
chlorine or bromine to allyl chloride and bromide :— 


CH,:CH.CH,.Cl + Cl, = CH,Cl.CHCI.CH,Cl; 


or by the action of PCl; upon dichlorhydrin, which is derived 
from glycerol :— . 
CH,Cl CH,Cl 


| 
CH.OH + PCI, = bye + POCI, + HCl. 


CH,Cl CH,Cl 
Moist silver oxide converts them into glycerol. 


Glyceryl Chloride, C,H,Cl,, allyl trichloride, trichlorhydrin, is a liquid with 
an odor resembling that of chloroform, and boiling at 158°. Its specific gravity 
at 15° equals 1.417. . 

Glyceryl Bromide, C,H,Br,, tribromhydrin, is best obtained by the action 
of bromine upon allyl iodide :— 


C,H,I + 4Br C,H, Br, + IBr. 
It crystallizes in colorless, shining leaflets, fusing at 16°, and boiling at 220°. 


Glyceryl Iodide, C,H,1,, appears not to exist. It decomposes at once into 
allyl iodide and I, (p. 98). 





Among the higher substitution products may be mentioned the 
following carbon haloids :— 

Tetrachlor-methane or.Carbon Tetrachloride, CCl, is 
formed by the action of chlorine upon chloroform, and by conduct- 
ing a mixture of Cl and CS, through tubes heated to redness. 


NITRO-DERIVATIVES OF HYDROCARBONS. 105 


Preparation. Chlorine is conducted through boiling chloroform exposed to 
sunlight, or through a mixture of CS, and SbCl,. In the latter case, sulphur 
chloride is formed at the same time. This may be decomposed by shaking with 
KOH. 


It is a pleasant-smelling liquid, boiling at 76-77°. Its specific 
gravity is 1.631 at o°. At — 30° it solidifies to a crystalline mass. 
Heated with alcoholic KOH, it decomposes according to the fol- 
lowing equation :— 


CCl, + 4KOH =CO, + 2H,0 + 4KCl. 


When the vapors are conducted through a red-hot tube, decom- 
position occurs; C,C], and C,Cl, are produced. 


Tetrabrommethane, CBr,, obtained by the action of brom-iodide upon 
bromoform or CS,, crystallizes in shining plates, melting at 92.5°, and boiling, 
with but little decomposition, at 189°. 

Tetraiodomethane, CI,, carbon iodide, is formed when CCl, is heated with 
aluminium iodide (p. 95). It crystallizes from ether in dark red, regular octa- 
hedra, of specific gravity 4.32 at 20°. On exposure to air it decomposes into 
CO, and I. Heat accelerates the decomposition. 

Perchlorethane, C,Cl,, is the final product in the action of Cl upon C,H,Cl 
or C,H,Cl,. Itisa crystalline mass, with a camphor-like odor and specific gravity 
2.01. It melts (in a capillary tube) at 187-188°. At ordinary pressure it vapor- 
izes without fusing, as its critical pressure (compare Inorganic Chemistry), lies 
above 760 mm. _ It boils at 185°.5 under a pressure of 776.7 mm. It is readily 
soluble in alcohol and ether. When its vapors are conducted through tubes heated 
to redness, it breaks up into Cl, and ethylene perchloride, C,Cl,. This is a 
mobile liquid, boiling at 121°. Its specific gravity at 20° is I. 6226, 

Perbromethane, C,Br,, is a colorless crystalline compound, sparingly soluble 
in alcohol and ether. At 200° it decomposes into Beye and ethylene perbromide, 
C,Br,, which consists of colorless crystals, melting at 53°. 

Perchlormesole, C ile, is formed on heating hexyl iodide or amyl chloride 
with ICI,. It melts at 39°, and boils at 284° (Berichte, 10, 804). 





_NITRO-DERIVATIVES OF THE HYDROCARBONS. 


By this designation is understood compounds of carbon in which 
the hydrogen combined with the latter is replaced by the mono- 
valent nitro-group, NO,. The carbon is directly united to the 
nitrogen by one affinity. A universal method for the production 
of nitro-compounds consists in acting upon the hydrocarbon deriv- 
atives with concentrated nitric acid :— 


C,H, + NO,H=C,H, (NO,) + H,0. 


The reaction is promoted by the presence of H,SO,, which serves to 
combine with the water that is generated. The fatty bodies capable 
of this reaction are exceptional ; the benzene derivatives, however, 
readily yield nitro-derivatives. : ; 


9 


106 ORGANIC CHEMISTRY. 


A common method for the preparation of the mono-nitro deriv- 
atives of fatty hydrocarbons — the nitro-paraffins — consists in 
heating the iodides of the alcohol radicals with silver nitrite 
(V. Meyer):— - 
C,H,I + AgNO, = C,H,.NO, + Agl. 

The isomeric esters of nitrous acid, such as C,H,.0.NO arise (see Berichte, 
15, 1574) in this reaction. From this we would infer that silver nitrite con. 
ducted itself as if apparently consisting of AgNO, and Ag.O.NO. (Potassium 
nitrite does not act like AgNO,). Since, however, CH,I only yields nitro- 
methane, and the higher alkyliodides decompose more readily into alkylens the 
greater the quantity of nitrous acid esters, it would appear that the formation of 
esters is influenced by the production of alkylens, which afterwards form esters 
by the union with HNO, (compare Avna/en, 180, 157, and Ber., 9, 529). 


The nitro-compounds generally decompose with an explosion, if 
quickly heated. They are not broken up by sodium or potassium 
hydroxide. These reagents convert the isomeric nitrous esters, 
with ease, into nitrous oxide and alcohol. Nascent hydrogen 
reduces the mono-nitro derivatives to amido-compounds, by con- 
verting the group NO, into NH,—the amido group :— 

| C,H,.NO, + 3H, = C,H,.NH, + 2H,0. 

The compounds resulting from the action of nitrogen tetroxide upon the alky- 
lenes, ¢. g., C,H,N,O,, are not nitro-derivatives; they belong to the class known 
as witrosates. 





The nitroso-compounds, containing the group NO attached 
to carbon, are classified with the nitro-compounds. Few of them are 
known. ‘The pseudo-nitrols probably belong to this class (p. 110). 
Most of the compounds resulting from the action of nitrous acid 
are isonitroso- and not nitroso-derivatives (Ber., 20, 331 ; 21, 1294). 
The nitroso-amines, (CH;),.N.NO, form another class of nitroso- 
compounds. In them the nitroso-group is linked to nitrogen. Their 
treatment will be found under the corresponding amines. 

The isonitroso-, or oximido-compounds—(CH;),.C : N.OH 
—containing the bivalent oximid group = N.OH linked to car- 
bon—are isomeric with the above nitroso-derivatives. They are 
formed, especially when nitrous acid acts upon bodies containing 
the group CH, attached to two CO groups. They also result from 
the action of hydroxylamine upon ketones R.CO.R, and aldehydes 
R.COH :— 

CH? »CO + H,N.OH = Gis Ae N.OH + H,0. 

Consequently these isonitroso-compounds will be treated with 
the derivatives from which they originate. The so-called alkyl- 
nitrolic-acids may be included with them. (See p. 109.) 





NITRO-PARAFFINS. 107 


The nitroso derivatives (of the benzene class and the nitroso-amines) give blue 
colorations in their action upon a mixture of phenol and sulphuric acid, especially 
after dilution with water and super-saturation with alkali. The isonitroso-com- 
pounds, however, do not yield this reaction ( Berichte, 15, 1529). 





NITRO-PARAFFINS C, Hon +. 1 (NO,.) 


Those formed by the action of silver nitrite upon the alkyl- 
iodides are colorless liquids almost insoluble in water. They are 
rather stable, distil without decomposition and decompose with 
difficulty. It is worthy of note that they possess an acidic charac- 
ter (distinctive from the halogen substitution products): this is in- 
‘dicated by the substitution of metals for one hydrogen atom, through 
the action of alkaline hydroxides :— 


CH,.CH,(NO,) + KOH = CH,.CHK(NO}) + H,0. 


The nitro-group always exerts such an acidic influence upon hy- 
drogen linked to carbon ; the further addition of halogens or nitro- 
groups increases the same, but it is confined to the hydrogen linked 
to the same carbon atom. ‘Thus the compounds: CH;.CHBr(NO,), 
brom-nitroethane, CH;.CH(NO,)., di-nitroethane, CH(NO,),, nitro- 
form, etc., are strong acids, while CH;.CBr,.(NO,) and (CH;),C 
(NO,)., 8-dinitro-propane, etc., possess neutral reaction and do not 
combine with bases. 


The nitro-paraffins may be viewed as isonitroso-compounds (Ber., 20, 531, and 
Ref. 296 

For saan resulting from the action of sodium ethylate and the alkyl 
iodides upon the nitro ethanes, ¢. 2., C,H,NO, see Ber., 21, Ref. 58 and 710. 

Zinc ethide converts the nitro- paraffins into tri-ethyl- hydroxylamines (Ber., 22, 
Ref. 250). Brom-nitro ethane, CH,.CHBr(NO,), and zinc methyl yield nitro- 
isopropane. 


Nitromethane, CH;.NO,, is produced by boiling chloracetate 
of potassium, CH,Cl.COOK, with potassium nitrite. In this in- 
stance it is very probable nitro-acetic acid is first formed, but it 
subsequently breaks up into nitromethane and carbon dioxide :— 


CH,.NO,.CO,H = CH,NO, + CO,. 


It is an agreeable-smelling, mobile liquid, sinking in water and 
boiling at tor°. Mixed with an alcoholic sodium hydroxide solu- 
tion it givesa crystalline precipitate, CH,Na(NO,) + C,H,O, which 
loses alcohol on standing over sulphuric acid. Salts of the heavy 
metals precipitate metallic compounds (like CH,Ag(NO,)) from 
the aqueous solution. These are in most cases violently explosive. 
Nitromethane is liberated again from the salts by mineral acids. 


108 ORGANIC CHEMISTRY. 


Heated with concentrated HCl to 150° nitromethane breaks up into 
formic acid and hydroxylamine :— 


CH,.(NO,) + H,O —CH,O, + NH,.OH. 


Chlorine water converts sodium nitromethane into nitrochlormethane, CH,Cl. 
(NO,), which is an oil boiling at 122°. In like manner, through the agency of 
bromine, we obtain bromnitromethane, CH,Br(NO),, a pungent smelling oil, 
boiling at 144°, from which are also prepared dibrom-, and tribrom- nitromethane, 
CHBr,(NO,) and CBr,(NO,).—Bromopicrin (p. 11 3). The first three bodies 
have an acid reaction and dissolve in alkalies. 


Nitroethane, C,H;.NO,, is similar to nitromethane. It boils at 
113-114° and its specific gravity at 13° equals 1.058. Nascent 
hydrogen converts it into C,H;.NH,. Heated to 140° with con- 
centrated hydrochloric acid, it "decomposes into acetic acid and 
hydroxylamine. Ferric chloride imparts a blood-red color and 
copper sulphate a dark green to the sodium compound. 


Bromine converts nitroethane, in alkaline solution, into bromnitroethane, CH,. 
CHBr(NO,), an oil with a pungent odor, boiling at 147°, and into dibromnitro- 
ethane, CH,.CBr,NO.,, boiling at 105°. The first reacts strongly acid and dis- 
solves in NaOH to CH,.CNaBr(NO,); the second is neutral and insoluble in 
alkalies. 

a—-Nitropropane, C,H,.NO, = CH,.CH,.CH,.NO,, boils at 125-127°. 
$-—Nitropropane, (CH,),.CH.NOg, boils from 115-117°. Both have an acid 
reaction and yield salts with the alkalies. 

Brom-a-nitropropane, CH,.CH,.CHBr(NO,), boiling at 160-165°, has a strong 
acid reaction and dissolves in alkalies. On the other hand, dibrom-a-nitro- 
propane, CH,.CH,.CBr,(NO,), boiling at 185°, is a neutral compound insoluble 
in alkalies. Brom-/-nitropropane, (CH,),CBr(NO,), boiling at 148—150° is also 
a neutral compound (see p. 107). 

Nitrobutanes, C,H,.NO, (compare Butyl alcohols). Normal nitrobutane, 
CH,.CH,.CH,.CH -NO,, boils at’ 1 51° and yields pee eon by 


reduction. Secondary nitrobutane, CH,.CH,.CH(NO,).CH, = 63 7 SCH. NO., 


boils about 140°. Vitrotsobutane, (CH,),CH.CH,.NO,, boils at 1 137-140°, and 
has an odor resembling that of peppermint. The three nitrobutanes are acid, dis- 
solve in alkalies and yield bromine derivatives. Tertiary nitrobutane,(CH,),C.NO,, 
on the contrary, boiling at 120° is a neutral compound, insoluble in alkalies. 

Nitroisoamyl, C,H,,.NO,, obtained from amyl]-alcohol of fermentation, boils 
at 150-160° and yields metallic compounds. 

Nitropropylene, C,H,.NO,, allyl nitryl, from allyl bromide, is an oil boiling 
at 96°. 

i dearcyicce. Cyn Hn — ,(NO,), are formed in the action of nitric acid. upon 
some alkylens and tertiary alcohols. ‘Thus there is a nitro-butylene, C,H (NO) ), 
obtained from isobutylene, (CH,),C:CH,, and trimethyl-carbinol (CH,),C. 

It boils about 156°. A nitroamylene, C sH,(NO,), is also obtained from Mrcthyi 


ethyl carbinol CoH \ C.OH, ‘Upon reduction, these nitroalkylens do not yield 


amido- compounds, but part with the nitrogen as ammonia or hydroxylamine. 


NITRO-PARAFFINS. ‘10g 


The varying deportment of the nitro-paraffins with nitrous acid (better NO,K 
and H,SQO,) is very interesting, according as they are derived from primary, 
secondary or tertiary radicals. (p. 46). 

On mixing the primary nitro-compounds (those in which NO, is attached to 
CH,) with a solution of NO,K in concentrated potassium hydroxide and adding 
dilute H 250.4, the solution assumes in the beginning an intense red color and 
the Ethyl-nitrolic acids are produced. Their structure very probably corre- 
sponds to the formula— 

N.OH 


CH,.C@ ethyl nitrolic acid. 


The nitrolic acids are colorless crystalline bodies, soluble in ether. They behave 
like acids. Their alkali salts are dark red in color—hence the appearance, in the 
beginning, of a red coloration, which disappears in presence® of excess of sul- 
phuric acid and reappears on addition of alkali. 

The nitro-compounds of the secondary radicals (those in which NO, is joined 
to CH), when exposed to similar treatment, yield a dark blue coloration, after 
which colorless compounds—the pseudo-nitrols—separate. These are not turned 
red by addition of alkali:— 


CH, NO 


Hs\\cHNO,' yields rere 
CH 3/ x cH,” NO, 


In the solid state pseudo nitrols are colorless; when liquid or in solution they 
are dark blue. 

The nitro-compounds of tertiary radicals (like (CH,),C.NO,) do not react with 
nitrous acid and do not yield colors, Therefore, the preceding reactions serve as 
a very delicate and characteristic means of distinguishing primary, secondary, and 
tertiary alcoholic radicals (in their iodides) from each other (secondary nitro-pen- 
tane no longer exhibits the reaction). Ina similar manner the primary and sec- 
ondary nitro-derivatives may be detected in a mixture at the same time ( Berichie, 
9, 539, and Annalen, 180, 139). 





The alkyl-nitrolic acids, produced by the action of nitrous acid 
(or NO,K and stag upon the primary nitro-paraffins (see 
above) :—_ 

cit ROR 
CH,.CH,(NO), -+ NO.OH = oH,.c¢ + H,0, 


N.OH 


may be prepared lipo is by treating the dibrom nitro-paraffins 
with hydroxylamine :— 

NO, 
CH,.CBr,(NO,) + H,N.OH = bt bP 


“SN.OH 
Therefore they are to be regarded as isonitroso- or oximid-com- 


pounds (see p. 106). 
The nitrolic acids are solid, crystalline, colorless, or faintly- 


+ 2HBr. 


IIo ORGANIC CHEMISTRY. 


yellow colored bodies, soluble in water, alcohol, ether, and chloro- 
form. They are strong acids, and form salts with alkalies that are 
not very stable, yielding at the same time a dark red color. They 
are broken up into hydroxylamine and the corresponding fat acids, 
by tin and hydrochloric acid. When heated with dilute sulphuric 
acid they split up into oxides of nitrogen and fatty acids. 

, NO, 


Methyl Nitrolic Acid, CH , forms colorless prisms, fusing at 54°. 


It decomposes into formic acid and nitrogen oxides. 
NO 
Ethyl Nitrolic Acid, CH p00 i . Bright yellow prisms, of sweet taste, 
“SN.OH 


melting at 81-82°, and decomposing when covered with concentrated H,SO,, 
into acetic acid and nitrogen oxides. 


NO 
Propyl Nitrolic Acid, CHyCHyCC Bright yellow prisms, melting 


‘at 60°, with decomposition. 

By the action of sodium amalgam upon the alkyl-nitrolic acids, and also upon 
dinitro-paraffins, the Leucaurolic acids, like (C,H,N,O),, are produced. These 
probably correspond to the azo-compounds of the benzene group (Azna/len, 


214, 328). 
The pseudo-nitrols, isomeric with the nitrolic acids, and formed 
by the action of nitrous acid upon the secondary nitro-paraffins (see 


p. 109) :— 
(CH;.),CH(NO,) -+ NO.OH = (CH,),C¢ Cod 4+. H,0, 


Isonitro-propane 
are to be viewed as nitro-nitroso compounds. They are more easily 
produced by the action of N,O, upon ketonoximes (see these) (Ber., 


21, 507) :— : 
NO; 
4(CH,),C : NOH + 3N,0,=4(CH,),C¢ + 2H,O + 2NO. 
NO 


They are, in all probability, the nitric acid esters of the acetoximes, 
(CH;).C = N.O.NO, (Ber., 21, 1294). The pseudo-nitrols are 
crystalline bodies, colorless in the solid condition, but exhibiting 
a deep blue color when fused or dissolved (in alcohol, ether, chloro- 
form). They show a neutral reaction, and are insoluble in water, 
alkalies and acids. Dissolved in glacial acetic acid, they are 
oxidized by chromic acid to dinitro-compounds. 


Propyl Pseudonitrol, (CH s)aCC es , nitro-nitroso-propane, is a white 
\NO 


powder, crystallizing from alcohol in colorless, brilliant prisms. It melts at 76°, 
to a dark blue liquid, and decomposes into oxides of nitrogen and dinitropro- 
pane. Chromic acid changes it to 6-dinitropropane and acetone. 


NITRO-PARAFFINS. Itt 
CHa, NO: 


CH,” NO 
ing at 58°. In its fused state, or when dissolved, it exhibits a deep blue color. 


Butyl Pseudonitrol, , is a colorless, crystalline mass, melt- 





The dinitro-derivatives of the paraffins are obtained by the oxida- 
tion of the pseudo-nitrols, and by the action of KNO,, upon the 
monobrom-derivatives of the nitro-paraffins :— 


O 
CH,.CHBr(NO,) + NO,K = CH, .CH * 4. KBr. 
, NO 


They also result from the acetones by action of concentrated HNO,. Thus 
from diethyl ketone, (C,H,),CO, we get dinitroethane, from a-dipropyl ketone, 
(C,H,),CO, a-dinitropropane, etc. Methyl-propyl ketone yields a-dinitro-propane 
(Ber., 15, Ref. 56). 

They are also produced in an analogous manner from the alkylized aceto-acetic 
esters (see these) on warming the latter with HNO, (Berichte, 15, 1495) :— 


CH,.CO.C(R)H.CO,.C,H, yields CH,.CO,H + C(R)H(NO,), + CO,. 


The secondary alcohols (isopropyl alcohol excepted) yield dinitro-paraffins 
with nitric acid, sustaining at the same time a decomposition analogous to that of 
the corresponding ketones (er., 18, Ref. 217). 

Dinitroethane, CH,.CH(NO,),, from brom-nitroethane, is a colorless oil, of 
specific gravity 1.35 at 23°. It boils at 185-186°. Tin and hydrochloric acid 
change it to hydroxylamine, aldehyde and acetic acid. It reacts acid and dis- 
solves in potassium hydroxide, forming CH,.CK(NO,),, which crystallizes in 
yellow prisms. An oil, CH,.CBr(NO,),, that cannot be distilled, is produced by 
the action of bromine. 

a—-Dinitropropane, CH,.CH,.CH(NO,),, from brom-nitropropane, is a 
colorless oil of specific gravity 1.258 at 22°; it boils at 189°, reacts acid and 
dissolves in the alkalies, forming salts. 

$-Dinitropropane, (CH,),C(NO,)., is also produced by acting upon isobu- 
tyric and isovaleric acids (Berzchte, 15, 2325) with HNO,. It forms white camphor- 
like crystals, fusing at 53° and boiling at 185.5°. It is neutral and insoluble in 
alkalies. Tin and hydrochloric acid change it to acetone and hydroxylamine. 

8-Dinitrobutane, eos the 3» from butyl pseudo-nitrol, boils at 
199° and does not dissolve in alkalies. Hydroxylamine and methyl ethyl ketone 
are the products it furnishes when acted upon by tin and hydrochloric acid. 

Dinitrohexane, C,H,,(NO,),, from methyl hexyl carbinol, boils at 212°C. 





Nitrosates and Nitrosites. These compounds are produced by the action of 
nitrogen tetroxide and nitrogen trioxide upon the alkylenes : *— 


Cc Wiest CH font 
5**10 24 5 *\NO 

- got _/9.NO 
H,, + N,O, =C,H 
iy pies +. *\N.OH 





* Wallach, Aum., 241, 288; 245, 241; 248, 161. Ber., 20, Ref. 638; 21, 
Ref. 622. 


II2 ORGANIC CHEMISTRY. 


They contain an iso-nitroso-group, which is also present in the alkyl-nitrolic 
acids (p. 109), and the ketonoximes (see these). In addition to this the nitrate 
group (O.NO,), and nitrite group (O.NO) are present. In consequence they 
manifest at the same time the properties of nitric and nitrous acid esters. The 
nitrosates can be formed by the action of nitric acid and amyl nitrite on the 
alkylenes (Ber., 21, Ref. 622). If hydrochloric acid be substituted for nitric acid 
in this reaction the Witroso-chlorides will result. These contain chlorine instead 


of the nitrate group, ¢.g., amylene-nitroso-chloride, C Hae 
NN.OH. 
The nitroso-nitrates, or nitrosates, are very reactive, and like the nitric acid 
esters react so that the nitrate group is replaced. With the amines, such as ethyl- 
amine and aniline, they yield the Vitrolamines :-— 


ONO, NHC GH, 
CER on + NH,.C,H, = CoH on + NO,.OH. 
Amylene-nitrol- 


aniline. 


When these are boiled with water the isonitroso-group splits off (similar to the 
ketonoximes, see same), and is replaced by oxygen, thus giving rise to the Keéo- 
amines -— 

NH.C,H,; 
O.H,< 4 H,O = C,H,O.NH.C,H, + H,N.OH. 
X N.OH Amylene-keto- 
anilide. 


Cyanides (nitriles) result on treating the nitrosates with potassium cyanide :— 


ONO; Jn. 

C,H CNK = C,H from these th ding acid 
. °"\NLOH xi 5 °"\ NOH; rom these the corresponding acids 
can be obtained. 


b—Lsoamylene-nitrosate, C,H,(N.OH).O.NO,, formed from ordinary amylene 
(p. 84) (see above and Ber., 22, Ref. 16), crystallizes in cubes or needles, 
melting at 97°. Its JVitro-anilide, C,H,(N.OH).NH.C,H,, melts at 141°. 
Potassium cyanide converts the nitrosate into /sonztrosocyanide, C,H,.(N.OH). 
CN, melting at 100°. By saponification of the latter the acid, C;H,(N.OH). 
CO,H, is formed. This melts at 97° and suffers further decomposition into CO, 
and C,H,,(N.OH). The latter compound is identical with methyl-isopropyl 
ketoxime, (CH,),.CH.C(N.OH).CH,. The structure of these derivatives, there- 
fore, corresponds to the following formulas :— 


(CH,),.C.0.NO,  (CH,),.C.CN. (CH,),C.CO,H 


(CH,).C(N.OH) CH,.C(N.OH) CH,.C(N.OH). 
Iso-amylene Iso-amylene- Ketoxime- 
Nitrosate. iso-nitroso-cyanide. dimethyl-acetic Acid. 


We may note the following among the nitro-compounds, result- 
ing from the action of nitric acid :— 

Nitroform, CH(NO,),, Trinitromethane, is produced in slight 
quantity when nitric acid acts upon various carbon compounds. It 
is most conveniently prepared from trinitro-acetonitrile, C,(NO,),N. 


2 


-NITRO-PARAFFINS. Il3 


(See this.) When the latter is boiled with water, carbon dioxide is 
_ generated, and the ammonium salt of nitroform produced :— 
C(NO,),.CN + 2H,O0 = C(NO,),.NH, + €0,. 
Trinitro-acetonitrile Ammonium Nitroform, 

The last is a yellow crystalline compound, from which con- 
centrated sulphuric acid separates free nitroform. This is a 
colorless, thick oil, solidifying below + 15° to a solid, consisting 
of cubes. It dissolves rather easily in water, imparting to the 
latter a yellow color. It explodes when heated rapidly. 

Nitroform behaves like a strong acid; the presence of three 
nitro-groups imparts to hydrogen, in union with carbon, an acid 
character. Therefore it unites with NH, and the alkalies to form 
salts like C(NO,);K, from which acids again liberate nitroform 
(p. 107). The hydrogen of nitroform can also be replaced by 
bromine or NO,. 


Brom-nitroform, C(NO,),Br, Brom-trinitromethane, is produced by per- 
mitting bromine to act for several days upon nitroform exposed to sunlight. ‘The 
reaction takes place more rapidly by adding bromine to the aqueous solution of 
the mercury salt of nitroform. In the cold it solidifies to a white crystalline mass, 
fusing at 4+- 12°. It volatilizes in steam without decomposition. 


Tetranitromethane, C(NO,),, results on heating nitroform 
with a mixture of fuming nitric acid and sulphuric acid. It is a 
colorless oil that solidifies to a crystalline mass, fusing at 13°. It 
is insoluble in water, but dissolves readily in alcohol and ether. It 
is very stable, and does not explode on application of heat, but 
distils at 126° without sustaining any decomposition. . 

Nitrochloroform, C(NO,)Cl,—Chloropicrin,  trichlor-nitro- 
methane, is frequently produced in the action of nitric acid upon 
chlorinated carbon compounds (chloral), and also when chlorine 
or bleaching powder acts upon nitro-derivatives (fulminating 
mercury, picric acid and nitromethane). 


In the preparation of chloropicrin, 10 parts of freshly prepared bleaching powder 
are mixed to a thick paste with cold water and placed in a retort. To this is 
added a saturated solution of picric acid, heated to 30°. Usually the reaction 
occurs without any additional heat, and the chloropicrin distils over with the 
aqueous vapor {(Auza/en, 139, IIL). 


Chloropicrin is a colorless liquid, boiling at 112°, and having a 
specific gravity of 1.692 at o°. It possesses a very penetrating 
odor that attacks the eyes powerfully. It explodes when rapidly 
heated. When treated with acetic acid and iron filings it is con- 
verted into methylamine :— 


CCl,(NO,) + 6H, = CH,.NH, + 3HCl + 2H,0. 


Bromopicrin, CBr,(NO,)—Tribrom-nitromethane, is formed, like the pre- 
ceding chloro-compound by heating picric acid with calcium hypobromite (calcium 
- 10 


114 ORGANIC CHEMISTRY. 


hydroxide and bromine), or by heating nitromethane with bromine (p. 108). It 
closely resembles chloropicrin and becomes crystalline below + 10°, It can be 
distilled in a vacuum without decomposition. 





ALCOHOLS, ACIDS AND THEIR DERIVATIVES. - 


All organic compounds are derived from the hydrocarbons, 
the simplest derivatives of carbon, by the replacement of the 
hydrogen atoms by. other atoms or atomic groups. ‘The different 
groups of chemical bodies are characterized in their specific 
properties by. the presence of such substituting side-groups. Thus 
the alcohols contain OH, the aldehydes CHO, the acids COOH, 
etc., etc, 

In the following pages we will consider the carbon compounds 
according to the number of side groups yet capable of replace- 
ment—as monovalent, divalent, trivalent, etc., compounds. To 
each of these groups other derivatives are attached bearing intimate 
genetic connection with them. 

By the replacement of one atom of Coe of the hydrocarbons 
by the hydroxyl group OH we get the monovalent (monohy- 
dric) alcohols, ¢. g. C,H;.OH, in which the H of OH is capable 
of further exchange. The thio-alcohols or mercaptans, e. g. ethyl 
mercaptan, C,H,;.SH, are analogous to these. Ethers result from 
the union of two monovalent alcohol radicals through the agency 
of an oxygen atom; corresponding to those are the thio-ethers or 
sulphur alkyls :— 


oa OS CH,\e 
Caliy C,H,/ 
Ethyl Ether. Ethy! Sulphide. 


The Amines, C,H;.NH,., Phosphines and the so-called 
metallo-organic compounds are also derivatives of the alcohol 
radicals. 

When two hydrogen atoms of a methyl group, CH;, of the 
hydrocarbons are replaced by one oxygen atom the aldehydes 
result. These are easily obtained from the alcohols by oxidation :— 

CH,.CH,.0H + O = CH,.CHO + H,0. 

Ethyl Alcohol, Acetaldehyde. 
The group CHO (aldehyde group) is characteristic of aldehydes. 
The ketones are compounds in which two hydrogen atoms of an 
intermediate carbon atom (see p. 40) are replaced by one atom of 
oxygen :— 


CH,.CO.CH, = CH? »CO Ditadthy!-ketone. 


They are characterized by the group CO, united to two alkyls. 


ALCOHOLS, ACIDS AND THEIR DERIVATIVES. 115 


When the two hydrogen atoms attached to the carbon carrying 
OH are replaced by oxygen, we obtain the monobasic acids :— 


CH, CH, 
| yields | 
CH,.OH CO.OH 
Ethyl Alcohol. Acetic Acid, 


The carboxyl group—CO.OH—is characteristic of organic acids, 
The hydrogen atom present in it may be readily replaced by met- 
als, giving rise to salts. Or, the acids may be viewed as com- 
pounds of OH with residual atomic groups (e. g. CH;.CO —C,H,O, 
acetyl) designated acid radicals. The latter, like the alcoholic 
radicals, are capable of entering into further combinations :— 


C,H,0.Cl cto NO C,H,ONH 
Acetyl Chloride. 2.85 a Acety! Amide: 


The following formulas exhibit the connection between alcohols, 
aldehydes (or ketones) and acids :— 


C,H,O C,H,O C,H,0; 
Alcohol. Aldehyde. Acid. 


The unsaturated hydrocarbons also yield unsaturated alcohols, 
aldehydes, acids, etc. 


The dihydric alcohols, known as glycols, are formed when two 
hydrogen atoms of the hydrocarbons are replaced by hydroxyl :— 


CH,.OH 
b Ethylene Glycol. 
2-OH 


In these, four hydrogen atoms can be replaced by oxygen, giving 
rise to the dihydric monobasic and the dihydric abasic acids :— 


CH,OH CO.OH 
0.0H ee 
Dihydric Monobasic Acid. Dibasic Acid. 


The number of CO.OH groups in the acids determines their 
basicity. The number of hydroxyl groups present is indicated by 
the terms mono-valent, di-valent, etc. In the same’ manner, tri- 
valent (trihydric), mono-, di- and tri-basic acids, etc., are derived 
from the trivalent alcohols. 

The relations of the alcohols and acids to each other, with reference 
to their valence and basicity, is manifest from the following table :— 


116 ORGANIC CHEMISTRY. 
































ACIDS. 
ALCOHOLS. 
1-basic. 2-basic. 3-basic 
e CH,.0H CHO.OH 
‘g Methyl Alcohol. Formic Acid. 
° 
& | C,H,.0H CH,.COOH 
= Ethyl Alcohol. Acetic Acid. 
CH,.OH CH, OF CO.OH 
2 | | 
2 H,.0H CO.OH CO.OH 
S Ethylene Glycol. Glycollic Acid. Oxalic Acid. 
A OH CO.OH 
C,H,(OH), | ©2%«<co.on | CH2<co.oH 
Propylene Glycol. Lactic Acid. Malonic Acid. 
_| CH,.0H CH,.0OH © CO.OH 
2 I CO,H 
3 H.OH CH.OH H.OH C,H, | CO,H 
| | | CO;H 
H CH,.OH CO.OH CO.OH. Tricarballylic Acid. 
Glycerine. Glyceric Acid. Oxymalonic Acid. 
#2) C,H,.(OH), | C,H,O.(OH), | C,H,0,(OH), | C,H,0,.(OH), 
* s Erythrite. Erythric Acid. Tartaric Acid. * Citric Acid. 
eS C,H,.(OH), | C,H,O.(OH), | C,H,O,.(OH), 
vt Mannite. Mannitic Acid. Mucic Acid. 

















MONOVALENT COMPOUNDS. 
MONOVALENT ALCOHOLS. 
MONOHYDRIC ALCOHOLS. 


The monovalent alcohols contain one hydroxyl group, OH;. 
bivalent oxygen links the monovalent alcohol radical to hydrogen : 
CH;.0.H, methyl alcohol. This hydrogen atom is characterized 
by its ability, in the action of acids upon alcohol, to exchange 
itself for acid residues, forming compound ethers or esfers, corres- 
ponding to the salts of mineral acids :— 

C,H,.0H + NO,.0H = C,H,.0.NO, + H,0. 


Ethyl Alcohol. Ethyl Nitrate or 
Nitric Ethyl Ester. 


Alkyls and metals can also replace the hydrogen in alcohol :— 


C,H,.0.CH ‘C,H,.ONa. 
Ethyl-methyl Ether. Sodium Ethylate. 


MONOVALENT COMPOUNDS. 117 


Structure of the Monovalent Alcohols.—The possible 
isomeric alcohols may be readily derived from the hydrocarbons ; 
they correspond to the mono-halogen isomerides (p. 43). There is 
one possible structure for the first two members of the normal 


alcohols :— 


CH,.0H C,H,.OH. 
Methyl! Alcohol. Ethyl Alcohol. 


Two isomerides can be obtained from propane, C,H, = CH. 
Sel Ea Ga Pips 


CH,.CH,.CH,.OH and CH,.CH(OH).CH,, 
Sropyl ‘Alcohol. hopropyt Alcohol. 


Two isomerides correspond to the formula C,Hy» (p. 74) :— 
CH,.CH,.CH,.CH, and CH(CH,),. 


"Miscoal Sains: Isobutane. 


Two isomeric alcohols may be obtained from each of these :— 








| CH, f- CH, 
H, CH, /CH, /CH, 
og and + | CH—CH,.OH and C(OH)—CH, 
CH CH.OH CH CH 
Phe l Psp Tease Tert. Tsobutyl 
CH OH CH, conol, conol. 
ae Butyl Secondary “Butyl 
Alcohol. Alcohol. 


The following is a very good method of formulating the alcohols. 
They are considered as derivatives of methyl alcohol or cardinol, 
CH;.OH. By the replacement of one hydrogen atom in carbinol 
by alkyls (p. 46) the primary alcohols result :— 


rs CH, ct ipl 
Ch megs gi ahha ts 
on ae Ou CH,.0H 
Methyl Carbinol, or Ethyl Carbinol, or 
Ethyl Alcohol. Propyl Alcohol. 


If the replacing group possesses normal structure, the primary 
alcohols are said to be normal. In alcohols of this class the carbon 
atom carrying the hydroxyl group has two additional hydrogen 
atoms. Hence compounds of this variety may very easily pass into 
aldehydes (with group COH) and acids eae COOH group) on | 
oxidation. (see p. 114) :— 


CH, CH, CH, 


Ane ee m4 boon 


Primary ae Aldehyde. Acid. 


118 ORGANIC CHEMISTRY. ~ 


The secondary alcohols result when two hydrogen atoms in 
carbinol, CH;.OH, are replaced by alkyls :— 


fete) CHs (cH, C,H, 
2 ci CMs _ cH.oH ci Gis — CHoH 
=. | | | 
ac ioe” CH, een, 
Dimethyl! Carbinol, or Ethyl-methyl Carbinol, or 
Isopropyl Alcohol. Isobutyl Alcohol. 


In alcohols of this class the carbon atom carrying the OH group 
has but one additional hydrogen atom. They do not furnish 
corresponding aldehydes and acids. When oxidized they pass into 
ketones (p. 114) :— 


cue C CH. 
Ci? yelds Ci CH, = fo 
OH CH, 
Dimethyl! Carbinol. Acetone. 


When, finally, all three hydrogen atoms in carbinol are replaced 
by alkyls, we get the zer#iary alcohols :— 


CH 
eat Te 
C+ Gy® = CH;—C.OH  Trimethyl Carbinol. 
s CH, / 
OH 8 


These are not capable of forming corresponding aldehydes, acids 
or ketones. Under the influence of strong oxidizing agents they 
suffer a decomposition ; and acids having a less number of car- 
bon atoms result. 

Primary alcohols, therefore, contain the group CH,.OH joined to 
one alcohol radical (in methyl alcohol it is linked to H); the 
group CH.OH linked to two alkyls is peculiar to secondary alco- 
hols; while in tertiary alcohols the C in combination with OH has 
three alkyls attached to it :— 


px R\ 
R.CH,.OH Ryo On R—C.OH 
Primary Alcohols. Secondary Alcohols. R/ 
Tertiary Alcohols. 


The secondary and tertiary alcohols, in distinction from the pri- 
mary or true alcohols, are designated pseudo-alcohols. They 
are capable of forming esters (p. 116). | 

Formation of Alcohols.—The most important methods of pre- 
paring the monohydric alcohols are the following :— 
_ (2) The replacement of the halogen of monosubstituted hydro- 

carbons by hydroxyl. This is most easily effected by the action of 


MONOVALENT COMPOUNDS. 11g 


freshly precipitated, moist silver oxide. It acts in this instance 
like a hydroxide :— 


C,H,I + AgOH = C,H,.0H + Agl. 


In many cases the change is best brought about by heating the halogen deriva- 
tives with lead oxide and‘water; the formation of alkylens is avoided in this way. 
The iodides are more reactive than the chlorides or bromides. Even heating with 
water alone at high temperatures causes a partial transposition of halogen into 
hydroxyl derivatives. The halogen derivatives of the secondary and tertiary 
radicals are very reactive. If heated for some time with 10-15 volumes of water 
to 100° they are completely converted into alcohols (Azzalen, 186, 390). 

Water at ordinary temperatures converts the tertiary alkyl iodides into alcohols. 
Heated to 100° with methyl alcohol they pass into alcohols and methyl iodide 
(Annalen, 220, 158). 


It is often more practical to first convert the halogen derivatives 
into acetic acid esters, by heating with silver or potassium acetate :— 


C,H,Br + C,H,0.0K = C,H,.0.C,H,O + KBr, 
Potassium Acetate. Ethyl Acetic Ester. 


and then boil these with potassium or sodium hydroxide (saponi- 
fication), and obtain the alcohols :— 


C,H,.0.C,H,O + KOH = C,H,.0H + C,H,0.0K. 
(2) By decomposing the acid esters of sulphuric acid with boil- 
ing water :— 
PGs 
SO,’ + H,O — C,H,.OH + SO,H,. 
\OH 
Ethyl Sulphuric Acid. - 


‘These esters may be easily obtained by directly combining the 
unsaturated hydrocarbons with sulphuric acid (see p. 81) :— 
0.C,H 
CH wo: se." 

NOH. 

A like conversion of unsaturated hydrocarbons is attained by 
means of hypochlorous acid ; the chlorine derivatives first produced 
are further changed by nascent hydrogen :— 


CH, CH,Cl 
i + ClOH= | , and 
CH, « (CHlOH 


C,H,CI.OH + H, = C,H,.OH + HCl. 


Many alkylens (like iso- and pseudo-butylene) dissolve at once in dilute nitric 
acid, absorb water, and yield alcohols (Azma/en, 180, 245). 


(3) By acting on the aldehydes and ketones with nascent 


120 ORGANIC CHEMISTRY. 


hydrogen. The former yields primary, and the latter secondary 
alcohols (compare p. 118) :— 


CH,.CH, CHO + Hy = CH, CH, CH,.OH, 


Propy! Aldehyde. Propy! Alcohol. 
CHS. ee 
CH» CO + H, = Gy’ >CH.OH 
Acetone. Isopropy! Alcohol. 


Sodium amalgam in presence of dilute sulpburic or acetic acid will effect this 
reduction. It is, however, best to use iron filings and 50 per cent. acetic acid 
(Lieben), or zinc dust and glacial acetic acid; the acetic esters are the first pro- 
ducts (Berichte, 16, 1715). : 


(4) A very remarkable synthetic method, which led to the dis- 
covery of the tertiary alcohols, consists in the action of the zinc 
compounds of the alkyls upon the chlorides of the acid radicals. 
The product is then further changed by the action of water (But- 
lerow). Thus, from acetyl chloride and zinc methyl, we obtain 
trimethyl carbinol (CH;);.C.OH :— 


CH,.COCI yields CH,.C(CH,), OH. 
Acetyl! Chloride. Trimethy] Carbinol. 


The acid chloride (1 molecule) is added, drop by drop, to zinc methyl (2 mole- 
cules), cooled with ice, and allowed to remain undisturbed for some hours in the 
cold, until the mass has become crystalline. After subsequent exposure for two or 
three days, at ordinary temperatures, the product is decomposed with ice water. 
Ketones are formed if water be added any sooner (Anmalen, 188, 121 u. 113). 

The reaction divides itself into three phases. At first only one molecule of zinc 
alkyl reacts :— 


ye CH, 
(1) CH,CZ + Zn(CH,), = CH,C {O,zncH, 
Nel | Cl 
Acetyl Chloride. 


The resulting compound gives a crystalline product with the second molecule 
of the zinc alkyl, and this immediately decomposed with water yields acetone. By 
longer standing, however, further reaction takes place :— 


CH 


3 CH. Cl 
(2). CH,.C ree + Zn (CH,), = CH,;.C ee + Zn 
; 3 


CH,. 


__ If now water be permitted to take part, a tertiary alcohol will be formed from 
the first body. The equation is:— 


CH, CH, 
CH,.C 3 0.Zn.CH, + H,O = cH,c{ OH + ZnO + CH, 
CH, CH, 


If in the second stage the zinc compound of another radical be employed, the 
latter may be introduced, and in this manner we obtain tertiary alcohols with two 
or three different alkyls (Anna/en, 175, 261, and 188, 110, 122). 


MONOVALENT COMPOUNDS. 12t_ 


It is remarkable that only zinc methyl and ethyl furnish tertiary alcohols, while 
zinc propyl affords only those of the secondary type. (Berichte, 16, 2284.) 

(5) Just as we obtained tertiary alcohols from the acid radicals, so can we de- 
rive secondary alcohols from the esters of formic acid. Zine alkyls are allowed to 
react in this case (or alkyl iodides and zinc), and two alkyls are introduced, At 
first crystalline intermediate products are produced ; these yield the alcohols when 
treated with water :— 


O /CH, J CH, 

HGS yields HC—O.Zn.CH, and HC—OH 

NO.C,H,; \ CH, \ CH, 
Ethyl Formic Ester. Dimethyl Carbinol. 


Using some other zinc alkyl in the second stage of the reaction, or by working with 
a mixture of two alkyl iodides and zinc, two different alkyls may also be intro- 
duced here (Annalen, 175, 362, 374). 

Zinc and allyl iodide (not ethyl-iodide, however) react similarly upon acetic acid 
esters. Two alkyl groups are introduced and unsaturated tertiary alcohols formed 
(Annalen, 185, 175) :— 


go : A C,H, wr C,H, 
CH,.C yields CH,.C—O.ZnI and CH,.C—OH 
: . \C;H; \C,H, : 
Ethyl Acetic Ester. Methy]-diallyl Carbinol. 


When zinc alkyls act upon aldehydes, only one alkyl group enters, and the reaction 
product of the first stage yields a secondary alcohol when treated with water. 
(Compare Anna/len, 213, 369, and Berichte, 14, 2557) :— 


. C,H C.H 
CH,.CHO yields CHs.CHC 677°C, H, aad CH,.CH.¢ Cas 


Aldehyde. Methyl-ethy] Carbinol. 


All aldehydes (even those with unsaturated alkyls, and also furfuran) react in this 
way—but only with zinc methyl and zinc ethyl, while with the higher zinc alkyls 
the aldehydes suffer reduction to their corresponding alcohols (Aerich/e, 17, Ref. 
318). With zinc methyl chloral yields trichlorisopropyl alcoho!, CC],.CH(OH). 
CH, ; whereas with zinc ethy] it is only reduced to trichlorethyl alcohol (Anmalen, 
223, 162). 

The Xeéones do not react with the zinc alkyls. Even in the action of zinc and 
ethyl iodide upon such ketones as contain a-methyl group, the only result is the 
splitting-off of water. On the other hand, diethyl-acetone, (C,H,;),CO, and 
dipropyl ketone, (C,H,),CO, are converted by zinc and methyl bedi} iodide into 
zinc alkyl compounds; these, under the influence of water, pass into alcohols 
(Berichte, 19, 60; 24, Ref. 35) :— 


. (C,H,),CO and zinc ethyl give (C,H,),C.OH. 
Propione. Triethyl 
Carbinol. 


(C,H,),CO and zinc methyl give (C,H,),.C(CH,).OH. 
Butyrone. * tr st ec epe le 
arbinol. 


We get unsaturated tertiary alcohols from all the ketones by the action of zinc 
and allyl iodide (Anna/en, 196, 113) :— 


(CH,),CO yields (CH,)».(C,H,).C.OH. 
Dimethyl Dimethyl-allyl 
Ketone. Carbinol. 


122 ORGANIC CHEMISTRY. 


* 


(6) By the action of nascent hydrogen upon the chlorides of acid radicals or 
acid anhydrides :— 


CH,.COCl + 2H, — CH,.CH,.OH + HC, 
Acetyl 
Chloride. 


C,H,O 
CH'o 0 + 2H. = C.H, OH + C,H,0.0H. 


Acetic Acid 
Anhydride. 


Very ectoably aldehydes are produced at the beginning and are subsequently 
reduced to alcohols (see p. 121). Primary alcohols alone result by this reaction. 
Sodium amalgam, or better sodium, serves as the reducing agent. (Berichée, 9, 
1312.) 

(7) Action of nitrous aca upon the primary amines :— 

C,H,.NH, + NO.OH = C,H,;.0H + N, + H,0O. 


Very often transpositions occur with the higher alkyl-amines and instead of the 
primary we obtain secondary alcohols. (Compare Berichte, 16, 744.) 


In addition to the above universal methods, alcohols are formed 
by various other reactions. Their formation in the alcoholic 
fermentation of sugars in the presence of ferments is of great 
practical importance. Appreciable quantities of methyl alcohol are 
produced in the dry distillation of wood. Many alcohols, too, 
exist, as already formed natural products in compounds, eninly as 
compound ethers of organic acids. 





Conversion of Primary into Secondary and Tertiary Alcohols. By the elimina- 
tion of water the primary alcohols become unsaturated hydrocarbons C, Hop (p. 
79). The latter, treated with concentrated HI, yield iodides of secondary alco- 
holic radicals, as iodine does not attach itself to the terminal but to the less hydro- 
genized carbon atom (p. 93). Secondary alcohols appear when these iodides are 
acted upon with silver oxide. The successive conversion is illustrated in the follow- 
ing formulas :— 


CH, CH, CH, CH, 
| | 

CH, dur CHI CH.OH 
| I | | 

CH,.OH CH, CH, CH, 
Propyl Propylene. Isopropyl Isopropyl . 
Alcohol. Iodide. Alcohol. 


Primary alcohols in which the group CH,.OH is joined to a secondary radical, 
pass in the same manner into tertiary alcohols :— 


CH CH 
* \CH.CH,.OH SC ach. SN cL_cH, 
CH,” ous CH /. 
Isobutyl Alcohol. - _ Isobutylene. Periary Butyl Iodide. 


CH,. 
SC(OH).CH, 
WZ 


3 
Tertiary Butyl Aicohol. 


MONOVALENT COMPOUNDS. 123 


The change is better effected by the aid of sulphuric acid, 
The sulphuric esters (p. 80), arising from the alkylens, have the sulphuric acid 
residue linked to the carbon atom, with the least number of attached hydrogen 


atoms :-— 
CH, CH, 


| | 
CH + HO.SO,.0H = CH.O.SO,H. 
| | 
CH, CH, 
These pass into alcohols when boiled with water. 


Properties and Transpositions. ‘The alcohols are neutral, being — 
neither acid nor basic compounds. ‘They resemble the bases, in 
that by their action with acids they yield esters (compound ethers), 
which correspond to salts. In this change, the hydrogen atom of 
the OH group is replaced by an acid radical (p. 116). Naand K 
can also replace this hydrogen atom, and then we obtain the metal- 
lic alcoholates. 

In physical properties alcohols exhibit a gradation corresponding 
to their increase in molecular weight. This is true of other bodies 
belonging to homologous series. ‘The lower alcohols are mobile 
liquids, dissolving readily in water, and possessing the characteristic 
alcohol odor; the intermediate members are more oily, and dissolve 
with difficulty in water, while the higher are crystalline solids, with- 
out odor or taste. They resemble the fats. Their boiling points 
increase gradually (with similar structure) in proportion to the 
increase of their molecular weights. This is about 19° for the 
difference, CH,. The primary alcohols boil higher (about 5°) than 
the isomeric secondary, and the latter higher than the tertiary. 
Here we observe again that the boiling points are lowered with the 
accumulation of methyl groups (see p. 73). The higher members 
are not volatile without decomposition. By distillation they par- 
tially break up into water and hydrocarbons C,H,, (p. 80). 

Oxidizing agents (K,CrO, and H,SO,) convert the primary 
alcohols first into aldehydes and then into acids; those of second- 
ary form yield ketones, and the tertiary suffer a partial decom- 
position (p. 118). The three varieties of alcohols may be readily 
distinguished by converting them into their iodides and then into the 
nitro-derivatives, which afford characteristic color reactions (p.109). 


Primary and secondary alcohols, heated with acetic acid, yield esters of the 
latter; the tertiary, on the contrary, lose water and pass into alkylens (Anna/en, 
220, 165). 

The primary alcohols change to their acids when heated with soda-lime :— 


R.CH,.OH + NaOH = R.CO,H + 2H,. 


This reaction may be employed for the detection and estimation of this class of 
alcohols (Annalen, 223, 259). 


124 ORGANIC CHEMISTRY. 


When the alcohols are héated with the hydrogen haloids, or 
what is better, with the halogen derivatives of phosphorus, they 
are transformed into their corresponding halogen compounds 
(see p. 92) :— 

C,H,.0H + HCl = C,H,Cl + H,0, 
C,H,.0H + PCI, = C,H,Cl + POCI, + HCL. 


These derivatives are therefore designated also halogen esters of 
the alcohols. 

Hydrogen (nascent) acting on these, causes a change back into 
the corresponding hydrocarbons. 

Other changes of alcohols will be noted later. 





(1) THE ALCOHOLS, Cn Hon+41.0H. 


Methyl Alcohol, CH,O =CH,.OH. 

Ethyl ki ClO. ;. 2 fOr, 
Propyl Alcohols, C,H,O = C,H,.OH. 
Butyl 6 gti: gO eh, Oe 
Amy] vy Ct {0 220 8, OM: 
Eiexyl.:: * (CoH, {O = 0,8 .08: 
Heptyl “ C,H, ,O: =— C,Hj,.0H, ete. 
Cetyl Alenhol, ..C,,H,,0 — Cy,H,,-OH. 
Ceryl “ Co eles) Ce, re 
Melissyl tarps. el & Peg ae By 8 oe 3 


1. Methyl Alcohol, CH;.OH, wood spirit, occurs among the 
dry distillation products of wood. We find the methyl group in 
various natural products, and from them it may be eliminated in 
the form of the above alcohol. Thus methyl alcohol is obtained by 
boiling wintergreen oil, the methy] ester of salicylic acid, with potas- 
sium hydroxide. 

Methyl alcohol is a mobile liquid, with spirituous odor, boiling 
at 66° (the apparent boiling point can vary very much, according 
to the nature of the vessel), and having a sp. gr. of 0.796 at 20°. 
It mixes with water, alcohol, and ether. Its aqueous mixtures 
have a sp. gr. almost like that of mixtures of ethyl alcohol and 
equal amounts of water. 


The aqueous product obtained in the distillation of wood contains methyl alco- 
hol, acetone, acetic acid, methyl acetic ester, and other compounds. It is dis- 
tilled over burnt lime. The crude wood spirit that results contains acetone as its 
chief impurity. To remove this add anhydrous calcium chloride. The latter 
combines with the alcohol to a crystalline compound. This is removed, freed 
from acetone by distillation, and afterward decomposed by distilling with water. 
Pure aqueous methyl alcohol passes over; this is dehydrated with lime. To pro- 


THE ALCOHOLS. 125 


cure it perfectly pure, it is only necessary to break up oxalic methyl ester, or methyl 
acetic ester, with KOH. 

To detect ethyl in methyl alcohol, heat the latter with concentrated H,SO,, 
when acetylene wilt be formed from the first. Under this treatment, methyl 
alcohol becomes methyl ether. The amount of methyl alcohol in wood spirit is 
determined, quantitatively, by converting it into methyl iodide, CH,I, through 
the agency of PI, (Berichte, 9, 1928), We estimate the quantity of acetone by 
the iodoform reaction (Berichze, 12, 1000). 


Wood spirit is employed as a source of heat, and as a solvent 
for gums and resins. It combines directly with CaCl,, to form 
CaCl,.4CH,O, crystallizing in brilliant six-sided plates. The 
alcohol in this salt conducts itself like water of crystallization. 
Potassium and sodium dissolve in -anhydrous alcohol, to form 
methylates, ¢. g., CH;.ONa (see sodium ethylate, p.126). Barium 
oxide dissolves in it to yield a crystalline compound (BaO. 2CH,Q). 
When methyl alcohol is heated with soda-lime, sodium formate 


results :— ) 
CH,.0H + NaOH = CHO.ONa + 2H,. 


Oxidizing agents and also air, in presence of platinum black, change 
methyl alcohol to formic aldehyde and formic acid. 

2. Ethyl Alcohol, C,H;.OH, may be obtained from ethyl 
chloride, C,H;Cl, and from ethylene, C,H,, by the general methods 
previously described (p. 119). Its formation in the spirituous fer- 
mentation of different varieties of sugar ¢.g., grape sugar, invert 
sugar, maltose—is practically very important. It is induced by 
yeast cells, occurs only in dilute aqueous solution at temperatures 
ranging from 5—30°, and demands the presence of ‘mineral salts 
(especially phosphates) and nitrogenous substances (compare Fer- 
mentation). Alcoholic fermentation may set in under certain con- 
ditions, in ripe fruits, even in the absence of yeast. The various 
sugars, when fermenting, break up principally into ethyl alcohol. 
and carbon dioxide :— 

CHy,05 = 2C,HOg + 200, 

Other compounds, like propyl, butyl and amy] alcohols (the fusel 
alcohols), glycerol, and succinic acid, are produced in small quanti- 
ties at the same time. 


The crude spirit obtained from the fermented aqueous solution (of the fer- 
mented mash) by distillation is further purified on an extensive scale by fractional 
distillation in a column apparatus (p. 59). The first portion of the distillate con- 
tains the more volatile bodies, like aldehyde, acetal and other substances, Next 
comes a‘ purer spirit, containing 90-96 per cent. alcohol, and after this common 
spirit, containing the fusel oils. To remove, the latter entirely, the spirit, before 
distillation and after dilution with water, is filtered through ignited wood charcoal, 
which retains the fusel oils. 


126 . ORGANIC CHEMISTRY. 


To prepare anhydrous alcohol, the rectified spirit (90-95 per cent. alcohol).is 
distilled with substances having greater attraction for water than alcohol itself. 
For this purpose calcium chloride, ignited potashes, or, better, caustic lime 
(Annalen, 160, 249), or barium oxide may be employed. Absolute alcohol dis- 
solves barium oxide, assuming a yellow color at the same time. It is soluble 
without turbidity in a little benzene; when more than three per cent. water is 
present cloudiness ensues. On adding anhydrous or absolute alcohol to a mix- 
ture of very little anthraquinone and some sodium amalgam it becomes dark green 
in color, but in the presence of traces of water a red coloration appears (Berichte, 
10, 927). Traces of alcohol in solutions are detected and determined either by 
oxidation to aldehyde (see this) or by converting it by means of dilute potash and 
iodine into iodoform (Berichte, 13, 1002). 

Its conversion into ethyl benzoate, by shaking with benzoyl] chloride and sodium 
hydroxide (Berichte, 19, 3218), also answers for this purpose. 


Absolutely pure alcohol possesses an agreeable ethereal odor, 
boils at 78.3°, and has a specific gravity of 0.80625 at o°, or 
0.78945 at 20°. At —go® it isa thick liquid, at —130° it solidi- 
fies to a white mass. It absorbs water energetically from the air. 
When mixed with water a contraction occurs, accompanied by rise ’ 
of temperature; the maximum is reached when one molecule of 
alcohol is mixed with three molecules of water, corresponding to 
the formula, C,H,O + 3H,O. The amount of alcohol in aqueous 
solutions is given either in per cents. by weight (degrees according 
to Richter) or volume per cents. (degrees according to Tralles). 

Alcohol dissolves many mineral salts, the alkalies, hydrocarbons, 
resins, fatty acids, and almost all the carbon derivatives. The most 
of the gases are more readily soluble in it than in water; 100 
volumes of alcohol dissolve 7 volumes of hydrogen, 25 volumes of 
oxygen, and 13 volumes of nitrogen. 

Ethyl alcohol forms crystalline compounds with some salts, like 
calcium chloride and magnesium chloride. It plays the réle of 
water of crystallization in them. 


Potassium and sodium dissolve in it Sess in all other alcohols), separating 
hydrogen from the hydroxyl group and yielding the so-called metallic alcoholates, 
e.g.,C,H,.ONa. All the alcohol cannot be thus changed; on evaporating the 
excess, white crystalline compounds, C,H,.ONa or C,H,.OK, having two and 
three molecules of alcohol, remain. The alcohol does not escape until the com- 
pounds are heated to 200°; then the residual alcoholates form a white, volumi- 
nous powder. (Consult Berichte, 22, 1011, on the preparation of sodium alco- 
holate.) Excess of water converts them into alcohol and sodium hydroxide. 
When but little water is employed, the transposition is only partial. Hence the 
ethylates are also formed in dissolving KOH and NaOH in strong alcohol. Other 
metallic oxides, ¢. g., barium oxide, yield similar derivatives. When aluminium 
and iodine act upon ethyl and other alcohols, aluminium alcoholates, ¢. ¢., alumin- 
ium ethylate, Al(OC,H,),, result; these can be distilled in vacuo. 


Oxidizing agents (MnO, and H,SO,, chromic acid, platinum 
black and air) convert ethyl alcohol into acetaldehyde and acetic 


THE ALCOHOLS. 127 


acid. Nitric acid changes it at 20-30° into glyoxal, glyoxalic 
acid, glycollic acid and oxalic acid. When acted upon by chlorine 
and bromine, chloral and bromal (CCl,.CHO and CBr,.CHO) are 


produced. 


The ae CH,X.CH,.OH, will be described as halogen- 
hydrins under the glycols. 

Trichlor-Ethyl Alcohol, CCl,.CH,.OH, resulting from the action of zinc 
ethyl upon chloral, consists of white rhombic crystals, fusing at 17.8° and boiling 
at 151°; specific gravity 1.55 at 23°. It is slightly soluble in water, but readily 
soluble in alcohol and ether. When oxidized with nitric acid, it yields trichlor- 
acetic acid (Azmnalen, 210, 83). 

Nitro-Ethyl Alcohol, CH,(NO,).CH,.OH, is prepared in a manner similar 
to those employed for the nitro-paraffins—by the action of silver nitrite upon 
ethylene-iodhydrin, CH,1.CH,.OH. It forms an oil miscible with water. It 
yields a beautiful sodium ‘salt, and is capable of forming azo-dyes (Berichie, 21, 
3529; Annalen, 256, 28). 


3. Propyl Alcohols, C;H,.OH :— 


CH,.CH,.CH,.0H CH,.CH(OH)—CH,.. 
Propy! Alcohol. Isopropyl Alcohol. 


(1) Normal Propyl Alcohol, CH;.CH,.CH,.OH, is produced 
in the fermentation of sugars, etc. It may be-obtained from fusel 
oil by fractional distillation (p. 125). To get it perfectly pure, the 
corresponding bromide is converted into the acetate, and _ this 
broken up by potassium hydroxide. It may be artificially prepared 
from propyl aldehyde and propionic anhydride :by the action of 
nascent hydrogen (sodium amalgam). It is an agreeable-smelling 
liquid of specific gravity 0.8044 at 20°, and boiling at 97.4°. The 
boiling point is very materially affected by slight additions of water, 
as a hydrate, C,;H,0 ++ H,O, is formed, which boils at 87°. It is 
miscible in every proportion with water, but on the addition of 
calcium chloride and other easily soluble salts, it separates again 
from its aqueous solution. Hence it is insoluble in a saturated, 
cold calcium chloride solution, and this distinguishes it from ethyl 
alcohol. 


It passes into propionic aldehyde and propionic acid, under the influence of 
oxidizing agents. When heated with 5 volumes of H,SO,, it yields propylene. 
Its chloride boils at 46,5°, the dromide at 71°, the todide at 102° (p. 96). 


(2) Secondary or Isopropyl Alcohol, (CH,),.CH.OH, 
dimethyl carbinol, is prepared from the iso-iodide (p. 96); from 
acetone (CH;),.CO, by the action of sodium amalgam ; from acro- 
lein, C,H,O, propylene oxide, C,H,O, and dichlorhydrin, C;H;Cl,. 
OH, by means of nascent hydrogen; from glycol iodhydrin, 
C,H,I.OH, by action of zinc methyl; from propylamine (p. 122) 


128 ORGANIC CHEMISTRY. 


by action of nitrous acid, and from formic ester by the aid of zinc 
and methyl iodide (p. 121). 


Preparation.—A mixture of one volume acetone and five volumes of water is 
shaken with liquid solium amalgam, and the distillate repeatedly subjected to the 
same treatment, until an energetic liberation of hydrogen is perceptible. It is then 
distilled, the distillate dehydrated with ignited potashes ag afterwards mixed with 
pulverized calcium chloride. The resulting crystalline cOnpound is deprived of 
all adhering acetone by standing over sulphuric acid. If heated, it breaks up into 
CaCl, and isopropy] alcohol. 

The most practical method of obtaining it is to boil the iodide with ten parts of 
water and freshly prepared lead hydroxide in a vessel connected with a return 
condenser, or simply by heating the iodide with twenty volumes of water to 100° 
(Annalen, 186, 391). 


Isopropyl alcohol boils at 82.7°, and has a specific gravity 0.7887 
at 20°. It is miscible with water, alcohol and ether; potash will 
separate it again from the aqueous solution. Oxidizing agents 
convert it into acetone. Its chloride, C,;H,Cl, boils at 37°, the 
bromide at 60-63°, and the iodide at 89° (p. 96). The benzoic 
ester, C,H,O.C,H,O, breaks up on distillation into benzoic acid 
and propylene. 

CCl, 
Trichlorisopropyl Alcohol, dae \CH.OH, is produced in the action of 


zinc methyl on chloral. It is crystalline, fuses at 49°, and boils about 155° 
(Annalen, 210, 78). 

4. Butyl Alcohols, C,H,.OH. According to theory four isomerides are 
possible: 2 primary, I secondary, and I tertiary (p. 117) :— 


CH 
__ CH,,CH,CH, _ CGE 
CH,.0H CH,. OH 
Isobutyl Alcohol. 
Vipnaciank i oncant Carinol, 
CH, 
3. \CH.OH 4. (CH,),.COH 
CH2CH & Trimethyl Carbinol. 


(1) Normal Butyl Alcohol, C,H,.CH,.OH, forms in the faction of sodium 
amalgam upon normal butyl aldehyde, C,H,.COH, upon butyryl chloride, 
‘C,H ,.CO.Cl, and upon butyric anhydride. It is further produced by a peculiar 
fermentation of glycerol, brought about in the presence of a schizomycetes 
(Berichte, 16, 1438). It is prepared most readily in this way. It is a liquid with 
an agreeable odor, has a sp. gr. of 0.8099 at 20° and boils at 116.8°. It is soluble 
at 22° in 12 volumes of water. Calcium chloride and other salts separate it again 
from its solution. When oxidized it passes into butyl aldehyde and butyric acid. 
Its chloride, C,H,.CH,Cl, boils at 77.6°, the dromide at 99.8°, and the zodide at 
120°. 

-Trichlorbutyl Alcohol, CH,.CHCI.CCl,.CH,.OH, results when zinc ethyl 
and butyl chloral (see Trichlor-ethyl alcohol, p. 127) are brought together. It 


THE ALCOHOLS. 129 


crystallizes in prisms, fuses at 62°, and boils under 45 mm. pressure at 120°. If 
oxidized with nitric acid it yields trichlorbutyric acid (Annadlen, 213, 374). 


(2) Isobutyl Alcohol, C;H,.CH,.OH, dutyl alcohol of fermen- 
tation, occurs in several fusel oils and especially in the spirit from 
potatoes. It is a liquid possessing a fusel-oil odor, hasa sp. gr. of 
0.8020 at 20° and boils at 108.4°. It is soluble in ten parts of water, 
and is again separated from solution on the addition of salts. When 
oxidized it affords isobutyric acid. Its chloride, C,H,Cl, boils at 
69°, the dromide at 92°, and the zodide at 121°. Whenthe bromide 
is heated to 240° it is converted into tertiary butyl bromide ; very 
probably (CH;)..C:CH, forms at first, and subsequently yields 
(CH;);CBr with HBr (p. 94). 


When isobutyl alcohol is heated with HCl, HBr or HI there result, in addition 
to the normal halogen esters, also those of trimethyl carbinol, (CH,),CX, 
because isobutylene, (CH,),.C:CH,, is produced from the former, and this then 
combines with the halogen hydrides to compounds of the type (CH,),.CX.CH, 
(see p. 122). 


CH 
(3) Methyl-ethyl Carbinol,_ "CH.OH (Butylene Hydrate), is obtained 
H 
from its iodide, produced by heating. erythrite with hydriodic acid (p. 95); the 
same iodide is also formed from normal butylene (pp. 84 and 122). The alcohol 
may further be made by treating formic ester with Zn and CH,I and C,H,1; 
and from the dichlor-ether, CH,Cl.CHC1.0.C,H,, (see Ether) by the action of 
zine-ethyl and HI. It is a strongly smelling liquid, boiling at 98°—-100°. Its sp. 
gr. at O° iso.827. Heated to 240°-250° it decomposes into water and (-butylene, 
CH,.CH:CH.CH,. (Compare Berich/e, 19, Ref. 610). It yields methyl-ethyl 


ketone, 2500, when oxidized. Its zodide boils at 119-—120°, 


5 

(4) Trimethyl Carbinol, (CH,),.C.OH, ¢eréiary butyl alcohol, is found in 
small quantities in fusel-oil, and arises in the action of acetyl chloride upon zinc 
methyl (p. 120). It can also be obtained from the butyl alcohol of fermentation 
by means of isobutylene (p. 122). 

When perfectly anhydrous it crystallizes in rhombic prisms or plates, fusing at 
28° and boiling at 83-84°. Its sp. gr. at 30° is 0.7788. It is miscible with water 
in all proportions, forming the hydrate, 2C,H,,O + H,0, which crystallizes in a 
freezing mixture, and boils at 80°. When oxidized with chromic acid it yields 
carbon dioxide, acetic acid, acetone, and a little isobutyric acid. 

Its chloride, C,H,Cl, boils at 50-51°, and the zodide at 99°. When the latter 
is heated with zinc and water trimethyl methane, C,H,,, and isobutylene, 
C,H, = (CH,),C:CH,, result. On combining the latter with CIOH, 
(CH,),CCI.CH,.OH will be formed ; nascent hydrogen converts this into isobutyl 
alcohol, (CH,),.CH.CH,.OH. 

(5) Amyl Alcohols, C,;H,,.OH. Theoretically 8 isomerides are possible: 4 
primary alcohols, 3 secondary, and 1 tertiary :— 


It 


130 ORGANIC CHEMISTRY. 


a _ CH,—CH,—CH, sais 
rimary : , 2. 
CH,—CH,.0H CH,.OH 
C,H c(CH 
: rant oe 3)s 
CH, CHa, 
Secondary : 5. 7 6. Peete 
C, 5 C, 7 
CH 
yO NOT OT 
C, ae 
CH, CH... 
Tertiary : Paes 8. CH,—C.OH. 


CH, 7 


(1) Normal Amy] Alcohol, C,H,.CH,.OH (contains the normal butyl group), 
is obtained from valeraldehyde and from normal pentane. It is most easily prepared 
from normal amylamine (from caproic acid) by the action of nitrous acid (p. 122, and 
Annalen, 233, 252). It is almost insoluble in water, has a fusel-oil odor, and boils at 
137°. Itssp. gr. at 20° equals 0.8168. On oxidation it yields normal valeric acid. 

Its chloride boils at 106-107° C.; itis produced (together with C, H,.CHCI.CH, ) 
in the chlorination of normal pentane. The drvomide boils at 129°, and the zodide 


at 155.5° 


(2) Isobutyl Carbinol, (CH;),CH.CH,.CH,.OH (Inactive 
amyl alcohol, isopentyl alcohol), constitutes the chief ingredient of 
the amyl alcohol of fermentation obtained from fusel oil (p. 125), 
and occurs as esters of angelic and tiglic acids in Roman camo- 
mile oil. It may be obtained in a pure condition by synthesis from 
isobutyl alcohol, (CH;),.CH.CH,.OH, by converting the latter 
into the cyanide, the acid, the aldehyde, and finally into the alco- 
hol. It boils at 131.4°, and its sp. gr. at 20° is 0.8104. At 13° it 
dissolves in 50 parts water. Its chloride, C;H,Cl, boils at 100°, 
the bromide at 120.4°, and the zodide at 148°. When oxidized it 
yields inactive valeric acid. 

The so-called alcohol of fermentation, possessing a disagreeable 
odor and boiling at 129-130°, occurs in fusel oil and consists 
mainly of inactive isobutyl carbinol. In addition, methyl-ethyl 
carbinol (active amyl alcohol) and probably, too, normal amyl 
alcohol are present. It rotates the plane of polarization to the left ; 
its activity is due to the presence of active amyl alcohol. The 
latter distils over first when fusel oil is thus treated. 


Fermentation amyl-alcohol, treated with sulphuric acid, yields two amyl- 
sulphuric acids. The different solubilities and crystalline forms of their barium 
salts distinguish them. From the more sparingly soluble salt, which forms in 
rather large quantity, isobutyl carbinol may be obtained by boiling its acid with 
water. Active amyl alcohol is prepared from the more readily soluble salt. The 


THE ALCOHOLS. Lar 


first alcohol yields inactive valeric acid on oxidation, the second the active acid. 
A more complete separation of the alcohols is reached by conducting HCl into | 
the mixture. Isobutyl carbinol will be etherified first, the active amyl alcohol re- 
maining (Le Bel) (Annalen, 220, 149). When the crude fermentation alcohol is 
distilled with zinc chloride ordinary amylene is the product. This consists mainly 
of (CH,),C:CH.CH,, resulting from a transposition of isobutyl carbinol ; it con- 
tains, besides, y-amylene and a-amylene (compare p. 84). The iodide of the fer- 
mentation alcohol is made up principally of (CH,),.CH.CH,I an 

CH 
" CH.CH 21, and yields the amylenes, (CH,),.CH.CH:CH, and 
CH 


5 
CH. 
C.n./ 


5 


C:CH, (p. 85). 


CH 
(3) Active Amyl Alcohol, " SCH.CH,.OH, secondary butyl carbinol, 
oe - 

methyl-ethyl carbinol, is the active ingredient (about 13 per cent.) of the fermen- 
tation alcohol, and may be separated from this by the method above described. 
It boils at 127°. In accordance with its asymmetric structure (p. 63) it is 
optically inactive and is indeed levo-rotatory [a] 6 = 4.4° Its chloride, 
C,H,,Cl, boils from 97-99°, the dromide from 117-120°, and the zodide from 
144-145°. These are all optically active. The same may be noted in regard 
to ethyl dmyl and diamyl obtained from the iodide. Those derivatives, on the 
contrary, not containing an asymmetric carbon atom, are inactive, ¢. g., amyl 
CH 3\ 


Cis. 7 
hydride, : ‘CH.CH,, and y-amylene, JPoCHs (p. 63 and Annalen, 
C,H 


fed 


2°" 5 2°°5 


OH. 
220, 157). Active valeric acid, \CH.CO,H, results from the oxidation of 
Ci. 
active amyl alcohol. sibs 

Active amyl alcohol becomes inactive on boiling with NaOH, otherwise it 
manifests all the properties of the active modification. A mucor will render it 
again active, but dextro-rotatory (Berichte, 15, 1506). ag 

(4) Tertiary Butyl Carbinol, (CH,),.C.CH,.OH, has not yet been obtained, 
but no doubt may be prepared from tertiary butyl alcohol through the cyanide 
(as in the case of isobutyl carbinol). 

(5) Diethyl Carbinol, (C,H,),.CH.OH, is formed by the action of zinc and 
ethyl iodide upon ethyl formate (p. 121). It boils at 116-117°, and has a specific 
gravity at o° of 0.832. Its zodide boils at 145°, and the acetate at 132°. 
B-Amylene (p. 84) is obtained from the iodide. Diethyl ketone, (C,H,;),CO, 
results from the oxidation of the alcohol. Since B-amylene, C,H,.CH:CH.CH,, 
yields C,H,.CH,.CHI.CH, with HI, from which methyl normal propyl carbinol 
is obtained, we can in this manner convert the diethyl carbinol into the latter 
alcohol. - 


CH 
(6) Methyl Normal Propyl Carbinol, " CH.OH, is formed from methyl 
C,H 


propyl ketone by the action of nascent hydrogen. It may be obtained, too, from 
the zodide, C,H,.CHI.CH, (from a- and $-amylene, see above) and the chloride 
C,H,.CHCI.CH, (from normal pentane). It boils at 118.5°. Its sp. gr..at 0° is 
0.824. Its zodide boils at 144-145°, and’ the chloride at 103-105°. Methyl 


132 ORGANIC CHEMISTRY. 


normal propyl ketone is the oxidation product of the alcohol. The zodide yields 
B-amylene. 


CH 
(7) Methyl Isopropyl Carbinol, > CH.OH, is obtained by the action of 
C,H 


er 
sodium amalgam upon an aqueous solution of the corresponding ketone. It is an 
oil with a fusel odor, boils at 112.5°, and has a sp. gr. at 0° of 0.833. When 
oxidized it yields methyl isopropy] ketone. 
When acted upon by halogen hydrides and also PCI,, the derivatives of the 
CH, 
type, "CHX, do not form, but, in a singular manner, those of tertiary amyl 


alcohol :— 


"’S\CH.OH yields (CH,),CX.CH, CI 
yields : .CHg. 
ee ( s)e 2 ; 

Very probably amylene, (CH,),C:CH.CH,, is the first pfoduct, and this by 
addition of the halogen hydrides yields the derivatives of tertiary amyl alcohol 
(compare p. 122). 

The real derivatives of methyl-isopropyl-carbinol are obtained from a-isoamy- 
lene, (CH,),.CH.CH:CH, (p. 84), by the addition of halogen hydrides at ordinary 
temperatures or when warmed. The resulting zodide, (CH;),.CH.CHI.CH,, 
boils at 137-139°, the dromide at 114-116°, and the Misia at 91°. The iodide 
yields B-isoamylene, (CH,),C:CH.CH,. 


(8) Tertiary Amyl Alcohol, (CH 32h c OH, Dimethyl-ethyl-carbinol, Amy- 


lene hydrate. This is ey ‘prepared by the action of zinc methyl on 
CH, 

propionyl chloride. It may be obtained from y-amylene, Doce, and 
ort 


B-isoamylene, (CH,),C:CH.CH,; when their HI compounds are heated with lead 
oxide and water. Since ordinary amylene consists chiefly of B-isoamylene (p. 85), 
tertiary amyl alcohol is most practically prepared from the first by shaking it with 
sulphuric acid and boiling the solution with water (Ammaven, 190, 345). 

Tertiary amyl alcohol has an odor like that of camphor, boils at 102.5°, solidifies 
at —12.5° and melts at —12°. Its specific gravity at 0° is 0.827. Its zod7de boils. 
at 127-128°, the dromide at 108—-109°, and the chloride at 86°. At 200° it 
decomposes into water and f-isoamylene. Acetic acid and acetone are its oxida- 
tion products. 

6. Hexyl and Caproyl Alcohols, C,H,;.OH. Seventeen isomerides are 
theoretically possible: 8 primary (as there are eight amyl radicals), 6 secondary, 
and 3 tertiary. Of the eight known at present there may be mentioned :— 

(1) Normal Hexyl Alcohol, CH,.(CH,),.CH,.OH. This was first obtained 
(together with methyl butyl carbinol) Sete normal hexane. It can be prepared 

pure from caproic acid, C,H),,O,, by reduction, and by the transformation of hexy]- 
amine (from cenanthylic acid, C,H,,0,, Berichte, 16, 744). Hexyl butyrate 
occurs in the volatile products of some Heracleum varieties (together with octyl 
acetate). The alcohol rate be obtained from these by saponification with caustic 
potash. It boils at 157°, and has a specific gravity at 23° of 0.819. Normal 
caproic acid is its oxidation product, The zodide, C,H,,1, boils at 180°, and the 
chloride, C,H;,Cl, at 130-133°. 

(2) Methyl- -tertiary Butyl Carbinol, (CH,),.C.CH.OH.CH,, Pinacolyl alco- 
hol. Nascent hydrogen acting on pinacoline (see this) produces the above 


THE ALCOHOLS. 133 


alcohol. When cooled it crystallizes and melts at +4°. It boils at 120°, and has 
a specific _ a of o. 834. If oxidized with a chromic acid mixture it first yields 


H5)3C 
the ketone, se Sco, pinacoline, which afterwards breaks up into re 
CH 


dioxide and trimethyl] acetic acid. 

(3) Fermentation Hexyl Alcohol or Caproyl Alcohol, C,H,,.0H, is found 
in the fusel oil of grape spirit. It boils at 150°. Its constitution is not well deter- 
mined, That it isa primary alcohol is evident from the fact that when it is oxid- 
ized it cHanges to caproic acid. 

7- Heptyl or GEnanthyl Alcohols, C,H,,.OH. Thirteen of the thirty-eight 
possible isomerides are known. The following may be noticed :— 

(1) Normal Heptyl Alcohol, CH,(CH,),.CH,.OH, from cenanthyl aldehyde 
pio sere 200, 102) and normal heptane, boils at “175° and yields normal cenan- 
thylic acid on oxidation. 

(2) Dimethyl-tertiary Butyl Carbinol, C(CH;),.C(CH;),.OH, or Penta- 
methyl-ethyl alcohol, obtained from trichlor-methyl acetic anhydride, C(CH;). 
COCI, by means of zinc methyl, melts at + 17° and boils at 131-132°. It yields 
a crystalline hydrate, 2C,H,,O + H,O, with water. This melts at 83°. Its 
chloride boils at 136°, and the zodide at 141°. 

The following higher normal alcohols are known: Octyl, cetyl, ceryl, and melis- 
syl alcohols occur naturally as esters; the others are obtained from the correspond- 
ing aldehydes by reduction (p. 120). 

Octyl Alcohol, C,H,,O, occurs as octyl acetate in the volatile oil of Heraclewm 
spondylium, as butyrate in the oil of Pastinaca sativa, and together with hexyl 
butyrate in the oil from Heracleum giganteum. It boils at 190-1g2°, and at 16° 
it has a sp. gr. = 0.830, Caprylic acid is its oxidation product. 

Decyl Alcohol, C,,H,,.OH, from Kass aldehyde, melts at +7°, and under 15 
mm. pressure boils at 43.5°. 

Dodecatyl Alcohol, oi OH, from lauraldehyde, melts at a , and toils 
at 119° under a pressure of 15 mm. 

Tetradecatyl Alcohol, C,,H,..OH, from myrisitaldehyde, atts at 32°, and 
under a pressure like that given with the preceding compounds boils at 167°. 


Cetyl Alcohol, C,,H;,.0H, Hexadecyl Alcohol, formerly 
called etha/, is prepared from the cetyl ester of palmitic acid, the 
chief ingredient of spermaceti, by saponification with alcoholic 
potash :— 

C,,H,,0 ~ 
»o = KOH = CgHiy OH + CgHy,0.0K. 
Cross Palmitate, 
It may also be obtained in a pure condition by the reduction of 
palmitic aldehyde, whereas when prepared from spermaceti it is 
contaminated with octodecyl alcohol (Berichie, 175 1627). 

Ethal is a white, crystalline mass fusing at 49.5°, and distilling 
about 340° with scarcely any decomposition (under 1 5 mm. pressure 
it boils at 189°). It yields, when fused with potassium hydroxide, 
palmitic acid. 


Octodecyl Alcohol, C,.H,,.0H, from stearaldehyde, fuses at 59°, and boils at 
210° (under 15 mm.). 


134 ORGANIC CHEMISTRY. 


Ceryl Alcohol, C,,H,;.0H—Cerotin—as ceryl cerotic ester, 
constitutes Chinese wax. It is obtained by melting the latter with 
caustic potash :— 


C,,H,,0 
7 SQ 4+ KOH =< Ea. OW 4 C.H,,0.0K: 
CH” Cerotin. Potassium 

Cerotate. 


Ceryl alcohol is a white, crystalline mass, fusing at 79°. It yields 
cerotic acid when fused with potassium hydroxide. 

Melissyl Alcohol, C,H,.OH, myricyl alcohol, occurs as 
myricyl palmitate in beeswax. It is isolated in the same manner as 
the preceding compound, and melts at 85°. Its chloride melts at 
64°, and the zodide at 69.5°. 





2. UNSATURATED ALCOHOLS, CnHen—1.0H. 


These are derived from the unsaturated alkylens, C,H,,, in the 
same manner as the normal alcohols are obtained from their hydro- 
carbons. ‘In addition to the general character of alcohols they are 
also capable of directly binding two additional affinities. 


The lowest member of the series—the so-called vinyl alcohol—C,H,.0H = 
CH,:CH.OH, appears to exist in ordinary crude ether (Berichte, 22, 2000), but 
cannot be prepared artificially, because in all the reactions in which it should form, 
the isomeric acetaldehyde, CH,.CHO, is produced. It seems to be the universal 
rule, that the atomic grouping — C:CH.OH, in the act of formation, is transposed 
into = CH.CHO, as aldehydes result instead of the expected secondary alcohols. 
The group C.C(OH:CH, (with tertiary alcohol group) passes over into C.CO.CH,, 
since ketones are always produced (compareacetone).* These facts explain many 
abnormal reactions (compare Berichie, 13, 309,and 14, 320).. The samerule holds 
good for the unsaturated oxy-acids in free condition, but does not apply to their 
salts and esters (Berichte, 16, 2824). When the allyl alcohols are oxidized with 
potassium permanganate they yield triatomic glycerols (p. 82). 


1. Allyl Alcohol, C,H;.OH = CH,:CH.CH,.OH. This may 
be prepared by heating allyl iodide to 100° (p. 99) with 20 parts 
water. It is produced, also, when nascent hydrogen acts upon 
acrolein, CH,:CH.COH, and sodium upon dichlorhydrin. CH,Cl. 
CHCI1.CH,.OH. It is best prepared from glycerol by heating the 
latter with formic or oxalic acid. 


Preparation.—A mixture of four parts glycerol and 1 part crystallized oxalic 
acid, with addition of 14 per cent. ammonium chloride, is slowly heated to 100° in 
a retort. Carbon dioxide is disengaged, while formic acid and some allyl alcohol 





_ * The two isomeric forms are probably tautomeric (see p. 54). 


UNSATURATED ALCOHOLS. 135 


pass over. When the liberation of gas has ceased somewhat, the heat is raised to 
200°, and the distillate collected. The latter contains, besides ally] alcohol, some 
allyl formate and acrolein. To further purify it the distillation is repeated, the 
product warmed with KOH and dehydrated by distillation over barium oxide 
(Annalen, 167, 222). 

In this reaction the oxalic acid at first breaks up into carbon dioxide and formic 
acid, which forms an ester with the glycerol; this then decomposes into allyl alco- 
hol, ‘carbon dioxide, and water :— 


CH,.0.CHO CH, 

| I 

CH.OH — CH 4+ CO, + H,0. 
| | 

CH,.0H CH,.0H 


By this method 20—25 per cent. of the glycerol is changed to allyl alcohol. 


Allyl alcohol is a mobile liquid with a pungent odor, boiling at 
96-97°, and having at 20° a specific gravity of 0.8540. It solidifies 
at —50°. It is miscible with water and burns with a bright flame. 

It yields acrolein and acrylic acid when oxidized with silver 
oxide, and only formic acid (no acetic) when chromic acid is the 
oxidizing agent. Nascent hydrogen is apparently without effect 
upon it; when heated to 150° with KOH formic acid, normal 
propyl-alcohol and other products are obtained. 

For the halogen esters of allyl alcohol see page 98. 


It combines with Cl, and Br, to form the /- dichlorhydrins of glycerol (see these). 
The monosubstituted allyl alcohols are represented by two isomerides :— 


CH,:CC1.CH,.OH and CHCl:CH.CH,.OH. 
a-Chlorally!’ Alcohol. B-Chlorallyl Alcohol. 


The first of these is formed from a- -dichlorpropylene, CH,:CCI.CH,Cl, on 
boiling with a sodium carbonate solution; it boils at 136°. “When it is dissolved 
in sulphuric acid and distilled with water it becomes acetone alcohol, CH,.CO. 
CH, OH. 

B- “Chlorallyl Alcohol, from (-dichlorpropylene, CHCl:CH.CH,Cl, boils at 
153°, and causes painful blisters. 

p- Bromallyl Alcohol, CHBr:CH.CH,.OH, from £-dibrompropylene, boils at 
152°, and yields propargylic alcohol with KOH. 

2. Crotyl Alcohol, C,H,.OH = CH,.CH:CH.CH,.OH, is obtained from 
crotonaldehyde, CH, CH: CH. ‘CHO, by means of nascent hydrogen. It boils at 
117-120°, 

3- Higher unsaturated alcohols of the allyl series, having tertiary structure, 
arise in the action of zinc and allyl iodide upon ketones and in the decomposition of 
the resulting product with water (p.-121). 


(3) UNSATURATED ALCOHOLS, CpHon—3,0H. 


Propargyl Alcohol, C,H,O = CH:C.CH,.OH, is the only 
known alcohol of the acetylene series. There is a triple union of 
two carbon atoms present in this compound. It is produced on 


136 ORGANIC CHEMISTRY. 


heating #-bromallyl alcohol (see above) with potassium hydroxide 
and water :— 


CHBr:CH.CH,.OH yields°CH : C.CH,.0OH. 


Propargyl alcohol (or propinyl alcohol) is a mobile, agreeable- 
smelling liquid, with a sp. gr. at 20° of 0.9715. It boils at 114- 
115°, and dissolves readily in water. With an ammoniacal cuprous 
chloride solution (p. 87) it forms a yellow precipitate, (C,H,. 
OH),Cu,, from which the alcohol is again set free by acid. Silver 
solutions produce a white precipitate, C,H,Ag.OH. 


Trichloride of phosphorus converts the alcohol into the chloride, C,H,Cl. 

_ This boils at 65°. The dromide, C,H,Br, formed by PBr,, boils at 88-g90°; the 
todide boils at 115°. The acetate, C,H,.0.C,H,0, results when acetyl chloride 
acts upon the alcohol. Its boiling point is 125°. 

Ethyl-Propinyl Ether, C,H,.0.C,H,;, is made from glyceryl bromide, 
C,H,Br,, and the various dichlor- and dibrom-propylenes, C,H,Br,, by the 
aid of alcoholic potash. It is a liquid with a penetrating odor, of sp. gr. 0.8326 
at 20°, and boils at 80°. Its copper compound, (C,H,.0.C,H,),Cu, is yellow 
colored, while that with silver, C, H,Ag.0.C,H,, is white. 

Higher alcohols, in which the double union of carbon atoms occurs twice, are 
produced by the action of zinc and allyl iodide upon ethers of formic acid and even 
of acetic acid, whereby secondary and tertiary alcohols result (p, 120). These 
alcohols absorb four bromine atoms, but do not, however, enter into combination 
with copper and silver. This accords with their structure. 





ETHERS. 


The oxides of the alcohol radicals are thus designated. In the 
ethers of the monohydric alcohols two alkyls are present, joined to 
each other by an oxygen atom. ‘They may be considered also as 
anhydrides of the alcohols, formed by the elimination of water from 
two molecules of alcohol :— 


CoHyy 
a7 


y Sexe 


C,H,.0H + C,H,.0H = O + H,0. 


Ethers containing two similar alcohol radicals are termed simple 
ethers ; those with different radicals, mixed ethers :-— 


CoH, C,H 
ae me yo. 
Cit, . CH, 
Ethyl Ether, or Methyl-ethyl 
Diethyl Ether. Ether. 


We must make a distinction between the above and the so-called 


ETHERS. 137 


compound ethers or esfers, in which both an alcohol radical and an 
acid radical are present, ¢. g.,— 


C,H 5 
So Ethyl Acetic Ester. 
C,H,0% 


The properties of these are entirely different from those of the 
alcohol ethers. In the following pages they will always be termed 
esters. 

The following are the most important methods of preparing 
hy —_— ug 

. Action of the alkylogens upon metallic oxides, especially silver 


cae — 
2C,H,I + Ag,O =(C,H,),0 + 2Agl. 
2. The action of the alkylogens upon the sodium alcoholates in 
alcoholic solution. . Mixed ethers are also formed here :— 
CoH. | 
C,H,.ONa + C,H,Cl = >O + NaCl. 
C,H, 


CaHy. 
C,H,;.ONa + C,H,Cl = Pe. + NaCl. 
CH, 
Consult Berichte, 22, Ref. 381, upon the speed of these reactions. 


3. Heating the sulphuric esters with alcohols :— 


0.C,H, CiHyy 
sO, + CH On & 0 + S0,H,. 
oH C,H.” 
Ethyl Sulphuric Diethyl 
Acid. Ether. 
on eat sc eons guy oi Salen Bk | apy 
"NOH + zy 6? 3 a CH,” + 4°"“2° 
Methyl Sulphuric Methyl-ethyl 
Acid, . Ether, 


The formation of ethers by directly heating the alcohols with 
sulphuric acid is based on this reaction :— 


2C,H,.0H + SO,H, = (C,H,),0 + $O,H, + H,0. 


By mixing and warming alcohol with sulphuric acid, a sulphuric 
ester (together with water) is produced (p. 119). With excess of alco- 
hol, on application of heat, this breaks up into ether and sulphuric 
acid. The ether and water distil over while the sulphuric acid 
remains behind. If a new portion of alcohol be added to this residue 
the process repeats itself. In this way, an mplisnited amount of 

12 


138 ORGANIC CHEMISTRY. 


alcohol can be changed to ether by one and the same quantity or 
sulphuric acid, providing the latter does not sustain a slight and 
otherwise different transposition. Formerly, when the mechanism 
of the reaction was yet unexplained, this process was included in 
the category of catalytic actions. ‘The explanation of the etheri- 
fication process (by Williamson, in 1852) marks an important turn- 
ing point in the history of chemistry. 

When a mixture of two alcohols is permitted to act upon 
sulphuric acid, three ethers are simultaneously formed ; two are 
simple and one a mixed ether. Other polybasic acids, like phos- 
phoric, arsenic, and boric, behave like sulphuric acid. 





Ethers are neutral, volatile bodies, nearly insoluble in water. 
The lowest members are liquid; the highest, e¢. g., cetyl ether, are 
solids. Their boiling points are very much lower than those of the 
corresponding alcohols (Auna/en, 243, 1). 

Chemically, ethers are very indifferent, because all the hydrogen 
is attached to carbon, When oxidized they yield the same pro- 
ducts as their alcohols, They yield ethereal salts when heated with 
concentrated sulphuric acid. Phosphorus chloride converts them 
into alkyl chlorides :— . 


“Eo + PC], = C,H,Cl + CH,Cl + POCI,. 
3 


The same occurs when they are heated with the haloid acids, 
especially with HI:— 


C,H 
ar? >0 4 2HI = C,H,I + CH,I + H,0. 


When acted upon by HI in the cold, they decompose into alcohol and an iodide. 
With mixed ethers it is the iodide of the lower radical that is invariably produced 
(Berichte, 9, 852) :— 

CH 
cn’ >° 4+ HI = CH,1 + C,H,.OH. 
Many ethers, especially those with secondary and tertiary alkyls and those with 


unsaturated alkyls, break up into alcohols (Berichte, 10, 1903), when heated with 
water or dilute sulphuric acid to 150°. 





Methyl Ether, (CH;).O, is prepared by heating methyl alcohol 
with sulphuric acid. It is an agreeable-smelling gas, which may be 
condensed to a liquid at about — 23°. Water dissolves 37 volumes 
and sulphuric acid upwards of 600 volumes of the gas. 


ETHERS. 139 


In preparing it 4 parts methyl alcohol and 6 parts concentrated sulphuric acid 
are heated to 140°, in a flask, in connection with a return condenser. The liber- 
ated gas is purified by conducting it through potash. (Berichte, 7, 699.) 


Substitution products form when chlorine is allowed to act 
gradually : CH,Cl.0.CH; boils at 60°, (CH,Cl),O boils at 105°, 
and at last perchlormethyl ether, (CCl;),0, which decomposes 
about 100°. 

Ethyl Ether, (C,H;).O, is prepared by heating ethyl alcohol 
with sulphuric acid (p. 137). 


A mixture of 5 parts (80-90 per cent.) alcohol and g parts H,SO, is warmed 
in a flask connected with a condenser. A thermometer passes through the cork 
of the vessel and dips into the liquid. "When the temperature has reached 140°, 
a slow stream of alcohol is allowed to enter the flask through a tube leading into 
the latter. The temperature given must be maintained. The ethyl sulphuric acid 
produced at the beginning reacts at 140° upon the entering alcohol forming sul- 
phuric acid and ether, which regularly distils over with the water formed in the 
reaction. The distillate is a mixture of ether, water, and some alcohol. It is 
shaken with soda, to combine sulphurous acid, the lighter layer of ether is siphoned 
off and distilled over lime. There is always some alcohol in the product. To 
remove this entirely distil repeatedly over sodium, until hydrogen is no longer 
evolved. Any water in the ether may be detected by shaking the latter with an 
equal volume of CS,, when a turbidity will ensue. To detect alcohol, ether is 
agitated with aniline violet. When the former is absent the ether remains uncolored. 


Ethyl ether is-a mobile liquid with peculiar odor and specific 
gravity at o° of 0.736. When anhydrous, it does not congeal at 
— 80°. It boils at 35° and evaporates very rapidly even at medium 
temperatures. It dissolves in 10 parts water and is miscible with 
alcohol. Nearly all the carbon compounds insoluble in water, 
such as the fats and resins, are soluble in ether. It is extremely 
inflammable, burning with a luminous flame. Its vapor forms a 
highly explosive mixture with air. When inhaled, ether vapor 
brings about unconsciousness. Hoffmann’s Anodyne is a mixture of 
3 parts alcohol and 1 part ether. 


Ether unites with bromine to form peculiar, crystalline addition products, some- 
what like bromine hydrate; it combines, too, with water and metallic salts. When 
heated with water and sulphuric acid to 180° ethyl alcohol results. Chlorine act- 
ing upon cooled ether forms various substitution products: monochlorether, CH,. 
CHC1.0.C,H,, boiling point 98°, dichlorethyl oxide, CH,Cl.CHCI1.0.C,H,, 
boiling point 145°, and higher derivatives. An isomeric dichlorether, (CH,.CH. 
Cl),O, is produced when HCl acts upon aldehyde. It boils at 116°. Perchlori- 
nated Ether, (C,C1,),O, the last product of the action of chlorine on ethyl oxide, 
is a crystalline body, fusing at 68° and decomposing upon distillation into C,Cl, 
and trichloracetyl chloride, C,Cl,0.C1. 

When ozone is conducted into anhydrous ether, a thick liquid, having the com- 
position C,H,,O,, is formed. This explodes on being heated. It is considered 
an ethyl peroxide, (C,H,),0,. Water converts it into alcohol and hydrogen 
peroxide. 3 


140 ORGANIC CHEMISTRY. 


Methyl Ethyl Ether, CH,.0.C,H,, boils at 11°. Methyl Propyl Ether, 
CH,.0.C,H,, at 50°. : 

Normal Propyl Ether, SCaHx)20, boils at 86°. Isopropyl Ether, from 
isopropyl iodide, boils at 60—62°. 

Isoamyl Ether, (C,H,,),O, is formed together with amylene, and its poly- 
merides when fermentation amyl alcohol is heated with sulphuric acid. It boils 
at 176°, and has a specific gravity of 0.779. 

Cetyl Ether, (Cy gtig3)20, fromcetyl iodide, crystallizes from ether in brilliant 
leaflets, fuses at 55°, and boils at 300°. 

Vinyl Ether, (Cc as , _is obtained from vinyl sulphide by the action of dry 
silver oxide. It boils at : 

Allyl Ether, (C,H,;) “8 “from allyl iodide, boils at 85°. 

Vinyl Ethyl Ether, o H, .O.C,H,, is produced when chloracetal, CH,C1.CH. 
(O.C,H,), (obtained from acetal by chlorination and. from dichlor-ether, ‘CH al -L 
CHCL.O. C,H,, by aid of sodium alcoholate), is heated with sodium. It is a 
liquid with an *allyl- like odor, and boils at 35.5°. The addition of chlorine changes 
it again to dichlorether. When boiled with dilute sulphuric acid it decomposes into 
ethyl alcohol and aldehyde (p. 134). 

Allyl Ethyl Ether, C,H,.0.C,H,, from allyl iodide and sodium ethylate, boils 
at 66°. It combines directly with ‘Br, Cl, and CIOH. 





MERCAPTANS AND THIO-ETHERS, 


The sulphur analogues of the alcohols and ethers are the ¢hio- 
alcohols or mercaptans and thio-ethers or alkyl-sulphides :— 


C,H,.SH CAN 
’ ’ Ethyl Hydiostiphide, . 


C,Hs 7 
Ethyl Sulphide. 

Although they closely resemble the alcohols and ethers in general, 
the sulphur in them imparts additional specific properties. In 
the alcohols the H of OH. is replaceable by alkali metals almost 
exclusively ; in the mercaptans it-can also be replaced by heavy 
metals (by action of metallic oxides). The mercaptans react very 
readily with mercuric oxide, to form crystalline compounds :— 


2C,H,SH + HgO = (C,H;,.S),Hg ++ H,0. 
- Hence their designation as mercaptans (from Mercurium captans). 


The methods resorted to for their formation are perfectly analogous to those 
employed for the alcohols, They are produced : — 
(1) By the action of the alkylogens upon potassium sulphydrate in alcoholic 


solution :— _ 
C,H ate g KSH = C,H,.SH + KCl." 


Similarly, the thio-ethers are formed by action of the wie | upon potassium 
sulphide :— 


2C,H, Cl. eee (C,H,),S + 2KCl. 


MERCAPTANS AND THIO-ETHERS. I4I 


- When per at ae are employed instead of ees polysulphides of the alcohol 
radicals, like ce H S,, are obtained. 
Ethyl  Disilphide. 
The alkyl sulphides are also produced when the alkylogens act upon the metal- — 


lic compounds of the mercaptans. Mixed thio-ethers can also be made by this 
method :— 


C,H,.SK + C,H, (= ©? HN eo. 


Further, they are produced when the mercury mercaptides are subjected to heat :— 
(C,H,.S),Hg = (C,H,),S + Hgs. 


(2) By distilling salts of the sulphuric esters with. potassium sulphydrate or 
potassium sulphide (see p. 119) :— 


-— 
‘ 


$0.Cor? 2H; | KSH —C,H,SH + SO,K,. 
au ‘A ‘ 
250, OK? © + KS = (CiHs)a8 + 250,K, 


The neutral esters of sulphuric acid, e. g., SO,(0.C,H;), (p. 148), also yield 
mercaptans when heated with KSH 

(3) A direct replacement of the O of Rlephol and ethers by S may be scape 
- by phosphorus sniphide: _ 


5C,H,;.0H’ + P,S, 5c, H, SH 4+ P,0, and 
5(C,H,),0 + P,S, = 5(C,H,),S + P,0;- 


The P,O, is likely to react further upon the alcohols, and then phosphoric acid 
esters will appear simultaneously with the preceding compounds, | 





The alkyl disulphides (p. 140) are prepared just the same as the monosulphides : 
by distillation of salts of ethyl sulphuric acid with potassium disulphide ; also, by 
the action of iodine upon the mercaptides : — 


2C, H,.SK,-+ I, = (C,H;),S, - oKI. 


A simpler method is the action of sulphuryl chloride upon the mercaptans 
(Berichte, 18, 3178) :— 


2C,H,.SH + SO,Cl, =.(C,H,),S, -+ SO, + 2HCL 


Mixed alkyl disulphides result from the action of bromine upon a mixture of two 
mercaptans (Berichte, 19, 3132). 

Nascent hydrogen converts the alkyl disulphides into mercaptans, and zinc dust 
reduces them to mercaptides: (C,H;),S, + Zn = (C,H,.S),Zn, On heating 
with potassium sulphide they yield ‘potassium mercaptides (Berichte, 19, 3129). 
See also phenyl disulphide. 


142 ORGANIC CHEMISTRY. 


The mercaptans and thio-ethers are colorless liquids, mostly in- 
soluble in water, and possessed of a disagreeable, garlic-like odor. 
The metallic derivatives of the mercaptans—termed mercaptides— 
may be obtained by the double decomposition of the alkali com- 
pounds, and also by the direct action of the metallic oxides. 

They absorb oxygen from the air and yield alkyl disulphides. 
They become mercapials and mercaptols by their union with alde- 
hydes and ketones: When oxidized with nitric acid the mercaptans 
unite with three atoms of oxygen, and yield the so-called sulphonic 
acids (p. 152) :— | 

C,H,.SH + 30 =C,H,.SO,H. 
Ethyl Sulphonic Acid. 
Conversely, the mercaptans result by. the reduction of the sulphonic 
acids (their chlorides) (p. 152). 

The sulphur ethers (the alkyl sulphides) also, take up one and 
two oxygen atoms when treated with HNO,, and yield su/phoxides 
and sulphones :— 


IV VI 
cH, “oh | OP eg 
Diethyl Sulph-oxide. Diethyl-sulphone. 


These compounds may be compared to the ketones. Nascent 
hydrogen (Zn and H,SQ,) deoxidizes the sulphoxides to sulphides. 
The sulphones may be considered the esters of the alkyl sulphinic 
acids, inasmuch as they can be formed from the salts of the latter 
through the agency of the alkyl iodides (p. 154) :— 

C,H SO, 4 Cn GtEt SO, tats: 
Pot. Ethyl Sulphinate. ” Diethyl Sulphdne. 





Methyl Mercaptan, CH,.SH, is alight liquid, that will swim on water, and boils 
at 20°. Perchlor-methyl Mercaptan, CSCl, = CC1,.SCl, results from the action 
of chlorine upon S,C (Berichte, 20, 2377). It is a yellow liquid, boiling at 147°. 
Nitric acid oxidizes it to CCl,.SO,Cl (p. 153). Stannous chloride converts it into 
thiophosgene, CSClL,. Methyl Sulphide, (CH;),S, boils at 37.5°, and combines 
with bromine to yield a crystalline compound, (CH;),SBr,. Concentrated nitric 
acid oxidizes methyl sulphide to sulphoxide, (CH,;),SO, which forms the salt 
(CH,),SO.NO,H with an excess of acid. Barium carbonate separates the free 
sulphoxide from this. Silver oxide produces the same compound when it acts 
upon the bromide, (CH;),SBr,. The sulphoxide is an oil, soluble in water and 
congealed by cold. On heating methyl sulphide with fuming nitric acid we obtain 
dimethyl-sulphone, (CH,),SO,. This is a crystalline body, fusing at 109° and boil- 
ing at 238°. Methyl Disulphide, (CH,),S,, boils at 112° C. 


Ethyl Mercaptan, C,H,.SH, isa colorless liquid, boiling at 36°, 
and solidifying to a crystalline mass upon rapid evaporation. Its 


MERCAPTANS AND THIO-ETHERS. 143 


sp. gr. at 20° is 0.839. It is but slightly soluble in water; readily 
in alcohol and ether. 


It may be prepared by saturating a concentrated KOH solution with hydrogen 
sulphide, adding potassium ethyl sulphate to this, and then distilling, when the light 
mercaptan will swim upon the aqueous distillate. To obtain it perfectly pure, shake 
with HgO, recrystallize the solid mercaptide from alcohol, and then decompose it 
with H,S. 


Mercury mercaptide, (C,H;.S),Hg, crystallizes from alcohol in 
brilliant leaflets, fusing at 86°, and is only slightly soluble in water. 
When mercaptan is mixed with an alcoholic solution of HgCl, 
the compound C,H;.S.HgCl is precipitated. The potassium and 
sodium compounds are best obtained by dissolving the metals in 
mercaptan diluted with ether ; they crystallize in white needles. 


Ethyl Sulphide, (C,H,),S, obtained by the distillation of ethyl chloride with 
an alcoholic solution of K,S, boils at 91°. It combines with some metallic chlo- 
rides to yield double compounds, like (C,H ,;),S.HgCl, and [(C,H,),S],.PtCl,. 

If oxidized with dilute nitric acid it forms the sulphoxide, (C,H,),S0, an oily 
liquid, which decomposes when distilled. Fuming nitric acid produces diethyl 
sulphone, (C,H,;),SO,, soluble in water and alcohol, and crystallizing in large, 
colorless plates. It melts at 70°, and boils, undecomposed, at 248°. Nascent 
hydrogen (zinc and sulphuric acid) converts the sulphoxide into ethyl sulphide. 

Ethyl Disulphide, (C,H,),S,, is obtained from ethyl mercaptan either by 
means of iodine or sulphuryl chloride (p. 142). It is an oil with a garlicky odor. 
It boils at 151°. : : 

Propyl Mercaptan, C,H,.SH, boils at 68°, and the iso-derivative at 58-60°. 
Dipropyl sulphide, (C,H,),S, boils at 130-135°. 

Normal Butyl Mercaptan, C,H,.SH, boils at 98°; dibutyl sulphide at 182° ; 
di-isobutyl sulphide at 173°. The latter yields only one monoxide with nitric acid, 
while a dioxide is also obtained from dibutyl sulphide (Annalen, 175, 349). 

Cetyl Sulphide, (C,,H,,),5, crystallizes in shining leaflets, fusinz at 57°. 

Vinyl Sulphide, (C,H,),S (compare p. 97),is the principal ingredient of the 
oil of A/ium ursinum, and is perfectly similar to allylsulphide. It boils at ro1° ; 
its sp. gr. is 0.9125. It forms (C,H,Br,),SBr, with six atoms of bromine. 
Silver oxide changes it to vinyl oxide (C,H,),0(p.140). Like allyl sulphide, it 
combines with silver nitrate and mercuric chloride to form perfectly analogous com- 
pounds (Aznalen, 241, 90). 





Allyl Mercaptan, C;H;.SH, is very similar to ethyl mer- 
captan, and boils at go°. 

Allyl Sulphide, (C;H;).5, is the chief constituent of the oil of 
garlic (from A/dium sativum), and is obtained by the distillation of 
garlic with water. It occurs in many of the Crucifere. It may be 
prepared artificially by digesting allyl iodide with potassium sul- 
phide in alcoholic solution. It is a colorless, disagreeable-smelling 
oil, but slightly soluble in water. It boils at 140°. It forms crys- 
talline precipitates with alcoholic solutions of HgCl, and PtCl. 


144 ORGANIC CHEMISTRY. 


With silver nitrate it. yields the crystalline compound (C;H;),S. 
2AgNO;. 

Allyl mustard oil is produced on heating the mercury derivative 
with potassium sulphocyanide. Vinyl mustard oil is prepared in an 
analogous manner. 





Sulphine Compounds. The sulphides of the alcohol radicals 
(thio-ethers) combine with the iodides (also with bromides and 
chlorides) of the alcohol radicals at ordinary temperatures, more 
rapidly on application of heat, and form crystalline compounds :— 


IV 
C.H,),5 + C,H,.1l =(C.H,),SL 
( E s)a x “i are ety Iodide. 
' These are perfectly analogous to the halogen derivatives of the 
strong basic radicals (the alkali metals). By the action of moist 
silver oxide the halogen atom in them may be replaced by hydroxyl, 
and hydroxides similar to potassium hydroxide be formed :— 


(C,H,),SI + AgOH = (C,H,),S.0H + Agl. 


The sulphine haloids are also obtained on heating the sulphur ethers with the 
halogen hydrides :-— 


2(C,H,),S + HI = (C,H,),SI + C,H,.SH. 


The acid chlorides react similarly. Often when the alkyl iodides act on the 
sulphides of higher alkyls the latter are displaced (Berichte, 8, 325) :— 


(C,H,),S + 3CH,I = (CH,),SI + 2C,H,I. 


(C,H,),S.CH,I and Ht po Cabot are to be isomeric, in which case a 


; 2745 
difference of the 4 valences of S would be proven. 

As in similar cases, the most recent investigations have shown them to be identi- 
cal (Berichte, 22, Ref. 648). 


The sulphine hydroxides are crystalline, efflorescent, strongly 
basic bodies, readily soluble in water. Like the alkalies they pre- 
cipitate metallic hydroxides from metallic salts, set ammonia free 
from ammoniacal salts, absorb CO, and saturate acids, with the 
formation of neutral salts :— 


(C,H,),8.0H + NO,H = (C,H,),S.NO, + H,0. 


We thus observe that relations similar to those noted with the 
nitrogen group prevail with sulphur (also with selenium and _ tellu- 
rium), Nitrogen and phosphorus combine with four hydrogen 
atoms (also with alcoholic radicals) to form the groups ammonium, 
NH,, and phosphonium, PH,, which yield compounds similar to 


SELENIUM AND TELLURIUM COMPOUNDS. 145 


those of the alkali metals. Sulphur and its analogues combine in 
like manner with three monovalent alkyls, and give sulphonium and 
sulphine derivatives. Other metalloids and the less positive metals, 
like lead and tin, exhibit a perfectly similar behavior. By addition 
of hydrogen or alkyls they acquire a strongly basic, metallic char- 
acter (see the metallo-organic compounds). 


Only the sulphine derivatives of methane and ethane have been carefully 
studied ; the former are perfectly similar to the latter. 

Triethyl Sulphine Iodide, (C,H,),SI, obtained by heating ethyl sulphide 
and iodide to 100°, crystallizes from water and alcohol in rhombic plates. Pla- 
tinum chloride precipitates the double salt [(C,H,),SCl],.PtCl,, from a solution 
of the chloride. It forms red needles. 

Triethyl Sulphine Hydroxide, (C,H,),S.OH, forms efflorescent crystals and 
possesses an alkaline reaction. Its nitrate, (C,H,),S.0.NO,, crystallizes in 
efflorescent scales. Hydrochloric acid converts the hydroxide into chloride, 
(C,H,),SCL 





SELENIUM AND TELLURIUM COMPOUNDS. 


These are perfectly analogous to the sulphur compounds. The methods of 
formation are also similar. 

Ethyl Hydroselenide, C,H,.SeH, is a colorless, unpleasant-smelling, very 
mobile liquid. It combines readily with mercuric oxide to form a mercaptide. 

Ethyl Selenide, (C,H,;),Se, is a heavy, yellow oil, boiling at 108°. It unites 
directly with the halogens, ¢. g.,(C,H,),SeCl,. It dissolves in nitric acid with 
formation of the oxide, (C,H,),SeO, which yields the salt, (C,H,;),Se(NO,),. 

Methyl Telluride, (CH,),Te, is obtained by distilling barium methyl sul- 
phate with potassium telluride. It is a heavy, yellow oil, boiling from 80—82°. 
Dilute nitric acid converts it into the nitrate of the oxide, (CH,),Te(NO,),. 
From an aqueous solution of this salt hydrochloric acid precipitates a white, 
crystalline chloride, (CH,),TeCl,; this yields the oxide, (CH,),TeO, with 
silver oxide. This is a crystalline, efflorescent compound. In properties it 
resembles CaO and PbO. It reacts strongly alkaline, expels ammonia from am- 
monium salts, and forms salts by neutralizing acids. 

Methyl telluride combines with methyl iodide to form Trimethyl tellurium 
iodide, (CH,),TelI, which ~passes into the strongly basic hydroxide, 
(CH,),Te.OH, by the action of moist silver oxide. It resembles potassium 
hydroxide. yeti 

Tri-ethyl Tellurium Chloride, Te(C,H,),Cl, has been obtained by the 
action of zinc ethide on tellurium’ tetrachloride. It consists of colorless leaflets, 
melting at 174°C. MHydriodic acid converts it into the iodide, melting at 9° 
(Berichte, 21, 2043). 

Ethyl Telluride, (C,H,),Te, is a reddish-colored oil, soluble in nitric acid 
with formation of (C,H,),Te(NO,),. Hydrochloric acid precipitates the 
chloride, (C,H,),TeCl,, from an aqueous solution of the salt. Hydriodie acid 
precipitates the zodide,(C,H,;),Tel,. This is an orange-red powder, fusing at 
50°. 


146° ORGANIC CHEMISTRY. 


ESTERS OF THE MINERAL ACIDS. 


If we compare the alcohols with the metallic bases, the esters or 
compound ethers (see p. 137) are perfectly analogous in constitution 
to the salts. We can regard them as alcohol derivatives, arising 
by the substitution of acid radicals for alcoholic hydrogen, or they 
may be viewed as derivatives of the acids formed by substituting 
alcohol radicals for the hydrogen of acids. The various designa- 
tions of esters would indicate this :— 


C,H,.0.NO, or NO,.O.C,H,. 
Ethyl Nitrate. Nitric Ethyl "Ester. 


The first view is better adapted for esters of the polyhydric 
alcohols, while the second answers best for those of the polybasic 
acids. In these all or only one hydrogen atom can be replaced by 
alcohol radicals; thus arise the zeufra/ esters and the so-called ether- 
acids, which correspond to the acid salts :— 


/0.C,H, /0.C,H, 
503¢0.C,H, SO2< OH. 
Sulphuric Ethyl Ester. Ethyl Sulphuric Acid. 


Almost all the neutral esters are volatile; therefore the determi- 
nation of their vapor density is a convenient means of establishing 
the molecular size and also the basicity of the acids. The ether-acids 
are not volatile, but soluble in water and yield salts with the bases. 

All esters, and especially the ether-acids are decomposed into 
alcohols and acids when heated with water. Sodium and potassium 
hydroxides, in aqueous or alkaline solution, accomplish this with 
great readiness when aided byheat. The process is termed saponifi- 
cation :— 


ci8 SO + KOH = C,H,.0H + C,H ,0.0K. 
2,07 ‘Alcohol. Potassium Acetate. 
Ethyl Acetate, Ethyl Acetic Ester, 

There are two synthetic methods of producing the esters that 
favor the views of considering them derivatives of alcohols or acids. 
These are :— 

(1) By reacting on the acids (their silver or alkali salts) with 
alkylogens :— 


NO,.0.Ag + C,H,I = NO,.0.C,H, + Agl. 
(2) By acting upon the alcohols or metallic alcoholates with acid 
chlorides :— 
2C,H,.0H + SO,Cl, =SO KOC He + 2HCL. 
3C,H,.OH+ BCl,—B(0.C,H,), + 3HCI. 


In addition to these reactions, which generally occur with ease, 


NITRIC ACID ETHERS. 147 


the esters can also be prepared by allowing alcohols and acids to act 
directly ; water is also produced :— om, 


C,H,.0H + NO,.0H =C,H,.0.NO, + H,0. 


This transposition, however, only takes place gradually, progressing with time ; 
it is accelerated by heat, but is never complete. We always find alcohols and 
acids together with the esters, and they do not react any further upon each other. 
If the ester be removed, ¢. g., by distillation, from the mixture, as it is formed, an 
almost perfect reaction may be attained. These relations are perfectly similar to 
those observed in the action of two salts (compare Inorganic Chemistry). A 
more comprehensive statement of the processes taking place in the action of acids 
and alcohols will be given under the esters of the fatty acids. 


When acted upon by alcohols, the polybasic acids mostly yield 
the primary esters or ether-acids. The haloid acids behave just like 
the mono-basic acids; the alkylogens formed (see p. 93) may be 
termed haloid esters of the alcohols. 


NITRIC ACID ETHERS (ESTERS). 


Methyl! Nitrate, CH;.0.NO,, Mitric Methyl Ester, is produced 
by distilling methyl alcohol with nitric acid. It is a colorless 
liquid, slightly soluble in water, and boiling at 66°. Its specific 
gravity, at 20°, is 1.182. When struck or heated to 150° it ex- 
plodes very violently. 

It is prepared by distilling a mixture of methyl alcohol (5 pts.) with sulphuric 


acid (10 pts.) and nitre (2 pts.), or a mixture of wood spirit and nitric acid, 
adding a little urea at the same time (compare ethyl nitrate). 


Ethyl Nitrate. C,H;.O.NO,, Witric Ethyl Ester. When 
alcohol is heated with nitric acid, there is a partial oxidation of 
the alcohol, which causes the formation of nitrous acid and nitrous 
ethyl ester. If, however, we destroy the nitrous acid (best by 
addition of urea), pure nitric ethyl ester results. 


Distil 120-150 grms. of a mixture consisting of 1 volume nitric acid (of specific 
gravity 1.4) and 2 volumes alcohol (80-99 per cent.), to which 1-2 grams urea 
have been added. Explosions sometimes occur when larger quantities are employed. 
Lei? Paes is shaken with water, and the heavier ester separated from the aqueous 

iquid. 

Ethyl nitrate is a colorless, pleasant-smelling liquid, boiling at 
86°, and having a specific gravity of 1.112, at 15°. It is almost 
insoluble in water, and burns with a white light. It will explode 
if suddenly exposed to high heat. Heated with ammonia it passes 
into ethylamine nitrate. Tin and hydrochloric acid convert it into 
hydroxylamine. 

The propyl ester, C,H,.0.NO,, (Berichte, 14, 421) boils at 110°, the zso-propyl 
ester at 101-102°, and the isobutyl ester at 123°. Cetyl ester, C\gH,3.0.NO,, 
solidifies at 10°. ' 


148 ORGANIC CHEMISTRY. 


NITROUS ACID ETHERS (ESTERS). 


These are isomeric with the nitro-paraffins (p. 107). The group 
NO, is present in both; while, however, in the nitro-compounds 
nitrogen is combined with carbon, in the esters the union is effected 
by oxygen :— 


C,H,.NO, | C,H;.0.NO. 
Nitro-ethane, Nitrous Ethyl Ester, 


The nitrous esters, as might be inferred from their different 
structure, decompose into alcohols and nitrous acid when acted on 
by alkalies. ‘Similar treatment will not decompose the nitro-com- 
pounds. Nascent hydrogen (tin and hydrochloric acid) converts 
the latter into amines, while the esters yield alcohols. 

Nitrous acid esters are produced in the action of nitrous acid 
upon the alcohols. The latter are saturated with nitrous acid vapors 
and distilled ; ora mixture of alcohol, KNO, and H,SOQ, is distilled. 
A late procedure consists in adding the calculated quantity of alco- 
hol to the dilute solution of sodium nitrite. To this cold mixture 
add hydrochloric acid, then distil (Berichte, 19, 915). : 


Methyl Nitrite, Nitrous Methyl Ester, CH,.0.NO, is an agreeable-smelling gas. 
When exposed to great cold, it is condensed to a yellowish liquid, boiling at — 12°. 

Ethyl Nitrite, Nitrous Ethyl Ester, C;H;.O.NO, is a mobile, yellowish liquid, 
of specific gravity 0.947, at 15°, and boils at-+ 16°. It is insoluble in water, and 
possesses an odor resembling that of apples. It is best obtained by heating a mix- 
ture of alcohol and nitric acid with copper turnings, or may be made by distilling a 
mixture of alcohol and fuming nitric acid, after having stood for some hours. The 
distillate is shaken with water (to withdraw alcohol) and a soda solution, then de- 
hydrated and distilled (see Anna/len, 126, 71; Berichte, 21, Ref. 515). 

When ethyl nitrite stands with water it gradually decomposes, nitrogen oxide 
being eliminated; an explosion may occur under some conditions. Hydrogen 
sulphide changes it into alcohol and ammonia. 

Tertiary Butyl Nitrite, C(CH,),.0.NO, boils at 77°. 

Amy! Nitrite, C;H,,.0.NO, obtained by the distillation of fermentation amyl 
alcohol with nitric acid, is a yellow liquid, boiling at 96°; its sp. gr. is 0.902. An 
explosion takes place when the vapors are heated to 250°. Nascent hydrogen 
changes it into amyl alcohol and ammonia. Heated with methyl] alcohol, it is 
transformed into methyl nitrite and amyl alcohol. The result is the same if ethyl 
alcohol be used (Berichte, 20, 656). 


ESTERS OF SULPHURIC ACID (ETHYL SULPHATES). _ 


Sulphuric acid being dibasic forms two series of esters—the neu- 
tral esters and the primary esters or ether-acids -(ethereal salts) 
(p. 146.) | 

(1) The neutral esters are formed by the action of the alkyl 
iodides upon silver sulphate, SO,Ag,; they are also produced, in 


ESTERS OF SULPHURIC ACID. 149 


slight quantity on heating the primary esters or alcohols with sul- 
phuric acid. They can be extracted with chloroform from the 
product, and are heavy liquids, soluble in ether, possess an odor 
like that of peppermint, and boil without decomposition. They 
will sink in water, and gradually decompose into a primary ester 
and alcohol :— 


0.C,H / 0.CjH 
SO OCH 2 igieit 982 $0;¢ On 5 4 C,H,.OH. 
The Dimethyl Ester, SO,(O.CH,),—normal. methyl sulphate—boils, without 
decomposition, at 188°. The diethy/-ester, SO,(O.C,H;),, normal. ethyl sulphate, 
boils at 208°, sustaining at the same time a partial decomposition. When heated 
with alcohol, ethyl sulphuric acid and ethyl ether are formed (Berichte, 13, 1699 ; 
15, 947). 
_ (2) The primary esters or ether-acids are produced when the 
alcohols are mixed with concentrated sulphuric acid :— 


SO, (OH), + C,H,.0H = 30, on* 4.H,0. 


The reaction takes place only when aided by heat, and it is not complete, be- 
cause the mixture always contains free sulphuric acid and alcohol (compare p. 
147). To isolate the ether-acids, the product of the reaction is diluted with water 
and boiled up with an excess of barium carbonate. In this way the unaffected sul- 
phuric acid is thrown out’as barium sulphate; the barium salts of the ether-acids 
are soluble and crystallize out when the solution is evaporated. To obtain the 
acids in a free state their salts are treated with sulphuric acid or the lead salts 
(obtained by saturating the acids with lead carbonate) may be decomposed by 
hydrogen sulphide, and the solution allowed to evaporate over sulphuric acid. 


These acids are also prepared_by the union of the alkylens with 
concentrated sulphuric acid (p. 80). They are thick liquids, that 
cannot be distilled. They sometimes crystallize. In water and 
alcohol they dissolve readily, but are insoluble in ether. When 
boiled or warmed with water they break up into sulphuric acid 
and alcohol :— hy ort 


$0,¢ on" 4+ H,0 = S0,H, + C,H,.0H. 


When distilled they yield sulphuric acid and alkylens (p. 80.) 
Upon heating them with alcohols simple and mixed ethers (p. 136) 
are produced. . 

They show a strongly acid reaction and furnish salts that dissolve 
quite readily in water, and crystallize without great trouble. The 
salts gradually change to sulphates and alcohol when they are 
boiled with water. ‘Those with the alkalies are frequently applied 
in different reactions. Thus with KSH, and K,S they yield mer- 


150 ORGANIC CHEMISTRY. 


captans and thio-ethers (p. 140); with salts of fatty acids they 
furnish esters, and with KCN the alkyl cyanides, etc. 


Methyl Sulphuric Acid, SO,(CH,)H, is a thick oil, that does not solidify at 
—30°, The potassium salt (SO,)CH,K + %H,O), forms deliquescent leaflets. 
The barium salt, (CH,.SO,),Ba + 2H,0, crystallizes in plates. 

Ethyl Sulphuric Acid, SO,(C,H,)H, is obtained by mixing 1 part alcohol with 
2 parts concentrated sulphuric acid, and by the union of C,H, with sulphuric acid 
(p. 81). It is a thick, non-crystallizable liquid, having, at 16°,a specific gravity 
of 1.316. The potassium salt, SO,(C,H,;)K, is anhydrous; it crystallizes in 
plates, that dissolve quite readily. The barium and calcium salts crystallize in 
large tablets with two molecules of H,O each. Consult Anna/len, 218, 299, for 
two different barium salts of methyl and ethyl sulphuric acid. 

Amyl Sulphuric Acid, SO,(C;H,,)H. Two isomeric barium amy] sulphates 
are obtained by mixing ordinary fermentation amyl] alcohol with sulphuric acid, 
and then neutralizing with barium carbonate. These salts both crystallize in 
large tablets, and show varying solubility in water, and may be separated by 
repeated crystallization. The more sparingly soluble salt is produced in the 
greater abundance and furnishes isobutyl carbinol, while active amyl alcohol is 
obtained from the more readily soluble salt (p. 131). 

Allyl Sulphuric Acid, S0,(C,H,)H, has been made from allyl alcohol and 
sulphuric acid. 

0.C,H, 


The chlorides or chloranhydrides of the ether sulphuric acids (so,¢ Cl ) ’ 


called esters of chlorsulphonic acids, result in the action of sulphuryl chloride 
upon the alcohols :— 


O10 -80j;0o& 80,094 + HCl; 


Chloride of Ethyl 
Sulphuric Acid. 
860) by the action of SO, upon the esters of hypochlorous acids (Berich/e, 19, 
Cl 
SO, + ClO.C,H, = $0.6 6.c s 


All are liquids with penetrating odor, and boil with scarcely any decomposition. 
Cold water decomposes them very slowly, without the formation of the ether 
acids. These they yield, together with ethyl chlorides, on adding alcohol to them. 
The reaction is rather energetic. 

Chloride of Ethyl Sulphuric Acid, C,H,.0.SO,Cl, boils about 152°. 
Methyl Sulphuric Chloride, CH,.0.SO,CI, boils at 132°. 


SULPHUROUS ACID ETHERS (ESTERS). 


The empirical formula of sulphurous acid, SO,;H,, may have one 
of two possible structures :— 


Iv 
so’ 2 or ad 
\.OH HSO,.OH. 
Symm. Sulphurous Acid. Unsymm. Sulphurous Acid. 


The ordinary sulphites correspond to formula 2, and it appears 


SULPHUROUS ACID ETHERS. I51 


that in them one atom of metal is in direct combination with 


sulphur :— 


Ag.SO,.OAg. K.SO,.OH. 
Silver Sulphite. Prim. Pot. *Sulphite: 


This is evident from the following considerations :— 


(1) Esters of Symmetrical Sulphurous Acid. 
These are produced in the action of thionyl chloride, soci, , or sulphur mono- 
chloride, S,Cl,, upon alcohols :— 


SO,1, + 2C,H,.0H = SOX Oc H + 2HCl and 


S,Cl, + 3C,H,.0H =S0C 6, c? He 4. C,H,.SH + 2HCl. 


The mercaptan that is simultaneously formed sustains further decomposition, 
The sulphites thus produced are volatile liquids, insoluble in water, with an odor 
resembling that of peppermint, and decomposed by water, especially when heated, 
into alcohols and sulphurous acid. 

Sulphurous Methyl Ester, SO(O.CH,),,-methyl sulphite, boils at 121°. 

The Ethyl Ester, SO(O.C,H,),, boils at 161°. Its specific gravity at 0° is 


1.106. PCI, converts it into the chloride, SOX 6, C,H,? a liquid boiling at 


122°, and decomposed by H,O into alcohol, SO, and HCl. It is isomeric with 


ethyl sulphonic chloride, C, sH; SO,Cl (p. 1 53)- On mixing the ester with a 
dilute solution of the equivalent amount of KOH, a potassium salt, SO. ra oe 2H, 


separates in glistening scales, This is viewed as a salt of the unstable ethyl] sul- 
phurous acid. 


(2) Esters of the Unsymmetrical Sulphurous Acid.—These are 
formed by the action of silver sulphite upon the alkyl iodides in 
ethereal solution :— 


Ag.SO,.0Ag + 2C,H,I — C,H,.SO,.0.C,H, + 2Agl. 


One of the alkyl groups is joined to sulphur, the other to oxygen. 
When heated with water the latter one only is separated as alcohol, 
and sulphonic acids result :— 

C,H,.S0,.0.C,H, + H,O = C,H,.SO,.0H + C,H,.OH. 
Ethyl Sulphome Acid. 

Conversely, the esters can be prepared from the sulphonic acids, 
by acting on their salts with alkyl iodides or upon the sodium alco- 
holates with the chlorides of the sulphonic acids :— 


SO,Cl + C,H, .ONa = C,H,.SO,.0.C,H, + NaCl. 
Ethyl week houtie Chloride. Ethyl Sulphonic Ethyl Ester. 


Hence, the esters formed from silver sulphite may be regarded 
as esters of the sulpho-acids. They boil much higher than the 
isomeric esters of symmetrical sulphurous acid. They are distin- 


152 ORGANIC CHEMISTRY. 


guished from the latter by having but one of their alkyl groups 
separated out by alkalies (see above). 


Ethyl Sulphonic Ethyl Ester, C,H;.SO,.0.C 2H, produced as above 
described, boils at 213.4°, and has a sp. gr. * of 1. 171 at 0°. 
The methyl ester, C,H;.SO,.0.CHg, boils at 198°. 


3. Sulpho-acids, C a Hon 4.1,90,,0H. 

The sulpho- or sulphonic acids, which contain the group —SO, OH 
attached to carbon, may be viewed as esters of unsymmetrical sul- 
phurous acid, HSO,OH, inasmuch as they are produced from its 
neutral esters by the separation of an alkyl group (p. 151). Fur- 
thermore, their salts are directly obtained from the alkaline sulphites 
(preferably ammonium sulphite) by heating them with alkylogens 
(in concentrated aqueous solution to 120-150°):— 

K.SO,.0K ++ C,H,I = C,H,.SO,.0K + KI. 
Potassium Ethyl Sulphonate. 


2K.SO,,0K + C,H,Br, = C LC So Ont 2KBr. 


Potassium Ethylene ‘Disulphonate. 


The oxidation of mercaptans and alkyl disulphides (p. 142) 
(also sulphocyanides) with nitric acid also affords the sulpho- 
acids :— 


H + 30 — C,H, SO,.OH. 
Ethyl Meércaptan: Ethy Suiphotte Acid. 


Conversely, these sulpho-acids can be again reduced to mercaptans 
(by action of zinc and hydrochloric acid upon their chlorides—as 
C,H;.SO,Cl): C,H;.SO,Cl + 3H, = C,H;.SH + HCl-+ 2H,0. 
They may also be obtained by oxidizing the sulphinic acids and 
can be again converted into the latter (see p. 154). All these 
reactions plainly indicate that in the sulpho-acids the alkyl group 
is joined to sulphur, and that, therefore, it is very probable that in 
the sulphites the one atom of metal is directly combined with sul- 
phur. Finally, the sulpho-acids can be .prepared by the action of 
sulphuric acid or sulphur trioxide (SOs) upon alcohols, ethers and 
various other bodies. This reaction is very general and easily exe- 
cuted with the benzene derivatives. 

_ These acids are thick liquids, readily soluble in water, and gen- 
erally crystallizable. They suffer decomposition when exposed to 
heat, but are not altered when boiled with alkaline hydroxides. When 
fused with solid alkalies they break up into su/phites and alcohols :— 


- C,H,.SO,.0K +- KOH = KSO,.OK + C,H,.0H. 


_ PCI, changes them to chlorides, ¢. &-» C,H;.SO,Cl, which become mercaptans 
through the agency of hydrogen, or by the action of sodium alcoholates pass into 
the neutral esters—C,H,.SO,.C,H, (p. 151). 


ESTERS OF THIO-SULPHURIC ACID. 153 


Methyl Sulphonic Acid, CH;.SO,;H, is a thick, uncrystalliz- 
able liquid, soluble*in water. When heated above 130° it sustains 
decomposition. In order to obtain the pure acid it is converted 
into the lead salt, the solution of which is treated with H,S, the head 
sulphide filtered off and the filtrate concentrated. 


Its salts are readily soluble in water and ctyiiallize well. The barium salt, 
(CH,.SO,),Ba + 1%H,0, crystallizes in rhombic plates. Methyl sulphonic 
chloride, CH, .SO,Cl, boils near 160° and is slowly decomposed by water into the 
acid and hydrogen chloride. 

The following is an interesting method of preparing methyl sulphonic er : 
Moist chlorine is allowed to act upon carbon disulphide, CS,, when there is pro- 
duced the compound, CC1,.SO,, which must be considered as the chloride of tri- 
chlormethyl sulphonic acid, CCl,.SO,Cl. It is colorless and crystalline; it fuses 
at 135°, and boils at 170°. It is soluble i in alcohol and ether, but not in water. 
Its odor resembles that of camphor, and excites tears. To prepare the chloride a 
mixture of 500 gr. HCl, 300 grms. coarse-grained Cr,O,K,, 200 gr. nitric acid 
and 30 gr. CS,, are allowed to stand in an open flask, ‘Water is then added, to 
dissolve the salts, and the crystals of CC1,.SO, are filtered off. 

On boiling the chloride with potassium or barium hydrate salts of trichlormethyl 
sulphonic acid, CCl,.SO,H, are formed. The barium salt, (CC1,.SO,),Ba + H,O, 
crystallizes in leaflets. “Sulphuric acid releases the acid from it. It consists 
of deliquescent prisms. Nascent hydrogen (sodium a CHLCL in an aqueous solu- 
tion of the acid produces successively CHCl,.SO,H, CH,Cl.SO,H, and, finally, 
CH;.SO,H—methyl sulphonic acid. These Teactions represent one of the first 
instances of the conversion of an inorganic (mineral) substance (CS,) into a so- 
called organic derivative. 


Ethyl Sulptionic Acid, Cathe. SO,H, is a thick, crystallizable 
liquid. 


Its lead salt, (C,H;.SO,),Pb, crystallizes in readily soluble leaflets. Concen- 
trated nitric acid oxidizes it to ethyl sulphuric acid, SO,(C,H,)H. Its chloride, 
C,H;.SO,Cl, is a liquid, boiling at 173°. Its ethyl ester, C,H;.5O,.C,H,, boils at 


213. 4° (p. 151). 


ESTERS OF THIO-SULPHURIC ACID (AND ALKYL THIO- 
SULPHONIC ACIDS). 


On p. 151 we saw. how the alkyl sulphonic acids were obtained from the sul- 
phites by the alkyl iodides. In the same way the corresponding a/kyl thiosul- 
phonic acids can be prepared from the salts of thiosulphuric acid (hyposulphurous 
acid) :— 

KS.SO,K + C,H;I = C;H;.S.SO,K +- KI. 


Only the primary saturated alkyl iodides, however, react in this way (Berichte, 
15, 1939). The ethyl compound can be made, too, by letting iodine act on a | 
mixture of mercaptan and sodium sulphite, Na,SO,. 

The salts of these acids crystallize well. When boiled with hydrochloric acid 
they are decomposed into mercaptans and primary sulphates. When heated they. 
break up into alkyl disulphides, (C,H,),S,, and dithionates (SO,K, + SO,). 


13 


154 ORGANIC CHEMISTRY. 


The Alkyl Thiosulphonic Acids, R.SO,.SH, differ from the alkyl thiosul- 
phuric acids. They are formed by the action of the chlorides of sulpho-acids upon 
potassium sulphide: C,H,.SO,Cl + K,S = KCl + C,H,.SO,.SK. The esters, 
R.SO,SK, of this new ‘class were formerly called alkyl disulphoxides, R,S,0,, and 
are obtained from the alkali salts by the action of the alkyl bromides (Berichte, 
15, 123),C,H,.SO,SK + C,H,Br=C,H,.SO,SK -+ KBr; and by the ox- 
idation of mercaptans and alkyl disulphides with dilute nitric acid: (C,H;),S, + 
O, = C,H;.SO,SC,;H,;. These esters are liquids, insoluble in water, and pos- 
sessed of a disgusting onion-like odor. When distilled they suffer partial decom- 
_ position, but in a current of steam volatilize undecomposed. They are saponified 
by the alkalies, forming ‘sulphinic acids and disulphides, while the latter, in part, 
decompose into sulphinic acids and mercaptans (Berichée, 19, 1241). With potas- 
sium sulphide the esters yield alkyl thiosulphonates and mercaptides (Berichie, 19, 
3131). Zinc and sulphuric acid reduce the esters to disulphides and mercaptans, 
while zinc dust changes them to alkyl sulphinic acids (zinc salts) and zinc mercap- 
tides. Nitric acid oxidizes the esters to two molecules of the sulphinic acids. 
Ethyl Thiosulphuric Ethyl Ester, C,H,.SO,.S.C,H,, boils from 130°-140°. 

Esters of Hydrosulphurous Acid—Sulphinic Acids. oe eagles 


IV 
formulas are possible for hydrosulphurous acid : H.SO.OH and HN 50,. Re- 


place one hydrogen atom and the sulphinic acids result, ¢.g.: (1) C,H,.S0.0H or 


vI 
(2) if * 80, Both forms are probably identical or tautomeric (p. 54), where- 
as their alkyl derivatives are isomeric :— 


C,H,.SO.0.C,H, and = 6? 2H! SO 
Ethyl Sulphinic Diethyl-sulphone. 
Ester. 


These relations are exactly analogous to those of the isomeric esters of sulphurous 
acid (p. 151). 

When SO, acts upon the zinc alkyls, the sulphinic acids (their zinc salts) 
result :— 

(C,H;),Zn + 2S0, = (C,H,.SO,),Zn, just as the carbonic acids (e. g., 
C,H,.CO,H) are produced by the action of CO,. 

: "A simpler method would be to let zine dust act upon the chlorides of the sul- 

phonic acids: 2C,H,.SO,Cl + 2Zn = (C,H;.SO,),Zn + ZnCl,. To obtain 
the free acids the zinc > salts are converted into barium salts and these, in turn, de- 
composed by sulphuric acid. The sulphinic acids are thick, strongly acid liquids, 
decomposed by heat. Their sodium salts are formed in the ‘oxidation of the oxy- 
sodium mercaptides in the air: C,H,.SNa + O, = C,H,.SO,Na. 

The sulphones (p. 142) are produced i in the action of alley! iodides upon the 
alkaline sulphonates, while the vea/ esters result from the etherification of the acids 
with alcohol and hydrochloric acid, or by the action of chlorcarbonic esters upon 
o sulphinates Chelneane 18, 2493): R.SO,Na + Cl.CO,R = R.SO.OR + 

2 + NaCl. en these esters are saponified by alcohol or water they break 
eS into alcohol and sulphinic acid, while the isomeric sulphines are not altered. 
Free sulphinic acids are not very stable ; they rapidly oxidize to sulphonic acids. 
Potassium permanganate and acetic acid convert the sulphinic esters into sulphonic 
esters (Berichte, 19, 1225), whereas the isomeric sulphones remain unchanged. 
Methyl] Sulphinic Acid, CH,.SO,H, and Ethyl Sulphinic Acid,C,H,;.SO,H, 
are liquids, dissolving readily i in water. In aqueous solution they soon decompose 

with the separation of sulphur. 


ESTERS OF THE PHOSPHORIC ACIDS. 155 


ESTERS OF CHLORIC ACIDS. 


Ethyl Perchlorate, ClO,.0.C,H,, is obtained by the action of ethyl iodide 
upon silver perchlorate. It is a colorless liquid that explodes when heated. 

The Esters of hypochlorous acid, CIOH, form on mixing concentrated aqueous 
solutions of hypochlorous acid with alcohol. They separate as yellow oils. When 
carefully heated they boil without decomposition, but if overheated they explode 
with great violence ( Berichte, 18, 1767, and 19, 857). 

Methyl Hypochlorite, CIOCH,, boils at 12°; Ethyl Hypochlorite, CIOC,H,, 
boils at 36°. Both have a penetrating odor that attacks the respiratory organs 
powerfully. 

Sulphur dioxide converts these esters into chlorsulphonic esters (p. 150), while 
with KCN they yield chlorimide carbonic acid esters, C(NCl) (O.C,H;),. (see 
these). 


ESTERS OF BORIC ACID. 


The esters of the tribasic acid, B(OH);, are formed along with those of the 
monobasic acid, BO.OH, when BCI, acts upon the alcohols. The first are vola- 
tile, thick liquids, while the second decompose when distilled. Acid esters are not 
known. Water decomposes both the preceding varieties. 

Methyl Borate, B(O.CH,),, boils at 65°. 

Ethyl Borate, B(O.C,H,),, is obtained by distilling potassium ethyl sulphate 
together with borax. It boils at 119°. 


ESTERS OF THE PHOSPHORIC ACIDS. 


Tribasic phosphoric acid, PO(OH),, yields three series of esters—the primary, 
secondary and tertiary, all of which are thick liquids. Only the last volatilize 
without decomposftion. 

Triethyl Phosphoric Ester, PO.(O.C,H,),, is formed when phosphorus oxy- 
chloride acts upon sodium ethylate :— 


POCI, + 3C,H,.ONa = PO(O.C,H,), + 3NaCl. 


A thick liquid, soluble in water, alcohol and ether, and boiling at 215°. The 
aqueous solution decomposes readily into diethyl-phosphoric acid, the lead salt of 
which is made by boiling with PbO. 


Diethyl Phosphoric Acid, PO { eee atts)ae ‘is obtained by decomposing 


the lead salt with H,S. Itisathick syrup. The lead salt crystallizes in silky 
needles. When heated it passes into the triethyl ester and lead monoethyl 
phosphate, insoluble in water. The acid of this last salt has the formula 
PO(OH),.0.C,H;. 





The esters of symmetrical phosphorous acid, P(OH),, result when PCI, acts on 
the alcohols. Triethyl phosphite, P(O.C,H,),, boils at 191°. . 
Acids of the structure C,H,;.PO(OH),, corresponding to the sulpho-acids, 
C,H,.SO,.OH, (p. 152) may be derived from the unsymmetrical phosphorous 
acid, HPO(OH),. They are produced by the oxidation of primary phosphines 
(see these) with nitric acid : — 


P(CH,)H, + O, = CH, PO(OH),. 


156 | ORGANIC CHEMISTRY. 


They are spermaceti-like, crystalline bodies, soluble in water and reacting 
ie acid. They furnish both acid and neutral salts, that are mostly crystal- 
izable. 

Methyl Phosphite, CH,PO(OH),, melts at 105°. PCI; converts it into 
CH,.POCI,, which fuses at 32°, and boils at 163°. Water again produces the 
acid from the chloride. 

Ethyl Phosphite, C,H,.PO(OH)., melts at 44°. 

PCl, converts aldehydes into compounds, which yield oxy-alkyl phosphorous 
acids, ¢. g., CH,;.,CH.OH.PO(OH), (Berichte, 18, Ref..111), when treated with 
water. 





From hypophosphorous acid, H,.PO.OH, we obtain similar compounds that can 
be called phosphinic acids. ‘They result when nitric acid acts on the secondary 
phosphines :— 

P(CH,),H + O, = (CH,),PO.OH. 


Dimethyl Phosphinic Acid, (CH,),PO.OH, resembles paraffin, fuses at 76° 
and volatilizes without decomposition. : 


ESTERS OF ARSENIC ACIDS. 


_Ethyl Arsenate, AsO(O.C,H,),, is the product of the action of ethyl iodide 
upon silver arsenate, AsO,Ag,. It is a liquid, boiling at 235°. 

The esters of arsenious acid, As(OH),, form when AsBr, is distilled with 
sodium alcoholates, They distil without decomposition. Water immediately 
changes them to arsenious acid and alcohols. The methyl ester, As(O.CH,),, 
boils at 128°; the ethyl ester at. 166°. 

Arsenic- compounds analogous to the phosphorous and phosphinic acids, 
C,H,.PO(OH), and (C,H,),PO.OH, exist. They are: methyl arsinic acid, 
CH,.AsO(OH),, and dimethyl arsinic acid, (CH, ),AsO.OH, or cacodylic acid. 
These will be considered with arsenic alcoholic radicals. 


ESTERS OF SILICIC ACIDS. 


These are obtained by the action of SiCl, and SiFl, upon alcohols or sodium 
alcoholates. The esters of normal silicic acid, Si(OH),, of metasilicic acid, 
SiO(OH),, and disilicic acid, Si,O,H,, are formed together and can be separated 
by fractional distillation. 

_ The normal Methyl Ester, Si(O.CH,),4, boils at 120-1229; methyl disilicate, 
Si,0,(CH,),, at 202°. 

The Ethyl Ester, Si(O.C,H,),, boils at 165°. LZthyl disilicate, Si,0,(C,H;),, 
which can also be produced by action of silicon oxychloride, Si,OCI,, on alcohol, 
boils at 236°; ethyl-metasilicate, SiO.(O.C,H,),, boils at 360°. 

These derivatives on standing awhile in moist air, or by addition of water, slowly 
decompose with separation of silicic acid, which sometimes solidifies to a trans- 
parent hard glass. , 


AMINES. 157 


AMINES. 


Among the derivatives of carbon exists a series of very basic 
bodies, which have been designated organic bases or alkaloids. 
They all contain nitrogen and are viewed as ammonia derivatives ; 
this accounts for their basic character. We will consider here only 
the monamines derived from ammonia by the replacement of hydro- 
gen by monovalent alkyls. 

One, two and three hydrogen atoms of the ammonia molecule 
may suffer this replacement, thus yielding the primary, secondary 
and tertiary amines (also called amide, imide, and nitrile bases) :— 


/C,Hs / C,H, ACs 

“H N—C,H, N—C,H, 

H Se \ CoH 
Ethylamine. Diethylamine. . Triethylamine, 


Derivatives also exist that correspond to the ammonium salts and 
hypothetical ammonium hydroxide, NH,.OH :— 


v 
(C,H;),NCl (C,H;), N.OH, 
Tetra-ethyl Ammonium Chloride. Tetra-ethyl Activin iis Hydroxide. 


The following methods are the most important for preparing the 
above compounds :— 

(1) The iodides or bromides of the alcohol radicals are heated 
to 100°, in sealed tubes, with alcoholic ammonia (4. W. Hofmann, 
1849). In this way the alkyl displaces the hydrogen of ammonia ; 
the hydrogen haloid formed at the same time combines with the 
amine and yields ammonium salts :— 


NH, + C,H,I = NH,(C,H 


NH, 2 + 2C,HI = NH(C,Hi,) pat 4 At 
NH, + 3C,H,I — N(C,H,),.HI ° + 2HI 


Wher thesesalts are distilled with sodium o or potassium hydroxide, 
free amines pass over :— } 


NH(C,H,),.HI + KOH = NH(C,H,), + KI + H,0. 
It is interesting to know that the primary alkyl iodides form both secondary and 


tertiary amines, while the secondary alkyl iodides (like isopropyl iodide) only 
furnish primary amines (also alkylens) (Berichte, 15; 1288). 


In the same process tertiary amines further unite with alkyl 
iodides ae form tetra-alkyl ammonium salts: — 


N(C,H;); + C,H,I = N(C,H,),I. 





156 ORGANIC CHEMISTRY. 


These are zot decomposed when distilled with KOH; but if 
treated with moist silver oxide they yield ammonium hydroxides :— 


N(C,H,),I + AgOH = N(C,H,),.OH ++ Agl. 


By the action of primary alkylogens upon ammonia, a mixture of primary, 
secondary and tertiary amine salts and those of the ammonium bases, always 
results. The latter may be easily obtained pure by distilling the mixture with 
KOH, when the amines pass over and the ammonium bases make up the residue, 
inasmuch as their halogen compounds are not decomposed by alkalies. 

Fractional distillation is a poor means of separating the amines. The follow- 
ing procedure serves this purpose better (Berichte, 8, 760): The mixture of the 
dry bases is treated with diethyl oxalate, when the primary amine, ¢. g., methyl- 
amine, is changed to diethyl oxamide, which is soluble in water; dimethylamine 
is converted into the ester of dimethyl oxamic acid (see oxalic acid compounds) ; 
and trimethylamine is not acted upon :— 


0.C,H NH.CH 
2NH,(CH;) + C0. 0. a C,0.¢ NHCH + 2C,H,.OH. 
Diethyl Oxalate. Dimethyl Oxamide. 


0.C,H 0.C,H 
NH(CH,), + C0. 0.0°H i C0. NiG.§, 4. C.H,.OH, 


Dimethyl-oxamic Ester. 


When the reaction-product is distilled the unaltered trimethylamine passes 
over. Water will extract the dimethyl oxamide from the residue; on distillation 
with caustic potash it becomes methy/amine and potassium oxalate : — 


NH.CH 
C,0, CNHLCH +. 2KOH =C,0,K, +2NH,(CH,). 
The insoluble dimethyl-oxamic ester is converted, by distillation with potash, 
into dimethylamine :-— 


0.C,H 
C0: CnicH, 4+ 2KOH =C,0,K, + NH(CH,), + C,H,.OH. 


Another procedure furnishing a partial separation of the amines depends on 
their varying behavior towards carbon disulphide. The free bases (in aqueous, 
alcoholic or ethereal solution) are digested with CS,, when the primary and 
secondary amines form salts of the alkyl dithio-carbaminic acids (see these), while 
the tertiary amines remain unaffected, and may be distilled off. On boiling the 
residue with HgCl, or FeCl,, a part of the primary amine is expelled from the 
compound as mustard oil (Berichte, 14, 2754 and 15, 1290). 


The esters of nitric acid, when heated to 100° with alcoholic 
ammonia, react in a manner analogous to the alkyl iodides :— 
( C,H;.O.NO, + NH, =C,H,.NH, + HINO,. 
This reaction is often very convenient for the preparation of the 
primary amines (Berichte, 14, 421). 


Mono-, di-, and tri-alkylamines are obtained by directly heating the alcohols to 
250—300° with zinc-ammonium chloride (Berichte, 17, 640). 


| _ AMINES. 159 


(2) The ethers of isocyanic or isocyanuric acid are distilled with 
potassium hydroxide ( Wirtz, 1848):— 


CO:N.CH, + 2KOH = NH,.CH, + CO,K,. 


Cyanic acid is changed to ammonia in precisely the same man- 


BCr 
CO:NH + 2KOH = NH, + CO,K,. 


In the above reaction only primary amines are produced. 


To convert alcoholic radicals into corresponding amines, the iodides are heated 
together with silver cyanate ; the product of the reaction is then mixed with pul- 
verized caustic soda, and distilled in an oil bath (Berichte, 10, 131). 


Above we observed the decomposition of the isocyanic ethers by 
alkalies. Their analogues in constitution—the isothio-cyanic ethers 
(the mustard oils, etc.,)—are also broken up into primary amines 
by sulphuric acid. 


3. Warm the isocyanides of the alkyls with dilute hydrochloric acid; formic 
acid will split off (4. W. Hofmann):— 


C,H,.NC + 2H,O = C,H,.NH, + CH,0,. 


The isocyanides are obtained by heating the alkyl iodides with silver cyanide 
(see these). 
(4) By the action of nascent hydrogen upon the nitriles or alkyl cyanides 


(Mendius) :— 
HCN ++ 2H, — CH,.NH,, 
Hydrogen Cyanide. Methylamine. 
CH,.CN + 2H, = Ce Coe Nie: 


Acetonitrile. Ethylamine, 


A more advantageous course consists in allowing metallic sodium 
to act upon the nitrile dissolved in absolute alcohol, In this way 
the dicyanides can be converted into diamines (Berichte, 18, 2957 5 





19, 783 3 22, 812). 


(5) By action of nascent hydrogen (HCl and Zn) upon the nitro-paraffins 
(p. 106) :— 
CH,.NO, + 3H, = CH,.NH, + 2H,0. 


(6) A method entirely new, and especially adapted to the forma- 
tion of primary amines, consists in the transformation of fatty acids 
(A. W. Hofmann, Berichte, 15, 762). The amides of these acids 
are converted, through the agency of Br and KOH, into brom- 
amides :— 


C,H,.CO.NH, + Br, + KOH = C,H,.CO,NHBr + KBr + H,0, 


j 


\ 


\ 


160 ORGANIC CHEMISTRY. 


On further heating with alkali, carbon dioxide escapes and 
primary amines result :— 


C,H,.CO.NHBr + 3KOH = C,H,.NH, + CO,K, + KBr + H,0. 


When 1 molecule bromine and 2 molecules of the amide react, the product con- 
sists of mixed ureas :— 
7 NH.CO.CH, 
2CH,.CO.NH, + Br, = CO + 2HBr. 
\NH.CH, 
Methyl Aceto-urea. 


The fatty-acid amides, with more than 5 C-atoms, not only yield amines, but also 
large quantities of the nitriles of the next lower acids : -- 


C,H,,.CO.NH, yields C/H,,.CN. 


In this way CO is eliminated, and amines form. These yield dibromides with 
bromine, and by the further action of KOH are changed to nitriles ( Berichée, 17, 
1406, 1920) :— 


C,H,,.NBr,(C,H,,.CH,NBr,) _ yields C,H, ,.CN. 
These reactions are also adapted to the conversion of acid amides of the benzene 


series into amines (Berichte, 18, 2734, and 19, 1822). 


(7) For the conversion. of the aldehydes and ketones into their 
corresponding primary amines, their phenylhydrazine derivatives 
are treated with nascent hydrogen; best by the action of sodium 
amalgam and glacial acetic acid upon the alcoholic solutions (Be- 
richte, 19, 1925 ; 22, 1854):— 


CH,.CH:N,H.C,H, + 2H, = CH,:CH,.NH, + C,H,.NH,. 


The primary amines can also be obtained, in a similar manner, 


‘from the hydroxylamine derivatives of the aldehydes and ketones 


(see the aldoximes and acetoximes) (Berichte, 19, 3232). 

The methods above are those ordinarily employed ; others exist 
for the production of amines; ¢. g., they arise in the decomposition 
of complex nitrogenous derivatives, as shown in the case of the 
amido-acids. 

Tertiary, secondary and ‘primary amines may also be obtained by 
the dry distillation of the halogen salts of the ammonium bases :— 


N(CH,),C1 =N(CH ), ena 
N(CH,),HCl = NH(CH,), + CH,Cl 
NH(CH,),HCl — NH,(CH,) + CH, Cl, ete. 


These reactions. serve for the commercial production of methyl 
chloride from trimethylamine. 

On a large scale, the amines are best prepared by acting on the 
alkyl bromides with ammonia (Berichte, 22, 700). 


AMINES. 161 


The amines are very similar to ammonia in their deportment. 
The lower members are gases, with ammoniacal odor, and are very 
readily soluble in water; their combustibility distinguishes them 
from ammonia. The higher members are liquids, soluble in water, 
and only the highest are sparingly soluble. The amines are best 
dehydrated by distillation over barium oxide. Their basicity is 
greater than that of ammonia, and increases with the number of 
alkyls introduced ; the tertiary amines are stronger bases than the 
secondary, and the latter stronger than the primary. Therefore, 
they can expel ammonia from the ammonium salts. Like ammonia, 
they unite directly with acids to form salts, which differ from’ 
ammoniacal salts by their solubility in alcohol. They combine 
with some metallic chlorides, and afford compounds perfectly analo- 
gous to the ammonium double salts; ¢. g.:— 


[N(CH,)H,CI],PtCl,. N(CH,)H,CLAuCl, [N(CH,),HCl],HgCl,. 


The ammonia in the alums, the cuprammonium salts and other 
compounds may be replaced by amines. 

The behavior of amines with nitrous acid is very characteristic. 
The latter compound converts the primary amines (better to act on 
the haloid salts with AgNO,) into the corresponding alcohols (see 

. 122):— 
bie C,H,.NH, + NO.OH =C,H,.0H + N, + H,O. 


This is a reaction analogous in every respect to the decomposition 
of ammonium nitrite into water and nitrogen :— 


; NH, + NO.OH = H,O +N, + H,0. 


Nitrous acid changes the secondary amines into nitroso-amines 


(p. 164) :— 
(CH,),NH + NO.OH = (CH,),N.NO + H,0. 
Nitroso-dimethylamine. 


The tertiary amines remain intact or suffer decomposition. These 
reactions may also be employed to effect the separation of the amines. 


When aided by heat KMnO, breaks up the amines, nitrogen being eliminated 
and the alkyls being oxidized to aldehydes and acids (Berich/e, 8, 1237). 

Bromine in alkaline solution converts the primary amines (their HCl-salts) into 
alkylized nitrogen dibromides, ¢. g.,C,H,.NBr,, the secondary amines at the 
same time throw off alkylen bromides and become primary amines (Berichie, 16, 


558):— | 
(C,H,),NH + Br, = C,H,.NH, + C,H,Br,. 

The alkalies change the bromides of the higher alkylamines into 
nitriles (p. 160). Well characterized compounds are those obtained 
by the action of dinitrochlorbenzene upon the primary and secondary 
amines (Berichte, 18, Ref. 540). 

14 


- 


162 ORGANIC CHEMISTRY. 


_ The possible isomerides of the amines are very numerous; they 
are determined not only by the isomerism of alcoholic radicals, but 
also by the number of replacing groups, as is manifest from the fol- 
lowing examples :— 


C,H, C,H, CH, 
N | H N | CH, N | CH, 
H H CH,. 
Propyl and Methyl- Trimethyl- 
Isopropylamine. ethylamine. amine. 


They are thus distinguished: by the action of ethyl iodide the 
primary amines can receive two, the secondary, however, only one 
additional ethyl group, while the tertiary amines form ammonium 
bases directly. The power of forming carbylamines and mustard 
oils (see these) is especially characteristic of the primary amines ; 
these are easily recognized by their odor (Berichte, 8, 108 and 461). 





PRIMARY AMINES. 


“Mediylaxotria, CH;.NH,, is produced when the methyl ester of 
cyanic acid is heated with potash (p. 159); by the action of tin 
and hydrochloric acid upon chloropicrin, CCl,(N O,); when nascent 
hydrogen acts upon hydrogen cyanide; and by the decomposition 
of various natural alkaloids, like theine, creatine, and morphine. 
The best way of preparing it is to warm brom-acetamide with 
caustic potash (see p. 159 and Berichte, 14, 764) :— 


CH,.CO.NHBr + 3KOH = CH,.NH, + CO,K, + KBr + H,0. 


Methylamine is a colorless gas, with an ammoniacal odor ; it con- 
denses to a liquid at —6°. Its combustibility in the air distin- 
guishes it from ammonia. At 12° 1 volume of water dissolves 1150 
volumes of the gas. ‘The aqueous solution manifests. all the proper- 
ties of aqueous ammonia, but does not, however, dissolve the 
oxides of cobalt, nickel and cadmium. [Iodine (also Br) throws 
out a dark red. precipitate, CH;.NL, from the solutions of methyl- 


amine: a 
2CH,.NH, ++ 21, = CH,.NI, + 2CH,.NH,.HI. 


‘When methylamine is conducted over heated potassium it decom- 
poses into potassium cyanide and hydrogen :— 

a CH,.NH, + K=CNK + 5H. 
The salts of methylamine are soluble in water. Its Gyiivcehdotite crystallizes 
in Jarge, deliquescent leaflets, fusing at 100° and distilling without decomposition. 


It yields a yellow, crystalline, double salt—[NH 2(CH,)HC!];. PtCl,—with 
PtCl,. Its double salt with auric chloride i am ora in needles. 





SECONDARY AMINES. 16 3 


Ethylamine, C,H;.NH,, is a mobile liquid, that boils at 18° 
and has a sp. gr. of 0.696 at 8°. It mixes with water in all propor- 
tions. It expels ammonia from ammoniacal salts, and when in ex- 
cess redissolves aluminium hydroxide; otherwise it deports itself in 
every respect like ammonia. 


Its hydrochloride, NH,(C,H,)Cl, crystallizes in large, deliquescent leaflets, 
fusing at 80°. Its platinum double salt crystallizes in orange-red rhombohedra. 
Like ammonia, it also combines with PtCl, to form PtCl,(C,H,.NH,),.. It exists 
as a white mass when in union with CO,,and in this condition if added to a BaC), 
solution it gradually precipitates barium carbonate. It probably corresponds to 
ammonium carbaminate. 

$8-Brom-Ethylamine, CH,Br.CH,.NH,, is formed from brom-ethyl-phthalimide 
by the aid of HBr. Its hydrobromic acid salt melts at 155° (Berichte, 21, 566). 
Silver oxide or KOH converts the latter into vinylamine. For further derivatives 
consult Berichte, 22, 1139, 2222. 

Propylamine, C,H,.NH., boils at 49°; isopropylamine, C,H,.NH,, is 
most readily obtained by the reduction of dimethyl acetoxime, (CH,),C: N.OH 
(see p. 160); it boils at 31°-32°. (Berichte, 20, 505.) 

Butylamine, C,H,.NH, (normal), boils at 76°; isobutylamine, C,H,.NH,, 
obtained from fermentation butyl alcohol and from ordinary valeramide, boils 
at 66°. 

Normal Amylamine, C,H,,.NH,, from normal caproylamide, C,;H),. 
CO.NH,,boils at 103°. 

Isoamylamine, C,H,,.NH,, is a liquid boiling at 95°; it is obtained from 
leucine by distillation with caustic potash, or from isocaproylamide. It is miscible 
with water, and burns with a luminous flame. Nonylamine, C,H,,.NH,, ob- 
tained from normal caprylamide, boils about 195°, and is sparingly soluble in water. 
The higher alkylamines, containing an odd number of C-atoms, are most readily 
obtained by the action of sodium in alcoholic solution upon the nitriles of the 
fatty acids, CnH 2n.CN—(see p. 159 and Berichte, 22, 812); while those with an 
even number of carbon atoms are produced by the action of bromine, in alkaline 
‘solution, upon the acid amides (p. 159 and Berichte, 21, 2486). 

Vinylamine, C,H,.NH, (p. 134), results when silver oxide, or potassium hy- 
droxide, acts upon bromethylamine. It is only known in solution. When evapo- 
rated with concentrated hydrochloric acid it yields chlorethylamine, C,H,Cl.NH,. 
It forms taurine, CH,(NH,).CH,.SO,H, with sulphurous acid, amido-ethyl- 
sulphuric acid with H,SO,, and oxy-ethylamine, CH,.(NH,).CH,.OH (Berichie, 
21, 2664) with water (by the action of nitric acid). 

Allylamine, C,H,;.NH,, is obtained by the action of concentrated sulphuric’ 
acid, or zinc and hydrochloric acid, upon mustard oil (C,H,.N:CS) ; it is a liquid 
boiling at 58°. abe 

Brom-allylamine, C,H,Br.NH, is obtained from the dibromide of allyl- 
amine. It boils at 125° (Berichte, 21, 3190.) 2 (ORs 


SECONDARY AMINES. 


Dimethylamine, NH(CH;),, is a gas that dissolves readily in 
water. It is condensed to a liquid by cold, and boils at 7.2°. It is 
most conveniently obtained by boiling nitroso-dimethyl aniline or 
dinitro-dimethyl aniline with caustic potash (Aznalen, 222, 119). 
The platinum double salt crystallizes in large needles. 


S&S . 


$ 
a 


164 ORGANIC CHEMISTRY. 


Diethylamine, NH(C,H;)., is a liquid boiling at 56° and is 
readily soluble in water. Its HCl-salt fuses at 216° and boils at 
325°. : 


The secondary amines are also designated imide-bases. 





Sulphamides, ¢. ¢., so,< NCHS” are formed by the action of sulphuryl 
chloride, SO,Cl,, upon the free secondary amines, whereas their chlorides, 
SO, a" , tesult when the HCl-salts are employed. Water converts the chlorides 
into sulphaminic acids, 80.4 OH (Annalen, 222, 118). SO, reacts. similarly 


with the primary and secondary amines, forming mono- and dialkyl-sulphaminic 
acids ( Berichée, 16, 1265). 

Nitroso-amines. These are compounds having the nitroso-group attached to 
N (p. 106). All basic secondary amines (imines), like (CH,),NH and 


e i "6 NH, can become nitroso-amines through the replacement of the hydro- 


gen of the imide group. They are obtained from the free imides by the action of 
nitrous acid upon their aqueous, ethereal, or glacial acetic acid solutions, or by 
warming their salts in aqueous or acid solution with potassium nitrite (Berichie, 
9, 112). They are mostly oily, yellow liquids, insoluble in water, and may be 
distilled without suffering decomposition. Alkalies and acids are usually without 
effect upon them; with phenol and sulphuric acid they give the nitroso reaction 
(see p. 107). When reduced in alcoholic solution by means of zinc dust and 
acetic acid they become hydrazines (p. 166). Boiling hydrochloric acid decom- 
poses them into nitrous acid, and dialkylamines. 

Dimethyl Nitrosamine, (CH,),N.NO, is a yellow oil, of penetrating odor. 
It boils at 148°. 

Diethyl Nitrosamine, (C,H,),N.NO, is also an oil, boiling at 177°; it is ob- 
tained from HCIl- -diethylamine by “distilling it with KNO, in aqueous solution. 
Concentrated hydrochloric acid regenerates. diethylamine from it. 

Nitroamines, containing the nitro-group in union with nitrogen, are produced 
by the action of concentrated nitric acid upon various amide derivatives (Berichée, 
18, Ref. 146; 22, Ref. 295). 

Methyl-nitramine, CH -NH(NO,), from the esters of methyl carbaminate, 
melts at 38°. It has an acid reaction. Ethyl- -‘nitramine, C,H,;.NH(NO,), 
from ethyl carbaminate, solidifies on cooling, and melts at 3°. Dimethyl-nitra- 
mine, (CH,),.N(NO,), is formed by the action of potassium hydroxide and 
methyl iodide upon methylnitramine. It melts at 58°, and boils at 187° ( Berichze, 
22, Ref. 296). 


TERTIARY AMINES. 


Trimethylamine, N(CH,),. This is isomeric with propyl- 
amine, C,;H,.NH,, and is: present in herring-brine ; it is produced 
by distilling betaine (from the beet) with caustic potash. It is 
prepared from herring-brine in large quantities, and also by the 
distillation of the ‘‘ vinasses’’ of the French beet root. Trimethyl- 
amine is a liquid, very soluble in water, and boils at 3.5°. The 


: { eS ee 
» « L- AMMONIUM BASES. 165 


penetrating, fish-like smell is characteristic of it. Its HCt-salt is 
very deliquescent. 


Triethylamine, N(C,H,),, boils at 89° and is not very soluble in water. It 
is produced by heating ethyl isocyanate with sodium ethylate :—CO:N.C,H, + 
2C,H,.ONa = N(C,H,), + CO,Na,. 


AMMONIUM BASES. 


The tertiary amines combine with alkyl iodides and yield am- 
monium iodides; these are scarcely affected by the alkalies, even on 
boiling (p. 158) ; but when treated with moist silver oxide the am- 
montium hydroxides are formed :— 


N(C,H,),I + AgOH = N(C,H;),.0H + Agl. 


These hydroxides are perfectly analogous to those of potassium 
and sodium. They possess strong alkaline reaction, saponify fats, 
and deliquesce in the air. They crystallize when. their aqueous 
solutions are concentrated in vacuo. With the acids they yield 
ammonium salts ; these usually crystallize well. | 

On exposure to strong heat they break up into tertiary amines and 
alcohols, or their decomposition products (C,H,, and H,O) :— 


N(C,H,),-OH = N(C,H;), + C,H, + H,0. 


If the ammonium base contains different alkyls, it is usually the ethyl group that 
is split off (Berichte, 14, 494). 


If iodine is added to the aqueous solution of the iodides, com- 
pounds are precipitated which contain three and five atoms of 
iodine: (C,H,),NI.1, and (C,H;),NI. 21. 

The tri-iodides are mostly dark violet bodies ; the penta-iodides 
resemble iodine very much. : 


Tetraethyl Ammonium Iodide, N(C,H,),I, is obtained by mixing triethyl- 
amine with ethyl iodide; the mixture becomes warm and when it cools is crys- 
talline. It separates from water or alcohol in large prisms, that fuse when heated, 
and then decompose into N(C,H,), and. C,H,I. Moist silver oxide converts 
it into 
Tetraethyl Ammonium Hydroxide, N(C,H,),OH, which crystallizes in 
delicate, deliquescent needles. It absorbs CO, from the air with avidity. Its 
platinum double salt, [N(C,H,),Cl],.PtCl,, crystallizes in octahedrons. 

Tetraethyl Ammonium Cyanide, (C,H,),N.CN, is a white, crystalline 
mass. It is obtained by acting on the hydroxide with HCN, or upon the iodide 
with barium cyanide. When boiled with alkalies it decomposes into NH,, formic 
acid and ammonium hydroxide. (CH 

Dimethyl-diethyl Ammonium Chloride, CH a \ NCI, is obtained from 

2 


dimethylamine and ethy] iodide, and from diethylamine and methyl iodide :-— 


CH, C,H, 
cH, bw.cyH,t and Gi bw.cayt 
C,H, C 8 


166 ORGANIC CHEMISTRY. 2 


' These two compounds are identical (Anunalen, 180, 273). They 
demonstrate, too, that the ammonium compounds are not molecular 
derivatives as formerly assumed (the above formulas are only intended 
to exhibit the different manner of formation), but represent true 
atomic compounds. ‘They further show the equivalence of the five 
nitrogen valences (compare Le Bel, Berichte, 23, Ref. 147). 


HYDROXYLAMINE DERIVATIVES. 


The amines are derived from ammonia, “ Hydroxylamine also yields a series of 
analogous alkyl compounds, very similar to the amines, The entrance of one 
alkyl group produces two isomeric forms :— 


(a) NH,.0.CH, and (3) CH, .NHLOH. 
Hydroxylamine Ether. kyl Hydroxylamine. 


The derivatives of the first modification are also called Alkylhydroxylamines. 
They result from the decomposition of the ethers of a-benzaldoxime, e. g., 
C,H,.CH: N.O.CH,, on digesting them with acids, or from the esters of ethyl- 
benzhydroxamic acid (see this) (Berichte, 16, 827; 22, Ref. 587). The (-alkyl- 
hydroxylamines seem to be similarly derived from the ethers of 6-benzaldoxime 
(Berichte, 23, 599). 

a-Methylhydroxylamine, NH,.0.CH,, Methoxylamine, Brepered by the first 
two methods, yields an HCl-salt, which melts at 149°. It differs from hydroxyl- 
amine in that it does not reduce alkaline copper solutions. 

B-Methylhydroxylamine, CH,.N apie Ad from the methyl ether of {-isoben- 
zaldoxime, forms an HCl-salt, melting at 85—g0°. 

 a-Ethylhydroxylamine, NH,.0.C,H,(?), Zthoxylamine, derived from ethyl- 
benzhydroxamate, is a liquid, boiling at 68°. The compound obtained from ethyl- 
benzaldoxime has not been accurately studied (Berichte, 16, 829). 
The action of ethyl bromide upon ethoxylamine produces Diethylhydroxylamine, 
C,H,.NH.O.C,H,, and 7riethylhydroxylamine, (C,H,),.N.0.C,H,, boiling at 
98° ( Berichte, 22, Ref. 590). An isomeride of the latter has been prepared by 
the interaction of zinc ethide and nitro-ethane. It boils at 155° (Berichte, 22, 
Ref, 250). 





HYDRAZINES. 


‘ Just as the amines are derived from ammonia, NH,, so the hydra- 
zines are derived from hydrazine or diamide, H,N — NH,, an ana- 
logue of liquid hydrogen phosphide, H,P — PH,, and dimethyl- 
arsine (cacodyl), (CH;),As — As(CHs),. 

The preparation of hydrazine in a free state is of recent date. It 
has been obtained from diazo-acetic acid (see this). Its deriva- 
tives, however, have been known for quite a long time, and have 
been prepared by a variety of methods, They hold an important 
place in the benzene series (see phenyl hydrazine, C,H;. NH.NH,) 
(E. Fischer, Annalen, 99, 281). 

The mono- and dialkyl hydrazines are at present the only known 
derivatives. 


HYDRAZINES. 167 


In physical and chemical properties they closely resemble the 
amines, but are distinguished from them by their ability to reduce 
alkaline copper solutions. They are powerful bases, uniting with 
one and two equivalents of acids to form salts. 


The mono-alkyl hydrazines are obtained from the mono-alkyl ureas, NH,.CO. 
NH.R, and from the symmetrical dialkylureas by their conversion into nitroso- 
compounds, and the reduction of the latter to hydrazines of the ureas:— 


CH,NH\ CH,.NH\, CH,.NH\ 
CH'NH CO yields 3 CO and “CH DOO 


When the latter are heated with alkalies or acids they split up, like all urea deriva- 
tives, into their components, CO,, alkylamine and alkylhydrazine. — 

Methyl Hydrazine, CH,.NH.NH,, from methyl urea, is a very mobile liquid, 
boiling at 87°. Its odor is like that of methylamine. In the air it absorbs moist- 
ure and fumes (erich/e, 22, Ref. 670), 

Ethyl Hydrazine, (C,H,;)HN.NH,, obtained from diethyl urea, is perfectly 
similar to the methyl derivative. It boils at 100°. Both compounds reduce 
Fehling’s solution in the cold. 

When ethyl hydrazine is acted upon by potassium disulphate, and the product 
treated with monopotassium carbonate, potassium ethyl hydrazine sulphonate, 
_ C,H,;.NH—NH.SO,K, is formed. Mercuric oxide changes this to potassium 

diazo-ethyl sulphonate, C,H,.N==N.SO,K. This is tne only well-known repre- 
sentative in the fatty-series of a numerous and highly important class of derivatives 
of the benzene series—the diazo-compounds. They are characterized by the diazo 
group,—N=N—, which is in union with carbon radicals. 

Dialkylhydrazines, like (CH,),N.NH,, are formed by the reduction of 
nitroso-amines, in aqueous and alcoholic solution, by zinc dust and acetic acid :— 


(CH,),N.NO + 2H, = (CH,),.N.NH, + H,0. 
Nitroso-amines containing at the same time acid radicals, ¢.¢., Cag SN.NO, do 
not yield corresponding hydrazines, but revert to amides. gra ; 

Dimethyl Hydrazine, (CH,),N.NH,,and Diethyl Hydrazine, (C,H,),N. 
NH,, are mobile liquids, of ammoniacal odor, and readily soluble in water, alcohol 
and ether. Diethyl hydrazine boils at 97°, and the dimethyl compound at 62°. 
They reduce Fehling’s solution when warm. 

Diethylhydrazine unites with ethyl iodide and yields the compound (C,H,),. 


: Vv 
N.NH,.C,H,I, which is to be viewed as the ammonium iodide, (GH) NS 
I 


as it is not decomposed by alkalies, and moist silver oxide converts it into a strong 
alkaline hydroxide. Nascent hydrogen Saas and sulphuric acid) decomposes this 
iodide in the manner indicated in the following equation :— 


NA, 
(CaMls)sNC + 2H = (C,H;),N + NH, + HI. 


* 


This reaction is an additional proof that the ammonium compounds represent 
atomic derivatives of pentavalent nitrogen (Amne/len, 199, 318). When mercuric 
oxide acts upon diethylhydrazine /e¢razone, (C,H,),N.N:N.N(C,H;)., is formed, 
This is a strong basic liquid with an alliaceous odor. 


168 ORGANIC CHEMISTRY. 


PHOSPHINES OR PHOSPHORUS BASES. 


Hydrogen phosphide, PH, has slight basic properties. Its 
compound with HI—phosphonium iodide, PH,I—is not very 
stable. Through the introduction of alkyls (alcohol radicals), it 
acquires the strong basic character of ammonia; its derivatives— 
the phosphines or phosphorus bases—correspond perfectly to the 
amines. 

When the alkyl iodides act upon phosphine, tertiary phosphines 
and phosphonium iodides (Thénard) are the sole products :— 


PH, + 3C Hie P(C.H,),-HI + 2HI, and 
P(C,H;); 7 C,H,1 ve P(C,H;) 41. 


It was A. W. Hofmann (1871) who prepared the primary and secondary deri- 
vatives by letting the alkyl iodides act upon phosphonium iodide in the presence of 
certain metallic oxides, chiefly zinc oxide, the mixture being at the same time heated 
to about 150°. This procedure yields a mixture of the two classes (their HI 


salts) :-— 


2PH,I + 2C,H,I + ZnO = 2P(C,H,)H,.2HI + Znl, + H,0, and 
PH,1 + 2C,H,1 + ZnO = P(C,H,),H-HI + Znl, + H,O. 


Water releases the monophosphine from the crystalline mass :— 
P(C,H,)H,I + H,O = P(C,H,;)H, + HI + H,0. 


This is like the decomposition of PHI by water into PH, and HI. The HI 
salt of the diethylphosphine is not affected. But by boiling the latter with sodium 
hydroxide, diethylphosphine is set free. 

Thénard (1846) first discovered the tertiary phosphines by acting upon calcium 
phosphide with alkyl iodides, They also result when zinc alkyls are brought in 
contact with phosphorous chloride :— 


2PCl, + 3(CH,),Zn = 2P(CH,), + 3ZnCl,, 


and upon heating the alkyl iodides to 100° with amorphous phosphorus. The 
easiest course is to heat phosphonium iodide with alkyl iodides to 150°—180°, 
whereby phosphonium iodides are produced at the same time :— 


PH,I + 3CH,I = P(CH,),.HI ++ 3HI, and 
P(CH,),HI+CH,1 =P(CH,),I + HI. 


If these be digested with potassium hydroxide, the tertiary phosphine is elim- 
inated, while the iodide of the phosphonium base is unaltered (the case with the 
amines). 

The pee are colorless, strongly refracting, extremely powerful-smelling, 
volatile liquids. They are nearly insoluble in water. On exposure to the air they 
are energetically oxidized and usually inflame spontaneously; hence, they must be 
prepared away from air contact. They combine readily with sulphur and carbon 
disulphide. ‘They form salts with the acids. Primary phosphines are very slightly 
basic, therefore, water decomposes their salts (see above). 


PHOSPHINES OR PHOSPHORUS BASES. 169 


PRIMARY PHOSPHINES. 


Methyl Phosphine, P(CH,)Hg, is a gas, condensing at — 20° to a mobile 
liquid. It is readily soluble in alcohol and ether. Concentrated hydrochloric 
acid does not decompose its HCl-salt, P(CH,)H,.HCl. It yields a double salt 
with platinic chloride. Fuming nitric acid oxidizes it to methyl phosphinic acid, 
CH,.PO.(OH,) (p. 156). 

Ethyl Phosphine, P(C,H,)H,, boils at + 25° and swims upon water. It is 
very energetically onidized by air contact, and ignites when brought near chlorine 
and bromine. Its platinum double salt consists of red needles. 

eri Phosphine, P(C,H,)H,, boils at 41°, and the isobutyl deriva- 
tive, P(C,H,)H,, at 62°. 


SECONDARY PHOSPHINES. 


Dimethyl Phosphine, P(CH,),H, boils at 25° C., and takes fire on exposure 
tothe air. Concentrated nitric acid converts it into dimethyl phosphinic acid, © 
(CH,),PO.OH (p. 156). 

Diethyl Phosphine, P(C,H,),H, boils at 85° and inflames spontaneously. 
Nitric acid oxidizes it to diethyl phosphinic acid (C,H,),PO.OH. 

Di-isopropyl Phosphine, P(C,H,),H, boils at 118°, Di-isoamyl Phos- 
phine, P(C,H,,).H, boils at 210°-215°, fumes in the air, but is not self-inflam- 
mable. 

Water does not decompose the salts of the secondary phosphines. The HI 
salts and the double salts with platinic chloride are prepared with the least diffi- 


culty. 
TERTIARY PHOSPHINES. 


Trimethyl Phosphine, P(CH;);, is prepared by heating carbon 
disulphide with phosphonium’ iodide. It is a colorless, very dis- 
agreeably smelling liquid, which will swim upon water. It boils at 
40°. It fumes in the air, absorbing oxygen and igniting. When 
slowly oxidized it changes to trimethyl phosphine oxide, P(CH;),0, 
which forms crystals that are deliquescent in the air. Sulphur will 
dissolve in the base and give a crystalline sulphide, P(CH;),S. 
It combines in a like manner with the halogens, their hydrides, and 
also with CS,. It yields salts with the acids ; these are very soluble 
In water. 


Triethyl Phosphine, P(C,H,),, is analogous to the above compound. It 
boils at 117°, and has a specific gravity of 0.812 at 15°. It has a neutral reac- 
tion. It dissolves slowly in acids, yielding salts. Its platinum double salt, 
[P(C,H,;),HC1],.PtCl,, is sparingly soluble in water and crystallizes in red 
needles. "It forms crystalline halogen derivatives, P(C,H,),X,. 

Triethyl Phosphine Oxide, P(C,H,),0, results from the slow oxidation of 
phosphine in the air, and by the action of mercuric oxide :— 


P(C,H,), + HgO = P(C,H,),0 + Hg. 
It forms deliquescent needles, melting at 53°, and distilling without decompo- 


sition at 243°. With the haloid acids it yields dihaloids, e. g., P(C,H,;),Cl, 
from which triethyl phosphine is produced on warming with sodium, 


170 ORGANIC CHEMISTRY. 


Triethyl phosphine dissolves sulphur to form a sulphide, P(C,H,),S, which 
crystallizes from water in brilliant needles, fusing at 94° and distilling about 100°. 
Mercury or lead oxide converts it into the oxide. Carbon disulphide also com- 
bines with triethyl phosphine, and the product is P(C,H,),.CS,, crystallizing in 
red leaflets. It is insoluble in water, fuses at 95°, and sublimes without decom- 
position. 

According to almost all these reactions, triethyl phosphine resembles a strongly 
positive bivalent metal; for example, calcium. By the addition of three alkyl 
groups, the pentavalent, metalloidal phosphorus atom acquires the character of 
a bivalent alkaline earth metal. By the further addition of an alkyl to the phos- 
phorus in the phosphonium group, P(CH, ),, the former acquires the properties of a 
monovalent alkali metal. Similar conditions manifest themselves with sulphur, 
with tellurium, with arsenic, and also with almost all the less positive metals. 


PHOSPHONIUM BASES. 


The tertiary phosphines combine with the alkyl iodides to form phosphonium 
iodides, not decomposed by alkalies :— 


ial P(CH;), + CH;I = P(CH,),1. 
If, however, the iodides be treated with moist silver oxide the phosphonium 
bases result :— 
ah P(CH,),I + AgOH = P(CH,),.0H + AglI. 


These are perfectly analogous to the ammonium bases; they react alkaline, ab- 
sorb carbon dioxide, and saturate the acids to form salts, When strongly heated 
they break up into phosphine oxide and hydrocarbons of the paraffin series :— 


P(CH,),.0H = P(CH,),0 + CH,. 


Tetraethyl Phosphonium Iodide, P(C,H,),I, consists of very soluble, 
white needles. When heated these decompose into P(C,H,), and C,H,I. 

Tetraethyl Phosphonium Hydroxide, P(C,H,),.OH, is a crystalline com- 
pound that deliquesces on exposure. With acids it forms crystalline salts. The 
platinum double salt crystallizes in orange-red octahedra. 





ARSENIC BASES. 


Arsenic is quite metallic in its character; its alkyl compounds 
constitute the transition from the nitrogen and phosphorus bases to 
the so-called metallo-organic derivatives, 7. ¢., the compounds of the 
alkyls with the metals (p. 177). The similarity to the amines and 
phosphines is observed in the existence of tertiary arsines, As(CH,);, 
but these do not possess basic properties, nor do they unite with 
acids. They show in a marked degree the property of the tertiary 
phosphines, in their uniting with oxygen, sulphur and the halogens, 


TERTIARY ARSINES AND ARSONIUM COMPOUNDS. 17 


to form compounds of the type As(CH,);X,. They yield arsonium 
todides with the alkyl iodides :— 


As(CH,), + CH,I = As(CH,) 


and these in turn become hydroxides by the action of moist silver 
oxide :— 
As(CH,),I + AgOH — As(CH,),.OH + Agl. 

These hydroxides are analogous to the ammonium and phospho- 
nium bases ; they are very alkaline and yield salts with acids. 

The arsines analogous to the primary and secondary amines and 
phosphines, such as As(CH;)H, and As(CH;),H, are unknown, and 
probably cannot exist. Through an accumulation of alkyls, arsenic, 
like the metals, receives a more positive character; As(CH;),Cl 
and As(CH;)Cl, act like the chlorides of the more positive metals. 

By the acquisition of two halogen atoms the compounds of the 
form AsX; pass into AsX;:— 


As(CH,), yields As(CH,),Cl, 
As(CH,),Cl. “ As(CH,),Cl, 
As(CH,)Cl, “ As(CH,)Cl,. 


Heat converts these into the compounds of the form AsX, and 
alkylogens :— 
As(CH,),Cl =—As(CH,), -+CH,Cl 
As CH, she Cl, oe ANT ),Cl + CH, “Cl 
As( (CH,),C — As(CH,)Cl, + CH,Cl and 
ACH 1, = — AsCl, + CH,Cl. 


The readiness with which these compounds are decomposed in- 
creases with the accumulation of the halogen atoms, ¢. g., 
As(CH;)Cl, breaks up at 0°, while AsCl; has not been obtained. 





TERTIARY ARSINES AND ARSONIUM COMPOUNDS. 


The tertiary arsines are formed by the action of the zinc alkyls 
upon arsenic trichloride :— 


2AsCl, + 3Zn(CH,), = 2As(CH,), + 3ZnCl,; 
and by heating the alkyl iodides with sodium arsenide :— 
AsNa, + 3C,H,I = As(C,H,), + 3Nal. | 


Cacodyl, formed simultaneously, is separated by fractional dis- 
tillation. 


Trimethylarsine, (CH,),As, is a colorless liquid, insoluble in water, and 
boils below 100° C. Its odor is very disagreeable. It fumes in the air, and ab- 


172 ‘ ORGANIC CHEMISTRY. 


sorbs oxygen, to form the oxides, As(CH,),O, consisting of large deliquescent 
crystals. It also unites with the halogens and sulphur, forming As(CH,), Br, and 
As(CH,),S, soluble in water. At ordinary temperatures it combines with methyl 
iodide, forming tetramethyl-arsonium iodide, As(CH,),I, which crystallizes 
from water in brilliant tables. Heat decomposes this last derivative into As(CH,), 
and CH,I. By the action of moist silver oxide tetramethyl - arsonium 
hydroxide, As(CH,),.OH, is obtained. This substance has a strongly alkaline 
reaction, is deliquescent, expels ammonia from its salts, and yields crystalline salts 
with the acids. 

Triethylarsine, As (C,H,),, is a liquid sparingly soluble in water, and boil- 
ing at 140°, with partial decomposition. It fumes in the air, but only takes 
fire when heated. From its ethereal solution iodine precipitates the iodide, 
As(C,H,),1,, a yellow amorphous substance. The oxide, As(C,H,),O, is a 
heavy oil, of disagreeable odor. It seems to combine to a salt with nitric acid. 
The sulphide, As(C,H,),S, is a crystalline substance, soluble in water. 

Tetraethyl-arsonium Iodide, As(C,H,),I, is produced by the union of 
triethyl-arsine and ethyl iodide. It is a crystalline compound, which forms an 
hydroxide, As(C,H,),.OH, when treated with silver oxide. This is a strongly 
basic, deliquescent body, yielding salts with the acids. ‘The platinum double salt 
consists of sparingly soluble, orange-red crystals. 


DIMETHYLARSINE COMPOUNDS. 


The monovalent group, As(CH,),, is strongly basic (see p. 171), 
and can form a series of derivatives, which, owing to their ex- 
tremely disgusting odor, have been termed cacodyl compounds (from 
xaxds and ddctv) :— 


pate a Cacodyl Chloride. As(CHs), ge 

: ree Cacodyl. 
AGH >O Cacodyl Oxide. As(CH, 
As(CH,) As(CH;),.CN Cacodyl Cyanide. 


2>S  Cacodyl Sulphide. 
As(CHs3), As(CH,) ,0.0H  Cacodylic Acid, 


Cacodyl Chloride, As(CH,),Cl, is formed by heating trimethyl arsen- 
dichloride, As(CH,),Cl, (see above), and by acting upon cacodyl oxide with 
hydrochloric acid. It is more readily obtained by heating the corrosive subli- 
mate compound .of the oxide with hydrochloric acid. It is a colorless liquid, 
boiling at about 100°, and possessing a stupefying odor. It acts like a chloride 
of the alkali metals, and yields an insoluble double salt with PtCl,. It unites 
with chlorine to form the ¢richloride, As(CH,),Cl,, which decomposes at 50° 
into As(CH,)Cl, and CH,Cl. . 

The bromide and iodide, As(CH,).I, resemble the chloride, and are prepared 
in an analogous way. 

As(CH,), 


Cacodyl, As,(CH,), = | , diarsentetramethyl, is formed by heating 
. 1 Ais(CH 

the chloride with zinc filings a an meat of CO,. Itis a colorless liquid, 
insoluble m water. It boils at 170°, and solidifies at— 6°. Its odor is fright- 
fully strong, and may induce vomiting. Cacodyl takes fire very readily in the 
air and burns to As,O,, carbon dioxide and water. It yields cacody] chloride 
with chlorine and the sulphide with sulphur. Nitric acid converts it into a 
nitrate, As(CH,),.0.NO,. 


Te 


a 


DIMETHYLARSINE COMPOUNDS. 173 


‘9 "' As(CH;),\ hick Hs 9, 
Cacodyl Oxide, As(CH,), 7%, also termed a/carsin, is most 


easily made by distilling arsenic trioxide with potassium acetate :— 


4CH,.CO,K + AsO, = ANCHO 4. 2C0,K, + 2C0,. 


The distillate ignites spontaneously, because it contains some 
free cacodyl; the pure oxide does not act in this way. 

Cacodyl oxide is a liquid with stupefying odor ; it boils at 150°, 
and at — 25° solidifies to a scaly mass; its specific gravity at 15° is 
1.462. It is insoluble in water, but dissolves very readily in alcohol 
and ether. It unites with acids to form salts; these are purified 
with great difficulty. The sulphate appears to have the formula :— 


YO.As(CH,) 
POs COLA CH)? 


Slow oxidation converts the oxide into cacodyl cacodylate, which breaks up 
when distilled with H,O into the oxide and cacodylic acid :— 


E 
oAs(CH, O° + H,0 =[As(CH;),],0 + 2As(CH,),0.0H. 


Cacodyl Sulphide, ANCH')? >> is obtained by distilling cacodyl chloride 
3/2 


with barium sulphide. It is an oily liquid insoluble in water, and inflames in the 
air. Hydrochloric acid decomposes it into cacodyl chloride and H,S. Sulphur 
dissolves in both it and cacodyl, forming the disu/phide, [As(CH,),].Sz, crystal- 
lizing in rhombic tables, fusing at 50°. : 

Cacodyl Cyanide, As(CH,),.CN, is formed by heating cacodyl chloride with 
mercuric cyanide, or by the action of CNH upon cacodylic oxide. It crystallizes 
in glistening prisms, which fuse at 37°, and boil at 140°, 

Cacodylic Acid, (CH,),AsO.OH (see p. 156), (dimethyl-arsinic acid), is 
obtained by the action of mercuric oxide upon cacodylic oxide :— 


A 
ANCH's? DO 4. 2HgO + H,O = 2As(CH,),0.0H + 2Hg. 


It is easily soluble in water, and crystallizes in large prisms, which melt at 200°, 
with partial decomposition. Cacodylic acid is odorless, and appears to be non- 
poisonous. Its solution reacts acid, and forms crystallizable salts with the metallic 
oxides, ¢. g., (CH,),AsO.OAg. 

Hydriodic acid reduces the acid to iodide :— 


As(CH,),0.0H + 3HI = As(CH,)41-+ 2H,0 + I,. 


Hydrogen sulphide changes it to sulphide. 

The salts of the thio-cacodylic acid, (CH,),AsS.SH, corresponding to caco- 
dylic acid, are formed by the action of salts of the heavy metals upon cacodyl 
disulphide, 


174 ‘ORGANIC CHEMISTRY. . 


There are ethyl compounds analogous in constitution to the preceding methyl 
derivatives, but they have not been well investigated. 
es of oe ee 

Ethyl Cacodyl, | , diethylarsine, is formed together with triethyl- 

Ok ae eh Pe | Se 
arsine on heating sodium arsenide with ethyl iodide. It is an oil, boiling at 
185-195°, and takes fire in the air. When its alcoholic solution is permitted to 
slowly oxidize in the air, diethyl arsinic acid, (C,H,),AsO.OH (see p. 156), is 
produced ; this crystallizes in deliquescent leaflets. 


MONOMETHYL ARSINE COMPOUNDS. 


_Methylarsen-Dichloride, As(CH,)Cl,, results in the decomposition of ca- 
codylic acid with hydrochloric acid :— 


As(CH,),0.0H + 3HCl = As(CH,)Cl, ++ CH,Cl + 2H,0. 


- It is a heavy liquid, soluble in water, and boils at 133°. At —10° it unites with 

chlorine, forming As(CH,)Cl,, which at 0° breaks up into AsCl, and CH,Cl. From 
the alcoholic solution hydrogen sulphide precipitates the su/phzde, As(CH3)S, crys- 
tallizing in colorless needles, melting at 110°. 

When sodium carbonate acts upon the aqueous solution of the dichloride 
methyl-arsenoxide, As(CH,)O, is formed. This is soluble, with difficulty, in 
water, and crystallizes from alcohol in colorless prisms, which fuse at 95°, and 
distil along with steam. The oxide is basic, and may be converted by the haloid 
nue and H,S into the halogen derivatives, AsCH,X,, and the sulphide, 

me iy 

Silver oxide acting upon the aqueous solution of the above oxide changes it 
into the silver salt of mono-methyl arsinic acid, (CH,)AsO(OH),, an analogue of 
methyl phosphinic acid (p. 156). The free acid crystallizes in large plates, reacts 
acid, expels CO, from carbonates, and combines with bases to yield salts, like 
(CH,)AsO(O.Ag),. Phosphorus pentachloride converts it into As(CH,)Cl,. 
When ethyl iodide acts upon sodium arsenite, AsO,Na, (p. 152), sodium mono- 
ethyl arsinate, C,H,.AsO(ONa),, is produced. 





ANTIMONY COMPOUNDS. 


The derivatives of antimony and the alkyls are perfectly analogous to those of 
arsenic; but those containing one and two alkyl groups do not exist. 

-Trimethylstibine, Sb(CH,),, antimony trimethyl, is obtained by heating 
methyl iodide with an alloy of antimony and potassium. It is a heavy liquid, 
insoluble in water, fuming and also taking fire in the air. It boils at 80°. It 
dissolves with difficulty in alcohol, but readily in ether. It forms compounds 
similar to those of triethyl stibine with the halogens and with oxygen. Antimony 
pentamethyl, Sb(CH,),, is formed when zinc methyl is permitted to act upon 
trimethyl stibine di-iodide. _ It is a liquid, and boils at about 100°, It does not 
ignite spontaneously. 

Methyl iodide and trimethyl stibine unite, and yield ¢etramethy/stibonium todide, 
Sb(CH,),1, which crystallizes from water in beautiful tables. Digested with 
moist silver oxide it passes into the hydroxide, Sb(CH,),.OH,—a deliquescent, 
crystalline mass with strong alkaline reaction. The hydroxide forms beautifully 
crystallized salts with acids. 


‘ BORON COMPOUNDS. . 175 


Triethylstibine or Stibethyl, Sb(C,H;),. This is perfectly analogous to the 
methyl derivative. In all its reactions it manifests the character of a bivalent 
metal, perhaps calcium or zinc (see p. 170). With oxygen, sulphur, and the halo- 
gens, it combines energetically and decomposes the concentrated haloid acids, 
expelling their hydrogen :— 


Sb(C,H,), -+ 2HCl — Sb(C,H,),Cl, + H,. 


The dichloride, Sb(C,H,),Cl,, is a thick liquid, haying an odor like that of 
turpentine. The dromide solidifies at— 10°; the zodide crystallizes in needles, 
fusing at 70°. Stibethyl slowly oxidized in the air becomes ¢riethylstibine oxide, 
Sb(C,H,),0, an amorphous solid, soluble in water. It behaves like a di-acidic 
oxide, forming basic and neutral salts, which crystallize well, ¢. ¢.:— 


O—NO | O.NO 
Sb(C2H5)s€G_ NO? and Sb(C2Hs)3< OF. 2 
Neutral Nitrate. Basic Nitrate. 


Triethylstibine Sulphide, Sb(C,H,),S, is formed by the union of stibethyl 
and sulphur. It consists of shining crystals, melting at about 100°. It behaves 
somewhat like calcium sulphide. It dissolves readily in water, precipitates sul- 
phides from solutions of the heavy metals and is decomposed by acids with the 
formation of hydrogen sulphide and salts of triethylstibine oxide. 

Tetraethylstibonium Iodide, Sb( C,Hs),I, ‘is obtained from ethyl iodide and 
triethylstibine. It separates from water in large prisms. Silver oxide converts the 
iodide into /etraethylstibonium hydroxide, Sb(C,H,),-OH, a thick liquid, reacting 
strongly alkaline, and yielding well crystallized salts with acids. 





BORON COMPOUNDS. 


Triethylborine, or Borethyl, B(C,H;),, is formed by the action of zinc ethyl 
upon boric ethyl ester (p. 155) :— 


2B(O0.C,H5)3 + 3Zn(C,H5)2 = 2B(C,Hs)3 + 3(C,H;.0),Zn. 


It is a colorless, mobile liquid, of penetrating odor; its boiling point is 95°, and its 
Sp. gr. at 23° equals 0.696. It ignites in contact with the air and burns with a 
green flame. When heated together with hydrochloric acid it decomposes into 
diethylborine chloride and ethane :— 


B(C,H,); + HCl = B(C,H,),Cl + C,H,, 


Slowly oxidized in the air triethylborine passes into the diethyl ester of ethyl boric 

acid or Boron Etho-diethoxide, B(C,H,)(O.C,H,),. This is a liquid boiling at 

125°; water decomposes it.into alcohol and ethyl boric acid, C,H,.B(OH),. ‘The 

latter is a crystalline, volatile body, which has a faintly acid reaction and is soluble 

in water, alcohol and ether. 

4 pecnetiyt trimethylborine, B(CH,),, is a colorless gas, that may be condensed 
y cold. 


176 ORGANIC CHEMISTRY. 


SILICON COMPOUNDS. 


The nearest analogue of carbon is silicon, therefore its derivatives 
with alcoholic radicals are very similar to the hydrocarbons. 

Silicon-methyl, Si(CH,),, is formed on heating SiCl, with 
zinc methyl :— 


SiCl, + 2Zn(CH,), = Si(CH,), + 2ZnCl,. 


It is a mobile liquid, boiling at 30°. It is not changed by water, 
boils at ++ 10°, and behaves like a hydrocarbon (carbon tetra- 
’ methane, C(CH,),). ; 

Silicon-Ethyl, Silicon-Tetraethide, Si(C,H;),, 1s similar to 
the preceding, and boils at 153°. By the action of chlorine there 
is formed a substitution product, si] C a: boiling at 185°, 
which acts exactly like a chloride of a hydrocarbon. By the action 
of potassium acetate on this an acetic ester results :— 


IV 
(C,H,),Si.C,H,.0.C,H,0. 


Alkalies decompose this into acetic acid and the alcohol :— 


IV 
(C,H,),Si.C,H,.OH. 


This so-called silico-nonyl alcohol corresponds to nonyl alcohol, 
(C,H,;);C.CH,.CH,OH. It boils at 195°, and is insoluble in water. 


Silicon Hexethyl, or Hexethyl-silicoethane, Si,(C,H,),, is formed by the action 
of zinc ethyl upon Si,I, (obtained from I,Si by means of silver). It is a liquid, 
boiling from 250-253°. 

On heating ethyl silicate, Si(O.C,H;), (p. 156), with zinc ethyl and sodium, the 
ethoxyl groups, (O.C,H,), are successively replaced by ethyl groups. The product 
is a mixture of mono-, di- and triethylsilicon esters and silicon tetraethide, which 
are separated by fractional distillation. ty ; 

Triethylsilicon Ethylate, (C,H,),Si.0.C,H,, is a liquid, boiling at 153°, 
insoluble in water, and having a sp. gr. 0.841 at 0°. Acetyl oxide converts it into 
the acetic ester, which yields friethylsilicon hydroxide, (C,H;),Si.OH, when 
saponified with potash. The latter is sometimes called ¢riethy/lstlicol ; it is analo- 
gous to triethyl carbinol, (C,H;),C.OH, and deports itself like an alcohol. It is 
an oily liquid, insoluble in water. 

Diethylsilicon-diethylate, (C,H,),Si.(O.C,H;),. An agreeable - smelling 
liquid, insoluble in water, and boiling at 155.8°. Its sp. gr. equals 0.875 at 0°. 
On treating it with acetyl chloride the compounds (C,H,),Si< O.C, Hi, and 


\Cl 
(C,H,),SiCl,, are formed. The latter is a liquid, boiling at 148°. It fumes in air, 


and with water yields diethylsilicon oxide, (C,H,;),SiO, analogous to diethyl 
ketone, (C,H,),CO. 


Ethylsilicon-triethylate, (C,H,)Si(O.C,H,),, is a liquid with a camphor like 
odor, boiling at 159°, and slowly decomposed by water. Heated with acety] 


METALLO-ORGANIC COMPOUNDS. 177 


chloride it forms ethyl silicon trichloride, (C,H,;)SiCl,. This liquid fumes strongly 
in the air, boils at about 100°, and when treated with water passes into ethyl! silicic 
acid, (C,H;)SiO.OH (Silico-propionic acid), which is analogous to propionic acid, 
C,H,;.CO.OH, in constitution. It is a white, amorphous powder, that becomes 
incandescent when heated in the air, It dissolves in potassium and sodium hydrox- 
ides to form salts, 





METALLO-ORGANIC COMPOUNDS. 


Tie metallo-organic compounds are those resulting from the 
union of metals with monovalent alkyls; those with the bivalent 
alkylens have not yet been prepared. Inasmuch as we have no 
marked line of difference between metals and non-metals, the 
metallo-organic derivatives attach themselves, on the one side, by 
the derivatives of antimony and arsenic, to the phosphorus and 
nitrogen bases ; and on the other, through the selenium compounds, 
to the sulphur alkyls and ethers. The tin derivatives approach the 
silicon alkyls and the hydrocarbons. 


Upon examining the metals as they arrange themselves in the periodic system 
it is rather remarkable to find that it is only those which attach themselves to the 
electro-negative non-metals that are capable of yielding alkyl derivatives. In the 
three large periods this power manifests and extends itself only as far as the group 
of zinc (Zn, Cd, Hg). (Compare Jnorganic Chemistry.) ‘The alkyl derivatives 
of potassium and sodium, which cannot be isolated and are non-volatile, appear to 
possess a constitution analogous to that of the hydrogen compounds, Na,H and 
K,H, or sodium acetylene, C,H Na. 


Those compounds in which ‘the metals present their maximum 
valence, ¢.g., 


11 ur Iv IV v 
Hg(CHs), Al(CHsg)s Sn(CH;), Pb(CHs), Sb(CH;,);, 


are volatile liquids, usually distilling undecomposed in vapor form ; 
therefore, the determination of their vapor density is an accurate 
means of establishing their molecular weight, and the valence of the 
metals. Being saturated compounds, they are incapable of taking 
up additional affinities. 


The behavior of the metallo-organic radicals, derived from the molecules by 
the separation of single alkyls, is especially noteworthy. The monovalent radi- 
cals, ¢. g., 

Ir It IV IV Vv ‘ 
Hg(CH,)— T1(CH,),— Sn(CH,),— Pb(CH,),— Sb(CH,),—, 


show great resemblance to the alkali metals in all their derivatives. Like other 
monovalent radicals they cannot be isolated. They yield hydroxides, ¢. g., 


Hg(C,H,).OH  TI(CH,),.OH  Sn(CH,),.0H, 


perfectly similarto KOH and NaOH. Some of the monovalent radicals, when 
E5 


178 ORGANIC CHEMISTRY. 


separated from their compounds, double themselves ye pera of metals of the 


‘silicon group) : -— 
Si(CH,), Sn(CH,), Pb(CH,), 


Si(CH,),.  Sn(CH,), —_Pb(CH,), 


By the exit of two alkyls from the saturated compounds, the bivalent radicals 
result :-— 


ir Iv Iv Vv 
—Bi(CH,) .. =Te(CH,), . =Sn(C,H,), .. =Sb(CH,),. 


In their compounds (oxides and salts) these resemble the bivalent alkaline earth 
‘metals, or the metals of the zinc group. A few of them occur in free condition. 
As unsaturated molecules, however, they are highly inclined to saturate two affini- 
ties directly. Antimony triethyl, Sb(C,H,), (see p- 175), and apparently, too, 
tellurium diethyl, Te(C,H,),, have the power of uniting with acids to form salts; 
hydrogen is liberated at the same time. This would indicate a distinct metallic 
character. 

Finally, the trivalent radicals, like As(CH 3)g, can also figure as monovalent. 
This is the case, too, with vinyl, C,H,. .These may be compared to aluminium, 
and the so-called cacodylic acid, ‘As(CH,),0. OH (p. 173), to aluminium meta- 
hydrate, AlO.OH. 

We conclude, therefore, that the electro-negative inetale: by the successive 
union of alcohol radicals, always acquire a more strongly impressed basic, alkaline 
character. This also finds expression with the non-metals (sulphur, phosphorus, 
arsenic, etc,). (Compare pp. 145 and 170.) All the reactions of the alkyl com- 
pounds indicate that the various properties of the elementary atoms may be ex- 
plained by the supposition of yet simpler primordial substances. (See Inorganic 
Chemistry.) 


Most of the metallo-organic compounds can be prepared by the 
direct action of the metals, or their sodium rion ean upon the 
bromides and iodides of the alkyls :— 


/C,H 


ZnNa, + 2C,H vpmiacige OS H. 


5 + 2Nal. 


Derivatives of the electro-negative metals can also bé formed from 
the metallic chlorides by the action of zinc and mercury alkyls :— 


SnCl, + 2Zn(CH,), = Sn(CH,), + 2ZnCl,. 





_-COMPOUNDS OF THE ALKALI METALS. 


When sodium or potassium is added to zinc methide or ethide, 
zinc separates at the ordinary temperature, and from the solution 
that is thus produced, crystalline compounds deposit on cooling. 
The liquid retains a great deal of unaltered zinc alkyl, but it also 
appears to contain the sodium and potassium compounds—at least 
it sometimes reacts quite differently from the zinc alkyls. Thus, it 
absorbs carbon dioxide, forming salts of the fatty acids: — 

C,H,Na + CO, = C,H,.CO,Na, 


Solan Propionate, 


COMPOUNDS OF THE METALS OF THE MAGNESIUM GROUP. 179 


The ketones are produced by the action of carbon monoxide. 
These supposed alkali derivatives (p. 177) cannot be isolated, because 
when heat is applied to them, potassium and sodium separate and 
decomposition ensues. Their solutions are energetically oxidized 
when exposed to the air. Water decomposes them with extreme 
violence. ; 





COMPOUNDS OF THE METALS OF THE MAGNESIUM GROUP. ; 


_ I, Beryllium Ethide, Be(C,H,),, is formed by heating beryllium with mer- 
cury ethyl. It is a colorless liquid, boiling from 185°-188°. It fumes strongly in 
the air and ignites spontaneously. Water decomposes it with violence, beryllium 
hydroxide, Be(OH),, separating. Beryllium Propyl, Be(C,H,)., boils about 
245°. 

2. Magnesium Ethide, Mg(C,H,),. On warming magnesium. filings with 
ethyl iodide away from contact with the air, magnesium ethyl iodide first results :— 


Mg + C,H,I = Md 73h 


on applying heat to this it decomposes according to the following equation :— 
3 2Mg(C,H,)I = Mg(C,H,;), + Mgl,. 


Magnesium ethide is a liquid that takes fire on exposure to the air, and is decom- 
posed by water with the production of ethane :— 


_ Mg(C,H;), + H,0 = 2C,H, + MgO. 


3. Zinc compounds. 

The reaction observed above with magnesium may occur here, 
zt. é., when zinc filings act upon iodides of the alcohol radicals in 
sunlight, iodides are formed, which are decomposed by. heat :— 


ang ys — Zn(C,H,), + Zal,. 


The dialkyl derivatives may be obtained by heating a solution 
of the alkyl iodides, in absolute ether, with granulated zinc or zinc 
turnings, in closed vessels, to 100°—200° (Frankland). 


The reaction occurs at a lower temperature if an alloy of zinc and sodium be 
employed as a substitute for the metallic zinc. The operation is as follows: in a 
flask provided with a doubly perforated caoutchouc cork, bearing an inverted con- 
denser, there is introduced a mixture of the alkyl iodide with ether and zinc- 
sodium. The air is expelled from the vessel by a current of carbon dioxide, and 
the heat of a water bath is then applied to it. When the reaction is complete, the 
condenser is reversed, and the zinc compound distilled off in a current of CO,. 

Pure zinc turnings may replace the zinc-sodium if they have been previously 
attacked by sulphuric acid, and the pressure of the apparatus increased. This 
may be accomplished by connecting the inner tube of the condenser with another 
tube extending into mercury. The most convenient method of preparing zinc 
ethide is to let ethyl iodide act upon zinc-copper. (Berichte, 6, 200.) 


180 . _ ORGANIC CHEMISTRY. 


The zinc alkyls are colorless liquids, fuming strongly in the air 
and igniting readily; therefore, they can only be handled in an 
atmosphere of carbon dioxide. They inflict painful wounds when 
brought in contact with the skin. Water decomposes them very 
energetically, forming hydrocarbons and zinc hydroxide :— 


Zn(CH,), + 2H,O = 2CH, + Zn(OH),. 


Oxygen is added by slow oxidation in the air and compounds, ¢. g.,(CH,),ZnO,, 
; OR S| : 
analogous to peroxides, are — Zing CH : + i, Zag 0. ca. 
These explode readily and liberate iodine from potassium iodide (Berichte, 23, 396). 
The alcohols convert the zinc alkyls into zinc alcoholates and hydrocarbons :— 


is SOG 
Zn(C,H,), + C,H,.0H = an cif, 54.C,H,. 


The free halogens decompose both the zinc alkyls and those of other metals very 
energetically :— 
Zn(C,H,;), + 2Br, = 2C,H,Br + ZnBr,. 
Zinc Methide, Zn(CH,),, is a disagreeably smelling, mobile liquid, which boils 
at 46°. Its sp. gr. at 10° is 1.386. 


Zinc Ethide, Zn(C,H,),, boils at 118°, and has the sp, gr. 1.182 at 18°. 
With alcohol it yields zinc alcoholate and ethane :— 


Zn(C,H,), + 2C,H,.OH = Zn(0.CH,), + 2C,H,. 


Sulphur dissolves in it, forming zinc mercaptide, Zn(S.C,H,),. 
Zinc Isoamyl, Zn(C,;H,,).,, boils at 220°, fumes strongly in the air, but does 
not ignite spontaneously. 


The zinc alkyls are very reactive, hence, serve for the prepara- 
tion of many other compounds. ‘Thus, they readily react with 
chlorides of the heavy metals and the metalloids, whereby alkyl 
derivatives of the latter are produced (p. 178). The hydrocarbons 
(see p. 71) are produced when they are heated to 150° with alkyl 
iodides :— 

Zn(C,H,), + 2C,H,I = 2C,H,.C,H, + Znl,, 
Ethyl-allyl. 
Carbon oxychloride converts them into ketones ;— 


/CH, 


COCI,  Zn(CH,), = COK Gy" 


+ ZnCl,. 
The ketones are also produced in the action of the zinc alkyls 
upon the chlorides of the acid radicals in the cold :— 


». 


2CH,.CO.Cl -+ Zn(C,H,), = 2co¢ GMs + zaci,. 
Acetyl Chloride. Methyl-ethyl Ketone. 


When an excess of the zinc alkyl is employed, tertiary alcohols are 
formed (p. 120). 


COMPOUNDS OF THE METALS OF THE MAGNESIUM GROUP. 181 


The zinc alkyls unite with the aldehydes and ketones to form 
compounds, which are decomposed by water into higher secondary 
and tertiary alcohols (p. 120). The alkyl oxides and the alkylen 
oxides are not affected by the zinc alkyls (Berichte, 17, 1968). 


The zinc alkyls absorb sulphur dioxide and become zinc salts of the sulphinic 
acids (p. 154). Nitric oxide dissolves in zinc diethyl and forms a crystalline com- 
pound, from which the zine salts of the so-called dinitroethylic acid, C,H,. 
N,O,H, is obtained by the action of water and CO. 


4. Mercury Compounds. 

These are formed according to methods similar to those em- 
ployed for the zinc compounds. The alkyl iodides unite with 
mercury at ordinary temperatures to yield iodides (sunlight is 
favorable) :— | 


Hg + C,H,I = Hg yen 


The dialkyl compounds are produced when sodium amalgam acts 
upon the alkyl iodides :— 


/ CoH, 
\C.Hs 


The reaction may be executed as follows: Liquid sodium amalgam is gradually 
added to the mixture of the iodide or bromide with ;, volume ethyl acetate, 
accompanied by frequent shaking of the vessel; the reaction occurs then with 
increase of heat, When the mass becomes syrupy, it is distilled, and the opera- 
tion repeated until all the iodide is decomposed (until on boiling with HNO,, 
iodine no longer separates). The oily distillate is shaken with potassium hydroxide 
to decompose the ethyl acetate, the heavy oily mercury alkyl separated, and after 
drying with calcium chloride it is distilled. (Anmalen, 103, 105 and 109.) 


HgNa, + 2C,H,I = Hg + 2Nal, 


The action of zinc alkyls upon mercuric chloride also produces 
them :— 
HgCl, + (C,H,;).Zn = Hg(C,H,), + ZnCl,. 


These compounds are colorless, heavy liquids, possessing a faint, 
peculiar odor. Their vapors are extremely poisonous. Water and 
air occasion no change in them, but when heated they ignite easily. _ 

The haloid acids cause one alkyl group to split off, leaving salts 
of the monoalkyl derivatives :— ee 


fC Be ucts. Be ee 


Hex CH, XCl 5+ C,H,, 


and when moist silver oxide acts on the halogen derivatives, 
hydroxyl compounds are produced :— 
Hg(C,H,)Cl + AgOH = Hg(C,H,).0H + AgCl; 


these are strongly alkaline, and form crystalline salts with the acids. 


Se eee Ce EE ea ee a eA a eS wo, 


4 


Be ie ; ORGANIC CHEMISTRY. 


One and two alkyls separate from the mercury alkyls by the 
action of the halogens :— 


Hens + 1, = Hg(C,H,)I + C,HI and 
Hg(C,H,)1 + 1, = Hgl, + C,H,I. 


Mercury-Methyl, Hg(CH,),, is a liquid having a specific gravity of 3.069 ; 
it boils at 95°, and is but slightly soluble in water. When a molecule of iodine 
is added to its alcoholic solution there is formed mercury methyl iodide, 
Hg(CH,)I, insoluble in water, but soluble in alcohol, from which it crystallizes 
in shining leaflets, fusing at 143°. Potassium cyanide converts the iodide again 
into mercury-methy]. When treated with silver nitrate the salt, Hg(CH,).O.NO,, 
is produced. be! 

Mercury Ethide, Hg(C,H,;),, has a specific gravity of 2.44, and boils at 
159°. At 200° it decomposes into Hg and C,H, . Its chloride, Hg(C,H;)Cl, 
separates in brilliant needles, when its alcoholic solution is digested with HgCl,. 
Direct sunlight decomposes the iodide into Hg and C,H,,. These halogen 
derivatives when treated. with moist silver oxide, yield mercury ethyl hydroxide, 
Hg(C,H,).OH, a thick liquid of strong alkaline ‘reaction, and soluble in both 
water and alcohol. It forms crystalline salts with the acids. 

Mercury-Allyl Iodide, Hg(C,H,;)I, is obtained when allyl iodide is shaken 
with mercury. It crystallizes from alcohol in shining leaflets, fusing at 135°. 
Propylene results when hydriodic acid acts on the iodide :— 


Hg(C,H,)I + HI = Hgl, + C,H,. 





COMPOUNDS OF THE METALS OF THE ALUMINIUM GROUP. 


The aluminium alkyl derivatives attach themselves to those springing from 
boron (p. 175); however, it appears that only those exist in which three alkyls 
are present. They are produced by the action of the mercury alkyls upon 
aluminium filings :— . 


2Al + 3Hg(CH,), = 2Al(CH,), + 3Hg. 


Aluminium-Methyl, Al(CH,),, boils at 130°, and crystallizes at ‘o°. It 

fumes in the air,.and is spontaneously inflammable. Water decomposes it with 
great violence, forming ethane and aluminium hydroxide.. Its vapor density has 
been found to be 2.8 (or 35.6, H = 1) at 240°; this would answer to the mole- 
cular formula Al(CH,), = 72.3. It, however, appears that at low temperatures 
_ the molecules Al,(CH,), also exist (see Berichte, 22, 551). 
- Aluminium-Ethyl, Al(C,H,),, 1s perfectly analogous to the preceding com- 
pound, but does not solidify in the cold. It boils at 194°. At 240° its vapor 
density has been found equal to 4.5 (or 64, H = 1), almost corresponding to the 
molecular formula Al(C,H,;), == 114.3. 

The derivatives of trivalent gallium and indium have not been prepared. 

The thallium-diethy] compounds, Tl(C,H,;),X, are known. _ 

Thallium-Diethyl Chloride, Tl(C,H,;),Cl, is formed when zinc ethide is 
allowed to act upon thallium chloride :-— 


_TICl, +. Za(C,H,), = TUC,H,),Cl +.Z0Cl,, 


Thallium-diethyl salts, e. g., T1(C,H,),O.NO,, are obtained from this by double 
decomposition with silver salts. If the sulphate be decomposed with barium 


COMPOUNDS OF THE METALS OF THE GERMANIUM GROUP. 183 


hydrate, thadiium-diethyl hydroxide, T\(C,H,),.OH, is obtained. This is readily 
soluble in water, crystallizes therefrom in glistening needles, and has a strong 
alkaline reaction. 





COMPOUNDS OF THE METALS OF THE GERMANIUM GROUP. 


The alkyl derivatives of the tetravalent metals, germanium (72.3), 
tin (117) and lead (206), are perfectly analogous in constitution to 
those of silicon (p. 176) belonging to the same group; the dif- 
ferences in reaction of the tin and lead compounds are induced by 
the more positive, metallic nature of tin and lead (see p. 178). 
The compounds of germanium form the transition to those of sil- 
icon and tin. 

1. Germanium-Ethide, Ge(C,H,),, is formed when zinc ethide acts upon 
germanium chloride. It isa liquid with a leek-like odor. It boils at 160°, and 


its sp. gr. is 0.96. At ordinary temperatures it is not altered on exposure to the 
air, a 


2. Tin Compounds.—In addition. to the saturated derivatives 
with four alkyls, #z is also capable of uniting with three and two 
alkyls to groups which act like daszc radicals, ees salt-like com- 
pounds with negative groups :— 

SaetH) 4 Tin tetraethyl 
Sn(C,H,),Cl Tin triethyl chloride 
Sn(C,H,),Cl, Tin diethyl chloride. 

Tin diethyl, Sn(C,H,),, appears to exist as an unsaturated mole- 
cule (like tin dichloride, SnCl,), while the group, Sn(C,H;),, in 
free condition doubles itself :— 

Sn(C,H5)s0 
Sna,(C,H,)¢ =] — Di-tintriethyl. 
Sn(C,H;), 
Tin Tetraethyl, Stannic Ethide, Sn(C, H;),, is best pre- 
pared by distilling tin chloride with zinc’ethyl :— 
SnCl, + 2Zn(C,H;), = Sn(C,H,), + 2ZnCl,. 
It is a colorless, ethereal smelling liquid, boiling at 181° and_pos- 
sessing a specific gravity of 1.187 at 23°. Its vapor density equals 
8.02 or 116 (H =1). It is insoluble in water and does not suffer 
change on. exposure to the air. By the action of the halogens the 
alkyls are successively eliminated :— 
‘ S$n(C,H,), +1, =Sn(C, H)1 Se $8 OT 
Sn(C,H,;),I + L, OT Sat 2H;)el, + C,H,;I 
Sn(C, 2H;).l, +1, =Sn 
Hydrochloric acid acts op — 


Sn(C,H,), + HCl = Sn(C,H,),Cl + 2C,H 


+ 2C,H,I. 





184 . ORGANIC CHEMISTRY. 


Tin Tetramethyl, Sn(CH;),, is similar to the preceding, boils 
at 78°, and has a specific gravity at 0° of 1.314. 


On heating an alloy of tin and a little sodium (about 2 per cent.) with ethyl 
iodide, there results a mixture consisting of Sn(C,H,),I and Sn(C,H,),I,, 
which may be separated by fractionation, With an alloy rich in sodium (about 
20 per cent.) the products are Sn(C,H,), and Sn,(C,H,),; the latter is almost 
insoluble in alcohol, while the first is very soluble and can be re-precipitated by 
water. 

Tin-Triethyl Iodide, Sn(C,H,).,I, is a colorless oil, insoluble in water and 
having a disagreeable smell. It boils at 231°, and has a specific gravity of 1.833 
at 22°. Hydrochloric acid precipitates the chloride, Sn(C,H,),Cl, from tin 
triethyl salts, as a heavy oil, which solidifies at 0°, It boils from 208-210°, and 
has a specific gravity of 1.428. Alcohol isa solvent for both. When either one 
is acted upon by silver oxide or caustic potash, there is produced :— 

Tin-Triethyl Hydroxide, Sn(C,H,),.OH, crystallizing in shining prisms, 
melting at 66°, and boiling undecomposed at 272°. It volatilizes along with the 
steam. It is sparingly soluble in water, but dissolves readily in alcohol and ether. 
It reacts strongly alkaline, absorbs carbon dioxide, and yields crystalline salts with 
the acids, e. g., Sn(C,H;),.0.NO,. When the hydroxide is heated for some 
time to almost the boiling temperature, it breaks up into water and fin-triethyl 

i Sac, BooN hahtiege fick ae 
oxide, Sete HH}" et an oily liquid, which in the presence of water at once 
regenerates the hydrate. 

; ; Sn(C,H5)5 ‘ : 

Free Tin-Triethy]l, | = Sn,(C,H,),, or Stannoso-stannic Ethide, 

Sn(C,H;)s 
is produced, as already dence’, by heating tin-sodium with ethyl iodide; also 
on warming tin-triethyl iodide with sodium :— 


2Sn(C,H,),I + Na, =Sn,(C,H,), + 2Nal. 


Tt is a liquid, of mustard-like odor, insoluble in alcohol, but readily soluble’ in 
ether. It distils with slight decomposition at 265-270°. It combines with 
See a aae -, on(C,H,),\ ere . : 

oxygen, forming tin-triethyl oxide, 2775.3 \O, and with iodine yields tin- 
triethyl iodide :— SCs 1e7.,,' , 

* pamaieds di kese aSe(CH.).1 
2 = 20N(2415)31- 
n(C,H;); 





Tin-Diethyl, or Stannous Ethide, Sn(C,H,),. Its preparation is described 
above. It is a thick oil, decomposed when distilled, therefore its molecular 
weight has not been determined. It combines with oxygen and the halogens :— 


Sn(C,H;),+1,= Sn(C,H,),1,. 
When distilled it decomposes completely into tin and tin-tetraethyl :— 
2Sn(C,H,), =Sn(C,H,), + Sn. 
Tin-Diethyl Chloride, Sn(C,H,),Cl,, is best prepared by dissolving tin-diethyl- 


oxide in hydrochloric acid. It is insoluble in water, alcohol and ether, crystal- 
lizes in needles, fusing at 60° and boils at 220°. The zodide, Sn(C,H,),I,, is 


vee 


COMPOUNDS OF BISMUTH. 185 


also produced by the action of ethyl iodide in sunlight upon zinc filings. It crys- 
tallizes in needles, fuses at 44.5°, and boils at 245°. 

Ammonium hydroxide and the alkalies precipitate from aqueous solutions of 
both the halogen compounds :— 

Tin-Diethyl Oxide, Sn(C,H,),O, a white, insoluble powder. It is soluble in ex- 


cess of alkali, and forms crystalline salts with the acids, e. ¢., Sn(C,H;). CON 
. Ltd 


3, LEAD COMPOUNDS, 


These are very similar to the preceding; derivatives with two alkyls do not, 
however, exist :— 
Pb(C,H;), Lead tetraethyl. 
Pb(C,H,),Cl Lead triethyl chloride. 
Pb,(C,H;), ~ Di-leadtriethyl. 


Lead-Tetraethyl, Pb(C,H;,),, is obtained by heating lead chloride with zinc 
ethide :— 
2PbCl, + 2Zn(C,H;), = Pb(C,H;), + 2ZnCl, + Pb. 


It is an oily liquid, distilling out of air contact at about 200°, with partial decom- 
position. When heated in the air it takes fire and burns with an orange-colored 
flame. When hydrogen chloride acts upon it, ethane is evolved and Lead Tri- 
ethyl chloride, Pb(C,H;),Cl, formed, which crystallizes in silky, shining needles. 
The zodide, Pb(C,H,),I, is very similar to the last, and is produced when iodine 
acts upon lead-tetraethyl. On heating either of these derivatives with silver oxide 
or caustic potash, /ead-triethyl hydroxide, Pb(C,H;),.OH, distils over. This 
reacts very alkaline, and forms crystalline salts with the acids. The sulphate, 
[ Pb(C,H,),],SO,, dissolves in water with difficulty. 

Lead-Triethyl, Pb,(C,H;),, is obtained by the action of ethyl iodide on an 
alloy of lead and sodium :— 


2PbNa, + 6C,H,I = Pb,(C,H,), -+ 6Nal. 


Lead triethyl is a yellowish liquid, insoluble in water, possessing a sp. gr. of 
1.471 at 10°, and boiling with partial decomposition. It reacts energetically with 
the halogens :— 

Pb,(C,H;), + I, = 2Pb(C,H;),I. 


The lead-methyl derivatives are perfectly analogous to the ethyl compounds, 
Consult Berichte, 22, 467, for the experiments made with the view of preparing 
Titanium-Tetraethyl, Ti(C,H;),. 


COMPOUNDS OF BISMUTH. 


These arrange themselves with those derived from antimony and arsenic; but 
in accordance with the complete metallic nature of bismuth, we do not meet any 
compounds here analogous to stibonium (p. 171) or arsonium. 

Bismuth-Trimethyl, Bi(CH,),, results from the interaction of zinc ethide and 
bismuth tribromide. It is a mobile, strongly refracting liquid, with a disagreeable 
odor. Its sp. gr. is 2.3 at 18°. It fumes in the air, and oxidizes rapidly. It ex- 
plodes if heatedinair. Surrounded by an indifferent gas it boils at 110° without 
decomposition (Berichte, 20, 1516; 21, 2035). ; 

Bismuth-Triethyl, Bi(C,H,),, is formed by acting upon an alloy of bismuth 
and potassium with ethyl iodide. It is perfectly similar to the methide, and in- 


16 


186 ORGANIC CHEMISTRY. 


flames rapidly on exposure tothe air. It explodes if heated to 150°. It distils 
without deccmposition under reduced pressure (below 7.9 mm. at 107°). It 
reacts very energetically with the halogens, according to the equation :— 


Bi(C,H,), + 21, = Bi(C,H,)I, + 2C,H,I. 


Bismuth-ethyl Chloride, Bi(C,H;)Cl,, is formed when mercuric chloride acts 
on bismuth-triethy]:— 


Bi(C,H,); + 2HgCl, = Bi(C,H,)Cl, + 2Hg(C,H,)Cl. 


The zodide, Bi(C,H,)I,, results when the chloride is warmed with KI. This 
salt crystallizes in yellow leaflets. From its alcoholic solution the alkalies pre- 
cipitate Bismuth-ethyl oxide, Bi(C,H,;)O, an amorphous, yellow powder, which 
takes fire readily in the air. The nitrate BGH,) ONO! is produced by 
adding silver nitrate to the iodide, This crystallizes from alcohol, explodes on 


being warmed, and is decomposed by water with formation of bismuth dinitrate, 
Bi(OH)(NO,),. 


¢ 





ALDEHYDES AND KETONES. 
"Aldehydes and ketones contain the carbonyl group CO, which in 


_ the Jatter unites two alkyls, but in the former is combined with 


only one alkyl and one hydrogen atom :— 


co’ GHs Bet 
a Dimethyl Ketone. 


This expresses the similarity and the difference in character of 
aldehydes and ketones. : 

The methods of preparation common to both classes of com- 
pounds are :— 
_ 1. Oxidation of the alcohols, whereby the primary alcohols 


__ change to aldehydes and the secondary to ketones (see p. 118) :— 


CH, CH, 
+O= + H,O 
bur. on duo : 
Ethyl Alcohol. Aldehyde, 
CH,\, He oA 
CH? >CH.OH + O= Gy? >CO + H,0. 
Isopropyl Alcohol. Dimethyl! Ketone. 


The above oxidation may be effected by oxygen; or air in presence of platinum 
sponge, or by ozone. It takes place more readily on warming the alcohols with 
potassium dichromate (or MnO,) and dilute sulphuric acid. To prevent the oxid- 


_ ation extending too far, it is sometimes recommended to employ an aqueous 


solution of chromic acid (Berichie, 5, 699). 





ALDEHYDES. 187 


Conversely, aldehydes and ketones again become primary and 
secondary alcohols by an addition of hydrogen :— ; 


CH,.CHO + H, = CH,.CH,.0H 


Aldehyde. Ethyl Alcohol. 
at) 55 ee CH? SCH.OH. 
Acetone. lsopropy! Alcohol. 


Further oxidation converts the aldehydes into acids, but the ketones 
suffer decomposition by means of it :— 


CH,.CHO + O = CH,.CO.OH. 
Alive. Acetic Acid. 


Empirically, the aldehydes are distinguished from the alcohols by 
possessing two atoms less of hydrogen—hence their name (from 
Alkohol dehydrogenatus), e. g., ethyl aldehyde, propyl aldehyde, 
etc., etc. On account of their intimate relationship to the acids, 
their names are also derived from the latter, like acetaldehyde, - 
propionic aldehyde, etc. , 

2. The dry distillation of a mixture of the calcium, or better, 
barium salts of two monobasic fatty acids. Should in this case one 
of the acids be formic acid, aldehydes are produced :— 


CH,.CO.OM’ + HCO.OM’ = CH,.COH + CO,Me’,. 
An Acetate. Formate, Acetaldehyde. 


In all other instances ketones result, and they are either szmp/e, 
with two similar alkyls, or mixed, with two dissimilar alkyls :— 


CH,.CO.OM’ + CH,CO.OM’ = CH CO + CO,Me,/ 


erp ot: 
An Acetate. An Acetate. Dimethyl Ketone. 
CH,.CO.OM’ + C,H,.CO.OM/ = (77? CO + CO,M,’ 
An Acetate. A Propionate. Methyl-ethyl Ketone. 


When working with higher aldehydes, which volatilize with dif- 
ficulty, and ketones, it is advisable to distil in vacuo. 

Both aldehydes and ketones combine with primary alkaline sul- 
phites, yielding crystalline compounds (see later). 





ALDEHYDES, 


The aldehydes, ¢. g., acetaldehyde, CH,.CHO, are compounds 
containing the group COH, which is readily formed by the oxida- 
tion of the primary alcoholic group, CH,.OH (p. 117). Again, 
in accordance with their fatty acid origin, aldehydes may be 
viewed as the hydrogen derivatives of the acid radicals. ‘This would 


188 ORGANIC CHEMISTRY. 


explain their formation by the action of nascent hydrogen (sodium 
amalgam) upon the chlorides of acid radicals, or their oxides (the 
acid anhydrides) :— 


CH,.COCI + H,=— CH,.COH + HCl, 


Acetyl Chloride. Acetaldehyde. 
me Go? 4+. 2H, = 2CH,.COH + H,0. 
Acetic ‘Anhydride, Acetaldehyde. 


Hence, they may be regarded as the oxides of bivalent radicals 
(like CH,.CH = ethidene), or as the anhydrides of the very un- 
stable dihydroxy] derivatives of these. Wherever the formation of 
these latter compounds occurs we can expect, from their close anal- 
ogy to the glycols, that water will split off and the aldehydes 
result :— 


OH 
CH,.CHY 6 = CH,.CHO + H,0O. 


This explains the formation of e¢. g., acetaldehyde (ethidene oxide) from 
ethidene chloride, CH,CHCI,, when heated with water (more readily in presence 
of lead oxide), and also its production from the ethereal and ester-like compounds, 
such as ethidene diacetate, CH,.CH(O.C,H,O),, by saponification with alkalies or 
sulphuric acid. In a similar manner, on heating glycollic and lactic acids, 


CH, 7 Ou , CH, CHY Oe. , with acids, there occurs a splitting-off of formic 
2\ CO,H \CO,H Pads 


acid (or of CO and H 20) and the products are methylene oxide, CH,O (formic 
aldehyde), acetaldehyde, CH,.CHO, ete. 


Besides these general methods the aldehydes, as the transitional 
members to the acids, frequently appear in the oxidation (by means 
of manganese peroxide and dilute sulphuric acid, or a chromic acid 
solution) of complex substances such as the albuminoids. 

The aldehydes exhibit in their properties a gradation similar to 
that of the alcohols. The lower members are volatile liquids, 
soluble in water, and have a peculiar odor, but the higher are 
solids, insoluble in water, and cannot be distilled without decom- 
position. In general they are more volatile and dissolve with more 
difficulty in water than the alcohols. In chemical respects the alde- 
hydes are neutral substances, yet they are easily oxidized to acids 
on exposure to the air :— 


CH,.CHO + 0 = CH,.CO.OH, 


Their ready oxidation by the oxides and salts of the noble metals 
(the latter being separated in free condition) is characteristic of 
aldehydes. On adding an aqueous aldehyde solution to a weak 
ammoniacal silver nitrate solution, silver separates on the sides of 
the vessel as a brilliant mirror. 


ALDEHYDES. 189 


The reaction is more delicate in the presence of caustic potash (Berichte, 15, 
1635 and 1828); such a solution will even reduce cane sugar and glycerol when 
assisted by heat. Alkaline copper solutions are reduced, too, by many fatty alde- 
hydes (Berichte, 14, 675 and 1950). The reduction of alkaline silver and copper 
solutions is, however, not peculiar to the aldehyde groups alone, but belongs also 
to some other atomic groups (see acetone alcohol, glycid alcohol, hydrazine). A 

‘very delicate reaction of the aldehydes is their power of imparting an intense 
violet color to a fuchsine solution previously decolorized by sulphurous acid 
(Berichte, 14, 1848). Chloral hydrate and the glucoses do not, but some ketones 
do, show this reaction (Azrvichte, 14, 791). The following is more sensitive: Add 
an aldehyde and alittle sodium amalgam to the sodium hydroxide solution of diazo- 
benzene sulphonic acid and a violet-red coloration is produced. Grape sugar and 
other sugars, but not chloral, will do the same. Acetone and acetic ether produce 
a dark red coloration (Berichte, 16, 657, and 17, Ref. 385). 

When oxygen or air is conducted through the hot solution of an aldehyde (like 
paraldehyde) in alcoholic potash, an intense light-display is observed; many 
aldehyde derivatives, and even grape sugar, deport themselves similarly (Berichte, 
10, 321). 


Nearly all the aldehydes are converted into resin by the alkalies ; 
some are transformed into acids and alcohols by alcoholic alkali 
solutions :— 

2C,H,.COH + KOH = C,H,.CO.OK + C,H,.CH,.OH. 
Amyl Aldehyde. Pot. Valerate. Amy! Alcohol. 


Phosphorus pentachloride replaces the oxygen of aldehyde by 
two chlorine atoms (p. 92) :— 


CH,.CHO + PCl, = CH,.CHCI, + PCI,0. 


Notwithstanding they are really saturated compounds, aldehydes 
possess, in a remarkable degree, the property of uniting two affini- 
ties directly, and thereby changing the oxygen united with two 
affinities to the hydroxyl group :— 

CH,.CHO + HX = CH, CHC Oey 
Thus they become alcohols by the addition of two hydrogen atoms. 
They unite directly with ammonia to form crystalline compounds, 
called aldehyde-ammonias :— 
H 
CH,.CHO + NH, = CH, .CHY OH 2, 


These are readily soluble in water but not in ether, hence am- 
monia gas will precipitate them in crystalline form from the ethereal 
solution of the aldehydes. They are rather unstable and dilute 
acids again resolve them into their components. Aldehydes unite 
in a similar manner with acid alkaline sulphites, forming crystalline — 
compounds :— 


i OH 
CH,.CHO + SO,HNa = CH,.CH¢ 56 nao 


190 ORGANIC CHEMISTRY. 


which may be regarded as salts of oxysulphonic acids. ‘The alde- 
hydes may be released from these salts by distillation with dilute 
sulphuric acid or soda. This procedure permits of the separation 
and purification of aldehydes from other substances. 

Aldehydes also combine with hydrogen cyanide, yielding oxy- 
cyanides or cyanhydrins :— 


CH,.CHO + CNH = CH,.CH 


/OH 
\CN, 


from which oxyacids are prepared. 


These cyanides are often crystalline and may be prepared by prolonged heating 
of the aldehydes with a concentrated CNH solution, or by adding hydrochloric 
acid to a mixture of the aldehyde and pulverized potassium cyanide (Berichte, 14, 
235 and 1965). When these compounds are distilled they usually break up into 
their components. The alkalies also cause a separation of CNH. When hydro- 
chloric or sulphuric acid acts upon them they pass into oxyacids. 


With ammonium cyanide aldehydes form amdocyanides, like 
CH,.CH SON which yield amido-acids (see these). 

Being the oxides of the radicals, R.CH = (p. 188), aldehydes 
can, by direct additions, form ether and ester derivatives. Thus 
they combine at 100° with the alcohols and build the so-called 


acetals ;— 
0.C,H 
| CH,.CHO + 2C,H,.0H = CH,.CH( Oc? + H,0; 


Ethidene-diethyl Ether. 


and with the acid anhydrides they yield esters :— 


I CHO. /0.C,H,O 
CH,.CHO'+ 2735 SO = CH,.CH 28 
ro id Bikidese Dacha 
These compounds will be treated with the derivatives of the bivalent 
radicals. 

The polymerization of the aldehydes depends upon a similar par- 
tial separation of the oxygen atoms and the union through the latter 
of several aldehyde radicals, CH;,;CH=. This occurs especially 
with the lower members of the series. Thus from formic aldehyde, 
CH,O, arises trioxymethylene, (CH,O),, from acetaldehyde, C,H,O, 
paraldehyde, (C,H,O);, and metaldehyde, (C,H,O), (see p. 194). 


The readiness with which the polymerides break up into simple molecules 
shows that in them the carbon atoms are not in union with each other; their 
power of refracting light (p. 60) would also indicate this (Axmalen, 203, 44). 


Finally, the aldehydes condense readily, 7. ¢., two molecules 
unite by means of two carbon atoms, and water may or may not 
separate (aldehyde and aldol condensation see p. 194). 


ALDEHYDES OF THE PARAFFIN SERIES. Ig! 


By such an exit of water the aldehydes (also the ketones) are en- 
dowed with the power of entering into combination with free 
hydroxylamine (or its HCl-salt), and forming the so-called aldox- 
imes (acetoximes) (V. Meyer) :— 


CH,.CHO + H,N.OH = CH,.CH:N.OH + H,0. 
Acetaldehyde. Ethyl Aldoxime. 


These contain the bivalent oximide group, N.OH, combined with 
one carbon atom. ‘They are isomerides of the nitroso-compounds 
(see p. 106), hence also designated the ¢sonitroso-derivatives of the 
hydrocarbons. The aldoximes are, as a usual thing, liquid bodies 
that boil without decomposition. Ethers are produced when the 
hydrogen of their hydroxyl group is replaced by acid radicals, or by 
the alkali metals (by means of sodium alcoholate) and the alkyls. 
When boiled with acids they are again changed to aldehyde and 
hydroxylamine. By the action of acetic anhydride or acetyl chloride 
the aldoximes become nitriles, while the acetoximes are changed 
to acetyl esters (Berichte, 19, 1613, and 20, 501, 2196). Nascent 
hydrogen converts them into amines (p. 160). 


The aldoximes result from all compounds which, like the aldehydes, contain the 
aldehyde group, CHO, e¢. g., the aldehyde acids ( Berichte, 15, 2783, 16, 823, and 
1780). Paraldehyde and metaldehyde (see above) do not react with hydroxyl- 

‘amine. All the ketones and compounds containing the group CO, peculiar to 
them, yield corresponding acetoximes (see Ketones). These oximido- or isonitroso- 
derivatives do not show the nitroso reaction (see p. 164). 


All the aldehydes (and the ketones) react more readily with 
phenyl hydrazine (Berichte, 16, 661, 17, 574) than with hydroxyl- 
amine to form oily or solid condensation products—the hydra- 
ZONES :— 


CH,.CHO -++ H,N,.C,H, = CH,.CH:HN,,.C,H, + H,O. 


These serve for the characterization and recognition of the alde- 
hydes. Boiling acids break up the hydrazones into their compo- 
nents. Sodium amalgam decomposes them with the formation of 
amines (p. 160) (Berichte, 17, 574). 


The aldehydes also unite with p-amido-dimethylaniline (Berichte, 17, 2939). 
On boiling the aldehydes with an alcoholic solution of resorcinol and a trace of 
hydrochloric acid insoluble compounds are produced. The ketones do not react 
under these conditions (Berichte, 19, 1389). Mercaptals are formed by the union 
of the mercaptans with the aldehydes (and ketones). 


I. ALDEHYDES OF THE PARAFFIN SERIES, Ch HonO. 


1. Methyl Aldehyde, CH,O, called Formic Aldehyde, 
or oxymethylene, is only known in aqueous solution and in gaseous 
form, It arises in the oxidation of methyl alcohol, if its vapors 


192 “ORGANIC CHEMISTRY. 


mixed with air be conducted over an ignited platinum spiral; also 
by the distillation of calcium formate.and upon digesting methylal 
with sulphuric acid. 

It is noteworthy that formic aldehyde appears to exist in the plant 
cells which contain chlorophyll (Berichte, 14, 2147). 


Preparation ; (1) Mix methylal or other acetals with sulphuric acid, add water 

and distil. Aqueous formic aldehyde passes over (Berichie, 19, 1841); (2) con- 
duct a mixture of air and the vapors of methyl alcohol over a platinum spiral 
heated to redness (Hofmann). Ifa copper spiral be used a solution will be ob- 
tained, containing 30 to 40 per cent. formic aldehyde (Journ. prk. Ch., 33, 321. 
Berichte, 19, 2133; 20, 144; Annalen, 243, 335). 
The dilute solution may be concentrated by distillation. But little aldehyde is 
expelled in this way. When the solution is very concentrated and it is allowed to 
evaporate over sulphuric acid at a low temperature, or in a vacuum, paraformalde- 
hyde separates (Berichte, 16, 917, and 19, 2135). To determine the quantity of 
formic aldehyde present in a solution digest the latter with ammonia, when hexa- 
methyleneamine (p. 193) will be formed, and the excess of ammonia can be de- 
termined with sulphuric acid in the presence of litmus (Berichte, 22, 1565, 1929). 
Or the liquid can be evaporated below 50° to dryness and the residue, hexamethylene- 
amine weighed (Legler, Berichte, 16, 1333). 


_. The concentrated aqueous solution of formic acid not only con- 
tains volatile CH,O, but also the hydrate CA on , 2. é@., hypo- 


thetical methylene glycol, and non-volatile polyhydrates, e¢. g., 
(CH,),0(OH)., corresponding to polyethylene glycols. Therefore 
the determinations of the molecular weight of the solution, by the 
method of Raoult, have yielded different values (Berichte, 21, 3503; 
22, 472). On complete evaporation of the solution the hydrates 
condense to the solid anhydride (CH,O),, paraformaldehyde. 


Hydrogen sulphide precipitates formic aldehyde from its aqueous solution com- 
pletely as trithiomethylene (see below). It unites with ammonium to hexamethy- 
leneamine, (CH,),N, (see below). When heated with sodium hydroxide it 
yields methy!] alcohol and formic acid: 2CH,O + H,O = CH,0 + CH,0O,. 
The alkalies or alkaline earths in dilute solution convert formic aldehyde into 
methylenenitan and formose; these substances resemble the sugars. 

Paraformaldehyde, (CH ,O),, formerly called Trioxymethylene, is obtained 
by the action of silver oxide upon methene di-iodide, or by heating methene di- 
acetyl ester with water, to 100°. It is best prepared by distilling glycollic acid 
with a little concentrated sulphuric acid. It is most easily obtained by the con- 
densation of formic aldehyde (see above). It is a white, indistinctly crystalline 
mass, It sublimes below 100°. The sublimed compound melts at 171°. The 
vapors have the formula CH,O which corresponds to their density. When cooled 
they again condense to the trimolecular form. When paraformaldehyde is heated 
with water to 130° it changes to the simple molecule CHO. : 

When paramethaldehyde is heated with a trace of sulphuric acid to 120° ina 
sealed tube it is changed into the isomeric 777oxymethylene, (CH,O), crystal- 
lizing in long needles and melting at 60°. Its vapor density corresponds to the 
formula C,H,O, (Berichte, 17, Ref. 567). 

When hydrogen sulphide is conducted into the aqueous solution of CH,O, 


ALDEHYDES OF THE PARAFFIN SERIES. 193 


condensed oxysulphydrides, with exceedingly disagreeable odor, are produced. 
If these are boiled with concentrated hydrochloric acid, water splits off, 
and Trithiomethylene, Trithioformaldehyde, C,H,S, =. CHS CHS: 
results. When pure it is perfectly inodorous, and Trimethylene-trisulphone, 
CHa So CH? 802 (Berichte, 23, 60, 71), is produced when trithioform- 
aldehyde is oxidized with potassium permanganate. 

Another polymeric 7hiomethylene, (CH,S)n, obtained from hexamethylene- 
amine, results at 176° (Berichte, 19, 2344), and crystallizes in shining white 
needles, fusing “at 216°, and subliming readily. The vapor density answers to the 
formula C,H,S,. 

Hexamethyleneamine, (CH,),N4, is obtained by the action of ammonia on 
aqueous formic aldehyde (Berichte, 19, 1842). It is readily soluble in water and 
crystallizes from alcohol in shining rhombohedra. It sublimes in vacuo without 
decomposition. For the molecular weight of the solution see Berichte, 21, 1570. 
It is resolved into CH,O and ammonia again by distillation with sulphuric acid. 
It is a monacidic base, but does not react with litmus (Berichte, 22, 1929). It 
unites with the alkyl iodides (Berichte, 19, 1842). Formic aldehyde also com- 
bines with phenylhydrazine, amines and anilines (Berichie, 18, 3300). Nitrous 
acid produces peculiar nitrosamines (Berichte, 21, 2883). 


2. Acetaldehyde, C,H,O = CH;.CHO, is formed according 
to the methods described above, but is generally prepared by the 
oxidation of ethyl alcohol with potassium bichromate and dilute 
sulphuric acid. Commercial aldehyde, and especially that employed 
in the preparation of aniline colors, is obtained from the first run- 
nings in the rectification of spirit. It is made, too, in the oxida- 
tion of alcohol in running over wood charcoal. Its production 
from vinylsulphuric acid, SO,H(C,H;), (from acetylene), by boil- 
ing with water, is of theoretical interest. (Compare p. 134.) 


Preparation.—Pour 12 parts H,O over 3 parts K,Cr,O,, and then gradually add, 
taking care to have the solution cooled, a mixture of 4 parts concentrated H,SO,, 
and 3 parts alcohol (go per cent.); the heat of a water-bath is now applied, and 
the vapors that escape are condensed in a receiver. The resulting distillate, 
consisting of alcohol, aldehyde and acetal, is next heated to 50°, and the escaping 
aldehyde vapors conducted into ether, and this solution saturated with dry NH,, 
when the aldehyde-ammonia, C,H,O.NH,, will separate in a crystalline form. 
Pure aldehyde may be obtained from this by distilling it together with dilute 
sulphuric acid. The aldehyde vapors are freed from moisture by conducting them 
over heated calcium chloride. . 


Acetaldehyde is a mobile, peculiar-smelling liquid. It boils at 
20.8°, and has a sp. gr. of 0.8009 at o°. It is miscible in all pro- 
portions with water, ether and alcohol. It slowly oxidizes to 
acetic acid when exposed to the air. From an ammoniacal silver 
solution it immediately throws out metallic silver as a mirror-like 
deposit. Nascent hydrogen transforms aldehyde into ethyl alcohol. 
PCI, and PBr, convert it into CH;.CHCl, and CH;.CHBr, (p. 189). 

hy, 
Vv 4 


AY 5 
ease 


194 ORGANIC CHEMISTRY. 


Ethylaldoxime, CH,.CH:N.OH, isonitrosoethane, produced by the action of 
hydroxylamine upon acetaldehyde (p. 191), boils at 115°, possesses an aldehyde- 
like odor, and is miscible with water, alcohol and ether. 

Ethylidene-phenylhydrazone, CH,.CH:N:NH.C,H,, from aldehyde and 
phenylhydrazine, is a liquid boiling near 250°. 

When an ethereal solution of aldehyde is saturated with dry ammonia, alde- 
hyde-ammonia, C,H,O.NH, (p. 189), separates out. This compound is readily 
soluble in water, but not so readily in alcohol, and crystallizes in large, glistening 
rhombohedra, which fuse at 70°—80°, and vaporize undecomposed in a vacuum. 

On shaking aldehyde with aqueous solutions of acid alkaline sulphites, crystal- 
line compounds, e¢. g., CH,.CHO.HSO,K (see p. 189), separate. If these be 
heated together with acids, they break up into their components. 

With anhydrous hydrocyanic acid, aldehyde yields CH,.CH(OH)CN (see p. 
190), a liquid readily soluble in water and alcohol, and boiling with‘slight decom- 
position at 183°. The alkalies break it up into its components, and concentrated 
hydrochloric acid converts if into lactic acid. 

Polymeric Aldehydes. Small quantities of acids (HCI, SO,) or salts (espe- 
cially ZnCl,) convert aldehyde at ordinary temperatures into paraldehyde, 
(C,H,O,,) (see p. 192); the change (accompanied by evolution of heat and 
contraction) is particularly rapid, if a few drops of sulphuric acid be added to 
the aldehyde. Paraldehyde is a colorless liquid boiling at 124°, and of sp. gr. 
0.9943 at 20°. It dissolves in about 12 vols. H,O, and is, indeed, more soluble 
in the cold than in the warm liquid. This behavior would point to the formation 
of a hydrate. The vapor density agrees with the formula C,H,,0,. When dis- 
tilled with sulphuric acid ordinary aldehyde is generated. 

Metaldehyde, (C,H,O),, is produced by the same reagents (see above) act- 
ing on ordinary aldehyde at temperatures below 0°, It is a white crystalline body, 
insoluble in water, but readily dissolved by hot alcohol and ether. If heated to 
112°-115° it sublimes without previously melting, and passes into ordinary alde- 
hyde with only slight decomposition. When heated in a sealed tube the change 
is complete. 

There are many reagents that change meta- and paraldehydes to ordinary alde- 
hyde and its derivatives; ¢. g., PCl, converts them into ethidene dichloride, 
CH,.CHCl,. They do not combine with NH, or alkaline bisulphites, do not 
reduce silver solutions, nor do they give an aldoxime with hydroxylamine (p. I91). 
Paraldehyde is not attacked by sodium, even when assisted by heat. These facts 
go to prove that in the polymeric aldehydes, the aldehyde radicals are linked by 
oxygen atoms (see p. 190), the same as the alkyls in the ethers. Their refractive 
power and their specific volume would also indicate that the oxygen atoms present 
- in them are united to carbon by but one affinity. 





Condensation Products. When acetaldehyde is heated with 
zinc chloride, water separates and crotonaldehyde is produced :— 


CH,.CHO + CH,.CHO = CH,.CH:CH.CHO + H,0. 
2 Mols. Aldehyde. Crotonaldehyde. 


By long contact with dilute sulphuric acid, aldehyde first becomes 
aldol (see this) :— 


CH,.CHO + CH,.CHO = CH,.CH(OH).CH,.CHO, 
Aldol. 


ALDEHYDES OF THE PARAFFIN SERIES. 195 


and this when heated with zinc chloride, gives up water and passes 
into crotonaldehyde :— 


CH,.CH(OH).CH,.CHO = CH,.CH:CH.CHO + H,0. 


When chlorine is conducted into cold aldehyde chlor-crotonaldehyde, CH. 
CH:CCl,.CHO, and trichlorbutyraldehyde, C,H;Cl,O-(p. 197), are formed, and 
by the action of nascent hydrogen (sodium amalgam) there results butylene glycol, 
CH,.CH.OH.CH,.CH,.OH. 

Sulphuric acid, sodium acetate (Berichte, 16, 786), and alkalies (sodium hy- 
droxide and baryta water), exert the same power of condensation as zinc chloride 
and hydrochloric acid. 


Such a union of two or more molecules, by the linking of carbon 
atoms (followed either with or without water separation), and the 
formation of complicated carbon chains, is ordinarily termed con- 
densation, distinction being made at the same time between the 
aldol condensation and genuine aldehyde condensation, in which an 
exit of water does occur. 

In the case of the higher aldehydes (also ketones), the condensa- 
tion is so made that the oxygen of aldehyde unites with the hydro- 
gen of a CH, group. Thus, from propylaldehyde we get methyl- 
ethyl acrolein :— 

C.H,.cHo-en. ¢ SB 


2< CHO = C2Hs.CH:C(CH 2).CHO +H,0. 


The aldehydes act.in a perfectly similar manner upon the esters 
of malonic acid, CH,(CO,R),, acetic acid and analogous com- 
pounds (Annalen, 218, 121). 

Another very remarkable condensation is sustained’ by the alde- 
hydes through the action of ammonia (heating of aldehyde-ammo- 
nias) ; nitrogenous bases (pyridine bases) are produced. 


‘ 





Substituted Aldehydes. These are obtained by the action of chlorine upon 
acetaldehyde or ethyl! alcohol, the latter being simultaneously oxidized to aldehyde. 
The only pure compound that can be formed in this manner is the final chlorina- 
tion product, ¢richloraldehyde. 

Monochloraldehyde, CH,Cl.CHO, is obtained pure by distilling monochlor- 
acetal, CH,Cl.CH(O.C,H,),, with anhydrous oxalic acid, It is a liquid that 
boils at 85°, and polymerizes very rapidly to a white mass (Berichte, 15, 2245). 
When oxidized it yields monochloracetic acid; with CNH and hydrochloric acid 
it becomes -chlorlactic acid. 

Dichloraldehyde, CHC1,.CHO, is produced in the distillation of dichloracetal, 
CHC1,.CH(O.C,H,),, with concentrated sulphuric acid. It boils at 88°-g0°, 
and when .preserved, changes into a solid polymeric modification. The hydrate, 
CHCI,.CHO + H,0, corresponding to chloral hydrate, fuses at 57° and boils 
at 110°, When it is oxidized with HNO, dichloraldehyde is converted into 
dichloracetic acid. It yields dichlorlactic acid by the action of CNH and hydro- 
chloric acid. 


196 ORGANIC CHEMISTRY. 


Trichloracetaldehyde, CCl,.CHO, Chloral, is best prepared 
by conducting chlorine into alcohol and distilling the crystalline 
product with sulphuric acid. It isan oily, pungent-smelling liquid, 
which boils at 97°, and has the sp. gr. 1.541 at o°. With NH,, 
CNH, acid sulphites of the alkali metals, etc., chloral furnishes 
compounds similar to those of ordinary aldehyde ; it also reduces 
an ammoniacal silver solution. When kept for some time it passes 
into a solid polymeride. It yields trichloracetic acid when oxid- 
‘ ized by HNO; When heated with alkalies it breaks up into 
chloroform and a formate :— 


CCl,.CHO + KOH = CCl,H + CHO.OK. 


When it combines with a small quantity of water chloral 
changes to /OH 

Chloral Hydrate, C,HC],0.H,O = CCl;.CH OH? which con- 
sists of large monoclinic prisms, fusing at 57° and distilling at 
96-98°. The vapors dissociate into chloral and water. Chloral 
hydrate dissolves readily in water, possesses a peculiar odor and 
a sharp, biting taste; when taken internally it produces sleep. 
Concentrated sulphuric acid resolves the hydrate into water and 
chloral. 


Chloral and alcohol combine to Chloral Alcoholate,—trichlorethidene ethyl 
ether—CCl pCH{ on’ a crystalline solid, fusing at 56° and ‘boiling at 114- 
115°. When acetyl chloride is allowed to act upon the preceding derivative 
the acetyl ester, trichlorethidene ethyl acetin, is produced. This boils at 198°. 
Concentrated sulphuric acid reproduces chloral from the alcoholate. 

Acetic anhydride and chloral yield trichlorethidene diacetate, CC],.CH(O.C, 
H,0O),,which boils at 221°. It unites with ammonia to form chloral-ammonia,— 


trichlorethidene hydramine— CCl, .CH¢ Ny , melting at 63°. With prussic 
acid it furnishes chloral-cyanhydrate, Ccl,.cH da a crystalline derivative, 


fusing at 61-62°, and passing into trichlorlactic acid when treated with hydro- 
chloric acid. 





Dibromacetaldehyde, CHBr,.CHO, obtained by the bromination of alde- 


hyde or paraldehyde, is a liquid, boiling at 142°. After standing some time it 
becomes solid—a polymeric modification. It yields a crystalline hydrate with 


water. It combines with CNH to form the compound, CHBr,.CH/ poe from 
which dibromlactic acid may be obtained. fe 
Tribromaldehyde, CBr,.CHO, Bromal, is perfectly analogous to chloral. 
It boils at 172~173°, and with water forms a solid hydrate fusing at53°. The 
alcoholate melts at 44° and decomposes at 100°, Heated with alkalies bromal 
/ OH 


breaks up into bromoform and a formate. It yields a cyanide, CBry.CH CN 


with CNH and this hydrochloric acid converts into tribromlactic acid. 


— 





ALDEHYDES OF THE PARAFFIN SERIES. 197 


Iodo-acetaldehyde, CH,I.CHO, is made by acting on aldehyde with iodine 
or iodic acid. It is an oily liquid, with a very disgusting odor ( Berichie, 22, Ref. 
561). Silver cyanide converts it into cyanaldehyde, C,H,(CN)O (Berichte, 22, 
Ref. 563). 

Saree Compounds.—On passing hydrogen sulphide into an aqueous solu- 
tion of aldehyde the reaction proceeds in the same manner as with formic aldehyde. 
In the presence of hydrochloric acid two isomeric trithioaldehydes, (C,H,S),, 
are produced. They crystallize in long needles and prisms. a-77rithioaldehyde 
melts at 101°, and the 8- modification at 120°. Both boil about 245°. Concen- 
trated H,SO,, or acetylchloride, converts the a- into the Z- variety. When oxid- 
ized with K MnO, both varieties yield the same 7rialdehyde-trisulphone, (CH;: 
CH),(SO,), (Berichte, 22, 2600; 23, 60). 

Thialdin, C,H,,NS,, separates on conducting H,S into an aqueous solution of 
aldehyde-ammonia. It consists of large, colorless crystals, fusing at 43°. It is a 
monacidic, secondary base, and may be viewed as a trithioaldehyde in which an 
atom of sulphur is replaced by the imide group, inasmuch as it can also be made 
by allowing ammonia to act upon trithioaldehyde, In a similar manner methyl- 
amine produces Methylthialdin, (C,H,),5,(N.CH,), melting at 19° ( Berichte, 19, 
2378). 





3. Propionic Aldehyde, C,H,O = C,H;.CHO, is obtained 
from normal propyl alcohol, and by the dry distillation of calcium 
propionate and formate. It is very similar to acetaldehyde, boils 
at 49°, and has a sp. gr. 0.8066 at 20°. It is soluble in 5 vols. H,O 
at 20°. With PCI, it yields C,H;.CHCl,. 7 


Propyl Aldoxime, C,H,.CH:N.OH (see p. 191), boils at 131°. 

B-Chlorpropionic Aldehyde, CH,Cl.CH,.CHO. This is produced when HCl 
is added to acrolein; it fuses at 35°, and, when distilled, again breaks up into 
acrolein and HCl. Nitric acid oxidizes it to 8-chlorpropionic acid. 


4. Butyraldehydes, C,H,O = C;H,.CHO. Two isomeric 
aldehydes of this form exist; they correspond to the two primary 
butyl alcohols. 

(1) Normal Butyraldehyde, CH;.CH,.CH,.CHO, from nor- 
mal butyl alcohol and normal butyric acid (Berichte, 18, 3364), is 
a liquid boiling near 75°, and has a sp. gr. 0.8170 at 20°. It dis- 
solves in 27 parts H,O, and oxidizes readily to butyric acid. 
Heated with alcoholic ammonia it yields the base paraconine, 
C,H,;N, boiling at 170° and very similar to conine, C,H,,N. 
The isomeric paraconine obtained from isobutyraldehyde boils at 
146°. i 

B-Chlorbutyraldehyde, CH,.CHCI.CH,.CHO, is produced from crotonalde- 
hyde, CH,.CH:CH.CHO, by the addition of HCl, and consists of needles, fusing 
at 96°. Nitric acid oxidizes it to B-chlorbutyric acid. 

Trichlorbutyraldehyde, CH;.CHCI1.CCI,.CHO, formerly obtained from croton- 
aldehyde, C,H,C1,O, is produced by the action of chlorine upon acetaldehyde or 
paraldehyde, the first product being chlorcrotonaldehyde, CH,.CH:CCl.COH 
(p. 195), which further unites with Cl,, yielding butylchloral (Anua/en, 219, 374). 


~ 


198 ORGANIC CHEMISTRY. 


The latter compound, like the ordinary chloral, is a heavy, oily liquid, boiling at 
163—-165°, and forming with water the hydrate, C,H,C],O + H,O; this last crys- 
tallizes in tablets, fusing at 78°: The alkalies decompose butyl chloral into acetic 
acid, potassium chloride and allylene dichloride, CH,.CCl:CHCl. It yields-a 
trichlorbutyric acid when oxidized with nitric acid. 


(2) Isobutyraldehyde, (CH;),CH.CHO, obtained from fer- 
mentation butyl alcohol and calcium isobutyrate, has the sp. gr. 
0.7898 at 20°, and boils at 63°. It dissolves in nine volumes of 
water at 20°. A small quantity of concentrated sulphuric acid 
converts it into Para-isobutyraldehyde, (C,H,O);, which crys- 
tallizes in brilliant needles, melting at 60°, and boiling at 194°. 


5. Amyl Aldehydes, C;H,O = C,Hy.CHO, Valeraldehydes. There are four 
possible isomerides ; two of these are known :— 

Normal Amyl Aldehyde, (CH,)(CH,),CHO, from valeric acid, boils at 102°. 
Isoamyl Aldehyde, (CH,),.CH.CH,.CHO, from the amyl alcohol of fermenta- 
tion and from isovaleric acid, is a liquid, with fruit-like odor, boiling at 92°, and 
polymerizing readily. When oxidized it becomes isovaleric acid. On heating 
with alcoholic ammonia to 150° it yields two basic compounds, valeridine, C,)H,,N, 
and valeritrine, C,,H,,N, which boils near 250°. 

Normal Hexyl Aldehyde, C,H,,O = C,H,,.CHO, Caproyl Aldehyde, from 
caproic acid, boils at 128°. Normal Heptyl Aldehyde, C,H,,O, cenanthylic 
aldehyde, or cenanthol, is produced along with hendecatoic acid in the distilla- 
tion of castor-oil, best under diminished pressure. It is a pungent-smelling liquid, 
boiling at 153-154°. It becomes normal heptylic acid, C,H,,O,, when oxidized 
with dilute nitric acid (1 : 2 vols. H,O). 

The higher aldehydes are most advantageously prepared by the distillation, 
under diminished pressure, of the barium salts of the corresponding fatty acids 
with barium formate (Berichte, 16, 1716). Like their acids, they all have normal 
‘structure. They can be boiled without decomposition only under a somewhat 
diminished pressure. 

Decatoic Aldehyde, C,,H,,O, Capric Aldehyde, obtained from capric acid, 
boils at 106° under a pressure of 15 mm. 

Dodecatylic Aldehyde, C,,H,,0, Lauric Aldehyde, from lauric acid, crys- 
tallizes in shining tablets, fusing at 44.5°, and boiling at 142° (22 mm.). 

Tetradecatylic Aldehyde, C,,H,,O, Myrisitaldehyde, made from myristic 
acid, melts at 52.5°, and under 22 mm. pressure boils at 168° C. 

Hexdecatylic Aldehyde, C,,H,,0, Palmitic Aldehyde, from palmitic acid, 
fuses at 58.5°, and under 22 mm. pressure boils at 192° C. 

Octdecatylic Aldehyde, C,,H,,0, Stearaldehyde, consists of tablets having 
a bluish lustre. It fuses at 63.5°, and boils at 192° C. (under 22 mm. pressure). 


2. UNSATURATED ALDEHYDES, C,H, — 20. 


These derivatives bear the same relation to the alcohols of the 
allyl series as the aldehydes just considered bear to the alcohols 
C,H..420, of the saturated hydrocarbons. Inasmuch as they are 
unsaturated compounds they are capable of directly saturating two 
affinities. 

The first and lowest member of the series is :— 


UNSATURATED ALDEHYDES. 199 


Acrylaldehyde, C,H,O — CH,:CH.CHO, or Acrolein. This 
is produced by the oxidation of allyl alcohol and by the distillation 
of glycerol or fats :— 


C,H,(OH), = CH,O ++ 2,0. 
Glycerol. 


One part of glycerol is distilled with two parts of acid potassium sulphate. The 
distillate is redistilled over lead oxide (Annalen, Suppl., 3, 180). 


Acrolein is a colorless, mobile liquid, boiling at 52°, and possess- 
ing asp. gr. of 0.8410 at 20°. It has a pungent odor and attacks 
the mucous membranes in a frightful manner. The odor of burn- 
ing fat is occasioned by acrolein. It is soluble in 2-3 parts water. 
It reduces an ammoniacal silver solution, with formation of a mirror- 
like deposit, and when exposed to the air it oxidizes to acrylic acid. 
It does not combine with primary alkaline sulphites. Nascent 
hydrogen converts it into allyl alcohol. 


Phosphorus pentachloride converts acrolein into propylene dichloride, CH, : 


CH.CHCI,, boiling at 84°C. With hydrochloric acid it yields : ‘chlorpropionic: “3 


aldehyde (p. 197). With bromine it yields a dibromide, CH,.Br.CHBr. CHO, : 


which becomes £-dibrompropionic acid upon oxidation. 
When preserved, acrolein passes into an amorphous, white mass (disacry/). On 


warming the HCl compound of acrolein (see above) with alkalies or potassium — 


carbonate metacrolein is obtained. The vapor density of this agrees with the 
formula (C,H,O),. It crystallizes from alcohol in tablets, fusing at 45-46°, and 
dissociating at 160° C. 


Ammonia changes acrolein to the so-called acrolein-ammonia, C,H,NO +- 
4H,0 :— 
2C,H,O + NH, = C,H,NO + H,0O. 


This is a yellowish mass that on drying becomes brown, and forms amorphous 
salts with acids. It yields picoline, CHH,N (methyl-pyridine, C,H,N.CH;,), when 
distilled. , 


Crotonaldehyde, C,H,O = CH,.CH:CH.CHO, is obtained 
by the condensation of acetaldehyde (p. 194) when heated with 
dilute hydrochloric acid, with water and zinc chloride/or with a 
sodium acetate solution, to 100° C. (Berichte, 14, 514and 516) :— 
CH,.CHO + CH,.CHO = CH,.CH:CH.CHO + H,O7 a 
It is also produced when the sulphuric acid solution of brom- 
ethylene is boiled with water (see p. 134). Crotonaldehyde is a 
liquid with irritating odor, soluble in water ; at o° it has a sp. gr. 
of 1.033, and boils at 104~-105°. Onexposure to the air it oxidizes 
to crotonic acid ; it reduces silver oxide. It combines with hydro- 
chloric acid to form §-chlorbutyraldehyde (p. 197) ; on standing 
with hydrochloric acid it unites with water and becomes aldol. Iron 





200 ORGANIC CHEMISTRY. 


and acetic acid change it to croton-alcohol, butyraldehyde and 
butyl alcohol. : 


a-Chlorcrotonaldehyde, CH,.CH:CCl.CHO, is a by-product in the prepara- 
tion of butyl-chloral, and may also be obtained by the condensation of aldehyde 
with monochloraldehyde. It is a pungent-smelling oil, boiling at 150°. It com- 
bines directly with two atoms of chlorine to butyl chloral (p. 197). 

When the alcoholic solution of acetaldehyde-ammonia is heated to 120°, Cro- 
tonal-ammonia, C,H,,NO (Oxtetraldine), is produced. This bears the same 
relation to crotonaldehyde that acrolein-ammonia does to acrolein. It is a brown 
amorphous mass, yielding amorphous salts with acids. When heated it breaks 
up into water and collidine, C,H,,N = trimethylpyridine, C,;H,N(CH,);. 

Methyl-ethyl Acrolein, C,H;.CH:C(CH,).CHO, is produced by the con. 
densation of propionic aldehyde (p. 195), and boils at 137° C. 





KETONES. 


The ketones are characterized by the group CO in combination 
with two alkyls. They share many analogies with the aldehydes, 
indicated by the similar methods of production (see p. 186). We 
have the following specific methods for their formation :— 

1. The action of the zincalkyls (1 molecule) upon the chlorides 
of the acid radicals (2 molecules) :— 


2C,H,.COCI + Zn(CH,), = 2C,H,.CO.CH, + ZnCl, 
Propiony! Chloride. Methyl-ethyl Ketone. 
2C,H,.COCI + Zn(C,H,), = 2C,H,.CO.C,H, + ZnCl, 
Diethyl Ketone. 


= 


To the zinc alkyl (1 molecule), cooled by ice, there are added drop by drop at 
first, then rapidly, 2 molecules of the acid chloride, and the product of the reaction 
is immediately decomposed by a large quantity of water. The reaction is similar 
to that occurring in the formation of the tertiary alcohols (p. 120). At first the 
same intermediate product is produced :— 

C,H 
CH,.COCI + Zn(C,H,), = CH,.C | O.Zn.C,H,, 
Cl 


dee (with a second molecule of the acid chloride) afterwards yields the 
etone :— 


C,H, 
cH.C 0.20.CH, + CH,.COCI = 2CH,.CO.C,H, + ZnCl. 


In many cases, especially in the preparation of the pinacolines, it is, however, 
more advantageous to employ double the quantity of the zinc alkyl (1 molecule to I 
molecule ‘acid chloride) which will serve to dilute the mixture (Auzalen, 188, 
144); in this manner the intermediate product forms the ketone with water, and 
there occurs a simultaneous evolution of paraffins. The aqueous solution is dis- 
tilled, and the ketone separated from it by means of soda. 

2. By the action of anhydrous ferric chloride upon the acid radicals. At first 
hydrochloric acid gas is evolved and an intermediate product formed, which is 








KETONES, 201 
changed by water and evolution of CO, into a ketone (Berichte, 22, Ref. 141). 
Propiny! chloride, treated as above, yields diethyl ketone :-— 


CH 
2C,H,.COC] = C,H,,CO.CHE Gott HCl 


and C.H,.CO.CHY 662) + 1.0 = C,H. COiG;H, 4+ CO, + HCl. 


Butyryl chloride, C,H,.COCI, yields dipropyl ketone, C,H,.CO.C,H,,. 
3. The oxidation of the acids of the lactic series with secondary 


alkyls, by means of bichromate of potash and dilute sulphuric acid 
(see p. 188): — 


(CH,),C(OH).CO,H -+ 0 = (CH,),CO + CO, + H,O. 
Oxyisobutyric Acid, Dimethyl Ketone. 


4. The decomposition of the aceto-acetic acids and their esters 
(see these) :— 


CH,.CO.CH,.CO,.C,H, + H,O = CH,;.CO.CH, + CO, + C,H,.OH. 


The ketones are also produced in the dry distillation of wood, 
sugar, and many other carbon compounds. 





The names of the ketones are derived by combining the names 
of the alkyls with the syllable Zefone. A. Baeyer regards the ketones | 
as keto-substitution products of the hydrocarbons resulting from the 
replacement of two hydrogen atoms by one atom of oxygen. Ac- 
cordingly dimethyl ketone, CH;.CO.CHs, is called ketopropane, 
ethyl-methyl ketone, C,H;.CO.CH;, a-ketobutane, etc. (Berichte, 
19, 160). ; 

The SSE are generally ethereal-smelling, volatile liquids, in- 
soluble in water. They do not reduce ammoniacalsilver solutions. 
They combine, like aldehydes, with the primary alkaline sulphites ; 
but it appears that only those of the higher ketones, in which the 
group CO is in combination with the methyl group, are adapted to 
this reaction. Boiling alkaline carbonates again separate the ketone 
from these compounds (p. 190). Hence, these reactions serve both 
for the isolation and the purification of these derivatives. 

Nascent hydrogen (sodium amalgam) converts them into second- 


ary alcohols :— 
(CH,),CO + H, = (CH,),CH.OH. 


At the same time there occurs here, as with the aldehydes (p. 194), a condensa. 
tion of the ketone molecule, accompanied by the formation of dihydric alcohols :— 


(CH,),C.OH 
2(CH,),CO + H, = 
(CH,),C.OH. 
17 


202 ORGANIC CHEMISTRY. 


These are termed pixacones. When heated with acids they sustain a peculiar 
transposition of atoms, and are converted into ketones :— 


(CH,);C.0H |. (CHy)sC. 


(CH,),COH —CH,% 
Tertiary Butyl-methyl Ketone. 


‘SCO + HO. 


Such ketones, containing a tertiary alkyl group, are designated pzmacolines. 
They may be synthesized by the action of zinc alkyls upon the chlorides of such 
fatty acids as contain tertiary alkyls :— 


(CH,),C.COCI yields (CH,),C.CO.CH,. 
Trimethy] Acetyl Pinacoline. 
Chloride, 


The ketones also unite with HCN, forming oxycyanides, ¢. g., (CH,),C(OH). 
CN (see Berichle, 15, 2306), from which the corresponding oxyacids may be ob- 
tained (see p. 190). Similarly, acetone in the presence of caustic soda combines 


with chloroform, yielding acetone chloroform, (CH3),C cal This, too, can 
3° 
be converted into the corresponding oxyacid. 

All the ketones (like the aldehydes, p. 191) combine with hydroxylamine, and 
become oximid- or isonitroso-compounds, called acetoximes, or hetoximes (see p. 
205) :— 
(CH;),CO + H,N.OH = (CH;),C:N.OH + H,O. 


To prepare the ketoximes the ketones are allowed to stand for some time with 
hydroxylamine hydrochloride. The reaction is accelerated by heating in a water- 
_bath, or in asealed tube. Frequently the reaction will only occur in feebly alkaline 
solutions. Soda or caustic sodais then added in equivalent amount. At timesa 
great excess of caustic soda (3 mol.) must be added (Berichte, 22, 605). Instead 
of using hydroxylamine hydrochloride, potassium hydroxylamine-disulphonate (re- 
ducing salt) may be used (Anna/en, 241, 187). This salt is obtained by acting 
upon sodium nitrite with monosodium sulphite. 


The acetoximes, like the aldoximes, are split up into their compo- 
nents when boiled with acids. They are similarly transformed into 
amines by sodium amalgam and acetic acid (p. 160).. They are 
distinguished from the aldoximes in that the latter yield nitriles 
with acetyl chloride, while the acetoximes, under like influence, 
form oils with peculiar odor. Nitrogen tetroxide converts the ketox- 
imes into pseudo-nitrols, 


Acetoximes with tertiary hydrogen atoms, readily suffer molecular rearrange- 
ments under the influence of acetyl chloride (Berichte, 20, 506) :— 


(CH,),CH (CH,),CH.CO 
YOUN, -OH) yields 
(CH,),CH (CH,),CH.NH. 
i-isopropyl Acetoxime. gin aha 


All ketoximes sustain an analogous transformation by the action of hydrochloric, 


KETONES. 203 


sulphuric or acetic acid. Thus, methyl-propyl-ketoxime yields acetopropylamine 
(Beckmann, 21, 2530) :— 


C,H,.C(NOH).CH, = C,H,.NH.CO.CH,. 


All bodies possessing the ketone group CO (or the aldehyde group), e¢. g., the 
ketonic acids and alcohols, react with hydroxylamine in a manner similar to that 
of the ketones. Some acid anhydrides, ¢.¢., phthalic anhydride (Berichée, 16, 
1780), do the same. This is not, however, the case with the lactones and alky- 
len oxides. The diketones, such as glyoxal, CHO.CHO, are capable of a double 
reaction with hydroxylamine, yielding compounds known as acetoximic acids or 
glyoximes. The ketones react more readily with phenylhydrazine, forming crystal- 
line compounds (the hydrazones) than with hydroxylamine (Berichte, 17, 576; 16, 
661; 20, 513). 

Boiling nitric acid converts the ketones into dinitroparaffins. In this reaction 
the nitro-groups attach themselves to the higher alkyl of the mixed ketones. The 
ketones (like the aldehydes, p. 191) form mercaptols with the mercaptans. 





The ketones cannot be directly oxidized. When they are boiled with K,Cr,O, 
and dilute sulphuric acid, they break up in such a manner that the CO group 
passes out in combination with the lower alkyl, thus producing an acid. Should 
the other higher alkyl chance to be of a primary character, it, too, will be oxidized 
to an acid :— 


CH % j ? fis 
CH,.CH,.CH. 7/9 + 39 = Hees +. CH,.CH,.CO.OH. 
‘Methyl Propyl Acetic wx€id. Propionic 
Ketone. peas 


When the higher radical is secondary, it first becomes a ketone, and this de- 
composes further :— 


(CH) CH Sco + 20 = CH,.CO.OH + (CH,),CO. 
Methyl Isopropyl Acetic Acid. ~ Acetone. 
etone. 


When the CO group is united to carbon atoms carrying an equal number of 
hydrogen atoms, it remains with the higher alkyl when decomposition occurs 
(Berichte, 15, 1194). For further details of the decomposition, see Berichte, 18, 
2266, and Ref. 181. 

To oxidize ketones, proceed as follows: dilute a mixture consisting of 1 molecule — 
ketone, I molecule K,Cr,O, and 4 molecules H,SO,, with 5-10 parts water, and 
heat the same in a large flask, provided with a long, upright glass tube serving 
as acondenser. The reaction is complete when the mixture assumes the pure, 
green color of chromium sulphate (compare Aumaden, 190, 349) :— 


K,Cr,0, + 4H,SO,4 = (SO,),Cr, + K,SO, + 4H,0 + 30. 


The acids produced are distilled over with water. 
A similar decomposition is sustained by the ketones when oxidized by free 
chromic acid, potassium permanganate, PbO,, etc. (Amnalen, 186, 257.) 


Dimethyl Ketone, C,H,O = (CH;),CO, Acetone. In addi- 


204 ORGANIC CHEMISTRY. 


tion to the general methods of formation, acetone is produced by 
heating chlor- and brom-acetol (p. 101) with water to 160°-180° :— 


CH,.CCl,.CH, + H,O = CH,.CO.CH, + 2HCl; 


_and also by the dry distillation of tartaric and citric acids, sugar, 
wood, etc. This accounts for its presence in crude wood spirit 
(p. 124). It is usually obtained by the dry distillation of calcium 
acetate (p. 187). It occurs, too, in small quantities in the blood 
and normal urine, while in the urine of those suffering from diabetes 
it is present in considerable amount. 


Of theoretical interest is its formation from {-chlor- and brom-propylene, 
. CH,.CBr:CH,, when these are heated with water to 200°, or dissolved in sul- 
phuric acid and boiled with water. We would naturally expect an alcohol, CH. 
C(OH):CH,, to be formed here, but a transposition of atoms occurs and acetone 
results (see p. 134). Acetone is similarly formed from allylene, CH,.C; CH, by 
action of sulphuric acid or HgBr, in the presence of water (p. 87). 


Acetone is a mobile, peculiar-smelling liquid, boiling at 56.5° 
and having a sp. gr. of 0.7920 at 20°. It is miscible with water, 
alcohol and ether. Calcium chloride or other salts set it free from 
its aqueous solution. ‘The compound it forms with primary sodium 
sulphite has one molecule of water, and consists of pearly scales, 
easily soluble in water. Excess of sodium sulphite or alcohol sepa- 
rates it from its solution. When in aqueous solution, sodium amal- 
gam converts it into isopropyl alcohol. The chromic acid mixture 
oxidizes it to acetic and formic acids, which, as a general thing, 
are still further oxidized to CO, and water :— 


CH,.CO.CH, ++ 30 = CH,,CO.OH + CHO.OH. 
Acetic Acid. Formic Acid. 


The ketones are similarly decomposed when their vapors are con- 
ducted over heated soda-lime. 


An aqueous acetone solution, mixed with KOH and an iodine solution, yields 
iodoform (p. 103). ‘This reaction (Lieben) serves to detect acetone even in pres- 
ence of alcohol (Berzchte, 13, 1004). All ketones containing the group CO.CH,, 
do the same (evichie, 14, 1948). In the presence of alcohol it is better to use an 
iodine solution and ammonia, for then the alcohol will not yield iodoform (Gun- 
ning, Berichte, 17, Ref. 503). According to the reaction of Weyl and Legal, 
sodium nitroprusside and sodium hydroxide impart a brown-red color in the pres- 
ence of acetone (Berichte, 17, Ref. 503, and 18, Ref. 195). PCI; and PBr, con- 
vert acetone into chlor- and brom-acetol (p. Ior). 





ACETONE SUBSTITUTION PRODUCTs result by the direct action of chlorine or 
bromine upon acetone and by various other methods. 
Monochloracetone, CH,;.CO.CH,Cl, is obtained by conducting chlorine into 


KETONES. 205 


cold acetone (Berichte, 19, Ref. 48), or by the action of hypochlorous acid upon 
monochlor- or monobrom-propylene :— 


CH,.CBr:CH, + CIOH = CH,.CO.CH,Cl + HBr. 


It is a liquid, insoluble in water; its vapors provcke tears. 

There are two possible Dichloracetones, C,H,Cl,O: (a) CH;.CO.CHCI, and 
(8) CH,Cl.CO.CH,Cl. The first is formed on treating warmed acetone with 
chlorine, and is obtained from dichloraceto-acetic ester, on boiling the same with 
hydrochloric acid. (Berichte, 15,1164.) It is an oily liquid, with a sp. gr. of 
1.236 at 21°, and boils at 120°. The @-dichloracetone is produced in the oxida- 
tion of dichlorhydrin, CH,Cl.CH(OH).CH,Cl (see glycerol), with potassium 
dichromate and sulphuric acid. (Berichte, 13, 1701.) It consists of rhombic 
plates, fusing at 45°, and boiling at 172°-174°. 

For other chloracetones, see Berichte, 20, Ref. 48. 

Symmetrical Tetrachloracetone, CHCl,.CO.CHCL, is readily obtained by the 
action of potassium chlorate and hydrochloric acid upon chloranilic acid (Beriche, 
21, 318) and triamidophenol (Berichte, 22, Ref. 666), or of chlorine upon the 
finest phloroglucin (Beriche, 22, 1478). It isa yellow oil. Under a pressure of 
725 mm. it boils at 180°. It combines readily with water to the hydrate C,H, 
Cl,O + 4H,0, crystallizing in large prisms, and melting at 48°. It unites to the 
corresponding acid with HCN (Serzchie, 22, Ref. 810). Bromine yields similar 
substitution products. 

Monobromacetone, CH,Br.CO.CH,, and Symmetrical Dibromacetone, 
CH,.Br.CO.CH,Br ( Berichte, 21, 3288) are oils. They can only be distilled under 
reduced pressure. 

Iodo-Acetone, CH,.CO.CH,I, is produced when iodine and iodic acid act 
upon acetone. It isa heavy oil with a disagreeable odor ( Berichze, 18, Ref. 330). 

$B-Di-iodoacetone, CH,I.CO.CH,I, forms when iodine chloride acts upon 
acetone. It fuses at 62° and decomposes about 120°. 

Liquid acetone-chloroform is produced by the action of chloroform and caustic 
alkali upon acetone, It boils at 170°. In moist air it passes into the isomeric solid 
A cetone-chloroform, (CH)-C(OH).CCl], (compare p. 202). This consists of crys- 
tals, melting at 97° and boiling at 167°. They have an odor like that of camphor. 
Aqueous alkalies convert it into oxyisobutyric acid, Two complex acids result in 
the presence of acetone ( Berichte, 20, 2449). 

Acetone-cyanhydrin, (CH,),.C(OH).CN, is obtained from acetone and CNH. 
It is a liquid, boiling at 120°. 

Hydrogen sulphide converts acetone into 7rithioacetone, (C,H,S),. This is 
analogous to trithioaldehyde. Colorless needles, melting at 24° and boiling at 230° 
(Berichte, 22, 2592). KMnO, oxidizes this compound to 7riacetone-trisulphone, 


(CH,),C¢ 30 ie C(CHy! >S0r This also results from the action of NaOH and 
CH,I upon trimethylene trisulphone (p. 193) (Berichte, 22, 2609; 23, 71). 





Hydroxylamine- or Oximido-Derivatives (p. 106 and p. 
202). Acetoxime, (CH;),C:N.OH, dimethylacetoxime, formed 
in the action of hydroxylamine upon acetone (p. 202) (Berichie, 
20, 1505), is a compound readily soluble in water, alcohol and 
ether. It fuses at 60° and boils at 135°. Boiling acids regenerate 
acetone and hydroxylamine. 


206 ORGANIC CHEMISTRY. 


Hypochlorous acid converts acetoxime into an ester, (CH;),.C:N.O.Cl. Thisis a 
liquid with an agreeable odor. It boils at 134°. It explodes when rapidly 
heated (Berichte, 20, 1505). 

The hydroxyl hydrogen present in this compound may be replaced by acid 
radicals through the agency of acid chlorides or anhydrides. With sodium alco- 
holate, the sodium derivative results, which yields the alkyl ethers, (CH,),C:N.OR, 
when acted upon by the alkylogens. On boiling these ethers with acids, acetone 
and alkylized hydroxylamines, NH,OR (Berichte, 16, 170), are produced. The 
higher acetoximes show a perfectly analogous deportment. 


Isonitroso-acetone, CH;.CO.CH:N.OH. This is obtained 
from the isonitroso-aceto-acetic ester (Berichte, 15, 1326). Nitrous 
acid converts aceto-acetic acid directly into isonitroso-acetone and 
carbon dioxide :— 


CH,.CO.CH,.CO,H + ON.OH = CH,.CO.CH(N.OH) + CO, + H,0. 


The isonitroso-derivatives of the higher acetones are made directly, after the 
same manner, from monoalkylized aceto-acetic acids and their esters (Berichte, 20, 


555) 


ZR at ZR 
CH,.CO.CHC €o, 37 + NO.OH = CH.,CO.CC¥ opg + COs + 120. 


The dialkylic aceto-acetic acids are not reactive (Berichte, 15, 3007). 
The isonitrosoketones are the direct product of the action of amyl nitrite, in 
presence of sodium ethylate or hydrochloric acid, upon the ketones. At times 


sodium ethylate and again hydrochloric acid gives the best yield (Berichte, 20, 2194; 
22, 526) :— 


CH,.CO.CH, + NO.O.C,H,, = CH,.CO.CH(N.OH) + C,H, ,.0H. 


An excess of amy] nitrite decomposes the isonitroso-compound. The isonitroso- 
group is replaced by oxygen and a-diketone componnes are produced at the same 
time (Berichte, 22, 527). 

Isonitrosoketones are also produced by the action of nitrogen trioxide upon the 
ketones (Berichte, 20, 639). 


The isonitroso-acetones are colorless, crystalline bodies, readily 
soluble in alcohol, ether and chloroform; but, as a general thing, 
they dissolve with difficulty in water. They impart an intense 
yellow color to their alkaline solutions, and with phenol and sul- 
phuric acid yield a yellow coloration, but not the nitroso-reaction 
(see p. 107). When boiled with concentrated hydrochloric acid 
they lose hydroxylamine. : 


The isonitroso-group of the isonitroso-ketones can be split off and replaced by 
oxygen, The result will be diketo-compounds, CO.CO. This transformation may 
be effected by the action of sodium bisulphite, and subsequent boiling of the result- 
ing imidosulphonic acids with dilute acids ( Berichze, 20, 3162). The same effect is 
obtained by directly boiling the isonitrosoketones with dilute sulphuric acid ( Berichze, 
20, 3213). Nitrous acid sometimes produces the decomposition even more readily 
( Berichte, 22, 532). 


KETONES. 207 


Isonitroso-acetone, CH;.CO.CH(N.OH), is very readily soluble 
in water; crystallizes in silvery, glistening tablets or prisms; fuses 
at 65°, and decomposes at higher temperatures, but may be volatil- 
ized in a current of steam. 


By the action of sodium alcoholate upon benzylchloride we get the benzyl- 
ether, which is isomeric with benzyl-isonitroso-acetone, obtained from benzyl- 
aceto acetic acid :— 


rs C 7 H 7 
CH,.CO.CH:N.O.C,H, and CH,.CO.C 
\N.OH. 
Isonitrosoacetone-benzyl Ether. Benzyl-isonitrosoacetone. 


This is proof sufficient of the presence of the oximid-group N.OH in the isoni- 
troso compounds (Berichte, 15, 3073). For the.salts of the isonitrosoketones con- 
sult Berichte, 16, 835: ' 

Dehydrating agents, like acetic anhydride, convert the isonitrosoketones into 
acidyleyanides (Berichte, 20, 2196). 

When the isonitroso-acetones are reduced with tin and hydrochloric acid they 
yield peculiar bases, called Aetines (C,H, N,, ketine, C,H, ,N,., dimethyl ketine). 
Phenylhydrazine (2 mols.) converts the isonitrosoketones into osazones, @. £5 
acetone-osazone, CH, -C(N,H.C,H,).CH(N,H.C,H,). 

Any further action of hydroxylamine (or its HCl salt, Berichte, 16, 182) 
upon isonitroso-acetone (or upon a-dichloracetone, CH,.CO.CHC1,) leads to a 
replacement of the ketone oxygen and the formation of 

Acetoximic Acid, CH,.C(N.OH).CH(N.OH), or Methylglyoxime, a deri- 
vative of glyoxime, CH(N.OH).CH(N.OH), (see p. 202) obtained from glyoxal, 
CHO.CHO. The dialkyl. glyoximes, like CH,.C(N.OH).C(N.OH).CH,, dimethyl- 
. glyoxime, are similarly derived from the higher isonitroso-ketones. The glyoximes 
are solid, crystalline bodies, which dissolve with difficulty in water, and sublime 
without decomposition. Methyl glyoxime melts at 153°; methyl.ethyl glyoxime at 
170°. Glyoxime and methyl glyoxime show an acid reaction, and dissolve in 
alkalies without imparting color, because the hydrogen of the CH-group is 
replaced. The dialkylic glyoximes, on the other hand, are insoluble in alkalies 
and do not yield salts ( Berichée, 16, 180, 506, and 2185). 

Di-isonitroso-acetone, CH(N.OH).CO.CH(N.OH), is formed when nitrous acid 
acts upon acetone-dicarboxylic acid. A crystalline compound, melting at 144°. 
The acid solution rapidly decomposes on heating. It forms crystalline, yellow 
salts with alkalies (Berichte, 19, 2465). 

Hydroxylamine converts this compound into 777-dsonitroso-propane, CH(N.OH). 
C(N.OH).CH(N.OH). This crystallizes from water and alcohol in colorless 
needles, melting at 171° ( Berichte, 21, 2989). 

For the compounds of acetone and isonitroso-acetone with phenylhydrazine see 
_ the latter and Berichte, 11, 2995 ; 22,528. 

Condensation Products.—By the action of dehydrating agents (H,SO,, burnt 
lime, zinc chloride, hydrochloric acid) and sodium, acetone (like aldehyde, p. 195) 
loses a molecule of water, and condenses to complex molecules. Mesityl oxide, 
phorone and mesitylene are produced in this way :— 


2C,H,O = C,H,,0 + H,O 
Mesityl Oxide. 
3C,H,O = C,H,,0 + 2H,0. 
Ph C 


orone, 


208 ORGANIC CHEMISTRY. 


To prepare mesityl oxide and phorone, saturate acetone with HCl and let stand 
for some time, then treat the product with aqueous potash. On diluting with water 
an oily liquid separates, consisting of mesityl oxide and phorone, which are sepa- 
rated by fractional distillation (4Azza/en, 180, 4). 

Mesityl Oxide, C,H,,O, is a mobile liquid, smelling like peppermint and 
boiling at 130°. It acts like acetone; it takes on hydrogen, combines with sodium 
bisulphite and forms a chloride, C,H, ,Cl,, with PCl,. When boiled with dilute 


_ 


: 
; 


sulphuric or hydrochloric acid mesityl oxide decomposes into two molecules of ; 


acetone. It combines directly with Br, and HI. ae 

Mesitonic or dimethyl-levulinic acid, C,H, .O,, isa derivative of mesityl oxide 
(Berichte, 21, Ref. 643). 

Phorone, C,H,,0, crystallizes in large, yellow prisms, melting at 28° and 
boiling at 196°. Boiled with dilute sulphuric acid it breaks up into 3 molecules 
of acetone (mesityl oxide appears as an intermediate product). With bromine it 
forms a tetrabromide, fusing at 86°. 

Acetone condenses to mesityl‘oxide and phorone in the same manner that acet- 
aldehyde becomes crotonaldehyde (p. 194). Their structure probably agrees with 
the formulas (compare Berichte, 14, 253) :— 


CH; \cH = CH 


CHs Sc = CH.CO. CH, and Gyis~ Sco. 
bien jl 3 \CH = CH” 
Mesityl Oxide. CH, 7 


Phorone. 


Both mesityl oxide and phorone unite with hydroxylamine, yielding corres- 
ponding acetoximes ( Berichte, 16, 494). 
Mesitylene, CyH,.,, is produced when acetone is distilled with concentrated 
sulphuric acid :— 
3C,H,O = C,H,, + 3H,0. 


This is a derivative of benzene (see this). It is also produced from mesity] 
oxide and phorone, through the action of sulphuric acid, but if phorone be heated 
with P,O,, pseudo-cumene is obtained. Other ketones, when acted upon with 
sulphuric acid, also yield analogous benzene derivatives. 





Acetone Bases.—When ammonia acts on acetone a condensation of two and 
three molecules occurs, giving rise to the bases: Diacetonamine and Tri- 
acetonamine :— 


2C,H,O + NH, = C,H,,NO + H,O. 
Diacetonamine. 


Triacetonamine, 


Diacetonamine is a colorless liquid, not very soluble in water. When dis- 
tilled it decomposes into mesityl oxide and NH, ; conversely mesityl oxide and 
NH, combine to form diacetonamine. It acts strongly alkaline and is an amide 
base, forming crystalline salts with one equivalent of acid. If potassium nitrite 
be allowed to act on the HCl-salt dzacetone alcohol, (CH,),C(OH).CH,.CO.CH,, 
results; this loses water and becomes mesityl oxide. 

Triacetonamine crystallizes in anhydrous needles, melting at 39.6°. With one 
molecule of water it forms large quadratic plates, fusing at 58°. It is an imide 


ACETONE HOMOLOGUES. 209 


base (p. 167) with feeble alkaline reaction ; potassium nitrite converts its HCl salt 
into the nitroso-amine compound, C,H,.(NO)NO, which fuses at 73° and passes 
into phorone when boiled with caustic soda. Hydrochloric acid regenerates tri- 
acetonamine from the nitroso-derivative. k 
Diacetonamine and triacetonamine are intimately related to mesityl oxide and 
phorone (p. 208); their structure probably corresponds to the formulas :— 


(CH,),C—CH, 

CH, NH; St oo 
C and NH Co. 
CH, / \CH,.CO.CH, See 
pli PEN ES, CH,),C—CH, 
riacetonamine, 


By the oxidation of diacetonamine with a chromic acid mixture (p. 203) we 
get amido-isobutyric acid, (CH,),C(NH,).CO,H, and amido-isovaleric acid, 
(CH,)..C(N H,).CH,.CO, H. By the addition of 2H to triacetonamine, converting 
the CO group into CH.OH, there results an a/kamine, C,H,,NO, which may be 
viewed as tetramethyl oxypiperidine. By the abstraction of water from this the 
base C,H,,N, triacetonine, results. This approaches tropidine, C,H,,N, very 
closely (erichte, 16, 2236; 17, 1788). 





ACETONE HOMOLOGUES. 


Methyl. ethyl Ketone, Cr = CO = = C,H,O, is formed :— 


I. By oxidation of secondary butyl alcohol (p. 129). 
2. By action of zinc ethide on acetyl chloride or zinc methyl upon propionyl 
chloride. 
3. By distillation of a mixture of calcium propionate and acetate. 
4. By oxidation of methyl-ethyl oxyacetic acid and from methyl aceto-acetic ester 
(see this 
MehyLethel ketone is an agreeably smelling liquid, having a specific gravity 
of 0.812 at 13°, and boiling at 81°. It combines with the primary sulphites. 
When oxidized with chromic acid it yields two molecules of acetic acid. Its 
acetoxime, CH;.C(N.OH).C,H, (p. 205), is liquid and boils at 153°. The iso. 
nitroso compound, CH, 60’ ‘C(N, OH).CH,, csonitroso-methyl acetone, crystallizes 
in pearly tables, melting at 74°, and boiling at 185°. It is converted into diacetyl, 
CH,.CO.CO.CH,, by the replacement of the N. OH-group. Dimethyl glyoxime, 
CH, 3-C(N.OH). C(N. OH).CH, (p. 207) consists of colorless crystals, which melt 
on rapid heating. 
Ketones, C,H,,0:— 


catis’s pee) CH;\ co CH, Co. 
HyZ C,H, C,H, / 
Dicin —— eae eat a Methyl-isopropyl Ketone. 
tor? B.P.1 ‘B. P. 96°. 


These are produced according to the methods generally employed for making the 
ketones. When boiled with a chromic-acid mixture, they decompose according to 
the rules of oxidation (p. 203), and also otherwise exhibit all the usual ketone 
reactions. 

Diethyl Ketone, called Propione, because obtained by the distillation of cal- 


18 


210 . ORGANIC CHEMISTRY. 


cium propionate, is obtained from carbon monoxide and potassium ethylate (p. 
187). It is distinguished from the two methyl propyl ketones by not yielding 
compounds with the primary alkaline sulphites. Amyl nitrite converts it into 
isonitroso-diethyl-ketone, CH,.CH,.CO.C(N.OH).CH, (Berichte, 22, 528). 

Mention may here be made of the following higher ketones :— 

Methyl-tertiary Butyl Ketone, C,H,,0 = CH =* SCO, with . the tertiary 
butyl group (CH,),C, called Pinacoline, is obtained from the hexylene glycol 
termed pinacone, on warming with hydrochloric or dilute sulphuric acid (p. 202) ; 
also by the action of zinc methyl on trimethyl acetyl chloride. It boils at 106°, 
Its specific gravity at 0° is o. 823. When oxidized with chromic acid it decom- 
poses into acetic and trimethyl acetic acids. Nascent hydrogen converts it into 
pinacolyl alcohol (p. 129). 

Dipropyl Ketone, C,H,,O = (C,H,),CO, Butyrone, i is the principal sdodiat 
of the distillation of calcium butyrate. It boils at 144°, and at 20° has a specific 
gravity equal to 0.8200, A chromic acid mixture changes it to butyric and 
propionic acids. CH 

Methyl Hexyl Ketone, C,H «00, Methyl cenanthol, is formed by the 


oxidation of the corresponding octyl alcohol, and the distillation of calcium cenan- 
thylate and acetate. It boils at 171°; sp. a 0.818. It yields acetic and caproic 
acids when oxidized. He. 

-Methyl-nonyl Ketone, C,,H,,O0 = C1 H, SF ped is the chief constituent 


of oil of rue (from Ruta graveolens); it may be extracted from this by shaking 
with primary sodium sulphite. It is produced in the distillation of calcium 
caprate with calcium acetate. It is a bluish, fluorescent oil, which on cooling 
solidifies to plates, melting at + 13°, and boiling at 225°. When oxidized it yields 
acetic and pelargonic (C,H,,O,) acids. 

The following additional ketones have been obtained by distilling the barium 
salts of fatty acids with barium acetate (Berichze, 15, 1710) :-— 





CHO = queda CO.CH, from undecylic acid. a ake 
C0 = CH CO.CH, - lauric oe 28° 
C,,H,,0 = C..H..CO.CH, “« tridecylic “ au SF gg 
C\;H0 = C,,H,,.CO.CH, “ myristic «“ 22 |} 39° 
C,,H,.0 = C,,Hy9.CO.CH, “ pentadecatoic acid. & =} 43° 
C,,H,,0 = C,,H,,.CO.CH, ‘“ palmitic acid. wo | 48° 
C,,H,,0 = C,,H,,.CO.CH, “ margaric ‘ 3 <a 
C,,H,,0 = C,,H,,.CO. CH, a gat. s | 55.5° 


When the salts of the higher fatty acids are distilled alone (p. 187) the simple 
ketones (with two similar alkyls) result :— 


C,,H..0 = (C5H;,),CO caprone from caproic acid. = f 14.6° 
cay = teehee prem np “ cenanthylic acid. x, 30° 
= caprylone ‘“ caprylic Fie ee 0° 
Ci,H,,0 = (C.H,.),CO sents <6 ene O26 BE 38° 
C,H yO = (C, a)gCO laurone “ lauric “« £2 1 69° 
7H,,0 = aCe myristone “ myristic “ wo | 76° 
C,,H,0 = (C,;H,,),CO palmitone “ palmitic = 3 83° 
C,;H,,O = (C,,H,,),CO stearone ‘stearic Pe UL Oee 





es corresponding oe are obtained when these ketones are reduced ae 
p. 76 











MONOBASIC ACIDS. : 211 


MONOBASIC ACIDS. 


The organic acids are characterized by the atomic group, CO. 
OH, called cardoxy/. The hydrogen of this can be replaced by 
metals, forming salts (see p. 115). These organic “acids may be 
compared to the analogously constituted sulphonic acids, containing 
the sulpho-group, SO,.OH. 

The number of carboxy! groups present in them determines their 
basicity, and distinguishes them as mono-, di-, tri-basic, ete., or as 
mono-, di- and tri- -carboxylic acids :— 


/CO,H 
CH,.CO,H en 4 Sat C,H,—CO,H 
3 2 2\ CO A H 3 co: 2 = 
Acetic Acid. Malonic Acid. T 
Monobasic. . Dibasic. ricarballylic Acid, 
Tribasic. 


We can view the monobasic saturated acids as Combinations of 
the carboxyl group with alcohol radicals; they are ordinarily 
termed fatty acids. The unsaturated acids of the acrylic acid and 
propiolic acid series, corresponding to the unsaturated alcohols, are 
derived from the fatty acids by the exit of two and four hydrogen 
atoms. 

The most important and general methods of obtaining the 
monobasic acids are :— 

1. Oxidation of the primary alcohols sii aldehydes :— 


CH,.CH,.OH + 0, =CH,.CO.OH + H,0, 


Ethyl Alcohol. Acetic Acid. 
_» CH,.cCOH +0 =CH,.CO.OH. 
Aldehyde. ‘Acetic Acid, 


2. The transformation of the cyanides of the alcohol radicals 
(the so-called nitriles), by heating them with alkalies or dilute 
mineral acids. The cyanogen group changes to the carboxyl group, 
while the nitrogen separates as ammonia :— 


_» CH,.CN + 2H,O +HCl = CH,.CO,H +NH,Cl and 
CH,.CN + H,O +KOH = CH,.CO,K +NH,. 


The change of the nitriles to acids is, in many instances, most advantageously 
executed by digesting the former: with sulphuric acid (diluted with an equal 
volume of water); the fatty acid will then appear as an oil upon the top of the 
solution. (Berichte, 10, 262.) 

To convert the nitriles directly into esters of the acids, dissolve them in alco- 
hol, and conduct HCl into this solution, or warm the same with sulphuric acid. 
(Berichte, Q, 1590.) 

3. Action of carbon dioxide upon sodium alkyls (see p. 178):— | 


— C,H,Na -+ CO, = C,H,.CO,Na. 
4. Action of carbon monoxide upon the sodium alcoholates heated to 160°—200°, 
al Na + CO C,H,.CO,Na. 


.O 
Be sal rea acdaal Propionate. 


wr - ORGANIC CHEMISTRY. ° 


Formic acid results when the caustic alkalies are employed :— 
HONa + CO = H.CO,Na. 


Sodium Formate. 


Usually, the reaction is very incomplete, and is often accompanied by secondary 
reactions, resulting in the formation of higher acids. (Ammnalen, 202, 294.) 


5. By the action of phosgene gas upon the zinc alkyls. At first 
acid chlorides are formed, but they subsequently yield acids with 


water :— 
Zn(CH,), + 2COCI, = 2CH,.COC] + ZnCl, and 
Acetyl Chloride. : 
CH,.CO.Cl+ H,O =CH,.CO.OH + HCL. 
Acetic Acid. 


6. The following is a very interesting and a commonly applied method for the 
synthesis of the fatty acids. By the action of sodium upon acetic esters, the 
so-called aceto-acetic esters are produced, in which, by the aid of sodium and alkyl 
iodides, one and two hydrogen atoms can be replaced by alkyls (R) (see aceto- 
acetic esters) :— 


CH,.CO.CH,.CO.0.C,H, yields {eH COCR COOC.” and 


CH,.CO.C(R,).CO.0.C,H,. 


Sodium alcoholate decomposes these alkylic esters (or alkyl ketonic acids) in 
such a manner, that the group CH,.CO splits off and the fatty acid esters are pro- 
duced, but are at once saponified, yielding salts :— 


CH,.CO.CH(R).CO.O.C,H, yields CH,(R).CO.OH 
CH,.CO.C(R,).CO.0.C,H, “+ ~~CH(R,).CO.OH. 


We may regard the acids thus obtained as the direct derivatives of acetic acid, 
CH,.CO.OH, in which one and two hydrogen atoms of the CH, group are replaced 
by alkyls; hence, the designations, methyl and dimethy] acetic acid, etc. :— 


CH,.CH, CH,.C,H, CH(CH,), 
O.OH . CO.OH CO.OH. 
Methyl Acetic Acid Ethyl Acetic Acid Dimethyl Acetic Acid 
or Propionic Acid. or Butyric Acid. or Isobutyric Acid. 


Very many fatty acids have been prepared in the above way (first by Frankland 
~and Duppa). 


7-_ From the dicarboxylic acids, in which the two carboxyl groups 
_ are in union with the same carbon atom. On the application of 
heat, these sustain a loss of carbon dioxide :— 


CO,H 
CH. CoH = CH,.CO,H + CO. 
Malonic Acid. Acetic Acid. 


In malonic acid, as in aceto-acetic acid (its esters, see above), the hydrogen 

atoms of the group CH, may be replaced by alkyls; the resulting alkylic malonic 
acids, when heated, sustain a loss of carbon dioxide, and form alkylic acetic acids. 
_ (Berichte, 13, 595-) ; 


MONOBASIC ACIDS. 213 


The isomerisms of the monobasic acids are influenced by the 
isomerisms of the hydrocarbon radicals, to which the carboxyl 
group is attached. ‘There are no possible isomerides of the first 
three members of the series C,,H,,O, :— 


HCO,H CH,.CO,H C,H,.CO,H. 
Formic Acid. Acetic Acid. Propionic Acid. 


Two structural cases are possible for the fourth member, C,H,O, : 


CH,.CH,.CH,.CO,H and (CH,),.CH.CO,H. 
Butyric Acid. sobutyric Acid. 


Four isomerides are possible with the fifth member, C;H,,O, = 
C,H,.CO,H, inasmuch as there are four butyl, C,H,, groups, etc. 





The hydrogen of carboxyl replaced by metals yields salts, and 
when replaced by alkyls, compound ethers or esters are formed 


(see p. 146). 
CH,.CO..H + KOH  =CH,.CO,K + H,0. 


Potassium Acetate. 
CH,.CO.OH + C,H,.0H = CH,.CO.0.C,H, + H,0. 
Ethyl Acetic Ester, 
The residues combined in the acids with hydrogen are termed 
acid radicals :— 
CH,.CO— CH,.CH,.CO— CH,.CH,.CH,.CO— 
Acetyl. Propionyl. Butyryl. 
These are capable of entering various combinations. Their halo- 
gen derivatives, or the haloid anhydrides of the acids, like 
CH,.CO.Cl CH,.CH,.CO.Cl. 
Acetyl Chloride. Propionyl Chloride. 


are produced when the halogen derivatives of phosphorus act upon 
the acids or their salts (p. 92) :— 


CH,.CO.OH + PCI, = CH,.CO.Cl + PCI,O + HCl. 


The aldehydes are the hydrides of these acid radicals, and the 
ketones their compounds with alcohol radicals :— 
CH,.CO.H CH,.CO CH. 
Acetaldehyde. Acetone. 
The conversion of the acids into aldehydes and ketones has 
already received attention (pp. 188 and 200). 
When an atom of oxygen unites two acid radicals we obtain 
oxides of the latter, or the acid anhydrides :— 


214 ORGANIC CHEMISTRY. 
eee Cut On 
Oe OEE oe H,O.OK = ~7,;* 
2H,O0.Cl + C,H,0.0K = CiH.O/ 


Acetyl Chloride. Potassium Acetic 
Acetate. Anhydride. 


O + KCl. 


The amides of the acids appear by the union of the acid radicals 
with the amido group :— 


C,H,0.Cl + NH, =C,H,0.NH, + HCl. 


Acetamide. 


Sulphur Compounds, corresponding to the acids and their anhy- 
drides, exist :— 


CHO 
C,H,0.SH CH’o>S 
Thioacetic Acid. Acetyl Gulchide. 


Furthermore, substituted acids are obtained by the direct substi- 
tution of halogens for the hydrogen of the alkyls present in the 
acids :— 

CH,Cl.CO,H CCl,.CO,H. 


Monochlor-acetic Acid. Trichlor-acetic Acid. 


The fluorine derivatives (their esters) appear to form when HF! acts upon the 
esters of the diazo-fatty acids (see these): CN,HCO,H + HFl = CH,F1.CO,H 
+N,. 

The nitro-derivatives of the fatty acids are prepared by treating some of the 
iod acids with silver nitrite (see Nitropropionic acid), or by the action of nitric 
acid upon the fatty acids containing a tertiary CH-group (Berichte, 15, 2318). 

Lsonitroso-derivatives are obtained from the ketone acids by the action of hy- 
droxylamine (p. 203) .— 


_ CH,.CO.CO,H + H,N.OH — CH,.C(N.OH).CO,H + H,0. 


Acetyl-carboxylic Acid. a-Isonitroso-propionic Acid. 


In the same manner the {-isonitroso-acids are produced from the aceto-acetic 
esters (and their alkyl derivatives) by means of H,N.OH and saponification with 
alkalies (Berichte, 16, 2996) :-— 


CH,.CO.CH,.CO,R yields += CH,.C(N.OH).CH,.CO,H. 


Aceto-acetic Ester. B-Isonitroso-butyric Acid. 


Alcoholic sodium and NaNO, acting on the monoalkylic aceto-acetic esters, pro- 
duce the a-isonitroso-acids (Berichte, 15, 1057; 16, 2180) :-— 


CH,.CO.CHR.CO,R yields R.C(N.OH).CO,H. 


By reduction with tin and hydrochloric acid these derivatives become amido- 
acids. They do not give the nitroso-reaction with phenol and sulphuric acid 


(p. 107). 


Of the decomposition reactions of the acids those may be men- 
tioned again which lead to the formation of hydrocarbons. 
1. The distillation of the alkali salts with alkalies or lime (see 


ps9) :— 
CH,.CO,K + KOH = CH, + CO,K,. 


FATTY ACIDS. 215 


2. The electrolysis of the alkali salts in concentrated aqueous 
solution ; hydrogen separates upon the negative . pole, and carbon 
dioxide and the hydrocarbon upon the positive (see p. 71) :— 


2CH,.CO,K + HjO=C,H, + CO,K, + CO, + H,. 


It may not be amiss here to direct attention to the successive reduction of the 
higher into lower fatty acids. It serves as an excellent mode of preparing the 
latter. To this end the acid is first converted into its amide, and this, by the reac- 
tion of Hofmann (p. 159) (action of Br and NaOH), is changed into the next 
lower amine. The further action of bromine and sodium hydroxide changes the 
amine into a nitrile, and the latter is then readily converted into the corresponding 
acid-amide; from which again by the further action of Br and NaOH the next 
lower amine results (Berichte, 19, 1433) :— 


C,,H,,0, C,,H,,.CO.NH, C,,H,,NH, 
Myristic Acid. Myristic Amide. Sitiecplnmine: 


C,,H.,CN C,,H,;-CO.NH,, etc. 
Tridecyl "Nitrile. Tridecylamide. 





1. FATTY ACIDS, CnH,n0,. 


Formic Acid CHO, =—HCOw 
Acetic 5 C,H,0, = CH, CO,H 
Propionic ‘‘ C;H,O, = C,H;.CO,H 
Butyric sk C,H.O; = CH. Coe 
Valeric « C,;H,O, = C,H,.CO,H 
Caproic os CH Os = C.tia, CO,H 
CEnanthylic wed C.HyOy = CHa. CO,H 
Caprylic Acid C,H,O, +16°* Pelargonic Acid C,H,,O, + 12° 
Capric a c: HO, 31.4°  Undecylic: “ C,,H,,0, 28° 
Lauric “ C,,H,,0, 43-69 Tridecylic “ C,H,O, 40.5° 
Myristic * CjH,O, . 54° Pentadecatoic“ C,H,O, 51° 
Palmitic “* C,H,.O, 62° Margaric Bs Ge Oy 1 60? 
Stearic wc’ CHO, 65° Nondecylic “ C,H,.O,  65.5° 
Arachidie ©  (C,H,O, 75° Medullic me AL AOL 
Behent: =“ “CHO, > — 0 CHO 
Lignoceric “ C,,H,O, 80.5° Hyzenic « - C,H,O,  -77° 
Cerotic Acid C,,H;,0, 79° 
Melissic “ CoHg0, 91° 


Theobromic“ (?) (C,,H,,.0, 72° 


_The acids of this series are known as the fatty acids, because their 
higher members occur in the natural fats, and the free acids (ex- 
cepting the first members) resemble fats. The latter are ester-like 





* Melting points. 


216 ORGANIC CHEMISTRY. 


compounds of the fatty acids, amd are chiefly esters of the trihydric 
glycerol. On boiling them with caustic potash or soda (saponifica- 
tion) alkali salts of the fatty acids are formed, and from these the 
mineral acids release the fatty acids. 

The lower acids (with exception of the first members) are oily 
liquids; the higher, commencing with capric acid, are solids at 
ordinary temperatures. ‘The first can be distilled without decom- 
position ; the latter are partially decomposed, and can only be dis- 
tilled without alteration in vacuo. All of them are readily volatil- 
ized with steam. Acids of like structure show an increase in their 
boiling temperatures of about 19° for every--CH,. It may be 
remarked, in reference to the melting points, that these are higher 
in acids of normal structure, containing an even number of carbon 
atoms, than in the case of those having an odd number of carbon 
atoms (see above). The dibasic acids exhibit the same characteristic. 
As the oxygen content diminishes, the specific gravities of the acids 
grow successively less, and the acids themselves at the same time 
approach the hydrocarbons. ‘The lower members are readily solu- 
ble in water. The solubility in the latter regularly diminishes with 
increasing molecular weight. All are easily soluble in alcohol, and 
especially so in ether. Their solutions redden blue litmus, Their 
acidity diminishes with increasing molecular weight; this is very 
forcibly expressed by the diminution of the heat of neutralization, 
and the initial velocity in the etherification of the acids. 


A mixture of the volatile acids can be separated by fractionation only with great 
difficulty. It is advisable to combine this with a partial saturation. For instance, 
a mixture of two acids, ¢.g., butyric and valeric acids, is about half saturated with 
potash, and the aqueous solution distilled as long as the distillate continues to re- 
act acid. If enough alkali had been added to saturate the less volatile acid (in 
this case valeric), the more volatile compound (butyric acid) will be almost the 
sole constituent of the distillate. Should the contrary be the real condition, the 
distillate is subjected again to the same operation. The residue after distillation 
is a mixture of salts of both acids. This is true when the quantity of alkali was 
more than sufficient for the saturation of the less volatile acid (valeric). The acids 
are liberated from their salts by distillation with sulphuric acid, and the distillate 
again submitted to the process described above. 

To be assured of the purity of the acids, the aqueous solution of their alkali salts 
is fractionally precipitated with silver nitrate. The less soluble silver salts (of the 
higher acids) are the first to separate out. 





(1) Formic Acid, CH,O, = HCO.OH. 

Formic acid (Acidum formicum) is found free in ants, in stinging 
nettles, in shoots of the pine, in various animal secretions, and may 
be obtained from these substances by distilling them with water. It 
is produced artificially according to the usual methods (p. 211): by 


FATTY ACIDS. 217 


the oxidation of methyl alcohol ; by heating hydrocyanic acid with 
alkalies or acids :— 


HCN ++ 2H,O — HCO.OH + NH,; 
and on boiling chloroform with alcoholic potash :— 
CHCl, + 4KOH = HCO.OK + 3KCl + 2H,0. 


Worthy of mention, is the direct production of formates by the 
action of CO upon concentrated potash at 100°. The reaction 
occurs more easily if soda-lime at 200°—220° (Berichte, 13, 718) 
be employed :— 

CO + NaOH = HCO.ONa; 


also by letting moist carbon dioxide act upon potassium :— 
3CO, + 4K + H,O — 2HCO.OK + CO,K,; 
potassium carbonate is produced at the same time. 


Formates are also formed in the action of sodium amalgam upon a concentrated 
aqueous ammonium carbonate solution, or with the same reagent upon aqueous 
primary carbonates :—CO,KH + H, = HCO,K + H,O; likewise on boiling 
zinc carbonate with caustic potash and zinc dust. In all these methods it is the 
nascent hydrogen which, in presence of the alkali, unites itself to carbon 
dioxide :— 

CO, + 2H + KOH = HCO.OK + H,0O. 


The most practical method of preparing formic acid consists in 
heating oxalic acid :— 


C,0,H, = HCO.OH + CO,. 


This decomposition is accelerated by the presence of glycerol, be- 
cause free oxalic acid sublimes with partial decomposition :— 


Crystallized oxalic acid (C,O,H, + 2H,O) is added to moist concentrated 
glycerol and the whole heated to 100-110°. Carbon dioxide is evolved and 
formic acid distils over. As soon as CO, ceases generating, add more oxalic 
acid and heat anew, when a concentrated formic acid passes over. Continued 
addition of oxalic acid and the application of heat furnish a regular 56 per cent. 
aqueous formic acid. The mechanism of the reaction is this: on heating crys- 
tallized oxalic acid it parts with its water of crystallization and unites with the 
glycerol to form glycerol formic ester (see p. 135) :— 


OH OH 
CH {oH + C,0,H, =C,H, {OH -++ CO, + H,0. 
_ (OH O.COH 


On further addition of oxalic acid the latter again breaks up into anhydrous | 
acid and water, which converts the glycerol formic ester into glycerol and 
formic acid :— 


C,H,(OH),.(0.CHO) + H,O =C,H,(OH), + CHO.OH. 


218 ORGANIC CHEMISTRY. 


The anhydrous oxalic acid unites anew with the regenerated glycerol to produce 
the formic ester.. The quantities of acid and water distilling over in the latter 
part of the operation correspond to the equation :— 


C,H,0, + 2H,O = CH,O, + CO, + 2H,0. 


To obtain anhydrous acid, the aqueous product is boiled with PbO and the 
beautifully crystallized lead salt decomposed, at 100°, in a current of hydrogen 
sulphide. If anhydrous acid be employed in the reaction a 95-98 per cent. 
formic acid can be immediately obtained. Boron trioxide will completely dehy- 
drate this ( Berichte, 14, 1709). 


Anhydrous formic acid is a mobile liquid, with a specific gravity 
of 1.223 at o° and boils at 99°. It becomes crystalline at 0°, and 
fuses at +8.6°. It has a pungent odor (from ants) and causes 
blisters on the skin. It mixes in all proportions with water, alco- 
hol and ether, and yields the hydrate 2CH,O, + H,O, which boils 
at 105° and dissociates into formic acid and water. Concentrated, 
hot sulphuric acid decomposes formic acid into carbon monoxide 
and water: —CH,O, —= CO + H,O. A temperature of 160° suf- 
fices to break up the acid into carbon dioxide and hydrogen. The 
_» -Same change may occur at ordinary temperatures by the action of 
pulverulent rhodium, iridium and ruthenium, but less readily 
when platinum sponge is employed. 

According to its structure, HCO.OH, formic acid is also an alde- 
hyde, as it contains the group CHO; this would account for its 
reducing property, its ability to precipitate silver from a hot neu- 
tral solution of silver nitrate, and mercury from mercuric nitrate, 
the acid itself oxidizing to carbon dioxide. 


The formates, excepting the sparingly soluble lead and silver salts, are readily 
soluble in water. 
The alkali salts deliquesce in the air; heated carefully to 250° they become 


oxalates :— 
CO.OK 
ig 2CHO.OK = | + H,. 
CO.OK 


By strong ignition of the resulting oxalate with an excess of alkali it decom- 
poses with the formation of a carbonate and the liberation of hydrogen. These 
reactions serve for the preparation of pure hydrogen. The ammonium salt, 
CHO.O.NH,, decomposes into hydrogen cyanide and water when heated 
to 180°:— 

CHO,.NH, = CNH + 2H,0. 

The lead salt, (CHO,),Pb, crystallizes in brilliant needles, soluble in 36 parts of 
cold water. The silver salt, CHO,Ag, is obtained by the double decomposition 
of the alkali salt with silver nitrate. It is precipitated in the form of white needles 
that rapidly blacken on exposure to light. When heated, it decomposes into sil- 
ver, carbon dioxide and formic acid :— 

2CHO,Ag = 2Ag + CO, + H.CO,H. 


The mercury salt sustains a similar decomposition. 


FATTY ACIDS. 219 


Monochlorformic acid, CC1O.OH, is regarded as chlor-carbonic acid. 


(2) Acetic Acid, C,H,O, = CH;.CO,H. 

This acid (Acidum aceticum) is produced in the decay of many 
organic substances and in the dry distillation of wood, sugar, tar- 
taric acid, and other compounds. It may be synthetically prepared: 
1. By the action of carbon dioxide upon sodium methyl :— 


_> CH,iNa + CO, =CH,.CO,Na; 


2. By heating sodium methylate with carbon monoxide to 100° :— 


oak CH,.ONa + CO = CH,.CO,Na; 


3. By boiling methyl cyanide (acetonitrile) with alkalies or acids 


(p. 211) :— - 
RY, CH,.CN + 2H,O=CH,.CO,H + NH,. 


It is made on a large scale by the oxidation of ethyl alcohol, and 
by the distillation of wood. 


(1) In the presence of platinum sponge, the oxygen of the air converts ethyl alco- . ~ 
hol into acetic acid; this occurs, too, in the acetic fermentation induced by a minute 
organism (A/ycoderma aceti). The process is applied technically in the manufac- 
ture of vinegar (p. 220). Dilute aqueous solutions of whiskey, wine or starch mash 
are mixed with vinegar and yeast, and exposed to the air at a temperature of 
20-40°. To hasten the oxidation, proceed as follows: Large, wooden tubs are 
filled with shavings previously moistened with vinegar, then the diluted (10 per 
cent.) alcoholic solutions are poured upon these. The lower part of the tub is 
provided with a sieve-like bottom, and all about it are holes permitting the 
entrance of air to the interior. The liquid collecting on the bottom is run 
through the same process two or three times, to insure the conversion of all the 
alcohol into acetic acid. It is very evident that this process is based on accelerated 
oxidation, due to the increased exposure of the liquid surface to the air. 

Pasteur contends that the presence of porous substances von shavings) is not 
required in the vinegar manufacture, all that is necessary being the exposure of 
the alcoholic fluid, mixed with MZycoderma aceti, to the air. (French or Orlearfs 
Method. 

(2) Chusiderable quantities of acetic acid are also obtained by the dry distillation 
of wood in cast-iron retorts. The aqueous distillate, consisting of acetic acid, 
wood spirit, acetone, and empyreumatic oils, is neutralized with soda, evaporated 
to dryness, and the residual sodium salt heated 230°-250°. In this manner, the 
greater portion of the various organic admixtures is destroyed, sodium acetate 
remaining unaltered. The salt purified in this way is distilled with sulphuric 
acid when acetic acid is set free and purified by further distillation over potassium — 
chromate. 


Anhydrous acetic acid at low temperatures consists of a leafy, 
crystalline mass, fusing at 16.7°, and forming at the same time a 
penetrating, acid-smelling liquid, of specific gravity 1.0514 at 20°. 
It boils at 118°, and mixes with water in all proportions. In this 
case, a contraction first ensues, consequently the specific gravity 


220 ORGANIC CHEMISTRY. 


increases until the composition of the solution corresponds to the 
hydrate, C,H,O, + H,O (= CH;.C(OH);); the specific gravity 
then equals 1.0754 at 15°. On further dilution, the specific gravity 
becomes less, until’a 50 per cent. solution possesses about the same 
specific gravity as anhydrous acetic acid. Ordinary vinegar con- 
tains about 5-15 per cent. acetic acid. Pure acetic acid should not 
decolorize a drop of potassium permanganate. 

Acetates. The acid combines with one equivalent of the bases, 
forming readily soluble, crystalline salts. It also yields basic salts 
with lead and copper ; these dissolve with difficulty in water. The 
alkali salts have the additional property of combining with a mole- 
cule of acetic acid, yielding aczd salts, C,H,KO, + C,H,O,. In 
this respect, acetic acid behaves like a dibasic acid. The fact that 
it furnishes only neutral esters proves it, however, to be only mono- 
basic. The existence of acid salts points to a condensation of two 
molecules of the acid, analogous to that occurring with the alde- 
hydes. 


Potassium Acetate, C,H,KO,, deliquesces in the air, and dissolves readily in 
alcohol. Carbon dioxide will set free acetic acid and precipitate potassium car- 
bonate in such an alcoholic solution; but in an aqueous solution, acetic acid will 
displace carbon dioxide from the carbonates. On adding acetic acid to neutral 
potassium acetate, an acid salt, C,H,KO,.C,H,On,, crystallizes ‘out on evapora- 
tion; this consists of pearly leaflets. It fuses at 148°, and at 200° decomposes 
into the neutral salt and acetic acid, 

Sodium Acetate,C,H,NaO, + 3H,O, crystallizes in large, rhombic prisms, 
soluble in 2.8 parts water at medium temperatures. The crystals effloresce on ex- 
posure, and lose all their water. When heated, the anhydrous salt remains un- 
changed at 310°. 

Ammonium Acetate, C,H,(NH,)O,, is obtained as a crystalline mass on 
saturating acetic acid with ammonia. When the aqueous solution is evaporated, 
the salt decomposes into acetic acid and ammonia. Heat applied to the dry salt 
converts it into water and acetamide, C,H,.0.NH,. 

. ferrous Acetate, (C,H,O,),Fe, is produced on dissolving iron in acetic acid ; 

it consists of green colored, readily soluble prisms. The aqueous solution oxidizes 
in the air to basic ferric acetate, Neutral ferric acetate, (C,H,O,),Feg, is not 
crystallizable, and dissolves in water with a deep, reddish-brown color. On boil- 
ing, ferric oxide is precipitated in the form of basic acetate. The same may be 
said in regard to aluminium acetate. 

Neutral Lead Acetate, (C,H,0,),Pb + 3H,0, is obtained by dissolving lith- 
arge in acetic acid. The salt forms brilliant four-sided prisms, which effloresce 
on exposure. It possesses a sweet taste (hence, called sugar of lead), and is 
poisonous. When heated, it melts in its water of crystallization, loses all of the 
latter at 100°, and at higher temperatures passes into acetone, CO,, and lead 
oxide. If an aqueous solution of sugar of lead be boiled with litharge, dasic 
lead salts of varying lead content are produced. Their alkaline solutions find 
application under the designation—/ead vinegar. Solutions of basic lead acetates 
absorb carbon dioxide from the air and deposit dase carbonates of lead—white lead. 

Neutral Copper Acetate, (C,H,O,),Cu + H,0O, is obtained by the solution of 
cupric oxide in acetic acid, and crystallizes in dark-green rhombic prisms. It is 
easily soluble in water. asic copper salts occur in trade under the title of verd?- 


SUBSTITUTION PRODUCTS OF ACETIC ACID. 221 


They are obtained by dissolving copper strips in acetic acid in presence of 
air. The double salt of acetate and arsenite of copper is the so-called Schwein- 
Surt Green—mitis green. 

Silver Acetate, C,H,0,Ag, separates in brilliant needles or leaflets when con- 
centrated acetate solutions and silver nitrate are mixed. ‘The salt is soluble in 98 
parts water at 14° C. 





SUBSTITUTION PRODUCTS OF ACETIC ACID. 


The three hydrogen atoms of the methyl group in acetic acid can be replaced 
by halogens. The chlorine derivatives result by the action of chlorine in the 
sunlight upon acetic acid, or if chlorine be conducted into a boiling aqueous solu- 
tion of the acid containing iodine (compare p. 91). It ‘is more practicable to 
chlorinate acetyl chloride, C,H,O.Cl, and convert the product into the acids by 
means of water. In this way a mixture of the mono-, di-, and tri-substituted acids 
is always formed. They may be separated by fractional distillation, They are 
more powerful acids than acetic. The monohalogen fatty acids can be obtained 
from their corresponding oxy-fatty acids by the action of the haloid acids: 
CH,OH.CO,H + HBr = CH,Br.CO,H + H,O; as well as from the diazo- 
fatty acids (see these). 

Monochloracetic Acid, CH,Cl.CO,H (Preparation, Berichte, 17, 1286), 
crystallizes in rhombic prisms or plates, fusing at 62°, and boiling at 185°-187°. 
The silver salt, C,H,ClO, Ag, crystallizes in pearly, glistening scales, and at 70° 
decomposes into AgCl and glycolide. The ethy/ ester, C,H,ClO,.C,H,, obtained 
by conducting HCl into a mixture of the acid and absolute alcohol, boils at 143.5°. 

When monochloracetic acid is heated with alkalies or silver oxide, the chlorine 
is replaced by the hydroxyl group and we get glycollic acid (C,H,(OH)O,). 
Amido-acetic acid, CH,(NH,).CO,H, or glycocoll, results when the monochlor- 
acid is digested with ammonia. 

Dichloracetic Acid, CHCl,.CO,H, is produced when chloral is heated with 
CNK and some water :— 


CCl,.cCHO + H,O + CNK = CHCI,.CO,H +KCl + CNH, 


and by the action of alkalies upon trichloracetic acid ( Berichte, 18, 757). It boils 
from 190°-191°, and solidifies belowo°. The free acid is best obtained by heat- 
ing its potassium salt (prepared from the ethyl ester) in a current of HCl gas. * 

The ethyl ester, C,HCl,0.0.C,H,, is prepared by the action of potassium 
cyanide and alcohol upon chloral. (For the mechanism of this peculiar reaction, 
see Berichte, 10, 2120.) It is a heavy liquid, boiling from 156°-157°. Alcoholic 
potash decomposes it immediately into potassium dichloracetate and alcohol. When 
the acid is boiled with aqueous potash, it breaks up into oxalic and acetic acids. 
The salts-of the di-chlor acid reduce silver solutions, forming at first glyoxylic acid 
(Berichte, 18, 227). 

Trichloracetic Acid, CCl],.CO,H, is made by letting chlorine act in the sun- 
light upon tetrachlorethylene, C,Cl,. It is best obtained by the oxidation of 
chloral with fuming nitric acid, chromic acid, potassium permanganate, or potas- 
sium chlorate (Berichte, 18, 3336) :— 


CCl,.COH + O = CCI,.CO,H. 


It consists of rhombic crystals, which deliquesce, melt at 52°, and boil at 195°. It 
yields easily soluble, crystalline salts with bases, but on evaporation they aré soon 
broken up. The ethy/ ester, C,Cl,0.0.C,H,, boils at 164°. 


222 ORGANIC CHEMISTRY. 


When the acid is heated with ammonia or alkalies it yields CHC], and carbon 
dioxide: CCl,.CO,H = CCl,H + CO,. Sodium alcoholate changes it into 
potassium carbonate and formate, and potassium chloride. 

Nascent hydrogen (sodium amalgam) reconverts the substituted acetic acids into 
the original acetic acid. 





The bromine substitution acids result when anhydrous acetic acid is heated in 
sealed tubes along with bromine. 

The bromination is more readily effected (also in the case of the homologous 
acids) in the presence of amorphous phosphorus (Hill). Then, under certain 
circumstances, the reaction proceeds without pressure, and the monosubstituted 
acids are the sole products (Volhard) (Berichte, 21, Ref. 5; 21, 1725 and 1904). 

Monobromacetic Acid, C,H,BrO, (Preparation, see Berichte, 16, 2502), 
crystallizes in deliquescent rhombohedra, and boils at 208°. Its e¢hy/ ester, C,H, 
BrO,.C,H,, is a liquid which boils at 159°, and suffers a slight decomposition at 
the same time. 

Dibromacetic Acid, C,H,Br,O,, is a crystalline mass, melting at 54—56°, and 
boiling from 232-235°. Its salts are very unstable. The Z7¢hy/ ester, C,HBr,O. 
O.C,H,, like that of the dichloracid, may be-prepared from bromal with CNK and 
alcohol. It boils at 192-194°. 

Tribromacetic Acid, C,HBr,O,, made from tribromacetyl bromide, CBr,. 
COBr, and by the oxidation of bromal with nitric acid, consists of table-like crys- 
tals, permanent in the air. It melts at 135°, and boils at 245°. 

The iodine substitution acids (their esters) are obtained from the chlor- and 
brom-acid esters when the latter are heated with potassium iodide (p. 95). They 
are also produced on boiling acetic acid anhydride with iodine and iodic acid 
(Pp. 91). : 

Moniodacetic Acid, C,H,IO,, crystallizes in colorless plates, which melt at 
$2°, and decompose when more strongly heated. Its salts are unstable. The 
ethyl ester boils at 178-180°. When heated with HI it passes into acetic acid (p. 
91): CH,I.CO, + HI = CH,.CO,H + I,. 

Di-iodacetic Acid, CHI,.CO,H. Its ethyl ester, first prepared from dibrom- 
acetic acid ester and KI, may also be made by allowing iodine to act upon diazo- 
acetic ester (see this). It is a heavy, bright-yellow colored oil. It is volatile with 
by decomposes on heating, and when exposed to the air liberates iodine 
rapidly. 

Ethyl Nitroacetic Ester, CH,(NO,).CO,.C,H,, is produced in the action of 
silver nitrite upon bromacetic ester, and boils at 151~-152° with scarcely any de- 
composition. By reduction with tin and hydrochloric acid it yields amido-acetic 
acid. The free nitro-acetic acid at once decomposes into nitromethane, CH,. 
(NO,), and CO,. 

Ethyl Isonitroso-acetic Ester, CH(N.OH).CO,.(C,H,), or oximido-acetic 
ester (p. 205), is produced by the action of nitric acid upon the aceto-acetic ester. 
It is a yellow oil, which suffers decomposition when distilled (Annalen, 222, 48). 





3. Propionic Acid, C;H,O, = CH;.CH,.CO,H, may be pre- 
pared by the methods in general use in making fatty acids, and by 
the oxidation of normal propyl alcohol with chromic acid, or from 


SUBSTITUTION PRODUCTS OF ACETIC ACID. 223 


ethyl cyanide, C;H;.CN (propio-nitrile) by the action of sulphuric 
acid (p. 211). Especially noteworthy is its formation from acrylic 
acid, C;H,O,, through the agency of nascent hydrogen (sodium 
amalgam) ; likewise its production from lactic and glyceric acids 
when these are heated with hydriodic acid :— 


CH,.CH(OH).CO,H + 2HI = CH,.CH,.CO,H + H,O + I, 
Lactic Acid. 


Propionic acid is a colorless liquid, of penetrating odor, with 
specific gravity 0.992 at 18°, and boiling at 140°. Calcium chlo- 
ride separates it from its aqueous solution, in the form of an oily 
liquid. 


The barium salt, (C,H;O,),Ba +- H,O, crystallizes in rhombic prisms. The 
silver salt, C,H;O0,Ag, consists of fine needles, soluble in 119 parts water at 17°. 
Its ethyl ester boils at 98°. 





Substitution Products.—By the replacement of one hydrogen 
atom in propionic acid, two series of mono-derivatives, termed the 
a- and f-derivatives, arise :— 


CH,.CHX.CO,H CH,X.CH,CO,H. 


a-Derivative. B-Derivative. 


The isomeric compounds of the higher fatty acids are similarly 
designated as a-, B-, y-, etc. 

Whenever bromine is introduced into the fatty acids, it occupies 
preferably the a- position. In the formation of the halogen de- 
rivatives from the unsaturated acids by addition of the halogen 
hydride, the halogen enters in preference the f- or y- position (see 
Berichte, 22, Ref. 742) :— 


CH,:CH.CO,H + HI —CH,I.CH,.CO,H. 
Acrylic Acid. B-lodpropionic Acid. 


The a-halogen acids yield a-oxy-acids when heated with aqueous bases, whereas 
the -derivatives readily part with a halogen hydride, and become unsaturated 
acids (Annalen, 219, 322) :— 


CH,CI.CH,.CO,H CH,:CH.CO,H + HCl. 
Acrylic Acid. 


From the y-acids originate salts of y-oxy-acids through the action of bases. 
When in free condition they change to lactones. The alkaline carbonates imme- 
diately convert them into the latter. 

a-Chlorpropionic Acid, C,H,ClO,, is obtained by the decomposing action of 
water upon lactyl chloride (see lactic acid) :— 


CH,.CHCLCOCI + H,O = CH,.CHCI.CO.OH + HCl. 


224. ORGANIC CHEMISTRY. 


It is a thick liquid, of specific gravity 1.28, and boils at 186°. When heated 
with moist oxide of silver, it becomes a-lactic acid. The e¢iy/ ester boils at 146°. 
It is obtained by the action of alcohol upon lacty] chloride. 

8-Chlorpropionic Acid, C,H,CIO,, is produced by the action of chlorine 
water upon /-iodpropionic acid, and the addition of HCl to acrylic acid :— 


CH,:CH.CO,H + HCl = CH,CI.CH,.CO,H. 


Also upon heating B-oxypropionic acid (hydracrylic acid) to 120° with fuming 
hydrochloric acid. © 

It is crystalline, and melts at 41.5°. The ethy/ ester boils at 155° (162°). 

a-Brompropionic Acid, C,H,BrO,, is produced by the direct bromination of 
propionic acid in the presence of bromine (Berichte, 22, 162), and when a-lactic 
acid is treated with HBr. It is crystalline, melts at 24.5°, and boils near 202°. 
The ethy/ ester boils about 162°. 

8-Brompropionic Acid, C,H,BrO,, is formed when bromine water acts on 
B-iodpropionic acid, or by the addition of HBrto acrylic acid, and when hydracrylic 
acid is heated with hydrobromic acid. The acid crystallizes, and melts at 61.5°. 

a-lodpropioni¢ Acid, C,H,IO,, is produced by acting on a lactic acid, with 
phosphorus iodide. It is an oily liquid... 

B-lodpropionic Acid, C,H,IO,, forms when PI, and water are allowed to 
act on glyceric acid (Amnalen, 191, 284) :— 


CH,.0H.CH(OH).CO,H + 3HI = CH,I.CH,.CO,H + I, + H,0, 


and when HC] is added to acrylic acid. To prepare it, treat crude glyceric acid 
with iodine and phosphorus (Berichte, 21, 24). The acid crystallizes in large, 
colorless, six-sided plates, with peculiar odor. They melt at 85°. Hot water dis- 
solves the acid readily. Heated with concentrated hydriodic acid, it is reduced to 
propionic acid. The ethyl ester boils at 202° (Berichte, 21, 97). 





- B-Nitropropionic Acid, CH,(NO,).CH,.CO,H. This is formed, like the 
nitro-paraffins (p. 107), by the action of silver nitrite upon -iodpropionic acid. 
It is very readily soluble in water, alcohol and ether. It crystallizes from chloro- 
form in brilliant scales, melting at 66-67°. Reduced with tin and hydrochloric 
acid it becomes B-amidopropionic acid. The ethyl ester, obtained from /-iod- 
propionic ester, boils from 161—165°. 

a-Isonitroso-propionic Acid, CH,.C(N.OH).CO,H, is a white, crystalline 
powder, made from acetyl carboxylic acid and methyl aceto-acetic ester (p.214). It 
decomposes at 177° without fusing. Reduction converts it into a-amidopropionic 
acid (Alanine). 

The ethyl ester consists of shining crystals, melting at 94°, and boiling at 233°. 
It is also formed when nitrous acid acts upon isosuccinic ester (Berichte, 20, 533). 





The disubstitution products of propionic acid may exist in three isomeric 
forms :— 
CH,.CX,.CO,H CH,.X.CHX.CO,H CHX,.CH Geis 


- a-Derivatives. aB Derivatives. B-Derivatives. 


SUBSTITUTION PRODUCTS OF ACETIC ACID. 225 


The derivatives of the homologous acids are similarly named. ‘The a-deriva- 
tives are almost the exclusive product in the chlorination and bromination of the 
fatty acids or their derivatives. The addition of chlorine or bromine (best in 
CS, solution) to the unsaturated acids converts them into af-derivatives :— 


; CH,:CH.CO,H + Br, = CH,Br.CHBr.CO,H. 


Boiling water scarcely affects the a-derivatives; but the a6-compounds become 
halogen hydroxy-acids :— 


CH,Cl.CH(OH).CO,H and CH,,(OH).CHCI.CO,H. 


The alkalies convert these into anhydride or ether-acids (glycide acids). 

a-Dichlorpropionic Acid, CH,.CCl,.CO,H, is obtained from dichlorpropio- 
nitrile, CH,.CCl,.CN (by chlorination of propionitrile), with sulphuric acid (see 
p. 211). The ethyl ester may be formed from pyroracemic acid, CH,.CO.CO,H, 
by the action of PCl,; and the decomposition of the chloride produced at first 
with alcohol. It is a liquid that boils at 185°-190°, solidifies below 0°, and is 
volatilized in a current of steam. The ethy/ ester, C,H,Cl,.0,.C,H,, boils at 
156°-157°; its chloride boils at 105°-115°, and the amide, CH,.CCl,.CO.NH,, 
melts at 116°. 

When the aqueous solution of the a-dichlorpropionates are boiled, they sustain 
decomposition. Zinc and sulphuric acid convert the acid into propionic acid. 
The silver salt changes to CH,.CO.CO,H (pyroracemic acid), and a-dichlorpro- 
pionic acid (see Berichte, 18, 1227). a-Chloracrylic acid is produced on boiling 
with alcoholic potash. Zinc and hydrochloric acid convert it into propionic acid. 

a3-Dichlorpropionic Acid, CH,Cl.CHCI1.CO,H, follows from the oxidation 
of dichlorhydrin, CH,Cl.CHC].CH,.OH (from glycerol and allyl alcohol, p. 134), 
also by heating a-chloracrylic acid (melting at 64°) to 100° with HCl (Berichze, 
10, 1599), and by heating glyceric acid with hydrochloric acid (together with 
chlorlactic- acid, Berichte, 12, 178). If PCl, be allowed to act upon glyceric 
acid, the chloride, CH,Cl.CHCI.COCI, forms, and this yields the ester of the 
af-acid when treated with alcohol. «a -Dichlorpropionic acid crystallizes in fine 
needles which melt at 50° and boil at 210°, suffering slight decomposition. The 
ethyl ester boils at 184°. 

8-Dichlorpropionic Acid, CHCl,.CH,.CO,H, is produced by heating 
8-chloracrylic acid with hydrochloric acid. It melts at 56°, and is reconverted by 
caustic potash into 6-chloracrylic acid (Berichte, 20, Ref. 415). 

a-Dibrompropionic Acid, CH,.CBr,.CO,H, is obtained by heating propionic 
acid or a-brompropionic acid with bromine (Berichie, 18, 235). It crystallizes in 
quadratic tables, melting at 61°, and boils, with slight decomposition, at 220°. 
The ethyl ester is a liquid with camphor-like odor, and boils at 190°, The salts 
of the acid are tolerably stable. Zinc and sulphuric acid reduce it at once to pro- 
pionic acid. Alcoholic potash changes it to a-bromacrylic acid, CH,:CBr.CO,H, 
and the latter combines with HBr and becomes a{-dibrompropionic acid. When 
the a-dibrom-acid is heated to 100°, with fuming HBr, it is transformed into an 
isomeric a@8-dibrom-acid. It is very probable that a-bromacrylic acid forms at first 
and then takes on HBr. 

a8-Dibrompropionic Acid, CH,Br.CHBr.CO,H, is produced by oxidizing 
dibromhydrin, CH, Br. CHBr.CH,OH (dibromallyl alcohol, p. 134), and acrolein 
dibromide (p. 199) with nitric acid; also by adding Br, to acrylic acid and HBr 
to a-bromacrylic acid. This compound is capable of existing in two allotropic 
modifications, which can be readily converted one into the other. The one form 
melts at 51°, the other, more stable, at 64°. The acid boils at 227°, with partial 
decomposition. The ethy/ ester has a fruit-like odor, and boils at 21192149. 


=o 


226 ORGANIC CHEMISTRY. 


The salts are very stable. Zinc and sulphuric acid reduce the acid first to acrylic 
acid. Potassium iodide effects the same. Alcoholic potash changes the acid to 
a-bromacrylic acid. Brom-lactic acid is produced by digesting the silver salt with 
water (Berichte, 18, 236). The product is glyceric acid if an excess of silver oxide 
has been employed. 


4. Butyric Acids, C,H,O,. 
Two isomeric acids are possible :— 


CH,.CH,.CH,.CO,H Cit? >CH.CO,H. 
Normal Butyric Acid, Isdbutyric Acid. 


(1) Normal Butyric Acid, butyric acid of fermentation, oc- 
curs free and also as the glycerol ester in the vegetable and animal 
kingdoms, especially in the butter of cows. It exists as hexyl ester 
in the oil of Heracleum giganteum, and as octyl ester in Pastinaca 
-. sativa. It is produced in the butyric fermentation of sugar, starch 
and lactic acid, in the decay or oxidation of normal butyl alcohol, 
and by the action of nascent hydrogen upon crotonic acid, C,H,O,,. 
It is prepared synthetically from propyl cyanide (butyronitrile) on 
boiling with alkalies or acids :— 


C,H,.CN + 2H,O — C.H,,CO Jn + NH,; 


also, from ethylic-aceto-ethyl acetate, and ethylmalonic acid (p. 
212); hence the term ethyl acetic acid. 


Ordinarily the acid is obtained by the fermentation of sugar or starch, induced 
by the previous addition of decaying substances. According to Fiz, the butyric 
fermentation of glycerol or starch is most advantageously evoked by the direct 
addition of schizomycetes, especially butyl-bacillus and Bacillus subtilis (Berichée, 


II, 49, 53). 


Butyric acid is a thick, rancid-smelling liquid, which solidifies 
when cooled. It boils at 163°; its specific gravity equals 0.9587 
at 20°. It dissolves readily in water and alcohol, and may be 
thrown out of solution by salts. The e/hy/ ester boils at 120°. 


The butyrates dissolve readily in water. The barium salt, (C,H,O,),Ba + 
5H,0, crystallizes in pearly leaflets. The calcium salt, (C,H,O,),Ca + H,O 
(Annalen, 213, 67), also yields brilliant leaflets, and is less soluble in hot than in 
cold water (in 3.5 parts at 15°); therefore the latter grows turbid on warming. 
Silver nitrate precipitates silver butyrate in shining needles from solutions of the 
butyrates. It is soluble in 400 parts water at 14°. 

The butyrates unite to double salts with the acetates; these behave like salts 
of a butyro-acetic acid, C,H,O,.C,H,O,. The free acid appears in the fer- 
oc agra of calcium tartrate; when distilled, it breaks up into butyric and acetic 
acids. 

y-Chlorbutyric Acid, CH,Cl].CH,.CH,.CO,H, has been prepared from 
y-chlor-trimethylenecyanide. It solidifies in the cold and melts at 10°. When 
distilled it yields HCl and y-caprolactone (see this).. eet began 228i. 


SUBSTITUTION PRODUCTS OF ACETIC ACID. 227 


- a$-Dichlorbutyric Acid, CH,.CHCI.CHCI.CO,H. This results upon the 
addition of chlorine to crotonic acid. It melts at 63°. With KOH it forms 
chlorisocrotonic acid ( Berichte, 20, 1008). ; 

Trichlorbutyric Acid, C,H,;Cl,O,, appears in the oxidation of trichlorbutyr- 
aldehyde or alcohol (p. 197), in the cold, with concentrated nitric acid, or by 
means of chlorine. It consists of needles, melting at 60° and soluble in 25 parts 
of water. $-Chlorcrotonic acid is formed when the trichlor-acid is boiled with 
zinc and water: C,H,Cl,0, + Zn = C,H,ClO, + ZnCl,. 

Bromine converts butyric acid into a-Brombutyric Acid, CH,CH,.CHBr. 
CO.OH, which boils about 215°. Alcoholic potash changes this to crotonic acid. 
Its ethyl ester boils at 178°. With CNK the latter yields a-cyanbutyric ester, 
boiling at 208°. 

B-Brombutyric Acid, CH,.CHBr.CH,.CO,.H, is produced (together with a 
little a-acid) on heating crotonic acid with hydrobromic acid. Crotonic acid com- 
bines with bromine to form af-dibrombutyric acid, CH,.CHBr.CHBr.CO,H, 
which melts near 87°. 

y-Brom- and Iodobutyric acids result from butyrolactone (see this) by the 
action of HBr and H1; the first melts at 33°, the second at 41° (Berichie, 19, 
Ref. 165). ; 

B-Iod-butyric Acid is obtained by the union of crotonic acid and isocrotonic 
acid with hydriodic acid ; it melts at 110° (Berichte, 22, Ref. 741). 

a-Isonitroso-butyric Acid, C,H,.C(N.OH).CO,H, obtained from ethylic 
aceto-ethyl acetate (p. 214), consists of silky needles, melting with decomposition 
at 152°. The B-Isonitroso Acid, CH,.C(N.OH).CH,CO,H, from ethyl aceto- 
acetic ester and hydroxylamine, melts with decomposition at 140°. 


When a saturated solution of calcium butyrate is heated for some 
time it slowly passes into calcium isobutyrate (Annalen, 181, 126). 

(2) Isobutyric Acid, (CH;),.CH.CO,H, dimethyl-acetic acid, 
is found free in carobs (Ceratonia siliqgua), as octyl ester in the oil 
of Pastinaca sativa, and as ethyl ester in croton oil. It is prepared 
by oxidizing isobutyl alcohol, and from isopropyl cyanide:— ~* 


C,H,.CN + 2H,O = C,H,.CO,H + NH,. 


It is also obtained from dimethyl-aceto-acetic ester and from 
dimethyl malonic acid (p. 212), therefore the name dimethyl acetic 
acid. 

Isobutyric acid bears great similarity to normal butyric acid, but 
is not miscible with water, and boils at 155°. Its specific gravity 
at 20° is 0.9490. It is soluble in 5 parts of water. 


The calcium salt, (C,H,O,),Ca + 5H,0, crystallizes in monoclinic prisms 
and dissolves more readily in hot than in cold water. The silver salt, C,H,O,Ag, 
consists of shining leaflets soluble in 110 parts H,O at 16°. The ethyl ester boils 
at 110°; its specific gravity = 0.89 at 0°. Potassium permanganate oxidizes it to 
a-oxyisobutyric acid. 

a-Bromisobutyric Acid, (CH,),.CBr.CO,H, is produced when isobutyric 
acid is heated with bromine to 140°. It crystallizes in white tables, melting at 
48°, and boiling at 198°-200°. The ethyl ester boils at 163° (corr.); its sp. gr. 
== 1.328 at 0°. Moist silver oxide or barium hydrate converts it into @ oxyiso- 
butyric acid, (CH,),.C(OH).CO,H. When boiled together with silver it yields 
tetramethyl succinic acid and trimethyl glutaric acid. . : 4 


228 ORGANIC CHEMISTRY. 


5. Waleric Acids, C;H,O,. There are four possible isomer- 
ides :— 
CH, C.H, 


| | cu ch C(CH,); 
1, CH, 2. CH, ake 8 and 4. | 
CO,H 9 
Methyl-ethyl Tri 
CO,H Ost Acwig Acid Acetic Waid: 


Propy! Acetic Acid. Isopropyl 
Normal Valeric Acid. Acetic Acid. 
Isovaleric Acid, 


(1) Normal Valeric Acid, CH;.(CH,),.CO.H, formed in the oxidation of 
normal amyl alcohol and from butyl cyanides, is similar to butyric acid, but is more 
sparingly soluble in water (1 partin 27 partsat 16°). It boils at 186°. Its specific 
gravity at 0° equals 0.9568. It congealsin the cold, and melts at —20° (Berichie, 
21, Ref. 649). 

The a isonitroso-acid, C,H,.C(N.OH).CO,H, derived from propyl aceto-acetic 
ester (p. 212), melts with decomposition at 144°. The y zsonitroso-acid, CH3.C 
(N.OH).CH,.CH,.CO,H, formed from levulinic acid and hydroxylamine, fuses 
with decomposition at 96°, and when digested with sulphuric acid, passes into 
imido-lactone (Berichte, 20, 2671). 


(2) Isovaleric Acid, (CH;),.CH.CH,.CO,H, isopropyl acetic 
acid, or isobutyl carboxylic acid, is obtained from isobutyl cyanide, 
C,H,.CN, by saponification with alkalies, likewise from isopropyl 
aceto-acetic ester, and from isopropyl-malonic ester (see p. 212). 
It is an oily liquid with an odor resembling that of old cheese ; 
possesses a specific gravity of 0.947, and boils at 174°. It is 
optically inactive. 


The isovalerates generally have a greasy touch. When thrown in small pieces 
up6n water they have a rotary motion, dissolving at the same time. The 
barium salt, (C,;,H,O,),Ba, usually crystallizes in thin leaflets, and is soluble in 
2 parts water at 18°. The calcium salt, (C;H,O,),Ca + 3H,O, forms rather 
stable, readily soluble needles. The officinal zzzc salt, (C;H,O,),Zn + 2H,O, 
crystallizes in large, brilliant leaflets; when the solution is boiled a basic salt 
separates, The sz/ver salt, C;H,O,Ag, is very sparingly soluble in water (in 520 
parts at 21°). The ethy/ ester, C;H,(C,H,; )O,, boils at 135°. 

a-Brom-isovaleric acid, C,H,.CBr.CO,H, is formed in the bromination of iso- 
valeric acid in the presence of phosphorus. It melts at 40° (Berichte, 21, Ref. 5). 
Silver converts its ester into two dipropylsuccinic acids (Berichte, 22, 48). 

Potassium permanganate oxidizes isovaleric acid to B-oxyisovaleric acid, (CH,),. 
C(OH).CH,.CO,H. Nitric acid attacks in addition the CH-group, forming 
methyloxysuccinic acid and £ uitroisovaleric acid, (CH,)..C(NO,).CH,.CO,H, 
which crystallizes in large leaflets and is sparingly soluble in water; (-dinitro- 
propane, (CH,),C(NO,), (Berichze, 15, 2324), is produced at the same time. 


Ordinary valeric acid occurs free, and as esters in the animal and 
vegetable kingdom, chiefly in the small valerian root (Valeriana 
officinalis), and in the root of Angelica Archangelica, from which it 
‘may be isolated by boiling with water or a soda solution. It isa 
mixture of isovaleric acid with the optically active methyl-ethyl 


SUBSTITUTION PRODUCTS OF ACETIC ACID. 229 


acetic acid, and is therefore also active. A similar artificial mix- 
ture may be obtained by oxidizing the amy] alcohol of fermentation 
(p. 130) with a chromic acid solution. Inasmuch as the salts of 
methyl-ethyl acetic acid dissolve with difficulty, it is a general 
thing to obtain only isovalerates from the ordinary valeric acid. 
Valeric acid combines with water and yields an officinal hydrate, 
C;H,,.O, + H,O, soluble in 26.5 parts of water at 15°. 


(3) Methyl-ethyl Acetic Acid, CH! >CH.CO;H (active valeric acid), is 
say 


obtained by synthesis from methyl-ethyl-aceto-acetic ester, from methyl-ethyl-ma- 
lonic ester (p. 212), and from the so-called methyl-ethyl oxalic acid, z SC 


(OH).CO,H (see this); also from methylcrotonic acid (p. 241), C28.0., by 
addition of 2H (when heated with HI), and from brom- and iodmethyl ethyl 
acetic acid (from methylcrotonic acid and angelic acid) by reduction with sodium 
amalgam. 

The acid possesses a valerian-like odor, boils at 175° and has a specific gravity 
of 0.941 at 21°. The calcium salt, (C;H,O,),Ca + 5H,0, crystallizes in brilliant 
needles which slowly effloresce in the air. The darium salt, (C;H,O,), Ba, isa 
gummy amorphous mass, and is not crystallizable. The sz/ver salt, C;H,O,Ag, 
is much more soluble than that of the isovaleric acid (in 88 parts at 20°) and crys- 
tallizes in groups of feather-shaped, shining needles. 

The synthesized methyl-ethyl acetic acid is optically inactive. Am active modi- 
fication is present in the naturally occurring valeric acid, and is obtained by the 
oxidation of the amyl alcohol of fermentation (see above). The silver salt affords 
a means of separating it from the accompanying isovaleric acid (Anzalen, 204, 
159). The active acid has not yet been isolated in a pure condition; otherwise 
it exhibits all the properties of the inactive variety, and yields perfectly similar 
salts. eee 

(4) Trimethyl Acetic Acid, (CH,),C.CO,H (Pinalic acid), is formed from 
tertiary butyl iodide, (CH,),CI (p. 131), by means of the cyanide, also by the 
oxidation of pinacoline (p. 210). It is a leafy, crystalline mass, melting at 35° and 
boiling at 163°, The acid is’soluble in 40 parts H,O at 20°, and has an odor 
resembling that of acetic acid. 

The darium salt, (C,H,O,),Ba + 5H,O, and calcium salt, (C;H,O,),Ca + 
5H,0, crystallize in needles or prisms. The sd/ver salt, C,H,O,Ag, is pre- 
cipitated in glistening, flat needles. The ethyl ester, C;H,O,.C,H,, boils at 
118.5°. 


The Hexoic or Caproic Acids, C,H,,O, = C;H,,.CO,H. 

Eight isomerides are theoretically possible (because there are 
eight C;H,, (amyl) groups). Seven of these have been prepared. 
We may mention :— 


(1) Normal Caproic Acid or Hexoic Acid, CH,(CH,),.CO,H, which is 
produced in the fermentation of butyric acid, and may be obtained by the oxida- 
tion of normal hexyl alcohol, and from normal amyl cyanide, C,H,,.CN. In 
addition, it forms when butyl iodide acts on aceto-acetic ester. It is an oily liquid 
that has a sp. gr. of 0.928 at 20°, boils at 205°, solidifies in the cold and melts at 
—2°. Its darium salt, (C,H,,0,),Ba + 3H,0, is soluble in 9 parts of water 
at 10°. The ethyl ester boils at 167°. 


230 ORGANIC CHEMISTRY. 


(2) Isobutyl Acetic Acid, (CH,),.CH.CH,.CO,H, is obtained from isoamyl 
cyanide and from isobutyl aceto-acetic ester (p. 212). . Some fats apparently contain 
it. It has a specific gravity of 0.931 at 15° and boils at 200°. The e¢hy/ ester boils 
at 161°. By the oxidation of isobutyl acetic acid with potassium permanganate the 
lactone of y-oxy-isocaproic acid, (CH,),-C(OH).CH,.CH,.CO,H, is formed. 

(3) Methylpropyl Acetic Acid, “Aig! >CH.CO4H, is prepared from methyl- 

; 3 
propyl carbinol (p. 131) through the cyanide and from a-methyl valerolactone 
(from saccharin) by reduction with HI. It boils at 198° and has the specific 


gravity 0.941 at 0° (Berichte, 16, 1832). The same acid has been obtained from 
isosaccharin (Berichte, 18, 633). 





Heptoic Acids, C,H,,0, = C,H,,.CO,H. 

Six of the seventeen possible isomerides are known. 

(1) Normal Heptoic or Gnanthylic Acid, CH,(C,;H,);.CO,H, is pro- 
duced by the oxidation of cenanthol (p. 198) with nitric acid, and also from normal 
hexyl cyanide,C,H,',.CN. It is a fatty-smelling oil, boiling near 223°, and solid- 
ifying, when cooled, to a crystalline mass, which melts at —10.5°, The e¢hyl ester 
boils at 188°, CH 

(2) Methyl-n-butyl Acetic Acid, 1? >CH.CO,H, obtained synthetically 

9 


from aceto-acetic ester, has been prepared by reducing lzevulo-carboxylic acid. It 
boils at 210° (Berichée, 19, 224). C,H.\ 
(3) Ethyl-n-propyl Acetic Acid, cH > 

Sik © 


boils at 209° (Berichte 19, 227). 

The Octoic Acids, C,H,,O0, = C,H,,.CO,H. 

Normal Octoic or Caprylic Acid is present in fusel oil, and as glycerol ester 
in many oils and fats. It is produced by the oxidation of fats and oleic acid 
with nitric acid; also obtained from normal octyl alcohol. The acid crystallizes 
in needles or leaflets, whiclf melt at 16°—17°, and boil at 236°-237°. The barium 
salt is soluble in 50 parts boiling water, and crystallizes in fatty tablets. 

Nonoic Acid, C,H,,0,, Pelargonic Acid, occurs in the leaves of Pelargo- 
nium roseum, and is prepared by the oxidation of oleic acid and oil of rue 
(methyl nonyl ketone, p. 210), with nitric acid. It may also be obtained from 
normal octyl cyanide, C,H, ,.CN, and by the fusion of undecylenic acid (p. 242) 
with potassium hydroxide. It is, therefore, the normal nonoic acid. It fuses at 
+ 12.5° and boils at!25 3°-254°. 


CH.CO,H, from aceto-acetic ester, 





HIGHER FATTY ACIDS. 


These (p. 215) are chiefly solids at ordinary temperatures, and 
can usually be distilled without suffering decomposition. They are 
volatilized by superheated steam. They are insoluble in water, 
but readily soluble in alcohol and ether, from which they may 
be crystallized out. In the naturally occurring oils and solid. 
fats, they exist in the form of glycerol esters (see these).. When 


HIGHER FATTY ACIDS. 231 


fats are saponified by potassium or sodium hydroxide, salts of 
the fatty acids—soaps—are produced. The sodium salts are solids 
and hard, while those with potassium are soft. Salt water will con- 
vert potash soaps into sodium soaps. In small quantities of water 
the salts of the alkalies dissolve completely, but with an excess of 
water they suffer decomposition, some alkali and fatty acid being 
liberated. The action of soap depends on this fact. The remain- 
ing metallic salts of the fatty acids are sparingly soluble or insoluble 
in water, but generally dissolve in alcohol. The lead salts, formed 
directly by boiling fats with litharge and water, constitute the 
so-called dead plaster. 


The natural fats almost invariably contain several fatty acids (frequently, too, 
oleic acid). To separate them, the acids are set free from their alkali salts by 
means of hydrochloric acid and then fractionally crystallized from alcohol. The 
higher, less soluble acids separate out first. The separation is more complete if 
the acids be fractionally precipitated (see p. 216). The free acids are dissolved 
in alcohol, saturated with ammonium hydroxide and an alcoholic solution of mag- 
nesium acetate added. The magnesium salt of the higher acid will separate out 
first, this is then filtered off and the solution again precipitated with magnesium 
acetate. The acids obtained from the several fractions are subjected anew to the 
same treatment, until, by further fractionation, the melting point of the acid 
remains constant—an indication of purity. The melting point of a mixture of 
two fatty acids is usually lower than the melting points of both acids (the same is 
the case with alloys of the metals). 


The fatty acids existing in fats and oils all possess the normal 
structure of the carbon chains, inasmuch as they yield only lower 
and normal acids when oxidized. It is an interesting fact, that in 
the natural fats only acids exist that have an eyen number of carbon 
atoms. Those that possess an uneven number of carbon atoms (as 
undecylic and tridecylic) are artificially prepared by the oxidation 
of their corresponding ketones (p. 200). The latter are obtained 
by distilling the calcium salt of an acid having one carbon atom 
more, with calcium acetate. In this manner there is derived from 
lauric acid, C,,H,,.CO,H, the ketone, C,,H.;.CO.CH;, which is 
oxidized to undecylic acid, C,,H,.O, = C,,H,,.CO,H, by chromic 
acid. Undecylic acid yields the ketone, C,,H,,.CO.CH;, and this 
the acid, C,H O,, etc. Thus, starting with the highest acid, we 
can successively form all the lower members of the series. 


Capric Acid, C,,H,,O,, present in butter, in cocoanut oil and in many fats, 
forms a crystalline mass, melting at 31.4°, and boiling, with partial decomposi- 
tion, at 268°-270°, The darium salt crystallizes from alcohol in fatty, shining 
needles or scales. The ethy/ ester is a liquid, and possesses a fruit-like odor. It 
boils at 243°. 

Undecylic Acid, C,,H,,.0,, is obtained by oxidation from undecyl-methyl 
ketone, C, ,;H,,.CO.CH, (see above), and from undecylenic acid, when the latter 
is heated with hydriodic acid. It is a scaly, crystalline mass, which melts at 28.5°,. 


232 ORGANIC CHEMISTRY. 


and boils at 212° under a pressure of 100 mm. An acid obtained from the fruit 
of the California bay-tree appears to be identical with the preceding acid. 

Lauric Acid, C,,H,,0,, occurs as glycerol-ester in the fruitof Laurus nodzlis 
and in pichurium beans. It crystallizes in large, brilliant needles, melting at 43.6°. 
The ethy/ ester possesses a fruit-like odor, and boils at 269°. 

Tridecylic Acid, C,,H,,O,, is formed by the oxidation of tridecyl-methyl 
ketone, C,,H,,CO.CH, (from myristic acid), and crystallizes in scales, which 
melt at 40.5° and under 100 mm. pressure boil at 235°. 

Myristic Acid, C,,H,,0,, obtained from muscat butter (from Myristica mos- 
chata), from spermaceti and oil of cocoanut, is a shining, crystalline mass, melting 
at 54°. The ethy/ ester is solid. 

Pentadecatoic Acid, C,,H,,O,, is prepared from pentadecato-methyl ketone, 
C,,H,,.CO.CH, (from palmitic acid); it melts at 51°, and boils under a pressure 
of 100 mm. at 257°. 


Palmitic Acid, C,,H;,0,. The glycerol-ester of this acid and 
that of stearic acid constitute the principal ingredients of solid ani- 
mal fats. ‘The stearin employed in the candle nranufacture is a 
mixture of free palmitic and stearic acids. Palmitic acid occurs in 
rather large quantities, partly uncombined, in palm oil. Spermaceti 
is the cetyl-ester of the acid, while the myricyl ester is the chief 
constituent of beeswax. The acid is most advantageously obtained 
from olive oil, which consists almost exclusively of the glycerides of 
palmitic and oleic acid (see latter); also, from Japanese beeswax, a 
glyceride of palmitic acid (Berichte, 21, 2265). The acid is arti- 
ficially made by heating cetyl alcohol with soda-lime :— 


C,,H,,.CH,.0H + KOH = C,,H,,.CO,K + 2H,; 


also by fusing together oleic acid and potassium hydroxide. 
Palmitic acid crystallizes in white needles, which melt at 62°, and 
solidify to a crystalline mass. peitas 
Margaric Acid, C,,H;,0,, does not apparently exist naturally 
in the fats. It is made in an artificial way by boiling cetyl cyanide 
with caustic potash :— 


C,gH,,.CN + 2H,0 = C,,H,,.CO,H + NH,. 


The acid bears great resemblance to palmitic acid, and melts at 

Stearic Acid, C,,H,,O,, is associated with palmitic and oleic 
acids as a mixed ether in solid animal fats, the tallows. The acid 
crystallizes from alcohol in brilliant leaflets, melting at 62.2°. 

The so-called stearzn of candles consists of a mixture of stearic and 
palmitic acids. For its preparation, beef tallow and suet, both solid 
fats, are saponified with potassium hydroxide or sulphuric acid. The 
acids which separate are distilled with superheated steam. The yel- 
low, semi-solid distillate, a mixture of stearic, palmitic and oleic 
acids, is freed from the liquid oleic acid by pressing it between 


UNSATURATED ACIDS. 233 


warm plates. The residual, solid mass is then fused together with 
some wax or paraffin, to prevent crystallization occurring when the 
mass is cold, and molded into candles. 


Cetyl Acetic Acid, C,gH,,.CH,.CO,H, is probably identical with the above, 
and is obtained from cetyl aceto-acetic ester and cetyl malonic acid (see p. 212) 
(Berichte, 17, 1629). An isomeric acid, called docty? acetic acid (C,H,,),CH. 
CO,H, is prepared from digetyl- aceto-acetic ester and from dioctylmalonic acid. 
It melts at 38.5°. 

We may briefly mention the following higher acids (see p. 215) :— 

Arachidic Acid, C,,H,,O,, occurs in earth-nut oil (from Arachis hypogea), 
and is composed of shining leaflets, melting at 75°. It has been obtained syn- 
thetically from aceto-acetic ester and octodecyl iodide (from stearyl aldehyde) (Be- 
richte, 17, Ref. 570). 

Cerotic Acid, C,,H,;,0O,, or C,H;,O, (see Annalen, 224, 225), occurs in a 
free condition in beeswax, and may be extracted from this on boiling with alcohol. 
As ceryl ester, it constitutes the chief ingredient of Chinese wax. On boiling the 
latter with an alcoholic potash solution, potassium cerotate and ceryl alcohol are 
produced. The acid may also be obtained by oxidizing ceryl alcohol, or by fusing 
it with KOH :— 

C,,H;g0 + KOH =C,,H,,0,K + 2H,. 


It crystallizes from alcohol in delicate needles, melting at 78°. 

Melissic Acid, C,)H,,O,, is formed from myricyl alcohol (p. 134) when the 
latter is heated with soda-lime. It is a waxy substance, melting at 88°, and is 
really, as it appears, a mixture of two acids. The so-called Theobromic Acid, 
C.,H.,0., obtained from cacao butter, melts at 72°, and is apparently identical 
with arachidic acid. 


2. UNSATURATED ACIDS, CaHon—2O>. 


Acrylic Acid, CHO, HCO 
Crotonic a C_,.8,0, =:.CH. COR 
Angelic “ Cao. = Cia.Con 
Pyroterebic ‘‘ ~ CsHwO, = C;Hy.CO,H 


Oleic Acid, C,,H,,0O, — Erucic Acid, C,.H,,0,. 


The acids of this series, bearing the name Oleic Acids, differ 
from the fatty acids by containing two atoms of hydrogen less than 
the latter. They also bear the same relation to them that the alco- 
hols of the allyl series do to the normal alcohols. We éan consider 
them derivatives of the alkylens, C,H,,, produced by the replace- 
ment of one atom of hydrogen by the carboxyl group. In this 
manner their possible isomerides are readily deduced. 

As unsaturated compounds the oleic acids are capable of com- 
bining directly with two affinities, when the double union of the two 
carbon atoms becomes simple. Hence they unite directly with the 
halogens and halogen hydrides :— 

CH,:CH.CO,H + Br, = CH,Br.CHBr.CO,H. 


‘Aceyite Acid. aB- . Dibronipropivaic Acid. 
20 ‘ 


234 ORGANIC CHEMISTRY. 


On combining with two hydrogen atoms they become fatty 
acids :— 


CH,:CH.CO,H-+ H, — CH,.CH,.CO,H. 
Acrylic Acid. Propionic Acid. 


The lower members, as a general thing, combine readily with the H, evolved 
in the action of zinc upon dilute sulphuric acid; while the higher remain unaf- 
fected. All may be hydrogenized, however, by heating with hydriodic acid and 
phosphorus (erichte, 12, Ref. 376). The union with halogen hydrides occurs 
somewhat differently than observed with the alkylens. The halogen atom does 
not, as in the latter instance, attach itself to the carbon atom carrying the least 
number of hydrogen atoms, but prefers the 6 or y position (p. 225). 


The methods employed for the preparation of the unsaturated 
acids are similar to those used with the fatty acids, since the latter 
can be obtained from the unsaturated compounds by analogous 
methods. ‘They are formed from the saturated fatty acids by the 
withdrawal of two hydrogen atoms, just as the alkylens are derived 
from the normal hydrocarbons :— 

(1) Like the fatty acids they are produced by the oxidation of 
their corresponding alcohols and aldehydes; thus allyl alcohol and 
its aldehyde afford acrylic acid :— 


CH,:CH.CH,.OH and CH,:CH.CHO yield CH,:CH.CO,H, 
Allyl Alcohol. Acrolein, Acrylic Acid. 


- (2) Some may be prepared synthetically from the halogen deriv- 
atives, C,H,,,X, aided by the cyanides (see p. 211); thus allyl 
iodide yields allyl cyanide and crotonic acid :— 


C,H,I forms C,H,.CN and C,H,.CO,H. 


The replacement of the halogen by CN in the compounds C,H,,—,X is con- 
ditioned by the structure of the latter. Although allyl iodide, CH,:CH.CH,I, 
yields a cyanide, ethylene chloride, CH,:CHCI, and (- chlorpropylene, CH, CCl: 
CH,, are not capable of this reaction. 

( 3) Another synthetic method is to introduce the allyl group, C,H, (by means 
of allyl iodide), into aceto-acetic ester and malonic ester, and then further trans. 
pose the products first formed (p. 212). Allyl acetic acid, bon H,.CH,.CO,H, and 
diallyl acetic acid, (C,H,),CH.CO,H, have been obtained in this manner. 

(4) Some acids have been synthetically prepared by Perkins’ reaction. This 
is readily executed with benzene derivatives. It consists in letting the aldehydes 
act upon a mixture of acetic anhydride and sodium acetate (compare Cinnamic 
Acidy:~ C,H, ,CHO + CH,.CO,Na = C,H,,.CH = CH.CO,Na + H,O 

(Enanthol. Noavisnie Acid. 
(Annalen, 227,79). 

Pyroracemic acid acts analogously with sodium acetate; carbon dioxide splits 
off and crotonic acid results (Berichte, 18, 987). 

(5) Unsaturated Sy-acids are prepared by distilling alkylized paraconic acids. 
Thus merce gece acid yields ethylidene propionic acid (Berichte, 23, 
Ref. 91): C,xH,O, = C;H,O, + CO,. 


UNSATURATED ACIDS. 235 


Generally, the unsaturated acids are prepared from the satu- 
rated by 

(1) The action of alcoholic potash (p. 80) upon the monohalo- 
gen derivatives of the fatty acids :— 


CH,.CH,.CHCI.CO,H and CH,.CHCI.CH,.CO,H yield CH,.CH:CH.CO,H. 
a-Chlorbutyric Acid. B-Chlorbutyric Acid. Grotonic Acid. 


The -derivatives are especially reactive, sometimes parting with halogen hy- 
drides on boiling with water (p. 223). (The y-halogen acids yield oxy-acids and 
lactones.) Similarly, the a-derivatives of the acids (p. 225) readily lose two 
halogen atoms, either by the action of nascent hydrogen— 


CH,Br.CHBr.CO,H + 2H — CH,:CH.CO,H + 2HBr, 
a8-Dibrompropionic Acid. Acrylic Acid. 


or even more readily when heated with a solution of potassium iodide, in which 
instance the primary di-iod-compounds part with iodine (p. 99). 


CH,I.CH1.CO,H = CH,:CH.CO,H +4 I,. 


(2) The removal of water (in the same manner in which the 
alkylens C,H,, are formed from the alcohols) from the oxy-fatty 
acids (the acids belonging to the lactic series) :— 


CH,.CH(OH).CO,H and CH,(OH).CH,.CO,H yield CH,:CH.CO,H. 
a-Oxypropionic Acid. B-Oxypropionic Acid, Acrylic Acid. 


Here again the -derivatives are most inclined to alteration, losing water when 
heated. The removal of water from a-derivatives is best accomplished by acting 
on the esters with PCl,. The esters of the unsaturated acids are formed first, and 
can be saponified by means of alkalies. 


(3) From the unsaturated dicarboxylic acids, containing two car- 
boxyl groups attached to one carbon atom (see p. 212) :— 


CH,.CH:C(CO,H), = CH,.CH:CH.CO,H + CO,. 
Ethidene Malonic Acid. Crotonic Acid. 





Like the saturated acids in their entire character, the unsaturated 
derivatives are, however, distinguished by their ability to take up 
additional atoms (p. 234). Their behavior, when fused with potas- 
sium or sodium hydroxide, is interesting, because it affords a means 
of ascertaining their structure. By this treatment their double 
union is severed and two monobasic fatty acids result :— 

CH,:CH.CO,H +2H,O= CH,O, +4 CH,.CO,H + H,, 
Acrylic Acid. Formic Acid. Acetic Acid. 


CH,CH:CH.CO,H + 2H,0 = CH,.CO,H + CH,.CO,H + H,. 
Crotonic Acid. Acetic Acid. Acetic Acid. 


236 ORGANIC CHEMISTRY. 


Oxidizing agents (chromic acid, nitric acid, permanganate of potash) have the 
same effect. The group linked to carboxyl is usually further oxidized, and thus 
a dibasic acid results. 

When carefully oxidized with permanganate (see p. 82), the unsaturated acids sus- 
tain an alteration similar to that of the olefines; dioxy-acids result (Saytzeff, Fittig, 
Hazura, Berichte, 21, 919, 1648, 1878). For example, phenylacrylic acid yields 
phenylglyceric acid :-— 


C,H,.CH:CH.CO,H + O + H,0 = C,H,.CH(OH).CH(OH).CO,H. 
"Phenylacrylic ‘Acid. Phenylglyceric Acid. 


When the unsaturated acids are heated to 100°, with KOH or NaOH, they fre- 
quently absorb the elements of water and pass into oxy-acids. Thus, from acrylic 
acid we obtain a-lactic acid (CH,:CH.CO,H + H,O = CH,.CH(OH).CO,H), 
and malic from fumaric acid, etc. 





1. Acrylic Acid, C,H,O, = CH,:CH.CO,H, the lowest mem- 

ber of this series, is obtained according to the general methods :— 
_ (2) From iod-propionic acid by the action of alcoholic potash or 

lead oxide. 

(2) From af-dibrompropionic acid by the action of zinc and sul- 
phuric acid, or potassium iodide. 

(3) By heating 8-oxypropionic acid (hydracrylic acid). 

The best method consists in oxidizing acrolein with silver oxide. 


The aqueous solution (3 parts H,O) of acrolein is mixed with silver oxide, di- 
gested for some time in the cold and then heated to boiling. Sodium carbonate 
is next added, the filtrate concentrated and distilled with dilute sulphuric acid. 
The acrylic acid in the distillate is converted into the silver or lead salt, which is 
decomposed by heating in a current of H,S, that the acid may be obtained in an 
anhydrous condition. 


Acrylic acid is a liquid with an odor like that of acetic acid, and 
solidifies at low temperatures to crystals melting at + 7°. It boils 
at 139-140°, and is miscible with water. If allowed to stand for 
some time it is transformed into a solid polymeride. By protracted 
heating on the water bath with zinc and sulphuric acid it is con- 
verted into propionic acid. This change does not occur in the 
cold. It combines with bromine to form af-dibrompropionic acid, 
and with the halogen hydrides to yield f-substitution products of 
propionic acid (p. 224). If fused with caustic alkalies it is broken 
up into acetic and formic acids. 


The salts of acrylic acid, the silver salt excepted, are very soluble in water and 
crystallized with difficulty. They suffer decomposition when heated to 100°. 
- The st/ver salt, C,H,O, Ag, consists of shining needles which blacken at 100°. 
The ad salt, (C, H 502) 2Pb, eee in long, silky, glistening needles. 


UNSATURATED ACIDS. 237 


The ethy: ester, C,H,0,.C,H,, obtained from the ester of a-dibrompropionic 
acid by means of zinc and sulphuric acid, is a pungent-smelling liquid boiling at 
101-102°. The methyl ester boils at 85°, and after some time polymerizes to a 
solid mass. 

Substitution Products. There are two isomeric forms of mono-substituted 
acrylic acids (p. 223) :— 


CH,:CC1.CO,H and CHCI:CH.CO,H. 


a-Derivatives. B-Derivatives. 


a-Chloracrylic Acid is probably the acid which results when a{-dichlorpro- 
pionic acid is heated with alcoholic potash (Berichte, 18, 241). It crystallizes in 
needles, melts from 64-65°, and is even volatile at ordinary temperatures. It com- 
bines with HC] at 100° to produce af-dichlorpropionic acid (Berichze, 10, 1499 ; 
18, 244). 

8B-Chloracrylic Acid is produced together with dichloracrylic acid in the re- 
duction of chloralid with zine and hydrochloric acid (Axmnalen, 239, 263), also 
from propiolic acid, C,H,O, (p. 244), by the addition of HCl. It crystallizes in 
leaflets and melts at 84° (Annalen, 203, 83). The ethyl ester boils at 142-144°, 
and is most easily obtained from the ester of trichlorlactic acid by reduction with 
zinc and hydrochloric acid in alcoholic solution, The ester of dichloracrylic acid 
is obtained at the same time. 

a-Bromacrylic Acid is prepared from a- and af-dibrompropionic acids with 
alcoholic potash (Berichte, 14, 1867). It crystallizes in large plates melting at 
69-70°. It combines with HBr to form a-dibrompropionic acid. 

8-Bromacrylic Acid is obtained from the chloralid of tribromlactic acid when 
this is reduced with zine and hydrochloric acid, It may also be prepared from 
propiolic acid by the addition of HBr (Berichte, 19, 541). It consists of fine 
needles, melting at 115-116°. 

Iodoacrylic Acid, C,H,1O, (probably ), is obtained from propiolie acid by 
the addition of HI. It forms leaflets melting at 140°. There is also formed at 
the same time an acid melting at 65°, which probably is the second possible geo- 
metrical isomeride (Berichte, 19, 542). 





There are two disubstituted acrylic acids :— 


CHX:CX.CO,H and CX,:CH.CO,H. 


aB-Derivative. B-Derivative. 


a3-Dibromacrylic Acid is obtained from mucobromic acid and tribromsuccinic 
acid; and the 6-Dibromacrylic Acid from the latter and also from brompropiolic 
acid by the addition of HBr (p. 245). Both acids melt from 85-86° ( Berichie, 
19, 1396). 

sf bidntoa-aeeilis Acid, formed by the addition of iodine to propiolic acid, 
melts at 106°. $-Di-iodo-acrylic Acid is produced by the addition of HI to 
iodopropiolic acid. It melts at 133° (Berichte, 18, 2284). 


238 ORGANIC CHEMISTRY. 


2. THE CROTONIC ACIDS, C,H,0,-= C,H,.CO,H. 


According to the current representations of the constitution of 
the unsaturated monocarboxylic acids three isomerides of the above 
formula are possible :—* 

. cd. —.Ch —CH—CO,H- 2.. CHy=— CH — CH, —CO,H 


Normal Crotonic Acid. Isocrotonic Acid. 


CH, 
3 CH. cco: = 
Methylacrylic Acid. 


The first formula is attributed to the ordinary solid crotonic acid, 
while the second is ascribed to the liquid isocrotonic acid. Yet it 
would seem that the same structural formula (1) belonged to both 
acids, and that relations existed here similar to those noted with 
maleic and fumaric acids, for which the present structural formulas. 
give no explanation. 


Following J. Wislicenus, it is assumed that crotonic and isocrotonic acids have 
the same structural formula. They are geometrical or stereochemical isomerides, 
corresponding to the formulas :— 


HC.CH 3 HC.CH 8 
I| and | 
HC.CO,H HO,C.CH. 
‘Crotonic Acid. Isocrotonic Acid. 


The first occupies the plane-symmetric and the second the central symmetric 
position (p. 52). This seems to be confirmed by the formation of ordinary cro- 
tonic acid from tetrolic acid by means of sodium amalgam (Berichte, 22, 1183). 
_ The analogy with the two cinnamic acids, C,H,.CH:CH.CO,H, favors this as- 
sumption. The differences between these last two acids cannot be explained by 
structural formulas, 

Two mono-chloracids can be derived from each of the two stereo-isomeric cro- 
tonic acids (Berichte, 20, Ref. 449; 22, Ref. 51 and 816). 


1. Ordinary Crotonic Acid is obtained :— 

(1) By the oxidation of crotonaldehyde, CH,.CH:CH.COH (p. 
199). 
i5 ae the dry distillation of 8-oxybutyric acid, CH;.CH(OH). 
CH,.CO,H 
(ike): By the action of alcoholic potash upon a-brombutyric acid, 

and KI upon af-dibrombutyric acid. 

(4) From allyl iodide by means of the cyanide. 

(5) By the action of sodium amalgam on tetrolic acid (Berichie, 
21, Ref. 494). 





* A supposed fourth crotonic acid, the so-called vinyl acetic acid (from the 
so-called vinylmalonic acid) appears identical with trimethyl carboxylic acid 
derived from trimethylene. 


THE CROTONIC ACIDS. 239 


The most practicable method of obtaining crotonic acid is to 
heat malonic acid, CH,(CO,H),, with paraldehyde and acetic 
anhydride. ‘The ethidene malonic acid first produced decomposes 
into CO, and crotonic acid (p. 235) (Aznalen, 218, 147). 

Crotonic acid crystallizes in fine, woolly needles or in large plates, 
which fuse at 72° and boil at 182°. It dissolves in 12 parts water 
at 20°. . The warm aqueous solution will reduce alkaline silver solu- 
tions with the formation of asilver mirror. Zinc and sulphuric acid, 
but not sodium amalgam, convert it into normal butyric acid. It 
combines with HBr and HI to yield £-brom- and iodbutyric acid, 
and with chlorine and bromine to af-dichlor- and dibrombutyric 
acid. When fused with caustic potash, it breaks up into two mole- 
cules of acetic acid; nitric acid oxidizes it to acetic and oxalic 
acids. 


a-Chlorcrotonic Acid, CH,.CH:CCl.CO,H, is obtained when trichlorbutyric 
acid (p. 227) is treated with zinc and hydrochloric acid, or zinc dust and water. 
Further, by the action of alcoholic potash on a-dichlorbutyric ester (Berichze, 21, 
Ref. 243). It melts at 99°, boils at 212°, and is not affected when boiled with 
alkalies (see below). 

8-Chlorcrotonic Acid, CH,.CCl:CH.CO,H, is obtained in small quantities 
(together with 3-chlorisocrotonic acid) from aceto-acetic ester, and by the addition 
of HCl to tetrolic acid (Berichte, 22, Ref. 51). It melts at 94.5° and boils at 208°. 
Sodium amalgam reduces it to crotonic acid, and with boiling alkalies it yields te- 

_trolic acid (p. 244). Sodium amalgam converts both a- and /-chlorcrotonic acid 
into ordinary crotonic acid. : 

a-Bromcrotonic Acid, from the ester of dibrombutyric acid, melts at 106.5°. 
$-Bromcrotonic Acid, formed by the addition of HBr to tetrolic acid, melts at 
92° ( Berichte, 22, Ref. 243). 

(2) Isocrotonic Acid, CH,:CH.CH,.CO,H(?), is obtained from 3-chlorisocro- 
tonic acid by the action of sodium amalgam and similarly from the a-chlor-acid. It 
is a liquid which does not solidify ; boils at 172°, and has a specific gravity of 
1.018 at 25°. When heated to 170°-180°, in a sealed tube, it changes to ordi- 
nary crotonic acid. Thisalteration occurs partially, even during distillation. This 
explains why upon fusing isocrotonic acid with KOH, formic and propionic acids 
(which might be expected), are not produced, but im their stead acetic acid, the 
decomposition product of crotonic acid. Sodium amalgam does not change it. It 
combines with HI to yield (-iodo-butyric acid (Berichte, 22, Ref. 741). It yields 
a liquid dichloride, C,H,Cl,O, (Iso-a-dichlorbutyric acid), with Cl,. This passes 
into a-chlorcrotonic acid. Sodium amalgam converts this acid into butyric acid. 

a-Chlor-isocrotonic Acid, CH,.CH:CCl.CO,H (?), is obtained by the action 
of sodium hydroxide on free a{-dichlorbutyric acid. It is the most soluble of the 
four chlor-crotonic acids. It crystallizes in needles, melting at 66.5° (Berichte, 22, 
Ref. 52). 

When PCl, and water act upon aceto-acetic ester, CH,.CO.CH,.CO.C,H,, 
8-chlorisocrotonic acid (with /-chlorcrotonic acid) is produced. It is very probable 
that -dichlorbutyric acid is formed at first, and this afterwards parts with HCl. It 
is also formed by protracted heating of 6-chlorcrotonic acid. 

Sodium amalgam converts both the a- and -chlorisocrotonic acid into liquid iso- 
crotonic acid (Berichte, 22, Ref. 53). 

a-Bromisocrotonic Acid, CH,.CH:CBr.CO,H (?), is produced by the action 


240 ORGANIC CHEMISTRY. 


of sodium hydroxide upon free af-dibrombutyric acid. It melts at go°-g2° (Be- 
richte, 21, Ref. 242). /CH 
(3) Methacrylic Acid, CH,:C \.CO Hy Its ethyl ester was first obtained 
a 7 


by the action of PCl, upon oxy-isobutyric ester, (CH,),.C(OH).CO,.C,H;. It 
is, however, best prepared by boiling citrabrom-pyrotartaric acid (from citraconic 
acid and HBr) with water or a sodium carbonate solution :— 


C,H, BrO, = C,H,O, + CO, + HBr. 


It consists of prisms that are readily soluble in water, fuse at -+-16°, and boil at 
160.5°. NaHg converts the acid into isobutyric acid. It combines with HBr and 
HI to form a-brom-, and iod-isobutyric acid, and with bromine to form af-dibrom- 
isobutyric acid, which confirms the assumed constitution (Journ. pr. Chemie, 25, 
369). When fused with KOH, it breaks up into propionic and acetic acids. 


3. ACIDS OF FORMULA C,H,0, = C,H,.CO,H. 


Of the many isomerides of this formula angelic and tiglic acids appear to bear 
the same relation to each other that was observed with crotonic and isocrotonic 
acids (p. 238). Both probably have the same structural formula (Anza/en, 216, 
161). According to Wislicenus they are only geometrical isomerides. They cor- 
respond to the stereochemical formulas :— 


CH,.cCH ~ HC.CH, 
I and I 
CH,.C.CO,H CH,.C.CO,H. 
a-Methyl-isocrotonic Acid. a-Methyl-crotonic Acid. 
Angelic Acid. Tiglic Acid. 


When fused with alkalies, both acids split up into acetic and propionic acids, 
They yield methyl-ethyl acetic acid when heated with HI and phosphorus. They 
form two different dibromides with bromine; these yield two different brombuty- 
lenes (Annalen, 250, 240). 


1. Angelic Acid, C,H,.CO,H, exists free along with valeric 
and acetic acids in the roots of Angelica archangelica, and as butyl 
and amyl esters in Roman oil of cumin. 


To prepare the acid, boil the angelica roots with milk of lime, and distil the 
solution of the calcium salt with sulphuric acid. From the oily distillate, con- 
taining acetic, valeric and angelic acids, the latter crystallizes on cooling. The 
ang of Roman cumin oil with potash, also furnishes the acid (dzza/len, 
250, 242). . 

Roman oil of cumin (from Artemis nodilis) contains the esters of several acids. 
The following fractions may be obtained from that portion of it which boils up to 
210° :— 

1. Isobutyl butyrate, boiling 147-—148°. 
OF “+ Cangelate, “> 199-478". 
3. Amyl angelate, “200-2019. 
4. Amy] tiglate, “6 204-205°. 


When these esters are saponified and distilled with sulphuric acid, the free acids 
are obtained. We can separate angelic and tiglic acids by means of the calcium 
salts, that of the first being very readily soluble in cold water. (Berichte, 17, 
2261). 2 


TERACRYLIC ACID. 241 


Angelic acid crystallizes in shining prisms, melts at 45°, and boils - 
at 185°. When boiled for some time it is converted into tiglic 
acid. Concentrated sulphuric acid at 100°, effects the same. The 
acid dissolves readily in hot water and alcohol. It is volatile with 
steam. Its ethyl ester, C;H,O,.C,H;, boils at 141°. 


2. a-Methylcrotonic Acid, CH,.CHiCC 65" (?) Tiglic Acid, present in 

2°" 9 5 
Roman oil of cumin (see above), and in Croton oil (from Croton tiglum), is a 
mixture of glycerol esters of various fatty and oleic acids. It is obtained artificially 


by acting with PCl, upon methyl-ethyl oxy-acetic acid, CH oS C(OH).CO,H 
eee 


(its ester), and from a-methyl-3-oxybutyric acid, CH ,.CH(OH).CH(CH,).CO,H, 
on heating the latter to 200° (Anzmalen, 250, 243). 

Tiglic acid crystallizes in prisms or tables, is soluble with difficulty in water, 
melts at 64.5°, and boils at 198°. Its ethyl ester, C;H,O,.C,H,, boils at 152°. 

3. Allyl-acetic Acid, CH,:CH.CH,.CH,.CO,H, obtained from allyl-aceto- 
acetate and allyl malonic acid (p. 235), is an oil, smelling like valeric acid, and 
boiling at 188°. Nitric acid oxidizes it to succinic acid. It unites with concen- 
trated hydrobromic acid, and forms y-bromvaleric acid (a non-solidifying oil), 
which, upon heating with water, parts with HBr and yields the lactone of y-oxy- 
valeric acid (see Lactones). 

4. Propylidene Acetic Acid, CH,.CH,.CH:CH.CO,H, is obtained from 
propylidene malonic acid, C,H,:C(CO,H), (p. 235), and boils at 196° (Azna- 
len, 218, 160). It has also been obtained from pyrocatechol and amidophenol 
(Berichte, 22, 495). 

5. Ethidene Propionic Acid, CH,.CH:CH.CH,.CO,H, is produced by the 
distillation of methyl paraconic acid,C,H,O,. It is a liquid boiling at 104°. It 
unites with HBr to y-bromvaleric acid, which readily passes into valerolactone 
(Berichte, 23, Ref. 91). 

6. Dimethyl Acrylic Acid, (CH,),C:CH.CO,H, is obtained from f-oxy- 
isovaleric acid, (CH,),.C(OH).CH,.CO,H, by distillation with dilute sulphuric 
acid. It melts at 70°. 

Tetramethylene carboxylic acid (see this) is isomeric with these unsaturated 
acids. 

The following higher, unsaturated acids, may also: be mentioned. Little is 
known concerning their constitution. They frequently sustain molecular transpo- 
sitions :— 

Pyroterebic Acid, C,H,,O, = (CH;),.C:CH.CH,.CO,H, is formed in small 
quantity (together with the isomeric lactone of y-oxy-isocaproic acid) (see this), in 
the distillation of terebic acid, C,H,,O, (Anunalen, 208, 39 and 119). It is an oil 
which does not solidify at —15°. The calcium salt, (C,H,O,),Ca + 3H,0, 
crystallizes in shining prisms. Protracted boiling causes the free acid to change 
to isomeric isocaprolactone :— 


(CH,),.C:CH.CH,.CO,H forms (CHy), GCH..CH, 


? 


PE 2 


concentrated hydrobromic acid effects the same change. 

Teracrylic Acid, C,H,,0, = C,H,.CH:CH.CH,.CO,H, is obtained by the 
distillation of terpentic acid, C,H,,O, (see this), just as pyroterebic acid is formed 
from terebic acid. An oily liquid, with an odor resembling that of valeric acid, 
and boiling at 208° without decomposition. HBr converts it into the isomeric 
lactone of y-oxyheptoic acid, C,H, ,(OH)O,° 


a 


242 ORGANIC CHEMISTRY. 


Nonylenic Acid, C,H,,O0, = CH,(CH,);CH:CH.CO,H, is obtained from 
cenanthol (p. 198) by Perkins’ reaction (p. 234). It is an oily liquid, which vola- 
tilizes with steam. 

Decylenic Acid, C,,H,,0,, formed together with decylacetone in the distilla- 
tion of hexylparaconic acid ( Berichte, 18, Ref. 144), solidifies in the cold and melts 
at + 10° C. 

Undecylenic Acid, C,,H,,0,, is produced by distilling castor oil under 
reduced pressure, when the ricinoleic acid, C,,H,,O, (p. 243), present as a glycer- 
ide, breaks up into cenanthol, C,H,,O, and undecylenic acid. It melts at 24.5°, 
and boils with partial decomposition at 275°. It distils unchanged under reduced 
pressure. When fused with caustic potash, it splits up into acetic and nonoic 
acid, C,H,,O. Hence its structure corresponds to the formula, C,H, ,.CH:CH. 
CO,H (compare Berichte, 19, Ref. 338, and 19, 2224); 

Hypogeic Acid, C,,H,,O,, found as glycerol ester in earthnut oil (from the 
fruit of Arachis hypogea), crystallizes in needles, and melts at 33°. Nitrous acid 
converts it into an isomeric modification—gaeidinic acid, melting’ at 38°. 


Oleic Acid, C,,H,,0O,, occurs as glycerol ester (triolein) in 
nearly all fats, especially in the oils, as olive oil, almond oil, cod- 
liver oil, etc. It is obtained in large quantities as a by-product in 
the manufacture of stearin candles. 


In preparing oleic acid, olive or mandel oil is saponified with potash and the 
aqueous solution of the potassium salts precipitated with sugar of lead. The lead 
salts which separate are dried and extracted with ether, when lead oleate dissolves, 
leaving as insoluble lead palmitate, stearate and the salts of all other fatty acids. 
Mix the ethereal solution with hydrochloric acid, filter off the lead chloride, and 
concentrate the liquid. To purify the acid obtained in this way, dissolve it in am- 
monium hydroxide, precipitate with barium chloride, crystallize the barium salt 
from alcohol, and decompose it away from the air by means of tartaric acid. 


Oleic acid is a colorless oil, which crystallizes on cooling. It 


melts at -- 14°. Ina pure condition it is odorless, and does not 
/redden litmus. On exposure to the air it oxidizes, becomes yellow 


and acquires a rancid odor. On fusion with caustic potash it splits 
up into palmitic and acetic acids. Nitric acid oxidizes it with for- 
mation of all the lower fatty acids from capric to acetic, and at the 
same time dibasic acids, like sebacic acid, are produced. A per- 
manganate solution oxidizes it to azelaic acid, C,H,,O,. Moderated 
oxidation produces dioxystearic acid. The oleates are very similar 
to the salts of the fatty acids. Much water decomposes them. 
The solubility of the lead salt, (C,;H;,0,),.Pb, in ether is charac- 
teristic. 

When heated to 200° with hydriodic acid and phosphorus, or 
with iodine (1 %) to 280°, oleic changes to stearic acid, C,;H,,0,. 
It unites with bromine to form liquid dibromstearic acid, C,,H,,Br,O,, 
which is converted by alcoholic KOH into monobromoleic acid, 
C,,;H;,;BrO,, and then into stearoleic acid. 

2 


LINOLEIC ACID. 243 


Nitrous acid changes oleic into the isomeric crystalline 

Elaidic Acid, C,,H,,O,. This consists of brilliant leaflets, 
melting at 44°-45°. If fused with potash it decomposes into pro- 
pionic and acetic acids. Hydriodic acid and phosphorus convert 
it into stearic acid. With bromine it yields the bromide, C,,H;,Br, 
O,, which melts at 27°, and when acted upon with sodium amal- 
gam, passes back into elaidic acid. 


Tso-oleie acid, obtained -by the distillation of oxystearic acid, appears to be dif- 
ferent from elaidic acid. It also melts at 45° (Berichte, 21, Ref. 398; 21, 1879). 

Erucic Acid, C,,H,,0O,, is present as glyceride in rape-seed oil (from Bras- 
sica campestris) and in the fatty oil of mustard. For its preparation, rape-seed oil 
is saponified with lead oxide, and the lead erucate removed with ether. Erucic 
acid crystallizes from alcohol in long needles, which melt at 33°-34°. It forms 
a dibromide, C,,H,,Br,O,, with bromine. This crystallizes in warty masses, 
melting at 42°, and when acted upon with alcoholic potash, changes to bromerucic 
acid, melting at 33°. 

Hot nitric acid (Berichte, 19, 3321) converts erucic acid into isomeric drassidic 
acid, melting at 56°. 

The fetrolic acids, found in the different varieties of petroleum, are isomeric 
with the oleic acids. Up to the present time the following have been isolated: 
C,,H,,0., C;}3;H,40, and C,,H,,0,. In all probability they are the carbox- 
ylic acids of the naphthenes (p. 78) (Berichte, 20, 596; 23, 868). 


Linoleic and ricinoleic acids, although nof belonging to the same 
series, yet closely resemble oleic acid. The first is a simple, unsat- 
urated acid, the second an unsaturated oxy-acid. 

Linoleic Acid. C,,H;,0,, occurs as glyceride in drying oils (see 
glycerol), such as linseed oil, hemp oil, poppy oil and nut oil. In 
the zon-drying oils we have the oleic-glycerol ester. To prepare 
linoleic acid, saponify linseed oil with potash, precipitate the aque- 
ous solution of the potassium salt with calcium chloride and dis- 
solve out calcium linoleate with ether. Linoleic acid is a yellowish 
oil that has a specific gravity of 0.921. It is not altered by nitrous 
acid. 


Various oxy-fatty acids are produced when linoleic acid is oxidized with potas- 
sium permanganate. From the fact that they can be formed it has been concluded 
that certain other acids (like linolenic and isolinolenic acid, C,,H,,O,) exist in 
the crude linoleic acid (Berichte, 21, Ref. 436 and 659). 


Ricinoleic Acid, C,,H;,O;, is present in castor oil, in the form 
of a glyceride. It is a colorless oil, which solidifies in the cold to 
a hard, white mass, melting at 16-17°. The lead salt is soluble in 
ether. Subjected to dry distillation ricinoleic acid splits into 
cenanthol, C,H,,O, and undecylenic acid, C,,H»O,. Fused with 
caustic potash it changes to sebacic acid, C,;H,(CO,H),, and 


CHis\cH.OH. It combines with bro- 


secondary octyl alcohol, CH, / 
3 


244 ORGANIC CHEMISTRY. 


mine to a solid abromide. When heated with HI (iodine and 
phosphorus) it is transformed into iodstearidic acid, C,,H,,IO,, 
which yields stearic acid when treated with zinc and hydrochloric 
acid. Nitrous acid converts ricinoleic acid into isomeric ricine- 
laidic acid. ‘This melts at 53°C. (see Berichte, 21, 2735). 


UNSATURATED ACIDS, Cy HonsO,. 
PROPIOLIC ACID SERIES. 


The members of this series have four hydrogen atoms less than 
the normal acids. ‘They can be obtained from the acids of the 
acrylic series by treating the halogen derivatives of the latter with 
alcoholic potash—just as the acetylenes are produced fom the ole- 
fines (see p. 87). Thus tetrolic acid, C,H,O,, is obtained from the 
bromide of crotonic acid, C,H,Br,O,, and from bromcrotonic acid, 
C,H;BrO,. They must be viewed as acetylene derivatives, formed 
by the replacement of one hydrogen atom by carboxyl; conse- 
quently they can be obtained by letting CO, act upon the sodium 
compounds of acetylene (p. 88) :— 

CH,.C: CNa + CO, = CH,.C: C.CO,Na. 
Sodium Allylene. Sodium Tetrolate. 
Like the acetylenes’they are capable of directly binding 2 and 
4 affinities. From their structure they may contain one triple union 
or two double unions of two carbon atoms (see p. 87). 
Propiolic Acid, C,H,O, CH: C.CO,H, Propargylic Acid 
(p. 135), corresponds to propargyl alcohol. ‘The fotassium salt, 
- C,HKO, -++ H,O, is produced from the primary potassium salt of 
acetylene dicarboxylic acid, when its aqueous solution is heated :— 
C.CO,H CH 
I =|I| + CO;. 

3 COOK CO. 

Acetic acid results in like manner from malonic acid (p. 212). 

The aqueous solution of the salt is precipitated by ammoniacal 
silver and cuprous chloride solutions, with formation of explosive 
metallic derivatives. By prolonged boiling with water the potassium 
salt is decomposed into acetylene and potassium carbonate. 

Free propiolic acid, liberated from the potassium salt, is a liquid 
with an odor resembling that of glacial acetic acid. When cool it 
solidifies to silky needles which melt at + 6°. The acid dissolves 
readily in water, alcohol and ether, boils with decomposition at 144° 
and reduces silver and platinum salts. Exposed to sunlight (away 
from air contact) it polymerizes to trimesinic acid, 3C,H.CO,H = 
C,H,(CO,H);. Sodium amalgam converts it into propionic acid. 
It forms #-halogen acrylic acids with the halogen acids (p. 237) 
(Berichte, 19, 543)- 


UNSATURATED ACIDS. 7 245 


The ethyl ester, C, HO,.C,H,, is formed on digesting the acid with alcohol and 
sulphuric acid. It boils at 119°. With ammoniacal cuprous chloride it unites to 
a stable yellow-colored compound. Zinc and sulphuric acid reduce it to ethyl 
propargylic ester (p. 135) (Berichte, 18, 2271). 

Chlorpropiolic Acid, C, HCIO,, and Brompropiolic Acid, C,BrHO,, have 
been obtained as barium salts from dichloracrylic and mucobromic acids, C,H,Cl,O, 
and C,H,Br,O,. They are readily decomposed with evolution of chlor- and brom- 
acetylene. LIodopropiolic Acid, C,HIO, = CI: C.CO,H, is obtained by saponi- 
fying its ethyl ester with NaOH. It crystallizes from ether in small prisms, melting 
at 140°. On warming its alkali salts with water carbonates and iodoacetylene are 
produced. The acid combines with iodine to form tri-iodo-acrylic acid, C,HI,O, 
( Berichte, 18, 2274 and 2282). The ethyl ester, C,IO,.C,H,;, may be prepared 
from the Cu- derivative of propiolic ester (see above) by the action of iodine. It 
crystallizes from ether in large prisms, melting at 68°. What-is remarkable about 
this compound is the stable union of the iodine contained in it (Berichte, 19, 540). 

Tetrolic Acid, C,H,O, = CH,.C: C.CO,H, is obtained from -chlorcrotonic 
acid and £-chlorisocrotonic acid (p. 239) when these are boiled with potash 
(Annalen, 219, 346); from sodium allylene by the action of CO, (see above), and 
from ‘the chloride of allylene by means of Na and CO,. The acid consists of tables, 
very readily soluble in water, alcohol and ether. It melts at 76° and boils at 203°. 
At 210° the acid decomposes into CO, and allylene, C,H,. Potassium perman- 
ganate oxidizes it-to acetic and oxalic acids. It combines with HCl and forms 
£-chlorcrotonic acid. 

Propyl-acetylene Carbonic Acid, C,H,.C : C.CO,H, from propylacetylene 
sodium, C,H,.C : CNa, melts at 27°. Isopropyl-acetylene Carbonic Acid, 
from isopropyl! acetylene, melts at 38° (Berichte, 21, Ref. 178). 

Sorbic Acid, C,H,O, — C,H,.CO,H, occurs together with malic acid in the 
juice of unripe mountain-ash berries (from Soréis aucuparia). Liberated from its 
salts by distillation with sulphuric acid (Anmna/len, 110, 129) it is an oil which does 
not solidify until after it has been heated with potash. In cold water it is almost 
insoluble, but crystallizes from alcohol in long needles, melting at 134.5°, and dis- 
tilling at 228° without decomposition. It combines with bromine and yields the 
bromides, C,H,Br,O, and CgH,Br,O,—the first melting at 95° and the second at 
183°. The ethyl ester boils at 195°. Nascent hydrogen converts the acid into 
hydrosorbic acid, C,H,,O,. This possesses an odor like that of perspiration, 
boils at 208°, and, when fused with KOH, yields acetic and butyric acids. 

Diallylacetic Acid, C,H,,0, = (C,H,),.CH.CO,H, is obtained from ethyl 
diallyl-aceto-acetate and diallyl malonic acid. It is a liquid, boiling at 221°. 
Nitric acid oxidizes it to tricarballylic acid :— 


CH,.CH:CH, CH,.CO,H 
| 
Diallyl-acetic Acid CH.CO,H yields CH.CO,H Tricarballylic Acid. 


€ | 
CH,.CH:CH, CH,.CO,H 


Undecolic Acid, C,,H,,O,, is obtained from the bromide of undecylenic acid 
(p. 242). It fuses at 59.5°. Palmitolic Acid, C,,H,,O,, isomeric with linoleic 
acid (p. 243), is obtained from the bromide of hypogzeic acid and gzidinic acid 
(p. 242). It melts at 42°. Stearoleic Acid, C,,H,,0O,, is obtained from oleic 

and elaidic acids. It melts at 48°. Behenolic Acid, C,,H,,O,, from the bro- 

mides of erucic and brassidic acids, melts at 57.5°. On warming the last three 
acids with fuming nitric acid they absorb 3 atoms of oxygen in a very peculiar 
manner, and yield the monobasic acids: palmitoxylic, C,,H,,04, stearoxylic, 
C,,H3,04, and dbehenoxylic, C,,.H, O04, which melt at 67°, 86° and 96°, 
respectively. . 


246 ORGANIC CHEMISTRY. 


DERIVATIVES OF THE ACIDS. 


1. THE ACID HALOIDS. 


The haloid anhydrides of the acids (or acid haloids) are those 
derivatives which arise in the replacement of the hydroxyl of acids 
by halogens; they are the halogen compounds of the acid radicals 
(p. 213). Their most common method of formation consists in 
letting the phosphorus haloids act upon the acids or their salts—just 
as the alkylogens are produced from the alcohols (p. 92). 


(1) At ordinary temperatures phosphorus pentachloride acts very energetically 
upon the acids :— 


we C,H,0.0H + PCI, = se + POCI, + HCl. 


The product of the reaction is subjected to/fractional distillation. It is better 
to have PCl, act upon the alkali salts or the free acids; heat is then not neces- 
sary :— 


3C,H;0.0K + PCI, = 3C,H,0.Cl + PO,K,. 


By this method the pure acid chloride is at once obtained in the distillate— 
while the phosphite remains as residue. Or, phosphorus oxychloride (1 molecule) 
may be permitted to act on the dry alkali salt (2 molecules) when a metaphosphate 
will remain :— 


2C,H,0.0Na + POCI, — 2C,H,0.Cl + PO,Na + NaCl. 


Should there be an excess of the salt, the acid will also act upon it and acid anhy- 
drides result (p. 248). 

Phosphorus bromides behave similarly. A mixture of amorphous phosphorus 
and bromine may be employed as a substitute for the prepared bromide (p. 95). 
Phosphorus iodide will not convert the acids into iodides of the acid radicals; 
this only occurs when the acid anhydrides are employed. 

(2) Carbon oxychloride acts upon the free acids and their salts the same as the 
chlorides of phosphorus. Acid chlorides and anhydrides are producéd. This 
method has met with technical application (Berichte, 17, 1285; 21, 1267) :— 


v C,H,0.0H + COCI, = C,H,OCl + CO, + HCL. 


(3) An interesting method for preparing the acid bromides consists in letting 
air act upon certain bromide derivatives of the alkylens, whereby oxygen will be 
absorbed. Thus, from CBr,:CH, we obtain bromacetyl bromide, CH,Br.COBr ; 
from CBr,: CHBr, dibromacetyl bromide, CBr,H.COBr (p. 97 and Berichte, 13, 
1980; 21, 3356). 


The acid haloids are sharp-smelling liquids, which fume in the 
air, because of their transformation into acids and halogen hydrides. 
They are heavier than water, sink in it, and at ordinary tempera- 
tures decompose, forming acids :— 


C,H,0.Cl + H,O = C,H,0.0H + HCl. 


The more readily soluble the resulting acid is in water, the more 
energetic will the reaction be. 


ACID CYANIDES. 247 


The acid chlorides act similarly upon many other bodies. They 
yield compound ethers, or esters, with the alcohols or alcoholates 
(p. 251). With salts or acids they yield acid anhydrides (p. 248), 
and with ammonia, the amides of the acids, etc. 

Sodium amalgam, or better, sodium and alcohol, will convert the 
acid chlorides into aldehydes and alcohols (pp. 122 and 188). They 
yield ketones and tertiary alcohols when treated with the zinc alkyls 
(pp. 200 and 120), < 





Acetyl Chloride, C,H,OCl — CH;.CO.Cl, is produced also by 
the action of hydrogen cl chloride and phosphorus pentoxide upon 
acetic acid, and when chlorine acts on aldehyde. It is a colorless, 
pungent- -smelling liquid which boils at 55°, and has.a specific gravity 
of 1.130 at o°. Water decomposes it very energetically. 


Preparation.—Bring PCI, into a retort with a tubulure, and through the latter 
gradually add anhydrous acetic acid. After the first violent action, apply heat and 
fractionate the distillate. It would be better to distil carefully a mixture of acetic 
acid (3*parts) and PCI, (2 parts). Or, heat POCI, (2 molecules) with acetic acid 
(3 molecules), as long as HCf esc , then distil (Annalen, 175, 378). The 
acetyl chloride is purified by again distilling over a little dry sodium acetate. 

Acetyl chloride forms the following substitution products with chlorine: 
C,H,CI10.Cl, boiling at 106°; C,HCI,O.Cl and C,Cl,0.C1; the latter boil at 118°. 
These are also obtained when phosphorus chloride acts on the substituted acetic 
acids. Monobromatetyl chloride, C,H, BrO.Cl, boils at 134°. 

Acetyl Bromide, C,H,0O. Br, boils at 81° and forms substitution products with 
bromine. Monochloracetyl Bromide, C,H,ClO.Br, from monochloracetic acid, 
boils at 134°. 

Acetyl lodide, C,11,0.1, is obtained by letting I ond P act upon acetic an- 
hydride. It boils at 108° and is colored brown by separated iodine. 

Propi®hyl Chloride, CH,.CH,.CO.Cl, boils at 80°; the dromide, C,H,O.Br, 
at 97°, and the zodide, CyH 0.1, at 127°. 

Butyryl Chloride, C,H,O.Cl, from normal butyric acid, boils at 101°. Sodium 
amalgam converts it into normal butyl alcohol. Isobutyryl Chloride, (CH,),. 
CH.CO.Cl, boils at 92°. 

Isovaleryl Chloride, C,H,O.Cl, from isovaleric acid, boils at 115°. 





2, ACID CYANIDES. 


When.the chlorides of the acid radicals are heated with silver cyanide, cyanides 
of the acid radicals, like acetyl cyanide, CH,.CO.CN, result. They can also be 
obtained by the action of dehydrating agents, e¢. e. , acetic anhydride upon isonitroso- 
ketones (Berichte, 20, 2196) :— 


CH,.CO.CH:N.OH = CH,.CO.CN + H,O.. 


Water or alkalies will readily convert these into their corresponding acids and 
hydrogen cyanide, CH,.CO.CN + H,O = CH,.CO.OH + CNH. With con- 


248 ORGANIC CHEMISTRY. 


centrated hydrochloric acid, on the contrary, they sustain a transposition similar 
to that of the alkyl cyanides (p. 211), z. ¢., carboxyl derivatives of the acid radi- 
cals—the so-called a-ketonic acids (see these)—are produced :— 


CH,.CO.CN’-- 2H,O + HCl = CH,.CO.CO,H + NH,Cl. 


Acetyl Cyanide, CH,.CO.CN, boils at 93°. When preserved for some time, 
or by the action of KOH or sodium, it is transformed into a polymeric, crystalline 
compound, (C,H,OCN),, diacetyl cyanide. This melts at 69° and boils at 208°. 
Concentrated hydrochloric acid converts it into pyroracemic acid. 

Diacetyl cyanide is also produced by the action of potassium cyanide upon acetic 
anhydride (Berichze, 18, 256). 

Propionyl Cyanide, CH,.CH,.CO.CN, from propiony] chloride, boils at 108- 
110°. Dipropionyl Cyanide, (C,H,O.CN),, formed by the action of silver 
cyanide upon propionyl bromide, melts at 59°, and boils at 200—-210° ( Berichde, 
18, Ref. 140). Butyryl Cyanide, C,H,.CO.CN, boils at 133-137°; isobutyryl 
cyanide, C,H,.CO.CN, at 118-120°. These polymerize readily to dicyanides. 





3. ACID ANHYDRIDES AND PEROXIDES. 


The acid anhydrides are the oxides of the acid radicals. In those 
of the monobasic acids two acid radicals are united by an oxygen 
atom ; they are analogous to the oxides of the monovalent alcohol 
radicals—the ethers. They cannot, however, be made by the 
direct withdrawal of water trom the acids. Anhydrides do indeed 
result by the action of P,O;, but their quantity is very small. The 
following methods are employed in their preparation :— 

(1) The chlorides of the acid radicals are allowed to act on anhy- 
drous salts, viz., the alkali salts of the acids :— 


2 
C,H,O\, 


C,H,0.0K + C,H,0.Cl= 64776 D 


O + KCl. 
The simple anhydrides, those containing two sémd/ar radicals, can as a general 


thing be distilled, while the #zxed anhydrides, with two dissimilar radicals, decom- 
pose when thus treated, into two simple anhydrides :— 


C4005 CIOS CADX } 
PCH OF, -Ca1.07- + CHO” ’ 
Hence they are not separated from the product of the reaction by distillation, but 
are dissolved out with ether. 
A direct conversion of the acid chlorides into the corresponding anhydrides may 


be effected by permitting the former to act upon anhydrous oxalic acid (Anuza/en, 
226, 14):— 


2C,H,OCl + C,0,H, = (C,H,O,)O + 2HCl + CO, + CO. 


(2) Phosphorus oxychloride (1 molecule) acts upon the dry 
alkali salts of the acids (4 molecules). The reaction is essentially 


SSE: A inreataeiNiesusli 


ACID ANHYDRIDES AND PEROXIDES, "249 


the same as the first. The acid chloride which appears in the 
beginning acts immediately upon the excess of salt :— 


2C,H,O.OK + POCl, =2C,H,O.Cl + PO,K + KCl, and 
C,H,0.OK + C,H,0.Cl = (C,H,0),0 + KCl. 


Phosgene, COCI,, acts like POCI,. In this reaction acid chlorides are also 
produced. 

The anhydrides of the fatty acids can be produced further by the action of acetyl 
chloride on the latter ( Berichte, 10, 1881). 





The acid anhydrides are liquids or solids of neutral reaction, 
and are soluble in ether. Water decomposes them into their 
constituent acids :— 


(C,H,0),0 + H,O = 2C,H,0.0H. 
With alcohols they yield the acid esters (p. 251) :— 
(C,H,0),0 -- C,H,.0H = “Ee 50 +. C,H,0.0H. 
2°75 


Chlorine splits them up into acid chlorides and chlorinated 
acids :— 


(C,H,0),0 + Cl, = C,H,0.Cl + C,H,CIO.OH. a 
Heated with hydrochloric acid they decompose into an acid 
chloride and free acid :— ee 
(C,H,0),0 + HCl = C,H,0.CI'+ C,H,0.0H. 


HBr and HI act similarly. Asthe heat modulus is positive in this reaction, the 
reverse reaction (action of acid chloride upon the acid) is generally not adapted 
to the formation of anhydrides (compare Avua/en, 226, 5). 





_ Acetic Anhydride—Acetyl Oxide, (C,H,O),0, is a mobile 
liquid boiling at 137°. Its specific gravity equals 1.073 at 0°. 

To prepare it, distil a mixture of anhydrous sodium acetate (3 parts) with 
phosphorus oxychloride (1 part); or, better, employ equal quantities of the salt 


and acetyl chloride. The distillate is redistilled over sodium acetate, to entirely 
free it from chloride. 


Nascent hydrogen converts it first into aldehyde and then into 
alcohol (p. 188). 


Propionic Anhydride or Propionyl Oxide, (C,H,O),O, boils at 168°. Bu- 
tyric Anhydride, (C,H ,O)., boils near 190°; its specific gravity 0.978 at 
21 ? ; 





— 250 ORGANIC CHEMISTRY. 


12.5°. Isovaleric Anhydride, (C;H,O),O, boils with partial decomposition 
about 215°. Its specific gravity at 15° equals 0.934. It possesses an odor like 
that of apples. 
The higher anhydrides do not volatilize without undergoing decomposition. 
Speitae Anhydride, (C,H,,O),O, melts at 0°. Myristic Anhydride, (C,, 
H,,O),0, forms a fatty mass, fusing at 54°. : 





The peroxides of the acid radicals are produced on digesting the chlorides or 
anhydrides in ethereal solution with barium peroxide :— 


2C,H,0.Cl + BaO, =(C,H,0),0, + BaCl,. 


ok Peroxide is a thick liquid, insoluble in water, but readily dissolved by 
alcohol and ether. It is a powerful oxidizing agent, separating iodine from potas- 
sium iodide solutions, and decolorizing a solution of indigo. Sunlight decomposes 
it, and when heated it explodes violently. With barium hydroxide it yields 
barium acetate and barium peroxide. 





4. THIO-ACIDS AND THIO-ANHYDRIDES. 


The thio-acids, ¢. g., thio-acetic acid, CH;.CO.SH, correspond 
to the thio-alcohols or mercaptans (p. 140), and are produced by 
analogous methods: by the action of acid chlorides upon potassium 
sulphydrate, KSH, and by heating acids with phosphorus penta- 


sulphide :— 
5C,H,0.0H + P,S, = 5C,H,0.SH + P,0,. 


The ¢hio-anhydrides arise in the same manner by the action of 
phosphorus sulphide upon the acid anhydrides. 

The thio-acids are disagreeably-smelling liquids, more insoluble 
in water and possessing lower boiling temperatures than the corre- 
sponding oxygen acids. Like the latter, they yield salts and esters. 
When heated with dilute mineral acids they break up into H,S and 
fatty acids. Water slowly decomposes the thio-anhydrides into a 
thio-acid and an oxy-acid. 


The esters are obtained when the alkylogens react with the salts of the thio- 
acids, and by letting the acid chlorides act upon the mercaptans or mercaptides :— 
C,H,0.Cl + C,H,.SNa = C,H,0.8.C,H,; + NaCl. 


They also appear in the decomposition of alkylic isothio-acetanilides with dilute 
hydrochloric acid :— 
S.C,H 
CH.CCN CH, + H,O = CH,.CO.S.C,H, -+ NH,.C,H,. 


Ethyl-isothio-acetanilide. Thioacetic Ester. Aniline, 


ESTERS OF THE FATTY ACIDS. 251 


Concentrated potash resolves the esters into fatty acids and mercaptans. E, 

Thiacetic Acid, C,H,O.SH, is a colorless liquid, boiling at 93°, and having 
a specific gravity of 1.074 at 10°. Its odor resembles that of acetic acid and hydro- 
gen sulphide. It is sparingly soluble in water, but dissolves readily in alcohol and 
ether. The /ead salt, (C,H,O.S),Pb, crystallizes in delicate needles, and readily 
decomposes with formation of lead sulphide. Ethyl Thiacetate, C,H,O.S.C,H,, 
boils at 115°. ; 

Acetyl Sulphide, (C,H,0),S, is a heavy, yellow liquid, insoluble in water ; 
and is slowly decomposed by this liquid into acetic acid and thiacetic acid. It 
boils at 121°. ; 

Acetyl Disulphide, (C,H,0),S,, is produced when acetyl chloride acts upon 
potassium disulphide, or iodine upon salts of the thio-acids :— 


2C,H,0.SNa + I, = (C,H,0),S, + 2Nal. 





5. ESTERS OF THE FATTY ACIDS. 


The esters of organic acids resemble those of the mineral acids in 
all respects (p. 146), and are prepared by analogous methods : — 

(1) By the action of acid chlorides (or acid anhydrides, p. 246) 
on the alcohols or alcoholates :— 


_————_ C,H, 0.Cl + C,H,.0H = 674; °>0 + HCL. 
2 oe 


Transpositions frequently occur when alcoholates are used, for example, when 
ethyl ester is converted into a methyl ester by the action of methyl sodium. It is 
also true in the reverse case (Berichte, 20, 1554). 


(2) By the action of the alkylogens upon salts of the acids :— 


C,H, 0 


- C,H,Cl + C,H,0.0Na = 7 
F ieseas  h 


>O + NaCl. 
(3) By the dry distillation of a mixture of the alkali salts of the 
fatty acids and salts of alkyl sulphates (p. 149) :— 


0.C,H CHN 
KOR : + C,H,0.OK = SO,K, ~- CH, o>: 


SO 
(4) By direct action of acids and alcohols, whereby water is 
formed at the same time :— 


2  C,H,.OH + C,H,0.0H = C,H,.0.C,H,O + H,0. 


This transposition, as already stated, only takes place slowly 
(p. 147); heat hastens it, but it is never complete. If a mixture 
of like equivalents of alcohol and acid be employed, there will 
occur a time in the action when a condition of equilibrium will 
prevail, when the ester formation will cease, and both acid and 
alcohol will be simultaneously present in the mixture. ‘This ensues, 


252 ORGANIC CHEMISTRY. 


because the heat modulus of the reaction is very slight, and hence, 
in accordance with the principles of thermo-chemistry, and under 
slightly modified conditions, the reaction pursues a reverse course, 
i. é., the ester is decomposed by more water into alcohol and acid, 
since heat is generated when they are dissolved by the water. Both 
reactions mutually limit themselves. With excess of alcohol, more 
acid can be changed to ester, and with excess of acid more alcohol. 
The formation of the esters is more complete and rapid, if the re- 
action products are assiduously withdrawn from the mixture. This 
may be effected either by distillation (providing the ester is readily 
volatilized), or by combining the water formed with sulphuric or 
hydrochloric acid, when the heat modulus will be appreciably aug- 
mented.* We practically have from the above the following 
methods of preparation. Distil the mixture of the acid or its salt 

- with alcohol and sulphuric acid. Or, when the esters volatilize with 
difficulty, the acid or its salt is dissolved in excess of alcohol (or 
the alcohol in the acid), and while applying heat, HCl gas is con- 
ducted into the mixture (or H,SO, added), and the ester precipi- 
tated by the addition of water. The acid nitriles can be directly 
converted into esters, by dissolving them in alcohol, and heating 
them with dilute sulphuric acid (p. 211). 


Berthelot has executed more extended investigations upon the es¢er formation. 
These are of great importance to chemical dynamics. He observed, for instance, 
that the reaction is materially accelerated by heat, but that a limit to the ester 
production invariably occurs, and that it equals that of the reverse transposition 
of the esters by water. This limiting point is independent of the speed of the 
reaction and temperature, but is controlled by the relative quantities, as well as 
the nature of the alcohol and acid. According to Berthelot the speed of the ester 
formation in the case of the primary normal alcohols is almost the same; the 
degree of the conversion or transposition equals about 66 per cent. of the mix- 
ture (with equivalent quantities of alcohol and acid). Proceeding from the simple 
assumption that the quantities of alcohol and acid combining in a unit of time 
(speed of reaction) are proportional to the product of the reacting masses, whose 
quantity regularly diminishes, Berthelot has proposed a formula (Ammalew chim. 
phis., 1862) by which the speed of the reaction in every moment of time, and its 
extent, can be calculated. van’t Hoff has deduced a similar formula ( Berzchie, 
10, 669), which Guldberg-Waage and Thomsen pronounce available for all lim- 
ited reactions (z/id, 10,1023). Fora tabulation of the various calculations relating 
to this matter, see Berichte, 17, 2177; 19,1700. Of late Menschutkin has ex- 
tended the investigations upon ester formations to the several homologous series of 
acids and alcohols (Amnalen, 195, 334 and 197, 193; Berichte, 15, 1445 and 
1572; 21, Ref. 41). 


Usually the esters of fatty acids are volatile, neutral liquids, sol- 
uble in alcohol and ether, but generally insoluble in water. Heated 
_with the latter they sustain a partial decomposition into alcohol and 





* Consult Annalen, 211, 208. 


ESTERS OF FORMIC ACID. 253 


acid. This decomposition (saponification) is more rapid and com- 
plete on heating with alkalies in alcoholic solution :— 


C,H,0.0.C,H, + KOH = C,H,0.0K + C,H,.OH. 


Consult Annalen, 228, 257, and 232, 103; Berichte, 20, 1634, upon the velocity 
of saponification by various bases. 
Ammonia changes the esters into amides (p. 256) :— 


C,H,0.0.C,H, + NH, =C,H,;.0.NH, + C,H,.OH. 
The haloid acids convert the esters into acids and haloid-esters (Amsaden, 211, 
Bae C,H,0.0.C,H, + HI = C,H,0.0H + C,H, 
PCI, introduces chlorine, and the radicals are converted into halogen deriva- 


tives :— 


C,H,0.0.C,H, + PCl, =C,H,0.Cl + C,H,Cl-+ POCI,. 


The esters of the fatty acids possess an agreeable fruity odor, are 
prepared in large quantities, and find extended application as @7/z- 
ficial fruit essences. Nearly all fruit-odors may be made by mixing 
the different esters. The esters of the higher fatty acids occur in 


: 


the natural varieties of wax.* ane 


ESTERS OF FORMIC ACID. 


Methyl Formic Ester, CHO,.CH,, is obtained by distilling sodium formate 
with-sodium methyl sulphate, or more advantageously by adding methyl alcohol 
(13 parts) saturated with HCl-gas to calcium formate (10 parts) and then distil- 
ling. Another course consists in conducting HCl into.a mixture of formic acid 
and alcohol, and then distilling, A mobile, agreeably-smelling liquid, that boils at 
32.5° and has a specific gravity of 0.9984 at 0°. In sunlight chlorine produces 
Perchlor-methyl formic ester, CC1O,.CCl,, which boils at 180-185°. Heated 
to 305° it breaks up into carbonyl chloride, C,C]1,0, == 2COCIl,. Aluminium 
chloride converts it into CCl, and CO,. 

Ethyl Formic Ester, CHO,.C,H,, boils at 54.4° and dissolves in 10 parts 
water. Its specific gravity equals 0.9445. To prepare it, distil a mixture of dry 
sodium ‘formate (7 parts), sulphuric acid (10 parts), and go per cent. alcohol (6 
parts). It is better to heat a mixture of oxalic acid, glycerol and alcohol ina 
flask with a return cooler, until the evolution of carbon dioxide ceases, then distil 
off the ester; at first a glycerol ester of formic acid is produced (p. 217), which 
the alcohol decomposes. 


v 


The above ester serves in the manufacture of artificial rum and arrack. wv 


The propyl ester, CHO,.C,H,, boils at 81°. The dzty/ ester, CHO,.C,H,, 
boils at 107°. The normal amyl ester boils at 130.4°. JLsoamyl ester, CHO,. 
C,H,,, has a fruity odor and boils at 123°. 

The allyl ester, CHO;.C,H,, is formed on heating oxalic acid with glycerol, 
and boils at 82-83° (p. 134). 

For higher esters consult Aznalen, 233, 253. 





* Ueber die Siedepunkte der Fettsdiureester und ihre spec. Gewichte s. Be- 
richte, 14, 1274 u. Annalen, 218, 337. Ueber die specif. Volumen. s, Aunalen, 
220, 290 u. 319; Annalen, 223, 249. 


254 ORGANIC CHEMISTRY. 


ESTERS OF ACETIC ACID. 


The Methyl Ester, Methyl Acetate, C,H,O,.CH,, occurs in crude wood- 
spirit, boils at 57.5°, and has a specific gravity of 0.9577 at o°. When chlorine 
acts upon it the alcohol radical is first substituted: C,H,O,.CH,Cl boils at 150°; 
C,H,O,.CHCI, boils at 148°. 

The Ethyl Ester, Ethyl Acetate—Acetic Ether—C,H,0,.C,H,, is a liquid 
with refreshing odor, and boils at 77°. At 0° its sp. gr. equals 0.9238. It dis- 
solves in 14 parts water, and readily decomposes into acetic acid and alcohol. In 
preparing it, heat a mixture of 100 c.c. H,SO, and 100 c.c. alcohol to 140°, and 
gradually run’ in a mixture of 1 litre alcohol (95°) and 1 litre acetic acid (Be- 
richte, 16, 1227). The distillate is shaken with a concentrated solution of salt, to 
withdraw all alcohol, the ether is siphoned off, dehydrated over calcium chloride, 
and finally rectified. 

Chlorine produces substitution products of the alcohol radicals. Sodium dis- 
solves in the anhydrous ester, forming sodium aceto-acetic ester. The profy/ ester, 
C,H,0,.C,H,, boils at 101°; sp. gr. 0.gogI at 0°. The zsopropyl ester boils at 

1° 


The dutyl ester, C,H,0,.C,H og, is obtained from normal butyl alcohol. It boils 
at 124°. The ester of primary isobutyl alcohol boils at 116°; that of the second- 
ary alcohol at 111°, and that of the tertiary at 96°. 

Amyl Esters, C,H,0,-C;H,,. The ester of normal amyl] alcohol boils at 
148° ; that of propyl-methyl carbinol at 133°, and that of isopropyl methyl carbinol 
at 125°. At 200° it splits up into amylene and acetic acid. The acetic ester 
of amyl alcohol of fermentation (p. 130) boils at 140°. A dilute alcoholic solu- 
tion of it has the odor of pears and is used as fear o7d. 

Flexyl acetic ester, C,H,0,.C,H, 3, with the normal hexyl group, occurs in 
the oil of Heracleum giganteum. It boils at 169—170° and possesses a fruit-like 
odor. The octyl ester, C,H,O,.C,H,,, is also present in the oil of Heracleum 
giganteum. It boils at 207° and has the odor of oranges. 

The allyl-ester, C,H,0.0.C,H,, obtained from allyl iodide, boils at 98—100°. 

Consult Annalen, 233, 260 for higher acetic acid esters. 


ESTERS OF PROPIONIC ACID. 


The methyl ester, C,H;O,.CH3;, boils at -79.5°. The ethyl ester, C,H,O,. 
C,H,, boils at 98°. The propyl ester, C,H;0,.C,H,, boils at 122°; the zsobuty/ 
ester, C,H,O,.C,Hg, at 137°; and the zsoamyl ester, C,H,O,.C,H, 1, at 160°; 
the latter has an odor like that of pine-apples. (See Anmalen, 233, 265.) 


ESTERS OF THE BUTYRIC ACIDS. 


Methyl Butyric Ester, C,H,O,.CH,, boils at 102.3°. The efhy/ ester, 
C,H,0,.C,H,, boils at 120.9°, has a pine-apple-like odor, and is employed in 

the manufacture of artificial ram. Its alcoholic solution is the artificial Azve-apple 
ott, ‘This is prepared on a large scale by saponifying butter with sodium hydroxide 
and distilling the sodium salt which is formed with alcohol and sulphuric acid. 

The normal propyl ester, CJH,O,.C,H,, boils at 143°; the zsopropy/ ester, 
C,H,0,.C,H,, at 128°. The zsobutyl ester, C,H,O,.C,Hg, boils at 157°. The 
tsoamyl ester, C§H,O,.C,H,,, boils at 178°, and its odor resembles that of pears. 
The hexyl ester and octyl ester are found in the oil obtained from various species 
of Heracleum (see above). See, also, dunalen, 233, 271. 

Ethyl Isobutyric Ester, C,H,O,.C,H,, boils at 110°. 


ACID AMIDES. 255 


The esters of the higher acids, as well as those of the substituted acids, are 
mostly mentioned along with the latter. We may yet notice here :— 

Isoamyl Isovaleric Ester, C;H,O,.C,H,,, boils at 196°, and is obtained by 
direct oxidation of the amyl alcohol of fermentation. Its odor is very much like 
that of apples, and it finds application under the name aff/e oti. 

See Annalen 233, 273-290, for esters of hexoic, heptoic, valeric and octoic acids. 

The complex esters, having high molecular weights, are solids, and cannot be 
distilled without suffering decomposition. Thus cety/ acetic ester, C,H,0,.C,.H33, 
melts at 18.5°; ethyl palmitic ester, CgH,,0,.C,H;, at 24°. These esters are pre- 
pared by dissolving the acid in alcohol, or the latter in the acid, and then satu- 
rating the solution with HCl (p. 252). The esters with high alkyls break up into 
olefines and fatty acids (p. 80) when distilled under pressure. 





ws 


Some of the higher’esters occur already formed in waxes and in 
spermaceti. 

Spermacett (Cetaceum, Sperma Ceti) occurs in the oil from pecu- 
liar cavities in the head of whales (particularly Physeter macro- 
cephalus), and upon standing and cooling it separates as a white 
crystalline mass, which can be purified by pressing and recrystal- 
lization from alcohol. It consists of Cetyl Palmitic Ester, 
C,,Hs,0,:C,g.H3, which crystallizes from hot alcohol in waxy, shin- 
ing needles or leaflets, and melts at 49°. It volatilizes undecom- 
posed in a vacuum. Distilled under pressure, it yields hexadecy- 
lene and palmitic acid. When boiled with caustic potash it 
becomes palmitic acid and cetyl alcohol. 


Chinese wax is Ceryl Cerotic Ester, C,,H,,0,.C,,H;;. Alcoholic potash de- 
composes it into cerotic acid and cery] alcohol. 

Ordinary beeswax is a mixture of cerotic acid, C,,H,,0,, with Myricyl 
Palmitic Ester, C,,H,,O0,.C,,H,,. Boiling alcohol extracts the cerotic acid and 
the ester remains. Anmnalen, 224, 225. 

Beeswax further contains the two hydrocarbons Aeptacosane, C,,H;g, and 
Hentriacontane, C,,Hg,, in addition to several alcohols, from C,,H;,0 to 
C3, Hg,O (Aunalen, 235,106). k 

Carnauba wax, from the leaves of the carnuba tree, melts at 83°. It contains’ 
free ceryl alcohol, and various acid esters (Azna/en, 223, 283). 





6. ACID AMIDES. 


These correspond to the amines of the alcohol radicals (p. 157). 
The hydrogen of ammonia can be replaced by acid radicals forming 
primary, secondary and tertiary amides. 

_ The following general methods for preparing primary amides are 
in use :— | 


256 ORGANIC CHEMISTRY. 


1. The action of acid chlorides upon aqueous ammonia :— 
Ge cme C,H,0.Cl + 2NH, =C,H,O.NH, + NH, Ck 


Acetamide. 


This method is Hesperian adapted to the higher fatty acids (Be- 
richte, 15, 1728). /If amine bases be substituted for ammonia, mixed 
amides result :— ; = 


C,H,0.Cl +. C,H » NH, =C?yj°9 >NH + HC. 


Ethylamine. Ethyl "Acetamide. 


The acid anhydrides have a similar action upon ammonia and 
the amines :— 


(C,H,0),0 + 2 NH, = C,H,0.NH, + C,H,0.0.NH,. 


_— Acetic Anhydride. Acetamide. 


2. The action of ammonia or amines upon the esters—a reaction 
that frequently takes place in the cold; it is best, however, to apply 
heat to the alcoholic solution :— 


C,H,0.0.C,H,+NH,  =C,H,O.NH, + C,H,.OH, 


2 3 2 
o ) Teiride. 


mY 


C,H,0.0.C,H, + C,H,.NH, = G at, 2° SNH + C,H,.0H. 
Ethyl "Kectamide. 


This is one of the so-called reversible reactions, inasmuch as the action of alco- 


~ hols upon acid amides again produces esters and ammonia (Berichte, 22, 24). 


3. The dry distillation of the ammonium salts of the acids of 
this series. This procedure is adapted to the preparation of vola- 
tile amides. A mixture of the sodium salts and ammonium chloride 
may be substituted for the ammonium salts; the latter will be pro- 
duced at first :— 

C,H,0.0.NH, = C,H,O.NH, + H,0. 


Ammonium Acetate. Aiotaade. 


A more abundant yield is obtained by merely acting the ammo- 
nium salts to about 230° (Berichte, 15,979). Consult Berichte, 
17, 848, upon the velocity and limit of the amide production. 


4. The distillation of the fatty acids with potassium sulphocyanide :— 
2C,H,0.0H + CN.SK = C,H,0.NH, + C,H,0.0K + COS. 


Simply heating the mixture is more practical Carini, 16, 2291, and 15, 978). 
In this reaction the aromatic acids yield nitriles. 


5. The addition of 1 molecule of water to the nitriles of the 
acids (cyanides of the alcohol radicals) :— 
CH,.CN + H,O = CH,.CO.NH,. 


RKisetonitrile, Aeneas. 


AMIDES. __ ; 257 


This conversion is often accomplished by acting in the cold with concentrated 
hydrochloric acid, or by mixing the nitrile with glacial acetic acid and concen- 
trated sulphuric acid (Berichte, 10, 1061). Hydrogen peroxide will also convert 
the nitriles, with oxygen liberation, into the amides (Berichte, 18, 355): R.CN + 
2H,0, = R.CO.NH, + H,O0+0 





The preceding methods are not applicable in the preparation of secondary and 
tertiary amides, as the acid chlorides do not generally act on the primary amides. 
They are obtained by heating the alkyl cyanides (the nitriles) with acids, or sain 
anhydrides, to 200° :— 


" CH,.CO\, 
CH,.CN + CH,.CO. OH = Gj" CONE, 


Methyl Cyanide. Acetic Acid. Dinectamide. 


CH,.CN + (CH,.CO),0 = (CH,,.CO),N. 
Acetic "anhoiride. ei tiacetamidd, 


The secondary amides can also be prepared by heating primary amides with dry 
hydrogen chloride :— 


2C,H,0.NH, + HCl =(C,H,0),NH + NH,Cl. 


Diacetamide. 


Mixed amides, which at the same time contain alcohol radicals, are further pro- 
duced by the action of esters of ordinary isocyanic acid upon acids or acid anhy- 
drides :— 
CO:N.C,H, + C,H,0.0H =“230\NH —-+€0,, 
Ethyl lencorsanae 2H; 7 


oh 
CO:N.C,H, + (C,H,0),0= 677 ‘5 NC: H, + CO,. 


* Ethyl Diacetamide. 


The amides of the fatty acids are usually solid, crystalline bodies, 
soluble in both alcohol and ether. The lower members are also 
soluble in water, and can be distilled without decomposition. As 
they contain the basic amido-group they are able to unite directly 
with acids, forming salt-like derivatives (¢. g., C,H,O.NH,.NO;H), 
but these are not very stable, because the basic character of the 
amido-group is strongly neutralized by the acid radical. Further- 
more, the acid radical imparts to the NH,-group the power of ex- 
changing a hydrogen atom with metals not very basic, forming 
metallic derivatives, ¢. g., (CH;.CO.NH),.Hg—mercury acetamide, 
analogous to the isocyanates (from isocyanic acid, CO:NH). 

The union of the amido-group with the acid radicals (the group 
CO) is very feeble in comparison with its union with the alkyls in 
the amines (p. 158). The amides,-therefore, readily decompose 
into their components. Heating with water effects this, although 
it is more easily accomplished by boiling with alkalies or acids :— 


CH,.CO.NH, + H,O — CH,.CO.OH + NH,. 
22 


258 ORGANIC CHEMISTRY. 


Nitrous acid decomposes the primary amides similarly (p. 161), 
whereby the ammonia breaks up with the evolution of nitrogen and 
the formation of water :— 


C,H,O.NH, + NO,H = C,H,0.0H + N, + H,0. 
Bromine in alkaline solution changes the primary amides to 
brom-amides (Berichte, 15, 407 and 752) :— 
C,H,;0.NH, + Br, = C,H,O.NHBr fe HBr, 
which then form amines (p. 160). On heating with phosphorus 


pentoxide, or with the chloride, they part with 1 molecule of water 
and become nitriles (cyanides of the alcohol radicals) :— 


CH,.CO.NH, = CH,.CN + H,0. 
In this action a replacement of an oxygen atom by two chlorine 
atoms takes place; the resulting chlorides, like CH;.CCl,.NH,, 


then lose, upon further heating, 2 molecules of Cl1H with the forma- 
tion of nitriles :— 


CH,.CCl,.NH, = CH,.CN + 2HCl. 





In the mixed amides, containing- an alcohol radical besides the acid radical in 
the amido-group, PCI, effects a similar substitution of 2Cl for an oxygen atom. 
The products are the so-called amid- chlorides, which readily part with HCl and 
become imid-chlorides :-— | 


CH,.CCl,.NH(C,H,) = CH,.CCI:N(C,H,) + HCl. 


These regenerate the amides with water :—CH,.CCl:N(C,H,) +- H,O = CH, . 
CO.NH(C,H,) + HCl. When heated they lose, however, hydrochloric acid 
and yield chlorinated bases :— 


2CH,.CCLN(C,H,) = C,H,,CIN, + HCl. 


The chlorine in the imid-chlorides is very reactive; the action of ammonia on 
amines produces the amidines (see these) :— 
ON.C,H 
CH,CCI:N(C,H,) + NH,.C,H, = CHCl nic, hy, + HCl. 


Hydrogen sulphide converts them into thio-amides. 

The chlorimides, containing the group NCI, but only known in the benzene 
series, are isomeric with the imid-chlorides, RN:CCl. They can be converted 
into the latter by a molecular rearrangement (see Benzoanilide, Berichée, 19, 992). 


AMIDES. 259 


Formamide, CHO.NH,, the amide of formic acid, is obtained 
by heating ammonium formate to 230°, or ethyl formic ester with 
alcoholic ammonia to 100° (Berichte, 15, 980); also by boiling 
formic acid with ammonium iigheoyanide: (Berichte 16, 2291). 
It is a liquid, readily soluble in water and alcohol, and boils with 
partial decomposition at 192°-195°. Heated rapidly, it breaks up 
into CO and NH,; P.O; liberates HCN from it. 


Mercuric oxide dissolves in it with the formation of mercury formamide, 
(CHO.NH),Hg. This is a feebly alkaline liquid, sometimes applied as a subcu- 
taneous injection. 

Ethyl Formamide, CHO.NH.C,H,, is obtained from ethyl formic ester and 
ethylamine ; also by distilling a mixture of the latter with chloral :— 


CCl,.CHO + NH,.C,H, = CHO.NH.C,H, + CCI,H. 
It boils at 199°. 


Acetamide, C,H;O.NH,, is produced on heating a mixture of Vv 
dry sodium acetate and ammonium chloride, or by digesting acetic 
ester with alcoholic ammonia (Berichte, 15, 980). Another method 
consists in supersaturating glacial acetic acid with ammonia, and 
then distilling in a current of ammonia (Berichie, 18, Ref. 436). 
It crystallizes in long needles, melts at 82-83°, and boils at 222° 
undecomposed. It dissolves with ease in water and alcohol, and 
when boiled with alkalies or acids; passes into acetic acid and 
ammonia. With acids, it forms unstable compounds, like C,H,;NO. 
NO;H and (C,H;NO),.HCl. When the aqueous solution is boiled 
with mercuric oxide, the latter dissolves, and on cooling mercury 
acetamide, (C,H,;0.NH),Hg, separates (p. 257). 


Acetbromamide, C,H,O.NHBr (p. 258), crystallizes from water and ether with 
I molecule H,0O, in large plates, and melts in an anhydrous condition at 108°.. 

Substituted ‘acetamides are derived from substituted acetic esters by the action ™ 
of alcoholic ammonia, and evaporation at ordinary temperatures. Ch/oracetamide, 
C,H,CIO.NH,, melts at 116°, and boils at 224°-225°.  Dichloracetamide, 
C,HC1,0.NH.,, melts at aide and boils at 233°-234°. TZvrichloracetamide melts 
at 136°, and boils at 238°—239° 

Diacetamide, (C,H,0),NH, obtained by heating acetamide in a stream of 
HCl (p. 257), is readily soluble in water, fuses at 59°, and boils at 210°-215°. 

Triacetamide, (Cy H 30),N, is prepared by heating acetonitrile (methyl 
cyanide) with acetic anhydride to 200° (p. 257). It melts at 78°-79° 

Propionamide, C,H,O.NH,, is similar to acetamide, melts at 75° and boils 
at 210°. 

Butyramide, C,H,O.NH,, crystallizes in leaflets, fusing at 115° and boiling 
at 216°. Isobutyramide fuses at 129°, 

Isovaleramide, C;H,O.NH,, from valeric acid, sublimes in leaflets, soluble 
in water and fusing at 126°, 

Lauramide, C,,H,,0.NH,, fuses at 102°; Myristamide, C,,H,,O.NH,, 
at 104°; Palmitamide, C,,H,,O.NH,, at 107°; Stearamide,C,,H,,O.NH,, 


260 ORGANIC CHEMISTRY. 


at 109° (Berichte, 15, 984 and 15, 1728). These higher amides may also be 
prepared by saponifying the fats with alcoholic ammonia, when the glycerol esters 
will react, in a manner similar to that of the monohydric alcohols. 

Hydroxamic Acids. 

These are produced when free hydroxylamine, or its hydrochloride, is allowed 
to act upon acid amides. They contain the isonitroso-group in the place of the 
carbonyl oxygen (Berichte, 22, 2854) :— 

CH,.CO.NH, -+ NH,.OH SCT + NH,. 


Ethyl-hydroxamic Acid. 


. They are crystalline compounds, acid in character, and form an insoluble copper 
salt in ammoniacal copper solutions. Ferric chloride imparts a cherry-red color to 
both their acid and neutral solutions. 

Ethyl Hydroxamic Acid, CH,.C(N.OH).OH, with %4H,0, is a crystalline 
hydrate, melting at 59°. It dissolves very easily in water and alcohol, but not in 
ether. Compare Benzhydroxamic acid. 





7, THIO-AMIDES. 


Thio-amides of the acids, ¢. ¢., thio-acetamide, CH,.CS.NH,, and thio-benza- 
mide, C,H,.CS.NH.,, are formed by letting phosphorus sulphide act upon the 
_ acid amides (p. 250), and by the addition of H,S to the nitriles :— 

CH,.CN + H,S = CH,.CS.NH,. 


Acetonitrile. Thio-acetamide. 


/ 
Phenyl thio-amides, in which the H of the amido-group is replaced by C,H,, 
- @.g., thio-acetanilide, CH,.CS.NH.C,H,, are obtained from the anilides (see 
these) by the action of P,S,; also by acting with H,S upon the amid-chlorides, 
imid-chlorides, and amidines, and by treating the latter with CS, (Berichte, 22, 
506). The thio-anilides of formic acid, ¢hio-formanilides, result by the addition 
of H,S to the isonitriles or isocyanides (of the benzene series) :— 

' C,H,.NC +H,S = C,H,.NH.CHS. 
Phenyl Isocyanide. Thioformanilide. 


The thio-amides resemble the amides and are readily broken up into fatty acids, 
SH,,NH, and amines. They manifest more of an acid character than the oxy- 
gen amides, dissolve in alkalies, and readily yield metallic derivatives by the 
replacement of 1 hydrogen atom of the.amido-group. 

In the action of hydroxylamine upon the thio-amides the S-atom is replaced by 
the iso-nitroso-group, with production of amidoximes (see these). 

When iodides of the hydrocarbons act on the sodium compound of thio-aceta- 
nilide, iso-thio-acetanilides containing alcohol radicals result :— 


Os oe /S.CH 
CHs-CON(Na).c,H, + CHsl = CHs-CON Cy, + Nal. 
Sodium Thio-acetanilide. Methyl-isothio-acetanilide. 


These are viewed as derivatives. of the so-called isothio-acetamide, CH,. 
CONT The latter compound has not yet been obtained free; it is isomeric 
with thio-acetamide (Berichte, 12, 1062, and 16, 144). ‘The forms CHC Ni 


and CH,.Cé nee are probably tautomeric. Hydrochloric acid converts the iso- 
2 


THIO-AMIDES. 261 


compounds having alcohol radical groups, into aniline and esters of thio-acetic 
acid (p. 250). 

The so-called imido-thio-ethers o these) possess a constitution like the isothio- 
amides. 





8. CYAN-, SULPHO- AND AMIDO-DERIVATIVES OF THE ACIDS, 


In the acids, the hydrogen of the acid radicals can be substituted, 
the same as in the hydrocarbons, by the monovalent groups, SO;H, 
sulpho-, CN, cyan-, NH,, amido-, etc. The resulting derivatives, 
having two side groups, belong to the divalent compounds, and are 
in part described with the divalent alcohols and acids, for the prepa- 
ration of which they serve as transition stages. Here we will merely 
call attention to the ordinary methods used in their production :— 

The Sulpho-derivatives of the monobasic acids correspond 
perfectly to the sulpho-compounds of the alcohol radicals (p. 152), 
and are obtained according to similar methods :— 


(1) By the action of sulphur trioxide upon the fatty acids :— 


CH,.CO,H + SO, = CH Gorn: 


Acetic Acid. Sulpho-acetic Mid. 


or by acting with fuming sulphuric acid on the nitriles, or amides of the acids, in 
which case the latter first change to acids. 

(2) By heating concentrated aqueous solutions of the salts of the monosubsti- 
tuted fatty acids with alkaline sulphites (p. 151) :-— 


CH,.Cl.GO,K ++ K.SO,K = CH, $07 


Some of the sulpho-fatty acids are analogously obtained by the addition of oe 
line sulphites to unsaturated acids (Berichte, 18, 483) :— : 


CH,.CH:CH.CO,H + K,SO, = CH,.CH,.C 


4+ KCl. 


/ S0,K 
HS COR. 


(3) By oxidizing the thio-acids corresponding to the oxy-acids with nitric 
acid :— 
F / SH / SO,H 
CHa. cos t 30 = Cas oaaH. 
Thioglycollic Acid. 


The formulas indicate these sulpho-acids to be dibasic (mixed 
carboxylic and sulpho- sh They correspond to the dicarboxylic 


acids, like CH, Cee HT malonic acid. They are mostly crys- 


talline substances, easily soluble in water and deliquescent in the 
air. Their salts generally crystallize-well. The sulpho-group in 
them is not so intimately combined as in the sulphonic acids of the 
alcohol radicals. Boiling alkalies convert them into oxy-acids :— 


/SO,H /OH 
CH,< Co’H + KOH = CH. <¢o, yy + SO,HK. 


262, ORGANIC CHEMISTRY. 


Sulpho-acetic Acid, Bae gas is obtained by oxidizing isothionic 


acid, CH,(OH).CH,.SO, H, with nitric acid. Sulphuric acid liberates it from its 
readily soluble barium salt. The acid crystallizes with 14% molecules H,O in 
deliquescent prisms, which fuse at 75°. The barium salt, CH < Co! >Ba + H,0, 
forms leaflets. Pentachloride of phosphorus converts it into the chloride, 
CH ey By Pea of the latter with tin and hydrochloric acid thio- 
glycollic acid, CH 2\ CO,H, is produced. 


Its ethyl ester results from the action of ethyl iodide upon its silver salt, The 
hydrogen atoms of the CH,-group in this ester (as in acetoacetic and malonic 
esters) can be replaced by alkyls (Berichte, 21, 1550). 

See Berichte, 22, 518, upon the sulpho-derivatives of the higher acids of the 
marsh-gas series. 





The Cyan-derivatives are obtained by heating the mono- 
halogen acids (their salts or esters) with aqueous or alcoholic potas- 
sium cyanide :— 

aoe /CN 
a ga + CNK = CH,¢ 9 x 

In this reaction,the halogen is not only replaced by cyanogen, but very often 

there is a simultaneous doubling of the acid ester (Berichte, 21, 3166 and 3399). 


+ KCl. 


As a usual thing they crystallize poorly and are unstable. When 
boiled with alkalies or acids they are converted into dibasic acids 
(p. 211) :— 3 


/CN eeu Coy 
CH,< 69,10 +2H.0 = CH. Co2y + NHs- 


Cyanacetic Acid. Malonic Acid. 


-Cyanformic Acid, CN.CO,H. In the following pages this will be considered 


as cyancarbonic acid. = 


Cyanacetic Acid, CH,(CN).CO,H, is derived from monochlor- 
acetic acid. It is a-crystalline mass, readily soluble in water, melt- 
ing at 65° (Berichte, 20, Ref. 477), and splitting up into CO, and 
acetonitrile, CH;.CN, at 165°. Malonic acid is produced when it 
is boiled with alkalies or acids. 


Preparation.—Boil monochloracetic ester (5 parts) with potassium cyanide (6 
parts) and water (24 parts), or alcohol, until the odor of prussic acid has disap- 
peared, then neutralize the solution with H,SO,, concentrate, supersaturate with 
sulphuric acid and withdraw the cyanacetic acid by shaking the liquid with ether. 


Ethyl Cyanacetate, CHC CH boils about 207°. The hydrogen of its 
"Ged Bed 


CH_,-group is replaceable by alkyls (Berichte, 20,Ref. 477) and acid radicals ( Ber- 
ichte, 21, Ref. 353). Aceto-cyanacetic ester is identical with cyan-acetoacetic 
ester (Berichte, 20, Ref. 477). 


CYANOGEN COMPOUNDS. | 263 


a-Cyanpropionic Acid, CH;. CH(CN).CO,H, from a-brompro- 
pionic acid, , yields 1 isosuccinic acid when saponified, Its ethyl ester 
boils at 197°. The hydrogen of its CH-group can be replaced by 
sodium and alkyls (Berichte, 21, 3164). §-Cyanpropionic Acid, 
CH,(CN).CH,.CO3H, from #-chlorpropionic acid, yields ordinary 
succinic acid when ‘saponified. 





CYANOGEN COMPOUNDS. 


The monovalent group. CN, in which trivalent nitrogen is linked 
with three affinities to carbon, N=C—., is capable of forming quite a 
number of different derivatives. It shows in many respects great 
similarity to the halogens, chlorine, bromine, and iodine. Like 
these, it combines with hydrogen, forming an acid, and combines 
with the metals to salts which resemble and are frequently i isomor- 


phous with the haloid salts. Thus, the alkali salts assume the cube — 


form in crystallizing, and silver cyanide is in all respects like silver 
chloride. Potassium and sodium burn in cyanogen gas, as in chlo- 
rine, forming cyanides. The monovalent group CN cannot exist 
free, but it doubles itself, just as all other monovalent groups, ¢.g., 
CH;, when it separates from its compounds, and we get the mole- 
cule :—: 

Dicyanogen, C,N, = NC—CN. 

In organic cyanogen compounds where CN is attached to alkyls 
the union of the cyanogen group is very firm. Yet the nitrogen 
atom in CN can be easily liberated as ammonia, and the carbon 
atom will pass into the carboxyl group, CO,H. This behavior 
ts characteristic of cyanogen derivatives. It may be effected by the 
absorption of water, which can occur by boiling with acids and 
alkalies :— ‘ 

R—CN + 2H,O —‘R—CO.OH + NH,. 

Nascent hydrogen causes a partial separation of nitrogen, pro- 
ducing amines :— 

CH=N + 2H, — CH,-NH,. 

An oxygen atom can be inserted into the CH group—see cyanic 
acid, 

_ A similar, partial separation accounts also for the condensation 
of the cyan-group to polymeric forms, ¢. g., dicyanogen, C,N,, 
and tricyanogen, C,N;. The following formulas express their 
structure :— 
—C=-N —C=—=N—C— 
ae and | | 
N=—C— N=C—N 
Dicyanogen, Divalent. 
Tricyanogen, Trivalent. 


° 


* vane 


— 264 . ORGANIC CHEMISTRY. 


Very many cyanogen derivatives readily adapt themselves to such 
polymerizations. 

Besides the above normal cyanogen derivatives there also exist 
isomeric Pseudo- and Jso-cyanogen compounds. These will receive 
attention further on (with the cyanic acids and carbylamines). 

The nitrogen atom in the cyanogen group is trivalent ; it may be 
considered as ammonia in which carbon replaces the hydrogen 
atoms. This would explain why so many cyanogen derivatives, in 
the same manner as the amides, combine directly with the haloid 
acids and metallic chlorides, yielding compounds similar to the 
ammonium salts :— 


my H 
CH,.CN.HCl = CH,.C=NC 
These are, however, unstable. Perhaps it is necessary to admit (p. 
258) that the halogen hydride has effected an entrance for itself in 
the CN group (as in CH;.CCl — N.CH;). 

Yellow prussiate of potash and potassium cyanide serve as start- 
ing-out substances in the preparation of the cyanogen derivatives. 
Potassium cyanide is obtained by the ignition of nitrogenous 
organic matter with KOH or potashes (see Text-Book of Inorganic 
Chemistry). The direct union of carbon and nitrogen to cyanogen 
is only effected with difficulty. It may be accomplished by con- 
ducting nitrogen over a mixture of carbon and metallic potassium 
or potassium carbonate raised to a red heat. Potassium cyanide is 
then formed. The yield is more abundant if ammonia gas be con- 
ducted over the mixture. The ignition of meee in ammonia gas 
yields ammonium cyanide :— 


C + 2NH, —CN.NH, + H,. 


All these methods, however, are not applicable on a large scale. 

Free Cyanogen or Dicyanogen, C,N, = NC.CN, is present 
in small quantity in the gases of the blast furnace. It is obtained 
by the ignition of silver or mercury cyanide :— 


Hg(CN), = C,N, + Hg. 


The transposition proceeds more readily by the addition of mercuric chloride. 

It is most readily prepared from potassium cyanide. To this’end the concen- 
trated aqueous solution of 1 part KCN is gradually added to 2 parts cupric sul- 
phate in 4 parts of water. Heat is then applied. At first a yellow precipitate of 
copper cyanide, Cu(CN),, is produced, but it ——e breaks up into cyanogen 
gas and cuprous cyanide, CuCN. 


Its preparation from ammonium oxalate: through the agency of 
heat, is of theoretical interest :— 


CO.O.NH, CN 


| = | + 4H,0. 
CO.O.NH, CN 


; | oe 
CYANOGEN COMPOUNDS. ; 265 


It is on this account to be considered as the nitrile of oxalic 
acid. 

Cyanogen is a colorless, peculiar-smelling, poisonous gas, of 
specific gravity 26 (H = 1). It may be condensed to a mobile 
liquid by cold of —25°, or by a pressure of four atmospheres at 
ordinary temperatures. In this condition it has a sp. gr. °. 866, 
solidifies at —34° to a crystalline mass, and boils at —21° It 
burns with a bluish-purple mantled flame. Water dissolves 4 vol- 
umes and alcohol 23 volumes of the gas. 


On standing the solutions become dark and break up into ammonium oxalate 
and formate, hydrogen cyanide and urea, and at the same time a brown body, the 
so-called azulmic acid, C,H,N,O, separates. With aqueous potash cyanogen 
yields potassium cyanide and isocyanate. In these reactions the molecule breaks 
down, and if a slight quantity of aldehyde be present in the aqueous solution only 
oxamide results :— 


CN CO.NH, 
| + 2H,0= | 
CN COLNE. 
CN 
With hydrogen sulphide cyanogen yields hydroflavic actd,C,N,.H,S= | 
CS.NH, CS.NH,, 
and hydrorubianic acid, C,N,.2H,S= | These two compounds may 
CS.NH,, 
be considered thioamides, or as tautomeric isothioamides (p. 260) :— 
CN CN CS.NH, C(NH).SH 
| O24 | or 
CS.NH, C(NH).SH CS.NH, C(NH).SH 
Hydroflavic Acid. Hydrorubianie Acid. 


The first consists of yellow crystals, the second of red, and is best prepared by 
conducting cyanogen gas into an alcoholic solution of potassium sulphydrate, and 
adding hydrochloric acid (Berichte, 22, 2305). It unites with two molecules of 
hydroxylamine (like the thioamides) to form oxaldiamidoximes. 

On heating mercuric cyanide there remains a dark substance, paracyanogen, a 
polymeric modification, (C,N,)n. Strong ignition converts it again into cyan- 
ogen. It yields potassium cyanate with caustic potash. 


Hydrocyanic Acid, CNH, Prussic Acid, is obtained from 
various plants containing amygdalin (from cherry-stones, bitter 
almonds, etc.), on standing in contact with water, when the 
amygdalin undergoes a fermentation, breaking up into hydro- 
cyanic acid, sugar and oil of bitter almonds. Its production 
from ammonium formate by the application of heat is of theoretic 
interest :— 

CHO.O.NH, = CHN + 2H,0. 


This reaction would show it to be the nitrile of formic acid. 
Hydrogen cyanide may also be obtained by passing the silent 
electric discharge through a mixture of C,N, and hydrogen: 


C,N, + H, = 2CNH. 


266 ORGANIC CHEMISTRY. 


The metallic cyanides yield it when they are distilled with 
mineral acids. 

Anhydrous hydrocyanic acid is a mobile liquid, of specific grav- 
ity 0.697 at 18°, and becomes a crystalline solid at —15°. It boils 
at + 26.5°. Its odor is peculiar and resembles that of oil of bitter 
almonds. The acid is extremely poisonous. 


The following procedure serves for the preparation of aqueous prussic acid. 
Finely pulverized yellow prussiate of potash (10 parts) is covered with a cooled 
mixture of sulphuric acid (7 parts) and water (10 to 40 parts, according to the 
desired strength of the prussic acid), and then distilled from a retort provided 
with a condenser. The heat of a sand-bath is necessary. The decomposition of 
the yellow prussiate occurs according to the equation :— 


2FeCy,K, + 3S0,H, = Fe,Cy,K, + 380,K, + 6CNH. 


About half the cyanogen contained in the ferrocyanide is converted into hydro- 
cyanic acid. 

The anhydrous acid can be obtained from the hydrous by fractional distillation 
and dehydration by calcium chloride. 


The aqueous acid decomposes readily upon standing, yielding 
ammonium formate and brown substances. The presence of a 
very slight quantity of stronger acid renders it more stable. When 
warmed with alkalies or mineral acids it breaks up into formic acid 
and ammonia :— 

CNH + 2H,0 = CHO.OH + NH,. 


Nascent hydrogen (zinc and hydrochloric acid) reduces. it to 
methylamine (p. 159). 

Hydrocyanic acid is a feeble acid, and imparts a faint red color 
to blue litmus. Like the haloid acids, it reacts with metallic oxides, 
producing metallic cyanides. From solutions of silver nitrate it 
precipitates silver cyanide, a white, curdy precipitate.* 





* In hydrocyanic acid the hydrogen, replaceable by metals, is in union with 
carbon, whereas, ordinarily, it is only the hydrogen of hydroxyl (in acids and 
alcohols) that is capable of replacements like this. The acetylenes, —C=CH, 
nitro-paraffins (p. 107), aceto-acetic esters and the analogously constituted malonic 
esters manifest a similar deportment. In these compounds, two or three carbon 
valences are generally saturated by negative elements or groups, and they 
manifest also analogous behavior, in that their alkali salts are less stable than those 
with the heavy metals. 

The hydrogen attached to nitrogen possesses also the function of acid hydro- 
gen, if two affinities of the nitrogen are combined with negative groups, as in 
the imides :— 


—CO\ 
CO:NH and ang 


HALOGEN COMPOUNDS OF CYANOGEN. 267 


To detect small quantities of free prussic acid or its soluble salts, saturate the 
solution under examination with caustic potash, add a solution of a ferrous salt, 
containing some ferric salt, and boil for a short time. Add hydrochloric acid to 
dissolve the precipitated iron oxides. If any insoluble Prussian blue should re- 
main, it would indicate the presence of hydrocyanic acid. The foliowing reaction 
is more sensitive. A few drops of yellow ammonium sulphide are added to the 
prussic acid solution, and this then evaporated to dryness. Ammonium sulpho- 
cyanide will remain, and if added to a ferric salt, will color it a deep red. 


Dry prussic acid combines directly with the gaseous halogen 
hydrides (p. 264) to form crystalline compounds like CHN.HCI, 
easily soluble in water and ether. The aqueous solutions rapidly 
decompose, yielding formic acid and ammonium salts. The acid 
also unites with some metallic chlorides, ¢. g., Fe,Cl,, SbCl;. 


HALOGEN COMPOUNDS OF CYANOGEN. 


These result by the action of the halogens upon metallic cyanides. 
The chloride and bromide can condense to tricyanides, in which 
we assume the presence of the tricyanogen group, C;N; (p. 263). 

Cyanogen Chloride, CNCI, is produced by acting with chlo- 
rine upon aqueous hydrocyanic acid. It is a mobile liquid, solidi- 
fying at —5°, and boiling at + 15.5°. It is heavier than water, 
and only slightly soluble in it, but readily dissolved by alcohol and 
ether. Its vapors have a penetrating odor, provoking tears, and 
acting as a powerful poison. 


In preparing it, saturate a cold mercuric cyanide solution with chlorine. The 
cyanogen chloride which escapes on the application of heat, is conducted through a 
tube filled with copper turnings, to free it of chlorine. Or strongly cooled prussic 
acid (containing 20 per cent. CNH), is saturated with chlorine gas, the oily cyano- 
gen chloride separated, and then distilled over mercuric oxide, to remove excess of 
prussic acid. 


Cyanogen chloride combines with different metallic chlorides. 
With ammonia, it yields ammonium chloride and cyanamide, 
CN.NH,. Alkalies decompose it into metallic cyanides and iso- 
cyanates. Fe 


Tricyanogen Chloride, C,N,Cl,, solid chlorcyan, is produced when the liquid 
chlorine is kept in sealed tubes. It is formed directly by leading chlorine into an 
ethereal solution of CNH, or into anhydrous hydrocyanic acid exposed to direct 
sunlight (Berichte, 19, 2056). It appears, too, in the distillation of cyanuric acid, 
C,0,N,H,, with phosphorus pentachloride. It crystallizes in shining needles or 
leaflets, melts at 146°, and boils at 190°. It is not very soluble in cold water, but 
readily in alcohol and ether. Its vapor density equals 92(H =—1). When boiled 
with acids or alkalies, it breaks up into hydrochloric and cyanuric acids ( Berichie, 
19, Ref. 599) :— 


C,N,Cl, + 3H,O = C,N,(OH), + 3HCL. 


268 ORGANIC CHEMISTRY. 


Cyanogen Bromide, CNBr, is obtained when bromine acts on anhydrous 
prussic acid or upon mercuric cyanide :— 


Hg(CN), + 2Br, = HgBr, + 2CNBr. 


It is a very volatile, crystalline substance, readily soluble in water, alcohol and 
ether. On heating the anhydrous bromide or its ethereal solution in sealed tubes 
to 130-140°, it becomes polymeric tricyanogen bromide, C,N,Br,. The latter 
is more easily obtained by heating dry yellow or red prussiate of potash with bro- 
mine at 250° (Berichte, 16, 2893), or on conducting HBr into the ethereal solution 
of CNBr ( Berichte, 18, 3262). It is an amorphous white powder, soluble in ether — 
and benzene, It melts about 300°, and is volatile at higher temperatures. It 
decomposes in moist air, or upon boiling with water, into HBr and cyanuric acid. 

Cyanogen Iodide, CNI, is prepared by subliming a mixture of mercuric cya- 
nide (1 molecule) and iodine (2 molecules) ; or by adding iodine to a concen- 
trated aqueous solution of potassium cyanide. The cyanogen iodide which results 
is withdrawn by ether. It has a sharp odor, dissolves in water, alcohol and ether, 
and sublimes near 45°, without melting, in brilliant .white needles. Ammonia 
converts it into cyanamide and ammonium iodide. 

Cyanuric Iodide, C,N,I,, is produced by the action of hydriodic acid upon 
cyanuric chloride. It is a dark brown, insoluble powder. At 125° water decom- 
poses it into hydrogen iodide and cyanuric acid. At 200° it readily breaks up into 
iodine and paracyanogen, (CN), (Berichle, 19, Ref. 599). 

e 





METALLIC DERIVATIVES OF CYANOGEN. 


The metallic derivatives of cyanogen have already been considered 
in inorganic chemistry. Here attention will only be directed to 
certain generalizations. 

The properties of and the methods of preparing the metallic cyan- 
ides vary greatly. The alkali cyanides may be formed by the direct 
action of these metals upon cyanogen gas; thus, potassium burns 
with a red flame in cyanogen, at the same time yielding potassium 
cyanide, C,N, + K, = 2CNK. The strongly basic metals dissolve 
in hydrocyanic acid, separating hydrogen and forming cyanides. 
A more common procedure i is to act with the acid upon metallic 
oxides and hydroxides: 2CNH + HgO = Hg(CN), + H,O. The 
insoluble cyanides of the heavy metals are obtained by the double 
decomposition of the metallic salts with potassium cyanide. 

The cyanides of the light metals, especially the alkali and alkaline 
earths, are easily soluble in water, react alkaline and are decomposed 
by acids, even carbon dioxide, with elimination of hydrogen cya- 
nide; yet they are. very stable, even at a red heat, and sustain no 
change. The cyanides of the heavy metals, however, are mostly 
insoluble, and are only decomposed, or not at all, by the strong 
acids. When ignited the cyanides of the noble metals suffer de- 
composition, breaking up into cyanogen gas and metals. 


The following simple cyanides may be mentioned :— 
Potassium Cyanide, KCN, crystallizes in cubes or octahedra, and fuses at a 


) 


METALLIC DERIVATIVES OF CYANOGEN. 269 


bright red heat to a clear liquid. In moist air it deliquesces and gives up (by the 
action of carbon dioxide) hydrogen cyanide. It is scarcely soluble in absolute 
alcohol, but dissolves readily in aqueous alcohol. The best mode of preparing 
chemically pure potassium cyanide consists in conducting prussic acid into an 
alcoholic solution of KOH (in go per cent. alcohol). Take 1 part KOH for 3 
parts of the yellow prussiate (p. 266). The potassium cyanide separates as a 
powder or jelly, which is drained upon a filter, The so-called Liebig potassium 
cyanide, occurring in trade, contains potassium cyanide and isocyanate. It is 
made by igniting a mixture of dry yellow prussiate of potash (8 parts) with pure 
potashes (3 parts) :— 


FeCy,K, + CO,K, = 5KCy + CNOK + CO, + Fe. 


At present chemically pure potassium cyanide is obtained by mere ignition of 
potassium ferrocyanide :— 


Fe(CN),K, = 4KCN + FeC, + N,. 


The exceedingly finely divided iron carbide which adheres to the salt is re- 
moved by filtering the molten mass through porous clay crucibles. 
The aqueous or alcoholic solution becomes brown on exposure, and when boiled, 


- rapidly decomposes into potassium formate and ammonia. If fused in the air or 


with metallic oxides which are readily reduced, potassium cyanide absorbs oxygen, 
and is converted into potassium isocyanate. When fused with sulphur it yields 
potassium thiocyanate. 

Ammonium Cyanide, NH,CN, is formed by the direct union of CNH with 
ammonia, by heating carbon in ammonia gas, and by conducting carbon monoxide 
and ammonia through red-hot tubes. It is best prepared by subliming a mixture 
of potassium cyanide or dry ferrocyanide with ammonium chloride. An aqueous 
solution of it may be made by distilling the solution of ferrocyanide and ammonium 
chloride. It yields colorless cubes, easily soluble in alcohol and subliming at 40°, 
with partial decomposition into NH, and CNH. When preserved it becomes 
dark in color and decomposes. . 

Mercuric Cyanide, Hg(CN),, is obtained by dissolving mercuric oxide in 
hydrocyanic acid, or by boiling Prussian blue (8 parts) and mercuric oxide (1 
part) with water, until the blue coloration disappears. It dissolves readily in hot 
water (in 8 parts cold water), and crystallizes in bright, shining, quadratic prisms. 
When heated it yields cyanogen and mercury (p. 264). 

Silver Cyanide, AgCN, is precipitated as a white, curdy compound from silver 
solutions by potassium cyanide or prussic acid. It resembles silver chloride very 
much. It darkens on exposure to the air, and dissolves readily in ammonium 
hydrate and potassium cyanide. Say 

From some reactions, it would seem that silver cyanide may contain the iso- 
cyanogen group, C =N —, and that silver, consequently, is linked to nitrogen 
(as in silver nitrite, NO,Ag, p. 106). Compare Carbylamines (p. 287). 


Compound Metallic Cyanides. ‘The cyanides of the heavy metals 
insoluble in water dissolve in aqueous potassium cyanide, forming 
crystallizable double cyanides, which are soluble in water. _ Most 
of these compounds behave like double salts. Acids decompose 
them in the cold, with disengagement of hydrocyanic acid and 
the precipitation of the insoluble cyanides :— 


AgCN.KCN ++ HCI = AgCN + KCl + CNH. 


270 ORGANIC CHEMISTRY. 


In others, however, the metal is in more intimate union with the 
cyanogen group, and the metals in these cannot be detected by the 
usual reagents. Iron, cobalt, platinum, also chromium and man- 
ganese in their zc state, form cyanogen derivatives of this class. 
The stronger acids do not eliminate prussic acid from them, even 
in the cold, but hydrogen acids are set free, and these are capable 
of producing salts :— 

Fe(CN),K, -+ 4HCl = Fe(CN),H, + 4KCl. 


Potassium Ferrocyanide. Hydroferrocyanic Acid. 


It may be assumed that polymeric cyanogen groups—dicyanogen 
and tricyanogen (p. 263)—are present in these derivatives of 
cyanogen :— . 


nm /C.N,.K, 11Z7C,N,.K Rae HO PE 
Fe\ C,N,.K, Fe. C,N,.K2 Pt\ CLN,.K. 
Potassium Ferrocyanide. Potassium Ferricyanide. Potassium Platinocyanide. 


This view is sustained by the fact that these cyanides, although 
soluble in water, are yet not poisonous. We do not know of a 
sharp line of difference between cyanides of the first and those of 
the second variety; different compounds, e. g., potassium gold cy- 


iil 
anide, Au(CN),K, show an intermediate behavior. The most import- 
ant compound cyanides have been already treated in the Inorganic 
Chemistry. 





Witroprussides. These arise on‘treating the ferrocyanides with 
nitric acid. The most important of them is | 

Sodium Nitroprusside. Its constitution has not yet been 
definitely determined (Berichte, 15, 2613). The simplest expres- 
sion of it is given by the formula, Fe(CN),(NO)Na, + 2H,O. It 
crystallizes in beautiful red rhombic prisms, readily soluble in water. 
Sunlight decomposes it into nitric oxide and Prussian blue. 


Preparation.—Heat pulverized potassium ferrocyanide with two parts concen- 
trated nitric acid, diluted with an equal volume of water, until ferric chloride 
ceases to produce a blue precipitate. The cooled solution is filtered off from the 
separated saltpetre, saturated with soda, and evaporated until near the point of 
crystallization, when 3-4 parts of alcohol are added. 


Sodium nitroprusside serves as a very delicate reagent for alka- 
line sulphides, which give with it an intense violet coloration even 
in very dilute solution. 


It yields precipitates with most of the heavy metals. When hydrochloric acid 
is added to the nitroprussides, hydrogen nitroprusside, Fe(CN),(NO)H, + H,O, 
is liberated. This crystallizes*in vacuo from its aqueous solution, in dark-red 
prisms. 


~ 


OXYGEN COMPOUNDS OF CYANOGEN. 271 


OXYGEN COMPOUNDS OF CYANOGEN. 


The empirical formula, CNOH, of cyanic acid, has two possible 


structures :— Pais 
N=CO—H and CO=N—H. 
Normal Cyanic Acid. Isocyanic Acid. 


These formulas are probably tautomeric, so that they can both be assigned to the 
known cyanic acid. The difference between them is first observed when hydrogen 
is replaced by radicals. The ordinary salts of cyanic acid appear to be derivatives 
of the zsocyanic acid, CO:NH (or carbimide, the imide of carbonic acid), as iso- 
cyanic esters are produced by the action of alkyl iodides upon the silver salt. ‘The 
ordinary cyanic esters are constituted according to the formula, CO:NR, and are 
termed isocyanic esters, while the esters of normal cyanic acid, CN.OR, are desig- 
nated cyanetholines (p. 273). 


Ordinary Cyanic Acid, CONH, is obtained heating poly- 
meric cyanuric acid. The vapors which distil over are condensed 
in a strongly cooled receiver. 

The acid is only stable below 0°, and is a mobile, very volatile 
liquid, which reacts strongly acid, and smells very much like glacial 
acetic acid. It produces blisters upon the skin. About o°, the 
aqueous solution is rapidly converted into carbon dioxide and 
ammonia :— 

CONH + H,O — CO, + NH,. 


At 0°, the aqueous cyanic acid passes rapidly into the polymeric 
cyamelide—a white, porcelain-like mass, which is insoluble in water, 
and when distilled reverts to cyanic acid. Above o°, the conver- 
sion of liquid cyanic acid into cyamelide occurs, accompanied by 
explosive foaming. Cyanic acid dissolves in alcohols, yielding 
esters of allophanic acid. = 


The salts of the above acid are obtained by double decomposition from the 
potassium salt; those of the heavy metals are insoluble in water, and those of the 
earths are precipitated by alcohol. Heat decomposes both varieties into CO, and 
salts of cyanamide (see this). 


Potassium Isocyanate, CO:NK, ordinary cyanate of potassium, 
is formed in the oxidation of potassium cyanide in the air or with 
readily reducible metallic oxides (CNK -+- O = CO:NK). It 
results, too, on conducting dicyanogen, or cyanogen chloride into 
caustic potash (Berichte, 13,2201). The salt crystallizes in shining 
leaflets, resembling potassium chlorate, and dissolves readily in cold 
water, but with more difficulty in hot alcohol. In aqueous solution 
it decomposes rapidly into ammonia and potassium carbonate. 


Preparation.—Fuse in a crucible a mixture of: dehydrated yellow prussiate of 
potash (8 parts), potashes (3 parts), and gradually add, while stirring, lead oxide 


272 ORGANIC CHEMISTRY. 


or minium (15 parts): CNK + PbO = CNOK -+ Pb. The reduced lead melts 
together on the bottom of the vessel. The white mass is poured out and the 
potassium cyanate extracted with alcohol. 


Potassium isocyanate precipitates aqueous solutions of the heavy 
metals. The lead, silver and mercurous salts are white, the cupric 
salt is green in color. 


Ammonium cyanate, CN.O.NH, or CO:N(NH,), is a white crystalline powder, 
formed by contact of cyanic acid vapors with dry ammonia. Caustic potash decom- 
poses it into potassium isocyanate and ammonia. On evaporating the aqueous 
solution it passes into isomeric urea :— 


/NH, 


CON.NH, = CO¢ yyy”. 
2 


The cyanates of the primary and secondary amines are similarly converted into 
alkylic ureas, whereas the salts of the tertiary amines remain unchanged. 





Three molecules of CNOH condense to 7ricyanic or Cyanuric 
Acid, C;N;0;H; (p. 263). Here again two structural cases are pos- 
sible :— 


HO—C—=N—C—OH OC—NH—CO 
| | and | | 
N—C—N HN—CO—NH 

| Isocyanuric Acid 

OH or Tricarbimide. 


Normal Cyanuric Acid. 


Ordinary cyanuric acid is most probably constituted according to 
formula (1), because when sodium alcoholates act upon cyanuric 
bromide, C;N;Br;, and alkyl iodides upon ordinary silver cyanate 
esters of normal cyanuric acid result (p. 275). Isocyanuric acid 
(formula 2) is not known in a free state, and is probably tautomeric 
with normal cyanuric acid, since upon saponifying the isocyanuric 
esters (p. 276), constituted according to the carbimide formula 
(2), ordinary cyanuric acid invariably results (Berichte, 20, 1056). 
_ Ordinary Cyanuric Acid, C,0;N;H;, probably normal cyan- 
uric acid, C,N,(OH); (see above), is obtained from tricyanogen 
chloride, C,N,Cly, by boiling the latter with water and alkalies (see 
above). 

Dilute acetic acid added to a solution of potassium isocyanate, 
gradually separates primary potassium isocyanate, C;N,;0,H.K, from 
which mineral acids release cyanuric acid. It appears, too, on 
heating urea :— : 


3CON,H, = C,0,N,H, + 3NH,. 


ESTERS OF CYANIC ACID. 273 


Preparation.—Carefully heat urea until the disengagement of ammonia ceases 
and the mass, which at first fused, has become solid again. ‘The residue is dis- 
solved in potash and the cyanuric acid precipitated with hydrochloric acid. A 
better plan is to lead dry chlorine gas over fused urea at a temperature of 130- 
140° :— 

3CON,H, + 3Cl = C,0,N,H, + 2NH,Cl + HCl + N. 


Cold water is employed to remove the ammonium chloride from the residue, and 
the latter recrystallized from hot water. 

*Cyanuric acid is more easily obtained by heating tribromcyanide with water 
(Berichte, 16, 2893). 


Cyanuric acid crystallizes from aqueous-solution with 2 molecules 
of water (C,;N,;0,;H; + 2H,O) in large rhombic prisms, It is 
soluble in 40 parts cold water, and easily soluble in hot water and 
alcohol. When boiled with acids it decomposes into carbonic acid 
and ammonia. When distilled it breaks up into cyanic acid., PCl; 
converts it into tricyanogen chloride. 

Cyanuric acid is tribasic and yields three series of salts, all of 
which crystallize well. The salts of the heavy metals are not soluble 
in water. A characteristic salt is the trisodium salt, C,N,0,Na;. 
This separates from aqueous solutions of cyanuric acid upon warm- 
ing them with concentrated sodium hydroxide. It forms minute 
needles. 

Two supposed isomeric cyanuric acids are identical with ordinary 


cyanuric acid (Berichte, 19, 2022). 
1. ESTERS OF THE CYANIC ACIDS. 


Those of normal cyanic acid, CN.OH (p. 271), result when cyan- 
ogen chloride acts upon sodium alcoholates :— 


CNCI + C,H; ONa = CN.O.C,H, + NaCl. 





They are also termed cyanetholines. ‘They are liquids, of ethereal 
odor, are insoluble in water, and suffer decomposition when distilled. 
The ethyl ester is the only one that has been Chesely studied. 


Ethyl Cyanic Ester, CN.O.C,H;, cyanetholine, is obtained by the action of 
cyanogen chloride or iodide upon a solution of sodium ethylate in absolute alcohol. 
On diluting with water it precipitates out in the form of a colorless oil, of sp. gr. 
1,127 at 15°. It dissolves readily in alcohol and ether. When boiled with caustic 
potash it decomposes into CO,, NH, and ethyl alcohol. Acid esters of i isocyanuric 
acid are produced when it is biled with hydrochloric acid. It polymerizes into 
solid ethyl cyanuric esters after standing some time. 

The homologous esters are prepared in a similar manner, but they have been but 
little investigated. 


23 


~ 


274 ORGANIC CHEMISTRY. 


Listers of Tsocyanic Acid, CO:NH, ordinary cyanic acid esters. 
Wirtz prepared these, in 1848, by distilling potassium ethyl sulphate 
with potassium isocyanate :— 

SO,K(C,H,) + CO:NK = CO:N.C,H, + SO,K,. 


Esters of isocyanuric acid are formed at the same fime, in conse- 
quence of polymerization. Isocyanic esters are produced, too, by ° 
oxidizing the carbylamines with mercuric oxide :-— 


C,H,.NC + O = C,H,.N:CO; 


> 


and by the action of silver isocyanate upon alkyl iodides :— 
C,H,I + CO:NAg = CO:N.C,H; + Agl. 


These esters are volatile liquids, boiling without decomposition, 
and possessing a very disagreeable, penetrating odor, which provokes 
tears. They are decomposed by water and alcohol, but dissolve 
_ without decomposition in ether. On standing they pass rather 
rapidly into the polymeric isocyanuric esters. 

In all their reactions they behave like carbimide derivatives. 
Heated with KOH they become D eoasihé amines and potassium 
carbonate (p. 159) :— 


CO:N.C,H, + 2KOH = CO,K, + NH,.C,H,. 


Acids in aqueous solution behave similarly :— 
CO:N.C,H, + H,O + HCl = CO, + C,H,.NH,.HCl. 


With the amines and ammonia they yield alkylic ureas (see these). 
Water breaks them up at once into CO, and dialkylic ureas. In 
this decomposition amines form first, CO, being set free, and these 
combine with the excess of isocyanic ester to dialkylic ureas (see 
these). 


The esters of isocyanic acid unite with alcohol, yielding esters of carbaminic 
acid :— 
: _7n/NH.C,H 
Es iG, Hl, Ont = COC oc, H,. 5 

They react similarly with the polyvalent alcohols, forming complex carbaminic acid 
esters (Berichte, 18, 968). 

As derivatives of ammonia the isocyanic esters are capable of combining di- 
rectly with the haloid acids :— 


CON 
Soy + Ha= O Sswuci 


C,H,” C,H; / 
Water decomposes these products at once into CO, and amine ois: They very 
probably are identical with the alkyl urea chlorides, rie CH (see these), 


from which the isocyanic esters are again separated by distillation with lime. 


\ 


ESTERS OF THE CYANURIC ACIDS. 275 


Methyl Isocyanic Ester, CO:N.CH,, methyl carbimide, is obtained by dis- 
tilling potassium methyl sulphate with potassium isocyanate. It is a very volatile 
liquid, boiling at 44°. When boiled with KOH it forms methylamine, CH,.NH,. 

Ethyl Isocyanic Ester, CO:N.C,H,, ethyl carbimide. This boils at 60°, and 
has the specific gravity of 0.891. It produces ethylamine with boiling alkalies; 
with sodium ethylate it yields triethylamine :— 


CO:N.C,H, + 2C,H,.ONa = CO,Na, + N(C,H,)5. 


Isoamyl Isocyanic Ester, CO:N.C,;H,,, amyl carbimide, from amyl alcohol 
of fermentation, boils near 100°, 

Allyl Isocyanic Ester, CO:N.C,H,, is obtained by heating allyl iodide and 
potassium cyanate. It boils at 82°. 


s 





2. ESTERS OF THE CYANURIC ACIDS. 


The esters of the normal cyanuric acid, C;N,;(OH); (p. 272), are 
formed, as already observed, by the polymerization of the cyanic 
esters (cyanetholines) after long standing :— 


3CN.0.C,H, = C,N,(0.C,H;);, 


and are produced directly, together with the cyanic esters, in the 
preparation of the latter, by conducting cyanogen chloride into 
sodium alcoholates. 

A simpler procedure is to act upon the sodium alcoholates with 
cyanuric chloride or bromide (Berichte, 18, 3263 and 19,2063):— 


C,N,Cl, + 3Na.0.C,H, = C,N,(0.C,H,), + 3NaCl. Og 


The normal cyanuric esters are also formed by the action of alkyl iodides upon 
silver cyanurate, C,N,(OAg), at 100°. Since, however, the normal esters, under 
the influence of heat, are transposed into the isomeric isocyanuric esters (see below), 
the latter are produced in large quantities even at low temperatures, while at ele- 
vated temperatures they are the only products (Berichte, 18, 3269). The separation 
of the isomeric esters may be effected by the aid of mercuric chloride, since only 
the normal cyanuric derivatives yield with the latter double compounds, which are 
characteristic (see, on contrary, Hofmann, Berichte, 19, 2093). 

The normal cyanuric esters, on digesting with the alkalies, break up into cyanuric 
acid and alcohol. They combine with six atoms of bromine.. PCl, converts them 
into cyanuric chloride. 

Methyl Cyanuric Ester, C,N,(O.CH,),, crystallizes from hot water or alco- 
hol in needles, melting at 135°. It boils, with scarcely any alteration, at 160°- 
170°. The distillate contains but traces of the iso-ether. If it be boiled forsome time 
in connection with a return cooler, the conversion into isomeric isocyanuric ester is 
complete. It dissolves in concentrated HCl, and is reprecipitated unchanged by 
ammonia. Methyl chloride and cyanuric acid are produced on boiling with hydro- 
chloric acid. 

Ethyl Cyanuric Ester, C,N,(O.C,H;),, is produced when sodium alcoholate 
acts upon cyanogen bromide, or cyanuric chloride (see above) ; also from methyl 
cyanuric ester, and normal methyl thio-cyanuric ester, when boiled with sodium 


= 


276 ORGANIC CHEMISTRY. 


ethylate and alcohol. It crystallizes in needles, melts at 29°, and boils unaltered 
at 275°. Prolonged boiling, in connection with a return cooler, gradually leads to 
the isocyanuric ester (melting at 95°). 

Partial saponification of the normal cyanuric esters by NaOH or Ba(OH), gives 
rise to normal dialkyl cyanuric acids; these, when heated, rearrange themselves 
into dialkyl isocyanuric acids (Berichte, 19, 2067). 

Dimethyl Cyanuric Acid, C,N,(O.CHs),.OH, crystallizes in small leaflets, 
melting at 160°-180°, and suddenly passes into dimethyl isocyanuric acid (melting 
at 222°). This change i is accompanied by the evolution of much heat. 

Diethyl Cyanuric Acid, C,N,(0.C,H;),0OH, also melts at 160°-180°, and 
is suddenly converted into diethyl isocyanuric acid (m. p. 173°) (Berichte, 18, 
3268 

When acid ciborides act upon silver cyanurate mixed anhydrides are formed, 
and these are again resolved into their components upon heating with water (Be. 
richte, 18, 3261 and 19, 311). 

Cyanuric Triacetate, C,N,(O0.C,H ss melts with partial decomposition at 
170°. 





Esters of Isocyanuric Acid, C,0,(N.CH;);, Tricarbimide 
esters, are formed together with the isocyanic esters, when the latter 
are prepared by the distillation of KCNO with potassium ethyl 
or methyl sulphate. We have already spoken of their formation 
as a result of the molecular transposition of the cyanuric esters. 
They are solid crystalline bodies, soluble in water, alcohol, and 
ether, and may be distilled without decomposition. They pass 
into primary amines and potassium carbonate when boiled with alka- 
lies, similar to the isocyanates :— 


C,0,(N.C,H,), + 6KOH = 3CO,K, + 3NH,.C,H,. 


Methyl Isocyanuric Ester, C,O,(N. CH,)s) crystallizes in bright prisms. It 
melts at 175°, and boils undecomposed at 296°. Heated with PCl,, chlormethy] iso- 
cyanuric ester, C,O,(N.CH,Cl), is produced, whereas cyanuric chloride results 
from normal methyl cyanuric ester (erichie, 19, 2087). 

Ethyl Isocyanuric Ester, C,0,(N.C,H,),, consists of large rhombic prisms, 
melting at 95° and boiling at 276°. It volatilizes with steam. 

Dialkyl Isocyanuric Esters, or Isocyanuric Dialkyl Esters, as C,O, 
(N.CH,),.NH, are formed, together with the trialkyl esters and in the distillation 
of monoalkyl ureas. They are also obtained from the normal dialkyl cyanuric 
acids by a rearrangement in consequence of the action of heat (Berichte, Ig, 2069, 
2077). They volatilize without decomposition, and, when boiled with alkalies, 
break up into carbonate, primary amine and ammonia. See Berichte, 19, 2094, 
upon the structure of the dialkyl isocyanuric acids. 

Dimethyl-isocyanuric Acid, C,O,(N.CH,),.NH, crystallizes from water in 
needles, or leaflets, melting at 222°. Its silver salt crystallizes with %4 molecule 
of water, C,0;(NCH,),.NAg + 1%H,0. 

Diethyl- cyanuric Acid, C,0,(N.C,H;),.NH, crystallizes in hexagonal prisms, 
melting at 173°, and distilling without ‘decomposition. 


~ 


SULPHUR COMPOUNDS OF CYANOGEN. 277 


SULPHUR COMPOUNDS OF CYANOGEN. 
The thiocyanic acids are :— 


N=C—SH and S=C=NH. 
Thiocyanic Acid. Tsothiocyanic Acid. 
Sulphocyanic Acid. Thiocarbimide. 

These correspond to the two isomeric cyanic acids (p. 271). 

The known thiocyanic acid and its salts (having the group 
NC.S—) are constituted according to the first formula. They are 
obtained from the cyanides by the addition of sulphur, just as the 
isocyanates result by the absorption of oxygen. The different union 
of sulphur and oxygen in this instance is noteworthy :— 


CNK + O = CO:NK. CNK + S=CNSK. 


Isothiocarbimide, CS:NH, and its salts are not known. Its esters 
(the mustard oils) do, however, exist and are isomeric with those of 
sulphocyanic acid. 

Thiocyanic Acid, CN.SH, sitphocyanié acid, is obtained by 
distilling its potassium salt with dilute sulphuric acid, or decom- 
posing the mercury salt with dry H,S or HCl. It is a liquid, with 
a penetrating odor, and solidifies at —12.5°. It is soluble in water 
and alcohol. Its solutions react acid. The free acid, and also its 
salts, color solutions of ferric salts a dark red. The free acid 
decomposes readily, especially in the presence of strong acids, into 
‘hydrogen cyanide and perthiocyanic acid, C,N,S,H,. 

The alkali thiocyanates, like the isocyanates, are obtained by 
fusing the cyanides with sulphur. 

Potassium Thiocyanate, CN.SK, sulphocyanate of potash, crystal- 
lizes from alcohol in long, colorless prisms, which deliquesce in the 
air. : 


Preparation.—Fuse 32 parts sulphur with 17 parts dry potassium carbonate, 
add 46 parts dehydrated yellow prussiate of potash, and again heat until the latter 
is completely decomposed. The fusion is finally exhausted with alcohol. 

The sodium salt is very deliquescent, and occurs in the saliva and urine of dif- 
ferent animals. 


Ammonium Thiocyanate, CN.S.NH,, is formed on heating prussic 
acid with yellow ammonium sulphide, or a solution of ammonium 
cyanide with sulphur. It is most readily obtained by heating CS, 
with alcoholic ammonia :— 


CS, + 4NH, = CN.S.NH, + (NH,),S. v 


A mixture of 300 parts concentrated ammonia solution, 300 parts strong alcohol, 
and 70-80 parts carbon disulphide, is permitted to stand for a day.. Two-thirds 
of the liquid are then distilled off (the distillate, consisting of alcohol and some 


278 ORGANIC CHEMISTRY. 


ammonium thiocyanate, may be used in a second preparation), and the residue 
carefully evaporated until crystallization sets in. 


The salt crystallizes in large, clear prisms, which readily dissolve 
in water and alcohol. It melts at 147°, and at 170° molecular 
transposition into thiourea occurs (similar to ammonium cyanate 
(p. 272) :— 

CN.S.NH, yields cs Ns 

7 2 4 y at by 

The salts of the heavy metals are mostly insoluble, and are obtained by precipi- 
tation. The mercury salt, (CN.S),Hg, is a gray, amorphous precipitate, which 
burns on ignition and swells up strongly (Pharaoh’s serpents). The ferric salt, 
(CN.S),Fe.,, is a black, deliquescent mass, dissolving in water with a deep red 
color. 3 

Cyanogen Sulphide, (CN),S, is formed when cyanogen iodide in ethereal 
solution, acts on silver thiocyanate :— 

/ CN.S.Ag + CNI = AglI + (CN),S. 


“Vv 


The product is extracted with carbon disulphide, and the solution evaporated. 
Cyanogen sulphide forms rhombic plates, melting at 65° and subliming at 30°. 
Its odor resembles that of the iodide, and the compound dissolves in water, alco- 
hol and ether. KOH breaks it up into potassium thiocyanate and isocyanate :— 


(CN),S -+- 2KOH = CN.SK + CO.NK + H,0. 


Pseudo-Cyanogen Sulphide, C,N,HS,, is formed in the oxidation of potas- 
sium sulphocyanide with nitric acid or chlorine. It is a yellow, amorphous powder 
insoluble in water, alcohol and ether. It dissolves with a yellow color in alkalies. 

Kanarine is similar ‘to and probably identical with pseudo.cyanogen sulphide. 
It is obtained frog KCNS by electrolysis, or by oxidation with KC1O, and HCl 
( Berichte, 17, Ref. 279, and 18, Ref.676). It is applied as a yellow or orange dye 
for wool and does not require a mordant. 





ESTERS OF THE THIOCYANIC ACIDS. 


Those of normal thiocyanic acid, CN.SH, are obtained by distil- 
ling organic salts of sulphuric acid in concentrated aqueous solution 
with potassium sulphocyanide, or by heating with alkyl iodides :— 


J CN.SK + C,H,I = CN.S.C,H, +KI. 

Further, by the action of CNCI upon salts of the mercaptans :— 
Se, C,H,.SK + CNC] = C,H,.S.CN + KCl. 
They are liquids, not soluble in water, and possess a leek-like odor. 


Nascent hydrogen (zinc and sulphuric acid) converts them into 
‘hydrocyanic acid and mercaptans :— 


CN.S.C,H, + H, = CNH +C,H,.SH. 


ESTERS OF THE THIOCYANIC ACIDS. 279 


With aqueous potash they behave as follows :— 
2CN.S.C,H, + 2KOH = (C,H,),S, + CNK + CONK + H,0. 
On digesting with alcoholic potash the reaction is :— 
CN.S.C,H, + KOH = CN.SK + C,H,.OH. 


The isomeric mustard oils do not afford any potassium sulpho- 
cyanate. With H,S they yield the dithiourethanes, whereas the 
isomeric mustard oils are not attacked, or decompose into CS, and 
amines. Boiling nitric acid oxidizes them to alkylsulphonic acids 
with separation of the cyanogen group. 


Methyl Thiocyanic Ester, CN.S.CH,, boils at 133°, and has a specific 
gravity 1.088 at 0°. When heated to 180-185° it is converted into the isomeric 
methyl-isothiocyanic ester, with simultaneous polymerization to trithiocyanic ester, 
C,N,8,(CH,), (Berichle, 18, 2197). 

Ethyl Thiocyanic Ester, CN.S.C,H,, boils at 142°. Its specific gravity 
equals 1.033 at 0°. It combines directly with the haloid acids. 

Isopropyl Thiocyanic Ester, CN.S.C,H,, boils at 152-153°. The isoamyl 
ester, CN.S.C,H,,, boils at 197°. 

Allyl Thiocyanic Ester, CN.S.C,H,, is formed when allyl iodide or bromide 
acts upon alcoholic potassium thiocyanate at 0°. When heat is applied allyl 
mustard oil, CS:N.C,H,, results by molecular transposition. It is produced, too, 
when CNC1 acts upon lead allyl mercaptide. A yellow, oily liquid, smelling 
somewhat like CNH, and boiling at 161°. Its specific gravity equals 1.071 at 0°. 
On boiling it rapidly changes to isomeric allyl mustard oil, CS:N.C,H, ; at ordi- 
nary temperatures the conversion is gradual. In the cold zinc and hydrochloric 
acid decompose the ester into CNH and allyl mercaptan, C,H,.SH. 





The esters of isothiocyanic acid, CS: NH, are termed mustard oils, 
from their most important representative. “They may also be con- 
we as thiocarbimide derivatives. They are formed :— 

. By mixing carbon disulphide with primary (or secondary) 
amines in alcoholic, or better, ethereal solution. By evaporation we 
get amine salts of alkyl carbaminic acids (see these) :— 


ac /NH.CH, 
CS, + 2NH;.CH, = CSC cin’ CH,). 
On adding silver nitrate, mercuric chloride or ferric chloride, to 
the aqueous solution of these salts, formed with primary amines, 
and then heating to boiling, the metallic compounds first precipi- 
tated decompose into metallic sulphides, hydrogen sulphide and 
mustard oils, which distil over with steam :— 


ocg/ NH.CH; 


(Sag ° = 2CS:N.CH, + Ag,S + HLS. 


280 ORGANIC CHEMISTRY. 


Hofmann’s mustard oil test for the detection of primary amines 
(p. 162) is based on this behavior. 


It is advisable to use ferric chloride ( Berichze, 8, 108), because mercuric chloride 
will desulphurize the mustard oils, and the latter will be transposed into dialkyl 
ureas. Iodine, too, forms mustard oils from the amine salts of the dithiocarbaminic 
acids, but the yield is small. - 


2. By distilling the dialkylic thio-ureas (see these) with phosphorus 
pentoxide (Berichte, 15, 985) :— 


NH.CH 
CSC NE. CH? = CS:N.CH, + NH,.CH,, 


is Dimethyl Thio-urea. Methyl Mustard Oil. 


and by heating the isocyanic esters with P,S, (Berichte, 18, Ref. 72): CO:N.C,H,; 
yields CS:N.C,H,; 


The mustard oils are liquids, almost insoluble in water, and pos- 
sess a very penetrating odor. They boil at lower temperatures than 
the i isomeric thiocyanic esters. 

When’ heated with hydrochloric acid to 100°, or with H,O to 
200°, they break up into amines, hydrogen sulphide and carbon 
dioxide :— : 

J CS:N.C,H, + 2H,O = CO, + SH, + NH,*C,H,. 


On heating with a little dilute sulphuric acid carbon oxysulphide, 
COS, is formed together with the amine. Nascent hydrogen (zinc 
and hydrochloric acid) acts as follows :— 


\ CONG 4 so = Ge WH CH. 


The mustard oils change to urethanes on heating them with abso- 
lute alcohol to 100°, or with alcoholic potash. They unite with 
ammonia and amines, yielding alkylic thio-ureas (see these). Upon 
boiling their alcoholic solution with HgO or HgCl.,, a substitution 
of oxygen for sulphur occurs, with formation of esters of isocyanic 
acid. These immediately yield the dialkylic ureas with water (see 


Pp. 274). 


» Methyl Mustard Oil, CS:N.CH,, methyl isothiocyanic ester, methyl thio- 
carbimide. It is a crystalline mass, melting at 34° and boiling at 119°. 
_ Ethyl Mustard Oil, CS:N.C,H,, boils at 133° and has a specific gravity 
I.0Ig at 0°. Propyl Mustard Oil, CS:N.C,H,, boils at 153°. Isopropyl 
Mustard Oil, CS:N.C,H., boils at 137°. 
Butyl Mustard Oil, CS:N.C,H, (with normal butyl), boils at 167. Isobutyl 
Mustard Oil, CS:N. ¢ H, (from isobutylamine), boils at 162°; seat gravity 


0.9638 at 14°. The mustard oil having the secondary butyl group, Ch ne SCH, 


occurs in the ethereal oil of Coch/earea officinalis. It boils at 159.5°; its specific 
“gravity equals 0.944 at 12°. 
Isoamyl Mustard Oil, CS:N.C,;H, ,, boils at 183°. 


ESTERS OF TRITHIOCYANURIC ACID. 281 


The most important of the mustard oils is the common or— 

Allyl Mustard Oil, CS:N.C,H;—Allyl Thiocarbimide. This 
is the principal constituent of ordinary mustard oil, which is obtained 
by distilling powdered black mustard seeds (from Sinmapis nigra). 
In the latter there is potassium myronaze (see Glucosides), which in 
the presence of water, under the influence of a ferment, myrosin 
(also present in the seed), breaks up into grape sugar, primary 
potassium sulphate and mustard oil :— 


C,oHisKNO, <8, == C.H:,0, + $0,KH + CS.N.C,H,.  ¥ 


The reaction occurs even at o°, and there is a small amount of 
allyl sulphocyanate produced at the same time. 

Mustard oil is artificially prepared by distilling allyl iodide or 
bromide with alcoholic potassium or silver thiocyanate :— 


CN.SK + C,H,I = CS.N.C,H, + KI; 


a molecular rearrangement occurs here (p. 279). It may also be 
obtained by distilling the mercuric chloride of allyl sulphide with 
potassium sulphocyanide (p. 143). 

Pure allyl thiocarbimide is a liquid not readily dissolved by 
water, and boiling at 150.7°; its specific gravity equals 1.017 at 10°. 
It has a pungent odor and causes blisters upon the skin. When 
heated with water or hydrochloric acid the following reaction 
ensues :— 

CS:N.C,H, + 2H,O = CO, + SH, + NH,.C,H;,. 


bg 


It unites with aqueous ammonia to allyl thio-urea, When heated 
with water and lead oxide it yields diallyl urea. 


ESTERS OF TRITHIOCYANURIC ACID. 


Trithiocyanuric acid corresponds to thiocyanic acid, but thio-isocyanuric acid is 
not known. : 

Trithiocyanuric Acid, C,N,(SH),, is formed in the action of cyanuric chlo- 
ride upon sodium sulphide, and may be obtained from its esters by saponification 
with sodium sulphide. - Acids separate it from its salts in small yellow needles, 
which decompose but do not melt above 200° C. Its esters result when cyanuric 
chloride and sodium mercaptides interact, and by the polymerization of the thio- 
cyanic esters, CN.SR, when heated to 180° with a little HCl. More HCl causes 
them to split up into cyanuric acid and mercaptans. 

Methyl Trithiocyanuric Ester, C,N,(S.CH,),, melts at 188° and sublimes 
with scarcely any decomposition. Heating with ammonia causes a successive 
replacement of the mercaptan residues by amide groups, the final product being 
melamine (p. 290) :— 


(S.CH,), (S.CH}) 
C,N, an, NH and C,N,(NH,),. 


Melamine. 


2 2 


The esters react similarly with methylamine and dimethylamine (Berich/e, 18, 
2755): 
24 


282 ORGANIC CHEMISTRY. 


CYANIDES OF THE ALCOHOL RADICALS. 
(t) NITRILES. 


By this term we understand those derivatives of the alcohol radi- 
cals with the cyanogen group, CN, in which the fourth affinity of 
carbon is linked to the alcohol radicals. 

The following general methods serve for their formation :— 

1. The distillation of a potassic alkyl sulphate with potassium 
cyanide :— 

| Oc 4+ CNK = C,H,.CN + SO,K,; 


or by heating the alkylogens with potassium cyanide in alcoholic 
solution to 100° :— 


C,H,I + CNK = C,H,.CN + KI. 


Tsocyanides (p. 287) form in slight amount in the first reaction. For their re- 
moval shake the distillate with aqueous hydrochloric acid until the unpleasant 
odor of the isocyanides has disappeared, then neutralize with soda and dry the 
nitriles with calcium chloride. 


2. The dry distillation of ammonium salts of the acids with PO; 
or some other pony cry agent :— 
CH,.CO.O.NH, — 2H,0 = CH,.CN. 
Ammonium Acetate. Acetonitrile, 
This method of production explains why these cyanides are termed 
acid nitriles. 
3. By the removal of water from the amides of the acids when 
these are heated with P,O,;, P,S;—or phosphoric chloride (see amid- 
chlorides, p. 258) :— 


CH,.CO.NH, + PCl, = CH,.CN + POCI, + 2HCl, 
5CH,.CO.NH, + P,S,—=5CH,.CN + P,O, + 5H,S. 


The nitriles occur already formed in bone-oils.- 





The nitriles are liquids, usually insoluble in water, possessing an 
ethereal odor, and distilling without decomposition. When heated 
to 100° with water, they break up into acids and ammonia :— 


CH,.CN + 2H,0 = CH,.CO.OH + NH,. 


This decomposition is more readily effected on heating with acids 
or alkalies (p. 211). The acid amides result by the union of the 
nitriles with 1 molecule of water. 


CYANIDES OF THE ALCOHOL RADICALS. 283 


Nascent hydrogen (sodium amalgam) converts them into amines :— 
CH,.CN + 2H, = CH,.CH,.NH,. 


This conversion is most easily accomplished by means of metallic sodium and 
absolute alcohol (p. 159 and Berichte, 22, 812). 
The nitriles can unite directly with bromine and with the halogen hydrides :— 


CH,.CN yields CH,.CBr:NH and CH,.CBr,.NH,. 


These compounds are identical with those formed by the action of PCI, upon 
the amides (p. 258). 
The nitriles form thio-amides with H,S (p. 260) :— 


CH,.CN + SH, = CH,.CS.NH,. 


With monobasic acids and acid anhydrides they yield secondary and tertiary 


amides (p. 257). JNU 
They combine with alcohols and HCl to imido-ethers, R.CE OR (P: 292); thus, 


from CNH we get formido-ethers. The nitriles become amidines with ammonia 
and the amines (p. 293). Hydroxylamine unites with them to form oxamidines, 
or amidoximes (p. 294). Metallic sodium induces in them peculiar polymerizations ; 
bimolecular cyan-alkyls, like dicyan methyl (p. 284), being formed in ethereal 
solutions, If, however, sodium acts upon the pure nitriles at a temperature of 
150° the products are cyana/kines (thus methyl cyanide, C,H,N, yields cyanmeth- 
ine, C,H,N,; ethyl cyanide, C,H;N, yields cyanethine, C,H,,N,); these were 
formerly classed as tri-molecular cyanides, but really belong to the pyrimidine 
or metadiazine bases (see these, and Berichte, 22, Ref. 328). 





Formonitrile or Hydrogen Cyanide, H.CN 
Cc 


Acetonitrile “ Methyl ” CH,.CN 
Propionitrile “ Ethyl rs C,H,.CN 
Butyronitrile ‘** Propyl “ C,H,.CN 
Valeronitrile “ Butyl me C,H,.CN, etc. 


1. Hydrogen Cyanide, CNH (p. 265), the lowest member of 
the series, is to be regarded as formonitrile, because it is obtained 
from ammonium formate by the withdrawal of water :— 


CHO.O.NH, — 2H,O = CHN, 


Conversely, on boiling with acids or alkalies it yields formic acid 
and ammonia. Nascent hydrogen converts it into methylamine, 
CH;.NH,. 

Acetonitrile, Methyl Cyanide, CH;.CN = C,H,N, is best 
obtained by distilling acetamide with P,O;. It is a liquid with an 
agreeable odor, and boils at 81.6°. It is miscible with water, and 
burns with a violet light. When boiled with acids or alkalies it 
yields ammonia and acetic acid. Nascent hydrogen converts it 
into ethylamine. : 


284 ORGANIC CHEMISTRY. 


Dicyan-methyl, C,H,N,, is obtained by the action of sodium upon an ethereal 
solution of acetonitrile. It is constituted according to the tautomeric formulas :— 


C(NH).CH, C(NH,).CH, 
or 
H,.CN CH.CN. 
Imido-acetyl Nitrile of 
Cyanmethyl. B-Amidocrotonic Acid. 


It crystallizes from ether in colorless needles, melting at 53°. It forms cyan- 
acetone with concentrated hydrochloric acid (Berichte, 22, Ref. 325 and 327). 

Substituted acetonitriles are obtained from the substituted acetamides by distil- 
lation with P,O,. CH,CI.CN boils at 124°; its specific gravity at 11° equals 
1.204. CHCI,.CN boils at 112°, and its specific gravity is 1.374 at 11°. CCl,. 
CN boils at 83°; its specific gravity at 12° is 1.439. The direct chlorination of 
acetonitrile only occurs in the presence of iodine (Ammalen, 229, 163.) Trichloro- 
acetonitrile condenses in sunlight to the polymeride, C, N,(CCl,),, melting at 96°. 
Boiling potash changes it to chloroform and cyanuric acid. 

3- Propionitrile, Ethyl Cyanide, C,H,N— C,H,.CN. This is also formed 
by the action of cyanogen chloride and dicyanogen upon zinc ethyl. It is an 
agreeably smelling liquid, which boils at 98°. Its specific gravity equals 0.787. 
Salt separates it from its aqueous solution. In all its reactions, it is perfectly analo- 
gous to acetonitrile. 

Metallic sodium converts ethyl cyanide in ethereal solution into dicyan-ethyl, 

C(NH)C,H, 

C,H,N,. It is probably imido-propionyl-cyanethine, | (see above). 
es oe WE hg Sh 

It is crystalline, melts at 48° and boils at 258°. Acids convert it into propionyl- 


5 


dis, cH,.cN 
C,H,,N, = C,N,(CH,)(C,H,).(NH,), the amido derivative of methy]-diethyl- 
pyrimidine (see this), results on heating ethyl cyanide and sodium to 150°. 

Chlorine displaces two hydrogen atoms in propionitrile, yielding a-dichlorpro- 
pionitrile, CH,.CCl,.CN. This is a liquid, boiling at 103—107°, and upon stand- 
ing, it polymerizes to the solid (C,H,Cl,N),. Sodium, or sodium amalgam, 
effects the same more rapidly. The product crystallizes in plates, which melt at 
73.5°, and decompose when heated. Heated with sulphuric acid and water, both 
compounds yield @ dichlorpropionic acid, and with alcohol and sulphuric acid its 
ester (p. 225). When polymeric dichloropropionitrile is reduced with zinc dust it 
yields cyanur-triethyl (p. 285). 

4. Butyronitrile, Propyl Cyanide, C,H',.CN, boils at 118-119°, and has 
the odor of bitter-almond oil. Isopropyl Cyanide, C,H,.CN, is formed by the 
prolonged heating of isobutyric acid with potassium thiocyanate. It boils at 
107-108°, 

5. Valeronitriles, C;H,.N — C,H,.CN, Butyl Cyanides. 

(1) Normal butyl cyanide boils at 140-141°; its specific gravity is 0.816 at 0°. 
(2) Lsobuty! cyanide boils at 126+128°, and has the odor of oil of bitter almonds; 
its specific gravity equals 0 8227 at 0°. (3) Zertiary butyl cyanide is produced 
on heating tertiary butyl iodide, (CH,),CI, with potassio-mercuric cyanide. It 
boils at 105-106°, becomes crystalline in the cold, and melts at + 16°. 

The following higher nitriles may be easily derived from their respective acid 
amides by action of P,O, (Berichte, 15,1730): Lauronitrile, C,,H,,N(F.P. + 
4°); myristonitrile, C,,H,,N (19°); palmitonitrile, C,,H3,N (31°); and 
stearonitrile, C, ,H,,N (41°). 


cyanethine, (Berichte, 22, Ref. 833 ; 22, Ref. 325). Cyanacetone, 


NITRO-DERIVATIVES OF ACETONITRILE. 28 5 


Allyl Cyanide, C,H,.CN = CH,:CH.CH,.CN, is not known. The com- 
pound produced by heating allyl iodide with potassium cyanide is the isomeric 
Propenyl Cyanide, C,H;,.CN = CH,.CH:CH.CN,. This results from a molecu- 
lar rearrangement. It occurs in crude mustard oil. 

It is a liquid with an odor resembling that of leeks, boils at 118°, and has a 
specific gravity of 0.835 at 15°. It combines with bromine to a dibromide, 
C,H,Br,.CN. This becomes a # dibrombutyric acid by saponification (Berichte, 
22, Ref. 495). It yields nothing but acetic acid when oxidized with a chromic 
acid mixture. It yields crotonic acid when boiled with alcoholic potash (p. 238). 

Tricyanalkyls or Cyanur-trialkyls. Although the cyanogen derivatives fre- 
quently condense to tricyanogen or cyanuric compounds, yet tricyanhydride, or 
cyanuric acid, is not known. Its alkyl derivatives exist. 

Cyanuric Triethyl, C,N,(C,H,),, results from the action of zinc dust upon 
polymeric a-dichloropropionitrile (p. 284), or zinc dust and acetic acid (Berichte, 
22, 1446; 20, Ref. 55). It is very volatile, and has a narcotic odor. It melts at 
29° and boils at 119°. It is decomposed into propionic acid and ammonia (ZBe- 
richte, 23,766) by hydrochloric acid at the ordinary temperatures. 

A general method for the preparation of diphenylated cyanur-alkyls consists in 
the action of AIC], upon a mixture of benzonitrile and the chlorides of fatty acids. 
The nitriles of fatty acids do not yield analogous compounds (Berichte, 23, 765). 





NITRO-DERIVATIVES OF ACETONITRILE. 


In this section a class of compounds will be considered which, 
although not directly obtained from acetonitrile, are yet regarded 
as derivatives of it (Berichte, 16, 2419). 

Nitro-acetonitrile, C,H,N,O, = CH,(NO,).CN, or hypothe- 
tical fulminic acid, is considered the basis of the so-called fulminates, 
derived from it by the introduction of metals for two hydrogen 
atoms. The influence of the negative groups, CN and NO.,, ex- 
plains the acid nature of acetonitrile (p. 266). 


A compound having the composition of nitro-acetonitrile has been obtained by 
the action of concentrated sulphuric acid upon ammonium fulminurate. It is a 
crystalline solid, insoluble in water, melts at 40°, and volatilizes very readily 
(Berichte, 9, 783). 


Mercury Fulminate, C,HgN,O, = CHg(NO,).CN(?) (Be; 
richte, 18, Ref. 148), is formed by heating a mixture of alcohol, 
nitric acid and mercuric nitrate, 


I part mercury is dissolved in 12 parts nitric acid (sp. gr. 1.345), 5.5 parts 
alcohol of go per cent. added, and the whole well shaken, After a little time, as 
soon as energetic reaction commences, 6 parts alcohol more are gradually added. 
At first metallic mercury separates, but subsequently dissolves and deposits as 
mercuric fulminate in flakes (Berichte, 9, 787). Modifications of this method may 
be found in Berichte, 19, 993 and 1370. 


Fulminating mercury crystallizes in shining, gray-colored prisms, 
which are tolerably soluble in hot water. It explodes violently on 


286 ORGANIC CHEMISTRY. 


percussion and also when acted upon by concentrated sulphuric 
acid. Hydrogen sulphide precipitates mercuric sulphide from its 
solution, the liberated fulminic acid immediately breaking up into 
CO, and ammonium thiocyanate. Concentrated hydrochloric acid 
evolves CO, and yields hydroxylamine hydrochloride, a procedure 
well adapted for the preparation of hydroxylamine (Berichte, 19, 


993). 


Bromine converts mercuric fulminate into dibromnitroacetonitrile, CBr,(NO,). 
CN, which forms large crystals, soluble in alcohol and ether, and melting at 50°. 
Iodine produces the iodide, CI,(NO,).CN; colorless prisms, melting at 86°. 
Chlorine gas changes mercuric fulminate into HgCl,, CNCI and chloropicrin. 
Ammonia in aqueous solution decomposes it into urea and guanidine. 

On boiling mercury fulminate with water and copper or zinc, metallic mercury 
is precipitated and copper and zinc fulminates (C,CuN,O, and C,ZnN,O,) are 
produced. Silver fulminate, C,Ag.N,.O,, is prepared “after the manner of the 
mercury salt, and resembles the ‘latter. Potassium chloride precipitates: from hot 
silver fulminate one atom of silver as chloride and the double salt, C, AgKN,O,, 
crystallizes from the solution. Nitric acid precipitates from this salt acid salver 
fulminate, C, AgHN,O,, a white, insoluble precipitate. 





Dinitro-acetonitrile, CH(NO,),.CN. Its ammonium salt is produced when 
hydrogen sulphide acts upon ¢rinitro-acetonttrile :— . 


C(NO,),.CN + 4H,S = C(NH,)(NO,),.CN + 4S + 2H,0. 


Sulphuric acid liberates the nitrile from this salt, and it may be withdrawn from 
the solution by shaking with ether. It forms large, colorless crystals and con- 
ducts itself like a monobasic acid. The silver salt, C,Ag(NO,),N, explodes 
very violently. It forms C Hp ong with bromine. 

Trinitro-acetonitrile, C,(NO,),N, is obtained by the action of a mixture of 
concentrated nitric and sulphuric acids upon potassium fulminate. It separates out 
as a thick oil, with evolution of CO,, and on cooling solidifies. 

Trinitro-acetonitrile is a white, crystalline, camphor-like mass, melting at 41.5°, 
and exploding at 200°. It volatilizes at 60° in an air current. Water and alcohol 
decompose it, even in the cold, into CO, and the ammonium salt of nitroform 
(p. 112 . 

on Acid, C, N, O,H,, or Isocyanuric Acid. Its alkali salts are 
ebtained by boiling mercuric fulminate with potassium chloride or ammonium 
chloride and water. In its preparation 60-75 grams of mercuric fulminate are 
heated with 60 c.c. of a saturated ammonium chloride solution, and 700-800 c.c. 
of water, until mercuric oxide no longer separates. The solution will then con- 
tain HgCl, and ammonium fulminurate. Ammonium hydrate is now employed ~ 
to throw out all the mercury, when the solution is filtered and concentrated to 
crystallization. To obtain the free acid, add lead acetate to the solution of the 
ammonium salt, decompose the lead salt. with hydrogen sulphide, and evaporate 
the filtrate down to a small bulk. 

Fulminuric acid is an indistinctly crystalline mass, soluble in water, alcohol and 
ether, and deflagrating at 145°. It is a monobasic acid, yielding finely crystallized 
alkali salts. Especially characteristic is the Cuprammonium salt, C,N,0,H, 
(CuNH,), which precipitates from the aqueous solution of the acid or its alkali 


ISOCYANIDES OR CARBYLAMINES. a | 


salt when boiled with ammoniacal copper sulphate. It consists of glistening dark 
blue prisms. Mercury fulminurate is produced when mercury fulminate is heated 
with alcoholic ammonia. 

Trinitroacetonitrile is formed by the action of a mixture of concentrated nitric 
and sulphuric acids upon fulminuric acid :— 


C,N,0,H, + 2NO,H = C,(NO,),N + N H, + CO, + H,0O. 


The constitution of fulminuric acid: is not known. Consult Berichée, 19, Ref. 
22, upon an isomeric isofulminuric acid. 





(2) ISOCYANIDES OR CARBYLAMINES. 


These constitute a series of compounds parallel to, and isomeric 
with, the nitriles or alkylcyanides. They are obtained :— 

1. By digesting chloroform and primary amines with alcoholic 
potash (A. W. Hofmann) :— 


C,H,.NH, ++ CCI,H == C,H,.NC + 3HCl. 


The carbylamine test of Hofmann for detection.of primary 
amines is based on this (p. 162). 

2. By action of the alkyl iodides upon silver cyanide (p. 269) 
(Gautier) :— 


C,H,I + NCAg =C,H,.NC + Agl. 


Preparation.— Heat 2 molecules of silver cyanide with 1 molecule of the iodide, 
diluted with 24 volume of ether, in sealed tubes to 130°-140° for several hours. — 
Water and potassium cyanide (1% part) are added to the product (a compound of 
the isocyanide with silver cyanide) and the whole distilled upon a water bath 
(Annalen, 151, 239). 


3. The isonitriles are produced, too, in slight quantity, in the 
preparation of the nitriles from alkyl sulphates and potassium cyan- 
ide (p. 282). 

The carbylamines are colorless liquids which can be distilled, - 
and possess an exceedingly disgusting odor. They are sparingly - 
soluble in water, but readily soluble in alcohol and ether. 

While, in the nitriles, the carbon of the cyanogen group is firmly 
attached to the alcohol radicals, and nitrogen splits off readily as 
NH;, in all decomposition reactions of the isonitriles nitrogen 
remains in combination with the alcohol radical. Hence, in the 
latter we assume the presence of the isomeric ¢socyanogen group, in 
which nitrogen figures as a pentad :— 

CH, —.N=C. and ..CH,.._C=N. 
Isocyanide. Cyanide. 

The isocyanides are characterized by their ready decomposition 

by dilute acids into formic acid and amines :— 


* C,H;.NC + 2H,O = C,H,.NH, + CH,0,. 


288 ORGANIC. CHEMISTRY. 


The same decomposition occurs when they are heated with water 
to 180°. When oxidized by mercuric oxide they become isocyanic 


esters (p. 274) :— 
C,H,.NC + HgO = C,H,.N:CO + Hg. 


The isocyanides, like the cyanides, form crystalline compounds . 
with HCl; water decomposes these into formic acid and amine 
bases (p. 283). They pass into thio-formamides by their union 
with H,S (p. 260). 


Methyl Isocyanide, CH,.NC, methyl carbylamine, boils at 59° and dissolves 
in 10 parts of water. When "heated with water it decomposes. 

Ethyl tsocyanide, C,H,.NC, is an oily liquid which swims upon water and 
boils at 79°. 

Isoamyl] Isocyanide, C,H,,.NC, boils at 137° and swims on water. 

Allyl Isocyanide, C3 H, .NC, boils near 106° , and has a specific gravity of 
0.796 at 17°. 





AMIDE DERIVATIVES OF CYANOGEN. 


Cyanamide, CN.NH,, or carbodiimide, C(NH),, is formed by 
the action of chlor- or brom-cyan upon an ethereal or aqueous solu- 
tion of ammonia (Berichte, 18, 462), and also by the desulphurizing 
of thio-urea by means of mercuric chloride or lead peroxide (Berichte, 
18, 461) :— 

cs( Nis 4. HgO = CN,H, + HgS + H,0. 

It forms colorless crystals, easily soluble in water, alcohol and 
ether, and melting at 40°. If heated it polymerizes to dicyan- 
diamide and tricyan-triamide (melamine). It forms salts with 
strong acids, but these are decomposed by water. Again it unites 
with metals to salts. An ammoniacal silver nitrate solution throws 
. down a yellow precipitate, CN,Ag,, from its solutions. Copper sul- 
phate precipitates black CN,Cu. 

Such metallic compounds are obtained directly by heating the 
salts of isocyanic acid with the alkaline earths and the heavy 
metals :— 

(CO:N),Ca = CN,Ca + CO,. 

By the action of sulphuric acid or hydrochloric acid, it absorbs 
water and becomes urea: CN,H, + H,O = CO(NH,),. H,S con- 
verts it into thio-urea, and NH, into guanidine (p. 294). 

The transpositions and syntheses of cyanamide give no positive 
evidence as to whether it should be considered as amide, CN.NH,, 
or carbodiimide, HN:C:NH. Perhaps the forms are tautomeric. 
However, two isomeric varieties of alkyl derivatives do exist (same 
as with cyanic acid). 


AMIDES OF THE DICYANIC ACIDS. 289 


Alkylic Cyanamides are obtained by letting cyanogen chloride act upon primary 
amines in ethereal solution :— 


NH,.CH, + CNC] = NH(CH,).CN + HCl, 


They may be prepared also by heating the corresponding thio ureas with mer- 
curic oxide and water :— 


cs(NH-CHs | tHg0 = CN.NH(CH,) + HgS + H,0. 
\NH, 

Methyl Cyanamide, CN,H(CH,;), and Ethyl Cyanamide, CN,H(C,H,), 
are non-crystallizable thick syrups with neutral reaction. ‘They are readily con- 
verted into polymeric isomelamine derivatives. 

Diethyl Cyanamide, CN.N(C,H;),, is prepared by the interaction of silver 
cyanamide and ethyl iodide. It is a liquid, boiling at 186-190°. Boiling hydro- 
chloric acid resolves it into CO,, NH, and diethylamine, NH(C,H;),. 

Allyl Cyanamide, CN,H(C,H;), “called Sinamine, is obtained from allylthio- 
urea. It is crystalline and “polymerizes readily into triallylmelamine (see below). 





Dicyanamide, NH(CN),, is only known in its salts. The jotassium salt, 
C,N,K, is obtained by heating potassium cyanide with paracyanogen or with mer- 
curic cyanide (Berichte, 13, 2202). It crystallizes in thin needles. Silver nitrate 
precipitates a white silver salt, C,N,Ag, from its solution, . 


AMIDES OF THE DICYANIC ACIDS. 


Cyanamide, CN.NH,, may be considered as the amide of normal cyanic acid, 
CN.OH, and carbodi-imide the z#zide of hypothetical isocyanic acid, HN:CO (p. 
271). Similarly, there may be derived from the latter acid two isomeric dicyanic 
acids :— ° 


ZNN / NEN 
HO.CQ y YC-0H and COK yy DCO 


Normal Dicyanic Acid. Isodicyanic Acid. 


and their amide derivatives :— 


ZNN /NH\ 
H,N.C¢ y YC-NH, and HN:CC yy DC: :NH. 


Dicyandiamide. Isodicyandiimide. 


These are probably tautomeric forms and only isomeric in their alkyl derivatives 
(not yet known). 

Dicyandiamide, C,N,H,, Param, results from the polymerization of cyanamide 
upon long standing or by evaporation of its aqueous solution. It crystallizes in 
leaflets which melt at 205°. It is insoluble in ether. Its structure probably agrees 
with the formula, RECO cy. Hence, it can be called cyanguanidine 
(Berichte, 16, 1464; 18,3106). However, these reactions (together with guanyl- _ 
urea), are explained by the amide or imide formulas (Berichte, 19, 2086). 


H, 
Dicyandiamidine, C,Hg,N,O = NH: CNH CO.NH, (guanyl urea),is formed 


by the action of dilute acids upon dicyandiamide or cyanamide, or by fusing a 
guanidine salt with urea. It is a strongly basic, crystalline substance, and absorbs 


290 ORGANIC CHEMISTRY. 


CO,. When digested with baryta water it decomposes into CO,, NH,, and urea 
(Berichte, 20, 68). ry 

By boiling dicyandiamide with baryta water it is converted into Amido-dicy- 
anic Acid, COC NH CNH (?). This crystallizes in needles, and when heated 


with sulphuric acid changes to biuret. 


AMIDES OF THE CYANURIC ACIDS. 


There are also amide and imide derivatives of the cyanuric acids. These are 
probably tautomeric and only isomeric in the alkyl compounds :— 


OH NH, NH, NH, 
| | | | 
Cc CG es C 
LN Pat. * VN LS 
N N N N N N N N 
| | | | | | | | 
HO.C CO.H HO.C C.OH HO.C C.NH, H,N.C C.NH, 
le bs af 2 aa We 
N N N N 
Normal Cyanuric Cyanurmonamide Cyanurdiamide Cyanurtriamide, 
cid. Ammelide. Ammeline, Melamine. 
O NH NH NH 
| I | I 
C C i Be 
x shi fos WON 
HN NH HN NH HN NH HN NH 
| | | | | | 
OC CO OC CO be C:NH aed C:NH 
sale \ 4 ae ca a a 
N N N 
H H H H 
Isocyanuric Isocyanurmonamide _ Isocyanurdiimide Isocyanurtriimide 
Acid. Melanuric Acid. Isoammeline. Isomelamine. 


Melamine, C,H,N, = C,N,(NH,), (see above), Cyanuramide, is produced 
by :— 

The polymerization of cyanamide or dicyandiamide on heating to 150° (together 
with melam); by heating methyl trithiocyanuric ester to 180° with concentrated 
ammonia; and by heating cyanuric chloride to 100° with concentrated ammonia :— 


C,N,Cl, + 6NH, = C,H,(NH,), + 3NH,Cl. 


It is obtained from crude melam (p. 291) by extraction with water and precipi- 
tation with soda (Berichte, 19, Ref. 345); or more easily from cyanuric chloride 
(Hofmann, Berichte, 18, 2765). | 

Melamine is nearly insoluble in alcohol and ether. It crystallizes from hot 
water in’shining monoclinic prisms. It sublimes on heating and decomposes into 
melam and NH,. It forms crystalline salts with 1 equivalent of acid. 

On boiling with alkalies or acids melamine splits off ammonia and passes suc- 
cessively into ammeline, C,H;N,O = C,N,(NH,),.OH (a white powder insoluble 
in water, but soluble in alkalies and mineral acids) (Berichte, 21, Ref. 789) ; 
ammelide, C,H,N,O, = pas NH, )(O8)a» a white powder that forms salts with 
both acids and bases, and finally cyanuric acid, C,N,(OH),—( Berichte, 19, Ref. 
341). Potassium cyanate is directly formed by fusing melamine with KOH. 


COMPLEX CYANIDES. 291 


Melanurenic Acid, C,H,N,O,, from melam and melem (p. 292) when heated 
with concentrated H,SO, (Berichte, 19, Ref. 244), and from dicyandiamide by 
the addition of CO, (on heating (NH,),CO,), is a white amorphous powder, soluble 
in alkalies and acids with formation of salts, and breaks off into NH, and cyanuric 
acid when boiled with alkalies and acids, It is probably identical with ammelide 
(Berichte, 19, Ref. 341), or it is the isomeric isocyanurimide ( Berich/e, 18, 3106). 
According to its salts melurenic acid appears to have the doubled formula, C,H, 
N,O, (Berichte, 19, Ref. 245). 

Thioammeline, C,H,N,S —=(CN),(NH,),.SH, is obtained from dicyandiamide 
by the addition of thiocyanic acid, CN.SH, and from cyanuric chloramide, 
C,N,(NH,),Cl, by the action of potassium sulphydrate. It corresponds to amme- 
line (see above) (Berichte, 20, 1059). Its esters result from heating trithiocy- 
anuric esters with ammonia (p. 281). 





ALKYL DERIVATIVES OF MELAMINE. 


While melamine is only known in one form as cyanurtriamide, two series of 
isomeric alkyl derivatives exist—obtained from normal melamine and hypothetical 
isomelamine :— 


(1) C,N,(NHR), and C,H,(NR,);. (2) C,N,H,(NR),. 


Normal Alkylmelamines, Isoalkylmelamines. 


These are distinguished from each other not only in the manner of their prepa- 
ration but also in their transpositions. 

(1) Normal Alkylmelamines are obtained from the trithiocyanuric esters, 
C,N,(S.CH,),, and from cyanuric chloride, C,N,Cl,, upon heating with primary 
and secondary amines (Berichte, 18, Ref. 498): C,N,Cl, + 3NH(CH,), = 


CN, ( Neq") _ + 3HCl. Heating with hydrochloric acid causes them to split 


up into cyanuric acid and the constituent alkylamines. 

Trimethylmelamine, C,N,(NH.CH,),, dissolves readily in water, alcohol 
and ether. It melts at 115°. Triethylmelamine, C,N,(NH.C,H,),, crystal- 
lizes in needles and melts at 73-74° C. 

Hexamethylmelamine, C,N,[N(CH,),],, consists of needles, melting at 
171° C. Hexaethylmelamine, C,H,[N(C,H,),],, is aliquid, and is decom- 
posed by hydrochloric acid into cyanuric acid and 3 molecules of diethylamine. 

(2) Alkylisomelamines are formed by the polymerization of the alkylcyan- 
amides, CN.NHR, upon evaporating their solutions (obtained from the alkyl- 
thioureas on warming with mercuric oxide and water), They are crystalline bodies. 
When heated with hydrochloric acid they yield cyanuric esters and ammonium 
chloride (Berichte, 18, 2784). 

Trimethylisomelamine, C,N,H,(N.CH,), + 3H,O, melts at 179° when 
anhydrous. It sublimes about 100°, Triethylisomelamine, C,N,H,(N.C,H;), 
+ 4H,O, consists of very soluble needles. Consult Hofmann, Berichie, 18, 3217, 
for the phenyl derivatives of the mixed melamines (also amide and imide bodies). 


COMPLEX CYANAMIDES. 


Melam, C,H,N,,. Formed on rapidly heating CNSNH, or CNSK to 200° 
with ammonium chloride. Melam and sulphocyan-melamine are produced at the 
same time. The latter dissolves on boiling with water, while melam and melem 
constitute the residue, and are separated by alcohol, the first being soluble in this 


292 ORGANIC CHEMISTRY. 


solvent (Berichte, 19, Ref. 340). It is a granular powder insoluble in water. 
Boiling alkalies or acids decompose it into NH, and ammeline. Its constitution 
is, therefore, probably (NH,),C,N,(NH)C,N,(NH,)/(I. c). 

Melem, C,H,N,, (see above), decomposes on boiling with alkalies or acids 
into NH, and ammelide. Its composition is probably (NH,)C;N,(NH,)C,N,(NH,). 

Mellon, C,H,N, = C,N,(NH),C,N,, is produced on igniting ammonium a 
phocyanide, melam, ammeline, etc. Boiling acids decompose it into NH, and 
cyameluric acid, C,H,N,0, (Berichte, 19, Ref. 340). 





IMIDO-ETHERS, AMIDINES AND OXAMIDINES. 


The imido-ethers, the amidines, the oxamidines and guanidine (p. 294) are 
intimately related to the nitriles and cyanamides. 


(1) The Imido-Ethers, R. CC OR: (their HCl salts), are produced by the 


action of HCl upon a mixture of a nitrile with an alcohol (in molecular quantities) 
(Pinner, Berichte, 16, 353, 1654) :— 


ZNH.HCI 
CH,.CN + C,H,.OH + HCl = CH, (LOCH, 


Aoite ochee, 


Acetimido-ethyl Ether, when liberated from its HCl-salt by means of NaOH, 
is a peculiar-smelling liquid, boiling at 97°. Its HCl-salt crystallizes in shining 
leaflets, and like the other imido-ethers is readily decomposed by heat (with forma- 
tion of acetamide and ethyl chloride). 

The formimido-ethers are obtained from CNH, alcohol and HCl by a reaction 
analogous to that given above :— 

4 NH.HC1 . 


HCN + C,H;.0H + HCl = oe. 0.6.1 
Formimido- ethy Ether. 
These-are only known in their salts, which suffer various noteworthy transforma- 


tions. Upon standing with alcohols they pass into esters of orthoformic acid (see 
this) :— 


/O.CH, 
HcZ REC! 4 2CH,.0H = HC—O.CH, ae NH,Cl. 
Bes a \.0.C,H 


They yield amidines with ammonia and amines (primary and secondary) :— 


ZNH.HCI 
\.0.C,H, 


gNH 


He \NH, 


4+. NH, = HC HCl + C,H,.0H. 


All the other imido ethers react similarly. With hydroxylamine they yield the 
acidoximes (Berichte, 17, 185), corresponding to the aldoximes and acetoximes :— 


/ NH.HCI 


RCC OG, + NH;.0H = Rol MOM) 1. WHC: 
gad’ betas <j 


\0.C,H, 


See Berichie, 17, 2002, for the phenylhydrazine derivatives of the imido-ethers, 


IMIDO-ETHERS, AMIDINES AND OXAMIDINES, 293 


The imido-thio-ethers correspond to the imido-ethers. They are obtained by 
the action of HCl upon nitriles (of the benzene series), and mercaptans :— 


7 NH 
\5.C,H.3 


further, when the ¢hio-amides (of the benzene series) are treated with alkyl-iodides 
(Berichte, 15, 564) :— 


C,H,.CS.NH, + €,H,1 = C.H,.CZ 


C,H,.CN + HS.C,H, =C,H,.C 


NH 
S.C,H, 


This class of compounds has a constitution similar to that of the isothioamides 
(p. 260). 


+ HL 





(2) The amidines, RCONH , whose hydrogen atoms can be replaced by 
alkyls, are produced :— ' 

1. From the imid-chlorides, thio-amides, and isothio-amides (p. 255) (Berichée, 
16, 146), by the action of ammonia or amines (primary and secondary) :— 


N.CH 
CH,.CCI:N(C,H,) + NH,.CH, = CH,.CO NCH, + HCl, 


ZNH 
C,H,.CS.NH, + NH, = CoHs-COny, Hs = a 
2. From the nitriles by heating them with ammonium chloride, or HCl- 
amines :— 


N.C,H 
CH,.CN + NH,.C,H, = CH,.CO ny 5, 


3. From the amides of the acids when treated with HCl (Beriche, 15, 208) :— 


H 
2CH,.CO.NH, = CH,CC NH. +. CH,.CO,H. 
4. From the imido-ethers (p. 292) when acted upon with ammonia and amines 
(Berichte, 16,1647 ; 17, 179). 
The amidines are mono-acid bases. In a free condition they are quite unstable. 
The action of various reagents on them induces water absorption, the imid-group 
splits off, and acids or amides of the acids are regenerated :— 


ANH 


{ NH, + H,O = CH,.CO.NH, + NH, ° 


CH,.C 
HS causes the elimination of the imid- or amid-group from the amidines, and 
thus converts them into thio-amides (p. 260). CS, effects the same, sulpho-cyanic 
acid, CNSH, and mustard oils, CS.NR, being simultaneously produced (Anna/len, 
192, 30). Hydroxylamine supplants the imid-group in them with the oximid- 
group, N.OH, with formation of oxamidines, or amidoximes (see these). } 
Aceto-acetic ester, or acetic anhydride ( Berichte, 22, 1600), converts the amidines 
into pyrimidines or metadiazine derivatives (see these). They also combine with 
phenyl cyanates, with diazo compounds, with chloral, and other aldehydes (see 
benzamidine, and Berichte, 22, 1607). 


Formamidine, CN,H, = CHC Na (Methenylamidine), is only known 
2 


294 ORGANIC CHEMISTRY. 


in its salts. The HCl-salt, CN,H,.HCI, is obtained from CNH.HCI (p. 267) on 
heating it with alcohol :— 


2CNH.HCl + 2C,H, OH = CN, H HCl + C,H,Cl + cHo, .H,; 


It consists of very hygroscopic needles, melting at 81°, and is decomposed into 
NH, and formic acid by the alkalies. 

Acetamidine, C,H,N, — CH CONE, (Acediamine), is obtained by heat- 
ing acetamide in a stream of HCl. Its hydrochloric acid salt crystallizes in large, 
shining prisms that melt at 165°. The acetamidine, separated by alkalies, reacts 
strongly alkaline and readily breaks up into NH, and acetic acid. The ‘higher 
amidines and their alkyl derivatives are easily obtained by the usual methods (Be- 
richte, 17, 178). 

The so-called anhydro-bases and ethenyl derivatives of the benzene series (see 
these) are classed with the amidines. 


Methenyl-amidoxime, CH,N,0 = CH 


with urea, CO(NH,),. 

It appears on evaporating the alcoholic solution of hydroxylamine and hydrogen 
cyanide. It crystallizes in rhombic prisms, similar to those of urea, and melts with 
partial decomposition at 104°-105°. It reacts alkaline and forms crystalline salts 
with 1 equivalent of the acids. On heating the solutions of its salts, the latter 
decompose into formic acid, ammonia and hydroxylamine. 

Ethenyl-amidoxime, C,H,N,O <= CH Reet Ojy’ from acetonitrile and 
hydroxylamine, is very soluble in water, crystallizes in needles, and melts at 135°. 
Warm water breaks it up into H,N.OH and acetamide. Acid anhydrides or 
chlorides convert the amidoximes into azoximes (Berichte, 18, 1062; see Benzenyl 
amidoxime). 


Wok (Isuretine), is isomeric 


(3) Oxamidines, or Amidoximes, R CNH, These may be considered 


amidines, in which one H-atom of the amid- or imid- -groups is replaced by hy- 
droxyl. They arise :— 

1. From the action of hydroxylamine upon amidines. 

2. By the addition of hydroxylamine to the nitriles (Berichte, 17, 2746) :— 


/NH, 
CH,.CN + NH,OH = CH,.C¢ yy, 


Acetonitrile. Ethenylamidoxime. 
3. From the addition of hydroxylamine to thio-amides (Berichte, 19, 1668) :— 
CH,.CS.NH, -+- NH,OH shit AWE 1,S. 


The amidoximes are crystalline, very unstable bodies, which readily break up into 
hydroxylamine and acid amides or acids. 





ga re ef NE 
Guanidine, CN,;H; = HN:C< NH, 


amidine of carbonic acid. It may also be considered as urea, 
CO(NH,),, in which the oxygen has been replaced by the imid- 


carb-diamid-imide, is an 


IMIDO-ETHERS, AMIDINES AND OXAMIDINES. 295 


group. It was first obtained by the oxidation of guanine with hy- 
drochloric acid and potassium chlorate, hence its name. It is formed 
synthetically by heating cyanogen iodide and NH;, and from cyana- 
mide (p. 289) and ammonium chloride in alcoholic solution at 
100°:— 

/ NH, 

CN.NH, + NH,.HCl = C=NH.HCI1. 
\NH, 


This is analogous to the formation of formamidine from HCN. 
It is also produced by heating chloropicrin or esters of orthocar- 
bonic acid, with aqueous ammonia, to 150° :— 


CCl,(NO,) + 3NH, = CN,H,.HCl + 2HCl + NO,H. 


It is most readily prepared from the sulphocyanate salt, which is made by pro- 
longed heating of ammonium sulphocyanate to 180°—190°, and the further trans- 
position of the thio urea that forms at first :— 


HW HANS, 
21°N CS = tn DC-NHLCNSH + H,S. 


To get the free guanidine from this salt, evaporate the aqueous solution with an 
equivalent quantity of potassium carbonate, extract the potassium thiocyanate from 
the mass with boiling alcohol, and convert the residual guanidine carbonate into 
sulphate, and from this liberate the guanidine by means of baryta (Berichte, 7, 92). 


The crystals of guanidine are very soluble in water and alcohol, 
and deliquesce on exposure. It is a strong base, absorbing CO, 
from the air and yielding crystalline salts with 1 equivalent of the 
acids. The nitrate, CN;H;.HNOs, consists of large scales, which 
are sparingly soluble in water. The HCl-salt, CN,H;.HCl, yields a 
platinum double salt, crystallizing in yellow needles. The carbo- 
nate, (CN;H;),.H,COs, consists of quadratic prisms, and reacts alka- 
line. The sulphocyanate, CN;H;.HSCN, crystallizes in large leaf- 
lets, that melt at 118°, 


Guanidine is most readily detected by converting it into guanyl urea (p. 289) 
(Berichte, 20, 71). 

The substituted guanidines, resulting from the introduction of alcohol radicals, 
are obtained by reactions analogous to those employed in the preparation of guani- 
dine, viz., the heating of cyanamide with the HCl-salts of the primary amines :— 


CN.NH, + NH,(CH,).HCl = CN,H,(CH,).HCI. 


Methyl Guanidine, CN,H,(CH,). Silver oxide separates this from the HCI- 
salt. It forms a deliquescent, crystalline mass. Its salts with 1 equivalent of acid 
itr quite well. Itis also produced on boiling creatine with mercuric oxide 
and water. 


Triethyl Guanidine, CN,H,(C,H,),, is obtained by boiling diethyl thio-urea 


296 ORGANIC CHEMISTRY. 


and ethylamine in alcoholic solution with mercuric oxide whereby sulphur is 
directly replaced by the imid-group (see thio-ureas) :— 
NH.C,H 
CNC? 4+ NH,.C,H, + HgO = 
c/ NH.C,H 


C,H,.N: CNHCH? + Hes + H.0. 


CS 


Vice versa, the alkylic guanidines, when heated with CS,, have their imid- 
group replaced by sulphur (same as with the amidines, p. 293), with formation of 
thio-ureas. 

The guanidine-benzene derivatives are especially numerous. Acid residues may 
also replace the hydrogen of guanidine; these derivatives will receive attention 
when the urea compounds are described. 

Guanidine also forms salts with the fatty acids. When these are heated to 
220—230°, water and ammonia break off,and the guanamines result. These are 
produced by the union of 1 molecule of acid and 2 molecules of guanidine. They 
are mono-acids, and very probably have a structure similar to that of the amidines 
p- 293). Hormo-guanamine, C,H,N,, from guanidine formate, aceto-guanamine, 
C,H,N,, from the acetate, propio-guanamine, C,H, N,, dutyro- and isobutyro- 
guanamine, C,H,,N,, etc., (Berichte, 9, 454) belong here. 


DIVALENT COMPOUNDS. 


The introduction of ¢wo monovalent groups into the hydrocarbons 
for two hydrogen atoms produces the divalent compounds. 

The replacement of hydrogen by two hydroxyl groups yields the 
divalent alcohols or glycols, which we can also term dialcohols (see 


p-;114):-— 


4 -_—_ . 
oH CH,.0H 
Ethylene Glycol. 


By replacing two hydrogen atoms in the glycols by oxygen, we get 
the divalent (dihydric) monobasic acids, containing one carboxyl 
and one hydroxyl group :— 
: | OH  CH,.OH 
Canoe 3 
\oH  CO.OH 
Glycollic Acid. 


The substitution of two additional hydrogen atoms by oxygen yields 
the divalent, dibasic acids, with two carboxyl groups :— 


OH  CO.0OH 
‘ate Vegas 
1? Now heat 
Oxalic Acid. 


Numerous related derivatives attach themselves to these three prin- 
cipal groups of divalent compounds. 


DIHYDRIC ALCOHOLS OR GLYCOLS. 297 


The divalent compounds contain either two similar reactive atomic groups, like 
the dialdehydes (glyoxal), the diketones (diacetyl), the diamines (ethylene diamine), 
etc., and hence manifest the typical properties of the monovalent compounds 
doubly, or they contain two different typical atomic groups, present in the same 
molecule, and thus present simultaneously the typical characters of different groups 
of compounds. Derivatives possessed of this mixed function are in addition to 
the oxyacids or alcohol-acids (see above): the aldehyde alcohols (glycol aldehyde, 
CH,(OH).CHO), the ketone alcohols (acetyl carbinol, CH,.CO.CH,.OH), the 
aldehyde acids (glyoxylic acid), the ketonic acids, the amido-acids, etc. 





DIVALENT (DIHYDRIC) ALCOHOLS OR GLYCOLS. 


Wiirtz obtained the glycols in 1856, from the haloid compounds 
of the alkylens, C,H,,. They are formed as follows :— . 
1. By heating the alkylen haloids (p. 100) with silver acetate (and 
glacial acetic acid), or with potassium acetate in alcoholic solution :— 


C,H, Br, + 2C,H,0,.Ag = C,H, 2 OC? 4 Gace. 
\.0.C,H,O 
Ethylene Diacetate. 


The resulting acetic esters are purified by distillation, and then 
saponified by KOH :— 


0.C,H,O OH 
KOCHO 4+ 2KOH = CH. OH + 2C,H,0,K. 

Generally in using potassium acetate, a mixture of di-acetate and mono-acetate 
is produced with free glycol. The mixture is saponified with KOH,or Ba(OH),. 
A direct conversion of alkylen haloids into glycols may be attained by heating 
them with water and lead oxide, or sodium and potassium carbonate (p. 119). 
When ethylene bromide is heated for some time with much water above 100° it 
is completely changed to ethylene glycol, whereas with little water aldehyde 
results (Aunalen, 186, 393). 

2. Another procedure consists in shaking the alkylens, CnH,n, with aqueous 
hypochloronus,acid, and afterwards decomposing the chlorhydrins formed with 
moist silver pxide — 


C,H 


Cl 
C,H, + CloH = CHA on and 
Cl 4OH 
CHA On + AgOH = CyH,¢ Gy + AgCl 
The glycols appear in small quantities when hydrogen peroxide acts on the 
olefines CnHyn — 
C,H, + H,0O, = C,H,(OH),. 


3. By the oxidation of the olefines in alkaline solution (p. 82 and Berichie, 
21, 1230) with potassium permanganate :— 
rr. CH,.OH 
| RF O a H,0 ne a | . 
CH, CH.,OH 






Peeest UB RAB 


29 UNIVERSITY | 


Men a 


298 ORGANIC CHEMISTRY. 


Isobutylene, (CH ,),C:CH, yields isobutylene glycol, (CH,),C(OH).CH,.OH, 
etc. ; 





From the method of producing glycols out of the alkylens, C,H,n, by means 
of their addition products, it would appear that in the glycols the hydroxyl groups 
are bound to ¢wo different carbon atoms, One carbon atom can link but ome OH 
group. Thus from ethidene chloride, CH,.CHCI,, we cannot obtain the corre- 
sponding glycol, CH,.CH(OH),. When dihydroxides do form, water separates 
and the corresponding anhydrides—the aldehydes (p. 188)—result :-— 


ZO 
CH s‘CH< 6 
The union of two OH groups to one carbon atom is more stable if the neighboring 
carbon atom be attached to negative elements. Thus the rather stable hydrate of 
chloral, CCl,.CHO + H,O, can be viewed as a dihydroxy] derivative (as tri- 


chlorethidene glycol), CCl CHS On. compare glyoxylic and mesoxalic acids). 
Sty 3 \ OH pare gyory 


Such hydroxyl groups are usually not capable of further exchange, as is the case 
with those in the glycols. 

While, therefore, the union of two hydroxyl groups to one carbon atom is but 
feeble, two oxygen atoms may be firmly attached, if they are linked.at the same 
time with alcoholic or acid radicals, as in— 


tr yields CH,.CHO + H,0. 


/O.C,H /0.C,H,0 
CH,.CH(GC74q° and CH,.CHY 0:6 17°0, 
Ethidene-diethylate. Ethidene-diacetate. 


The possible isomerisms for the glycols are deduced from the 
corresponding hydrocarbons, according to the ordinary rules, with 
the single limitation that but one OH group can be attached to 
eachcarbon atom. ‘Thus two glycols,C,;H,(OH),, are derived from 
propane :— 


CH,.CH(OH).CH,.0H and CH,(OH).CH,.CH,.OH. 
a-Propylene Glycol. B-Propylene Glycol. 


The first contains both a primary and a secondary alcohol group 
(p. 118), and therefore can be called primary-secondary glycol; the 
second has two primary alcoholic groups, and represents a @z-primary 
glycol, etc. ‘The higher glycols are similarly named. 





The glycols are neutral, thick liquids, holding, as far as their 
properties are concerned, a place intermediate between the monohy- 
* dric alcohols and trihydric glycerol. The solubility of a compound 
in water increases according to the accumulation of OH groups in 
it, and it will be correspondingly less soluble in alcohol, and espe- 


y 
. 


DIVALENT ALCOHOLS OR GLYCOLS, 299 


cially in ether. There will be also an appreciable rise in the boiling 
temperature, while the body acquires at the same time a sweet taste, 
inasmuch as there occurs a gradual transition from the hydrocarbons 
to the sugars. In accord with this, the glycols have a sweetish taste, 
are very easily soluble in water, slightly soluble in ether, and_ boil 
much higher (about 100°) than the corresponding monohydric 
alcohols. 

The hydrogen of the hydroxyls may be replaced by the alkali 
metals (with formation of metallic glycollates, p. 126), and by acid 
and alcohol radicals. The acid esters are produced by the action 
of the salts of the fatty acids upon haloid compounds of the alky- 
lens, or even when the free acids act on the glycols (p. 250) ;— 


H.C on + C,H,0.0H =C oH On aHt,O % i760, oe 


0.C,H,O 
CH. on + 2C,H,0.0H =CH. OCHO + 2H,0. 


The formation of acid esters is an excellent means of proving the number of 
hydroxyl groups present in the polyvalent alcohols (the glycerols—sugars and the 
phenols). The benzoic esters are especially easy of production by merely shaking 
the substance under examination with benzene chloride and sodium hydroxide 
(Berichte, 21, 2744; 22, Refs. 668 and 817). The nitric acid esters are also quite 
well adapted to this purpose, and also the carbaminic esters, through the action of 
isocyanic acid esters (p. 273), more especially phenylisocyanic ester (see this). 

The alcohol-ethers are obtained from the metallic glycollates by the action of 
the alkyl iodides :— 


C Aion $iGgHighs C.H,¢ On? 2H; 4 Nal, J 
ON 0.C,H 
Cc oH. ONa of 2C,HI=C,HyC 6, C2yy® + 2Nal. 


, 


When the glycols are treated with hydrochloric and hydrobromic acid, the 
primary and secondary ha/oid esters (p. 124) are produced. The former are also 
called chlor- and brom-hydrins, while the latter represent the halogen compounds 
of the alkylens :— 


CHC On + BCL = Oe Renn + H,0, 
Ethylene Chlorhydrin. J 
/OH 
C2H4< On + 2HCl = C,H,Cl, + 2H,0. 
} Ethylene Chloride. 
When heated with HI, a more extensive reaction occurs (p. 98). 


The primary haloid esters can also be considered as substitution products of the 
monohydric alcohols :— 

OH 

CHA Gy — CH,C1.CH,.OH. 4 


Glycol Chlorhydrin. Chlor-ethyl Alcohol. 


300 ORGANIC CHEMISTRY. 


They can be obtained, too, by the direct addition of hypochlorous acid to the 
alkylens :— ; 
CH, CH,Cl 
| COOH = | 
CH, CH,.0H 


The hypochlorous acid is prepared by acting with chlorine upon HgO suspended 
in water, or by saturating a dilute and cold solution of NaOH with the gas (Ze- 
richte, 18,1767), or by the addition of an excess of boric acid to a solution of 
chloride of lime (Berichte, 18, 2287). 


Nascent hydrogen converts them into monohydric alcohols :— 


J 


C,H,Cl.OH + H, =C,H,.0H + HCl. 
When they are digested with salts they form primary esters :— 


/O.C,H,O 


Cl 
7) 4 'C | 8.0.0k = CH OF 


OH + KCL. 
By treating the haloidhydrins with alkalies we obtain the amhy- 
adrides of the glycols or alkylen oxides :— 


CH,Cl 
l +KoH=| "0 + KCl + H,0, 
CH,.0H 

@* } SE ac side, 


~ 


This is the only method of forming the a-alkylen oxides (those in which the 
Q-atoms are in union with adjacent C-atoms), whereas the y- and d-alkylen oxides 
(those in which the second union occurs in the y- or d-position with reference to 
the first) can be obtained from the corresponding glycols by direct withdrawal ot 
water when heated alone or upon boiling with 50% sulphuric acid (Berichie, 18, 
3285; 19, 2843). The a-glycols, under like treatment, yield either unsaturated 
alcohols, aldehydes or pinacolines, depending upon their constitution (p. 310). 


Such oxides, having the oxygen attached to two carbon atoms, 
are isomeric with the aldehydes and ketones, and boil at lower tem- 
peratures than the latter. Notwithstanding they show neutral reac- 
tion, they yet possess a strong basic character, precipitating metallic 
hydroxides from solutions of metallic salts and uniting with acids 

to form primary esters of the glycols :— 


C,H,O+ HO=C RAG 
/0.C,H,0 


C,H,O + C,H,0.0H = C,H,< 6 


With the acid anhydrides they yield secondary esters of the 
glycols :— 


0.C,H;0 
C3H,0 + (C,H;0),0 = CHA 6.0710. 


ETHYLENE GLYCOL. 301 


The alkylen oxides are readily soluble in water (distinction from 
alkyl oxides or esters). When the a-alkylen oxides are heated with 
water the glycols are regenerated. This is not the case with the ;- 
and é-glycols. It is also true that only the a-alkylen oxides form 
hydramines with ammonia (p. 314). All alkylen oxides unite with 
hydrochloric acid to form chlorhydrins. 

Like the monohydric alcohols, the glycols also form sulphur com- 
pounds, amines and sulphonic acids. 





Methylene Derivatives. 

Methylene Glycol, CH,(OH),, is not known and cannot exist (p. 298). 
Wherever it should occur it eliminates water and yields methylene oxide (2. ¢., 
formaldehyde), and trioxymethylene (p. 188). Its ethers and esters have been 
prepared. 

Methylene Diacetic Ester, CH,(O.C,H,O),, is produced on heating methy]l- 
ene iodide with silver acetate. An oily liquid, insoluble in water and boiling at 
170°. Boiling alcohols saponify it, but instead of yielding the expected methylene 
glycol, trioxymethylene is produced. 

Methylene Dimethyl Ether, CH,(O.CH,),, Aethylal or Formal, is obtained 
in the oxidation of methyl alcohol with MnO, and sulphuric acid. It is an ethereal 
liquid of specific gravity 0.855, and boils at 42°. It is miscible with alcohol and 
ether, and dissolves in 3 parts water. The diethyl ether, CH,(O.C,H,),, is pre- 
pared by the action of sodium ethylate upon methylene chloride, or iodide, and by 
distilling trioxmethylene with alcohol and sulphuric acid. It boils at 89° (82°). 
Its specific grawity is 0.8275 at 17°. Consult Berichte, 20, 553 for the higher 
methylals. 





1. Ethylene Glycol, C,H,O, = C,H,(OH),. 

This is a colorless, thick liquid, with a specific gravity of 1.125 
at o°, and boiling at 197.5°. It solidifies when exposed to low 
temperatures, and melts at — 11.5°. It is miscible with water and 
alcohol. Ether dissolves but small quantities of it. 


Preparation.—Heat a mixture of 195 grams ethylene bromide (1 molecule), 
1o2 grams potassium acetate (2 molecules) and 200 grams alcohol, of go per cent., 
until all the ethylene bromide is dissolved, then filter off the potassium bromide 
and fractionate the filtrate (Demo/e). 2. Boil 188 grams ethylene bromide, 133 
grams K,CO, and 1 litre of water, until all the ethylene bromide is dissolved 
(Annalen, 192, 240 and 250). 


On heating ethylene glycol with zinc chloride water is eliminated 
and acetaldehyde (and crotonaldehyde) (p. 199) formed. Nitric 
acid oxidizes glycol to glycollic and oxalic acids : -s 


CH,.0H CH,.0H CO.OH 
| d and | ; 
CH,.0H 0.0H CO.OH 
Glycol. Glycollic Acid, Oxalic Acid. 


302 : Qhrerae CHEMISTRY. 


The following aldehyde-compounds are ‘produced at the same 
time :— 


CHO CHO 
| and d 
CHO O.OH. 
Glyoxal. Glyoxylic Acid. 


And when glycol is heated, together with caustic potash, to 250°, 
it is oxidized to oxalic acid with evolution of hydrogen. 

Heated ta 200° with concentrated hydrochloric acid, glycol is 
converted into ethylene chloride, C,H,Cl,. 


Metallic sodium dissolves in glycol, forming sodium mono-ethylenate 
C,H shouts and (at 170°) disodium ethylenate,C,H,(ONa),. Both are white, 


crystalline bodies, regenerating ‘glycols _— water. The alkylogens convert them 
into ethers. : YOH 
Ethylene Ethyl Ether, C,H 4, 0.C,H,’ i 


oxide with ethyl alcohol. A pleasantly smelling liquid, boiling at 127°. 

Ethylene Diethyl Ether, C,H,(O.C,H,),, is insoluble in water, and boils 
at 123°. 

The following acid esters have been made :— 


Glycol Mono-acetate, C,H,” on 24,0) boils ‘at 182°. and $s mistible with 


s formed by the union of ethylene 


water. 
If hydrochloric ae ate be conducted into the warmed solution, os chlor- 


acetin, C,H sa? H30 or chlorinated acetic ethyl ester, ©H,CI.CH,.O. 


Ci ,O, is ar This boils at 144°. 

‘Glycol Diacetate, C,H,(O.C,H,O),, is obtained by cailee ethylene bromide 
with silver acetate. A liquid of specific gravity 1.128 at 0°, and boiling at 186°. 
It is soluble in 7 parts water. 

Glycol or Ethylene Chlorhydrin, CH,:Cl.CH,.OH(p. 299), is formed by 
heating glycol to 160°, and conducting HCl through it, or by the addition of ClOH 
to. C,H,. Itisa liquid, boiling at 128°, and is miscible with water. A chromic 
acid mixture oxidizes it to monochlor-acetic acid, CH,Cl.CO,H. Ethylene 
bromhydrin, C,H,Br.OH, is not very soluble in water, and boils at 147° ; its 
specific gravity at 6° equals 1.66. When chlorhydrin is heated with potassium 
iodide we get glycol iodhydrin, C,H,I1.OH. This is a thick liquid, which de- 
composes when distilled. OH 

Glycol or Ethylene- hydroxy-sulphuric Acid, C,H Kas SO,.0H? is pro- 


duced on heating glycol with sulphuric acid. It is perfectly similar to ethyl sul- 
phuric acid (p. 150), and decomposes, when boiled with water or alkalies, into 
glycol and sulphuric acid. 

Ethylene Nitrate, C,H,(O.NO,),., is produced on heating ethylene iodide 
with silver nitrate in alcoholic solution, or by dissolving glycol in a mixture of 
concentrated sulphuric and nitric acids :— 


C,H,(OH), + 2NO,.0H = C,H,(0.NO,), + 2H,0. 


J This reaction is characteristic of all hydroxyl compounds (the polyhydric alco- 
hols and polyhydrie acids); the hydrogen of hydroxyl is replaced by the NO, 


Sroup. 


ETHYLENE OXIDE. 303 


The nitrate is a yellowish liquid, insoluble in water, and has a specific gravity 
of 1.483 at 8°. It explodes when heated (like the so-called nitroglycerol). The 
alkalies saponify the esters with formation of nitric acid and glycol. 

Ethylene Cyanide, C,H,(CN),, is obtained on heating an alcoholic solution 
of ethylene bromide and potassium cyanide, and in the electrolysis of cyanacetic 
acid. It forms a crystalline mass, fusing at 54.5°. Boiled with acids or alkalies, 
it passes into succinic acid, hence may be looked upon as the nitrile of the latter. 
Nascent hydrogen converts it into butylene diamine, C,H,(NH,),. 


CH, Si 
Ethylene Oxide, C,H,O = i pe is isomeric with acetal- 
H, 

dehyde, and is produced on distilling ethylene chlorhydrin or 
ethylene chloracetin with caustic potash.. A-mobile, pleasantly 
smelling, ethereal liquid, which boils at 13.5°, and at o° has a 
specific gravity equal to 0.898. It is miscible with water, gradually 
combining with it to form ethylene glycol. : 

It unites with the acids to form chlorhydrins and glycol esters. 
It also precipitates metallic hydroxides from solutions of metallic 
salts (p. 300). 


It combines with bromine, forming a crystalline, red bromide, (C,H,O),Br, 
which melts at 65°, and distils at 95°. Mercury changes the bromide to diethylene 


H,—9—CH, 
oxidt; {CHO}, ==) | . This melts at 9°, and distils at 102°. It 
CH,—O—CH, 
combines with acetaldehyde to form ethylene-ethylidene ether, C,H mee CH. 


CH,, which boils at 82.5°. 





Ethylene Thiohydrate, C,H arp glycol mercaptan, is formed on heating 


an alcoholic solution of potassium sulphydrate with ethylene bromide ( Berichze, 19, 
3263 and 20, 461). The odor of this compound is something like that of mercap- 
tan. It boils at 146°; its specific gravity is 1.12. Insoluble in water, it dissolves 
in alcohol and ether. Acids reprecipitate it from alkaline solutions. It throws out 
mercaptides, ¢. g., C,H,.S,Pb, from the saltsof the heavy metals. It yields mer- 
captals with aldehydes (p. 306). Sodium ethylate and alkyl iodides convert it into 
dithio-ether, C,H,(S.R),; the stronger organic acids change it to a dithio-ester, 
é, g-, C,H,(S.C,H,O),. ; 


The monothiohydrate, C,H RG is obtained when ethylene chlorhydrin 


acts on potassium sulphydrate. It yields mercaptides with I equivalent of the 
metals. 

Ethylene Sulphide, C,H,S—isomeric with thioaldehyde, CH,.CHS,—is 
s.formed on heating ethylene bromide with alcoholic sodium sulphide. It is 
, only known in its polymeric forms. At fitst a polymeric ethylene sulphide, 

(C,H,S)n, is formed. This is a white, amorphous powder, insoluble in the ordi- 
nary solvents. It melts at 145°, but is not very volatile. Protracted boiling with 


q 
~ 


phenol, changes it to diethylene disulphide, C,H KS CH 4: It is analogous to 


304 ORGANIC CHEMISTRY. 


thiophene, and contains a closed chain of six members (Annalen, 240, 303). It is 
similar to naphthalene. It melts at 110°, and boils at 200°. Diethylene sulphide 
may be synthetically prepared from ethylene mercaptan, C,H,(SH),, by the action 
of sodium ethylate upon ethylene bromide, and this procedure will also yield the poly- 
meric derivative, if it is desired (Berichte, 19, 3263). Another polymeric ethylene 
sulphide (C,H,S), (this does not break up) is obtained from ethylene bromide | 
on boiling with aqueous potassium sulphide. It is very similar to the first, but is 
not decomposed on boiling with phenol. Bromine and diethylene disulphide yield 
the tetrabromide(C, H ,S), Br,,which silver oxide converts into the oxide(C,H,S,0),. 
Nitric acid oxidizes the disulphide into the disulphone (C,H,SO,), (p. 307). Me- 
thyl iodide and diethylene disulphide unite to the sulphiniodide (C,H,S),CH,I. 
H,.S.CH, 
Methyl Sulphurane, I ,is produced on distilling this iodide with 
H 


sodium hydroxide. The closed ring of diethylene disulphide is broken. 

The union of the derivatives of diethylene disulphide with the higher alkyl 
iodides yields homologous compounds known as sulphuranes. They are the 
alkyl vinyl ethers of thioethylene. Ethyl sulphurane or ethylvinyl ether has been 
synthetically prepared from glycolchlorhydrin (Berichte, 20, 1830; Annalen, 240, 
305). 

The mercaptals are closely related to diethylene disulphide. This is especially 
true of ethidine dithioethylene, in which there is a closed ring of five members. 
| Diethylene Tetrasulphide, C,H <5? CH 4» is produced by the action of 

2 
the halogens upon ethylene thiohydrate (or sulphuryl chloride or hydroxylamine, 
(p. 141). Itis a white, amorphous powder, melting about 150° (Berichie, 21, 1470). 





Polyethylene Glycols or Alcohols, 


The glycols, like the other dihydroxyl compounds (see disulphuric acid), can 
condense to polyglycols by the coalescence of several molecules, water sepa- 
rating at the same time. ‘These condensed forms arise by the direct union of the 
glycols with alkylen oxides, especially when heat of 100° is applied :-— 


OH 
Oh 
V C,H,0 + C,H,(OH), = Bs Diethylene glycol. 
2 *NoH 
OH ‘ 
C,H,f: 
2 ite 
J 2C,H,0+ CoH On = CHC Triethylene glycol. 
on 
, 


The polyglycols are thick liquids, with high boiling points. They behave like 
the glycols. Anhydro-acids may be obtained from them by oxidation with dilute 
nitric acid; thus diglycollic acid (see this) is formed from diethylene alcohol. 

Diethylene Glycol, (C,H,),O(OH),, boils at 250°. Triethylene Glycol, 
(C,H,),0,(OH),, boils at 285-290°. Tetraethylene Glycol boils above 300°. 








: 
3 


ern 


ETHIDENE-DIETHYL ETHER. 305 


Ethidene or Ethylidene Compounds. 


Ethidene Oxide, CH,.CHO, is ordinary acetaldehyde. On mixing with water 
heat is evolved, and we may suppose that, perhaps at the time, ethidene dihydrate, 
CH,.CH(OH),, is produced (p. 297). The ether derivatives, the acefa/s, on the 
contrary, are very stable. 

The alcohol ethers of ethylidene are formed in the oxidation of alcohols, whereby 
aldehydes are first produced, and in turn combine with two molecules of the alco- 
hols to yield acetals (p. 300). Hydrochloric acid acting on a mixture of an alde- 
hyde and an alcohol, also produces them, chlorhydrins, however, being the first 
products :— 


CH,.CHO + C,H,OH + HCl = cCH,CHCG + H,0, 


and from these, through the action of sodium alcoholates, mixed acetals, ¢.¢., me- 
thyl butyl acetal, can be obtained (Berichte, 19, 3007 ; see, however, Berichte, 17, 
Ref. 464). On heating the acetals with alcohols, the higher alkyls are displaced 
by the lower alkyls (Anma/en, 218, 44). On shaking or digesting the acetals with 
hydrochloric acid, they are readily resolved into their components and reduce an 
ammoniacal silver solution with the production of a silver mirror. 

The acid chlorides form chlorhydrins :— 


0.C,H,O 
CH,.CHO + C,H,OCI = CH,.CHC Gj 2H,0 


-from which mixed acid acetals can be made by the action of organic silver salts 


(Berichte, 17, 473): 
Ethidene-dimethyl Ether, CH _ CH ee Dimethyl Acetal, occurs in 
® 8 


crude wood-spirit, and is produced in the oxidation of a mixture of methyl and 
ethyl alcohols; also upon heating acetaldehyde with methyl alcohol. An ethereal 
liquid, boiling at 64°; its specific gravity, equals 0.867 at 1°. . 

Ethidene-methyl-ethyl Ether, CH,.CH CoCr, is produced together with 
the dimethyl ether in the oxidation of wood-spirit and alcohol, It boils at 80-85°. 
It is a mixture of dimethyl and diethyl acetal (see above). 

Ethidene-diethyl Ether, CH, CHC oat Acetal, occurs in the course 
of the distillation of crude spirit and is produced et . 

I. By oxidizing alcohol with MnO, and sulphuric acid. 

2. By heating alcohol and acetaldehyde to 100°, 

3. By the action of sodium ethylate upon ethidene bromide and monochlor- 

ether. 

Acetal is sparingly soluble in water, has an odor somewhat like that of alcohol, 
and boils at 104°; at 20° its specific gravity equals 0.8314. It is rather stable in 
presence of alkalies; dilute acids, however, easily convert it into aldehyde and 
alcohol ( Berichte, 16, 512). Chlorine produces substitution products; mono-, 
di-, and tri-chloracetal, CCl,.CH.(O.C,H;),. Sulphuric acid breaks these up into 
alcohol and aldehyde (p. 195). Monochlor-acetal, CH,.CCI(O.C,H,;),, is most 
readily obtained by boiling the dichlor-ether with absolute alcohol (erichie 21, 
617). It boils at 157°. When heated with alcoholic ammonia, it passes into ace- 
talamine, CH,.C(NH,)(O.C,H;),, an alkaline liquid, boiling at 163°. It yields 
condensation products quite readily (Berichte, 21, 1482; 22, 568). 

Acid esters of ethidene may be prepared by heating ethidene chloride with salts 


26 


‘ 


306 © - ORGANIC CHEMISTRY. 


of the fatty acids, and by the union of aldehyde with acids, acid chlorides, and acid 
anhydrides (p. 248). a 
Acid chlorides convert ethidene into chlorhydrin :— 


0.C,H,O 
CH,.CHO +. C,H,OC] = CH,.CHY Gj eae 


Mixed acid acetals are obtained from the latter by the action of organic silver 
salts (Berichte, 17, Ref. 473). 


~ Ethidene Chioracetate, CH,.CHC ¢ C,H30 chlorinated acetic ethyl ester, 


- boils. at 121.5°, and is gradually decomposed by water into aldehyde, acetic acid 
and HCl. 
0.C,H 


‘ Ethidene Diacetate, CH,.CH 5 C aa is not very soluble in water, 
tant | 


boils at 188.4°, and is split into aldehyde and ‘acetic acid when boiled with water. 
/ Ethidene Acetpropinate, CH,-CHC 6 claro» boiling at 178.6°, is identi- 
cal with ethidene propio-acetate (see above). This is a further proof of the equi- 
valence of the carbon affinities (Annalen, 225, 267). 


Aldehyde ammonia, CH CHC OH 2, and aldehyde hydrocyanide (oxycyanide), 
CH CB On (p- 190), are also ethidene compounds. 


SULPHUR COMPOUNDS. 


The thio-acetals are perfectly similar to the acetals. They have been called 
mercaptals and mercaptols. Mercaptals are formed from mercaptans and aldehydes 
by the interaction of HCl:—CH,.CHO + 2C,H,SH = CH,.CHC SCH 

shen essen 
+ H,O. The mercaptols are obtained in the same manner from the ketones, e. g., 
(CH,),CO. These thio-acetals are insoluble in water and generally liquid com- 
pounds. They are quite stable and are not changed by boiling with alkalies or 
acids (Berichte, 18, 883; 19, 2803). Analogous compounds are obtained with 
the ketonic acids (Berichte, 19, 1787). 

Instead of using the mercaptans for the preparation of the mercaptols, employ 
the alkyl-thiosulphates. Hydrochloric acid decomposes these into primary sul- 
phates and mercaptans, and the latter, in the presence of acetones, immediately 
yield the mercaptols (Berichte, 22, Ref. 115). 

Methylene Mercaptal, CH,(S.C,H,;),, has been obtained from methylene 
iodide by the action of sodium ethyl mercaptide. It is an oil, boiling at 180°. 

Ethidene Dithioethyl, CH,.CH(S.C,H,),, dithioacetal, the ethyl mercaptal 
of acetaldehyde, is a very mobile liquid, with an odor like that of thioaldehyde. 
It is lighter than water and boils at 186°. 

Acetone Dithioethyl, (CH,),C(S.C,H,),., the ethyl mercaptal of acetone, 
boils at 190° (Berichte, 19, 1787; 22,2595). Permanganate of potassium oxidizes 
it to sulphonal. 

Propidene-dithio ethyl, C,H,.CH(S.C,H,),, from propionic aldehyde and 
ethyl mercaptan, boils about 198°. 


CH,.S 
Ethylene Mercaptals, ¢. ¢., | »CH.CH 3, and Ethylene Mercaptols, 
CH, S 


2° 


DISULPHONES. 307 


are similarly produced by the action of ethylene mercaptan upon aldehydes and 
ketones (Berichte, 21, 1473) :— 


HS,CH, SCH, 
CH,.CHO + I = CH,.CHE I + H,0. 
HS.CH, S.CH, 


They contain a nucleus of five members. It is somewhat less stable than the 
nucleus of diethylene disulphide, containing six members (p. 304). 
Ethylene-dithio-ethidene, C,H,S,:CH.CH,. An oil boiling at 173°. 





DISULPHONES. 


These are produced in oxidizing the dithio-ethers or thigacetals with a perman- 
ganate solution. Each sulphur atom takes up two oxygen atoms :— 


V 
/SLH ie /SO,.C,H 
Dithio-ethyl-ethidene. Ethidene-diethyl Sainhone. 


Mercaptals yield disulphones of the type RCH(SO,.C,H;),, and the mercap- 
tols those of the form R,C(SO,.C,H,),. A third class of disulphones is known: 
CH,(SO,.C,H,),, obtained by oxidizing ortho-thio-formic ester, CH(S.C,H,;),. 

In the-disulphones of the first and third classes the hydrogen of the groups CH, 
and CRH can be easily replaced by the halogens, and by the alkali metals (Be- 
richte, 21, 652). This is similar to the substitutions in aceto-acetic ester and 
malonic ester. The alkali metals which enter can be further replaced by alkyls 
(Berichte, 21, 185; 22, Ref. 678) :— : 

CH, 


CH,.CH(SO,.C,H,), yields Gry SC(S0q-CaH,)s. 
Ethidene-diethyl Sulphone. Acetone-diethyl Sulphone. 


These disulphones are solid, crystalline and very stable compounds. Acids and 
alkalies do not attack them. 

Methylene-diethylsulphone, CH,(SO,.C,H,),., is formed by the oxidation 
of trithioformic ester and methylene mercaptal. It crystallizes in needles, melting 
at 104°. It is very soluble in alcohol and water. 

Ethidene-diethylsulphone, CH,.CH(SO,.C,H,),, from ethidene mercaptal, 
has also been prepared from a-dithio-ethylpropionic acid. It melts at 75° and 
boils at 320° without decomposition. 

Acetone-diethylsulphone, (CH,),C(SO,.C,H;),, Sulphonal, is made by 
oxidizing acetone-ethyl-mercaptol with permanganate. It also results from the 
action of sodium hydroxide and methyl iodide (Annalen, 253, 147) upon ethidene- 
diethylsulphone. It dissolves in 100 parts water at 16°, in 20 parts at 100°, and 
readily in alcohol. 

It crystallizes in colorless leaflets or plates, melting at 126°. It is odorless and 
tasteless. In doses of 0.5-3 gr. it is used as a hypnotic. 

Consult Berichte, 22, 678 and $29 for additional sulphones. 

CH,.SO,R CH,.SO, 
Ethylene Disulphones, | and b >CHL.R, result from the oxi- 
CH,.SO,.R H,.SO, 
dation of ethylene ‘dithio-ethers, C,H,(S.C,H;), (p. 303), and ethylene-mer- 
captals and mercaptols (p.-306). These sulphones are saponified and decomposed 
on boiling with alkalies (Berichte, 21, 1474). 


308 ORGANIC CHEMISTRY. 


CH,.S0,.C5H,; 
Ethylene-diethylsulphone, | _ , has been obtained from ethylene 
CH,.5O..C,H, : 
bromide by the action of 2 molecules of sodium ethyl sulphinate, and from sodium 
ethylene disulphinate (p. 303) by the action of 2 molecules of ethyl bromide. The 
hexavalence of sulphur in the sulphones is thus proved (see p. 144 and Berichte, 
21, Ref. 102). It yields colorless needles, melting at 137°. 


Diethylene Disulphone, CiH,C 552618 4, results from the oxidation of 
2 
diethylenedisulphide (p. 303), and ethylene disulphinate of sodium with ethylene 
bromide. 


Trimethylene trisulphone (p. 193), trialdehyde trisulphones (p. 197), and tri- 
acetone trisulphone (p. 205) are examples of trisulphones. 





2. Propylene Glycols, C;H,O, = C,;H,(OH).. 
The two glycols theoretically possible are known :— 


| CH,.CH(OH).CH,.OH and CH, (OH).CH,.CH,.OH. 
\ a-Propylene Glycol. B-Propylene Glycol. 


a-Propylene Glycol is obtained by heating propylene bromide 
with silver acetate and saponifying the acetic ester first produced 
with caustic potash. Propylene chloride heated with water and 
lead oxide also yields it. It is most readily prepared by distilling 
glycerol with sodium hydroxide (Berichie, 13, 1805). It is a thick 
V liquid, with sweetish taste. It boils at 188°. At 0° its specific 
gravity equals 1.051. Platinum black oxidizes it to ordinary lactic 
acid. Only acetic acid is formed when chromic acid is the oxidiz- 
ing agent. Concentrated hydriodic acid changes it to isopropyl 
alcohol and its iodide. 


When exposed to the action of the ferment Bacterium termo, ordinary pro- 
pylene glycol becomes optically active and yields an active propylene oxide 
(Berichte, 14, 843). 

Propylene Diacetate, C,H ,(O.C,H,O),, boils at 186°; specific gravity 1.109 
ato°. The a-chlorhydrin, CH,.CH(OH).CH,Cl, is produced when sulphuric 
acid and water act upon allyl chloride. It boils at 127° and is oxidized to 
mono-chloracetic acid by nitric acid. (6-Chlorhydrin, CH;.CHC1.CH,.OH, is 
produced by adding CIOH to propylene. This also boils at 127°, but on oxida- 
tion yields a-chlorpropionic acid, CH,.CHCI.CO.OH. a-Propylene Oxide, 
olen 50 from the chlorhydrins, boils at 35°, is readily soluble in water, and 
yields isopropyl alcohol, CH,.CH(OH).CH,, with nascent hydrogen. 


/ #-Propylene Glycol, CH,(OH).CH,.CH,(OH), trimethylene 
glycol, is formed by boiling trimethylene bromide with a large 
quantity of water or potassium carbonate (Berichte, 16, 393). Its 
formation from glycerol in the schizomycetes-fermentation is worthy 


BUTYLENE GLYCOL. 309 


of note. It is a thick liquid, miscible with water and alcohol, boil- 
ing at 216°, and having a specific gravity at 0° of 1.065. Hydro- 
bromic acid changes it to bromhydrin, which yields y-oxybutyric 
acid with potassium cyanide. Moderately oxidized it forms f-oxy- 
propionic acid. 


Its diacetate, CH,(CH,.0.C,H,0O),, boils at 210°; its specific gravity at 19° is 
1.07. The chlorhydrin, CH,,Cl.CH,.CH,.OH, is obtained by conducting HCl into 
glycol. It boils at 160°, and its specific gravity at 0° is 1.146. It is soluble in 


2 volumes of water, and, when oxidized with chromic acid, becomes (-chlorpro- 


pionic acid. TZrimethylene oxide, CHC GH? >, is prepared by heating chlor- 


hydrin with caustic potash. A mobile liquid, with penetrating odor, and boiling 
at 50°, It mixes readily with water and condenses without difficulty. 


3. Butylene Glycols, C,H,,O, = C,H,(OH),. 
Four of the six possible butylene glycols (p. 298) are known. 


(1) a-Butylene Glycol, CH,.CH,.CH(OH).CH,.OH, is obtained from a-buty- 
lene bromide ; boils at 191—192°, and at 0° has a specific gravity of 1.0189. Nitric 
acid oxidizes it to glycollic and glyoxylic acids. 


(2) 8-Butylene Glycol,CH;.CH(OH).CH,.CH,.OH, is formed 
in slight quantity, together with ethyl alcohol, in the action of 
sodium amalgam upon aqueous acetaldehyde (p. 193). Aldol very 
probably appears as an intermediate product in this reaction, and 
from it the glycol can be directly made by the use of sodium amal- 
gam (Berichte, 16, 2505) :— 


CH,.CH(OH).CH,.CHO + H, = CH,.CH(OH).CH,.CH,.OH. 


&-Butylene glycol is a thick liquid, which boils at 207°, and 
mixes with both water and alcohol. When oxidized by either nitric 
or chromic acid it forms acetic and oxalic acids (along with some 
crotonaldehyde). 

Aldol is the aldehyde of butylene glycol. 


(3) y-Butylene Glycol, CH,.CH(OH).CH(OH).CH,, is formed from $-buty- 
lene bromide. It boils at 183-184°. Its specific gravity at 0° equals 1.048. Nitric 
acid oxidizes it to oxalic acid. 

(4) Isobutylene Glycol, (CH,),.C(OH).CH,.OH, is obtained from isobuty- 
lene bromide. It boils at 176-178°. At 0° its specific gravity is 1.0129. Nitric 
acid converts it into a-oxyisobutyric acid, 

Its chlorhydrin, (CH,)..CCl.CH,.OH, is produced by adding CIOH to isobuty- 
lene. It boils at 128-130°, and when oxidized becomes chlor-isobutyric acid. 

(5) Tetramethylene Glycol, CH,(OH).(CH,),.CH,.OH, has been obtained 
from tetramethylene-diamine (p. 313). Its dibromide boils at 190°. 

4. Amylene Glycols, C;H,,O, = C POH) : 

(1) 8-Amylene Glycol, CH,.CH,.CH{ H).CH(OH).CH,, is derived from 


310 ORGANIC CHEMISTRY. 


B-amylene bromide (p, 84). It boils at 187°. Its specific gravity at 0° is 0.994. 
By oxidation it yields a-oxybutyric acid and acetic acid. 

(2) a-Isoamylene Glycol, (CH;),CH.CH(OH).CH,(OH), from a-isoamy- 
lene bromide, boils at 206°. Its specific gravity at 0° is 0.998. When oxidized 
it yields oxy-isovaleric acid. 

(3) B- Isoamylene Glycol, (CH;),C(OH).CH(OH).CH,, from £-isoamylene 
bromide, boils at 177°. Its specific gravity at 0° is 0.967. When oxidized it 
yields a-oxy-isobutyric acid. 

(4) y-Pentylene Glycol, CH,.CH(OH).CH,.CH,.CH,.OH, is formed from 
aceto-propy! alcohol, CH,.CO. CH, .<CH,.CH, OH (p. 322), ‘by the action of sodium 
amalgam. A thick oil, very soluble in water, and boiling at 219°. At this tem- 
perature it partly decomposes into water and y-pentylene oxide, C,H,,O, boiling 
about 80°. The latter product is tetrahydromethylfurfurane, C HO (Berichte, 


22, 2567). 

(5) Pentamethylene Glycol, CH CH CH OH , obtained by the action 
of silver nitrite upon pentamethylene-diamine hydrochloride (p. 313), boils at 260°. 

5. Hexylene Glycols, C,H,,0,. 

1) Hexylene Glycol, ¢ gtd,.(OH),, from hexylene bromide, boils at 207°. 
Its specific gravity at 0° is o. 967. 

(2) Diallyl Hydrate, C,H,,(OH),, is obtained from diallyl, (C,H;), (p. 89), by 
means of the HI. compound, C.H,,1,. It boils at 212-215°. 

(3) d-Hexylene Glycol, cH, CH(OH). CH,),.-CH,OH, is obtained from 
aceto-butyl alcohol, CH,.CO.C,H, ‘OH (p. uel: by the action of sodium amalgam. 
It boils near 235° (under 710 mm. pressure) and speedily passes into d-hexylene 
oxide, C,H,,0, boiling at 105° C. (p. 300). 

(4) Tetramethyl- ethylene Glycol, (CH;),.C(OH).C(OH.(CH,),, or Pina- 
cone, is formed, together with isopropyl alcohol, when sodium amalgam or sodium 
acts upon aqueous acetone (p. 203). 


CH,\ /CH, CN 


CH, . 
CH, 7 Von fs oe 


CO -+- CO cH: 


yd — C(OH) 
it can be obtained, too, from the bromide of tetramethyl-ethylene (from dimethyl- 
isopropyl- -carbinol). It crystallizes from its aqueous solution in the form of the 
hydrate, C,H,,O, -+- 6H,O, which consists of large quadratic plates, melting at 
42°, and gradually efflorescing on exposure. In the anhydrous state it is a crys- 
talline mass which melts at 38° and boils at 171-172°. 

When heated with dilute sulphuric or hydrochloric acid pinacone parts with 1 
molecule of water, and by molecular transposition, becomes Jznacoline, C,H,,0 


(p. 203). 





Dimethy]-pinacone is the representative of a series of similarly constituted 
glycols—the pinacones. These contain two hydroxyl groups attached to two 
adjoining carbon atoms, which in turn are linked to two alkyls. All the pinacones 
show similar deportment, in that when they are heated with acids they part with 
water and suffer molecular transposition into ketones—the pinacolines (p. 202)— 
see also benzpinacone. 

Another pinacone of the et ae is :— 


fag Ste Pinacone, C. a> Sc(OH). C(OH)< This is obtained 
from e. vA? CO. It is a iesiites mass, melting e ae. ‘and boiling at 200- 


CCH, 


AMINES OF THE DIVALENT RADICALS. 311 


205°. It does not form a hydrate with water. When heated with sulphuric acid 
(diluted with 1 part water) it yields pinacoline by a transposition of the methyl 
group :— 

CH,\ 
CH,—C—CO—C,H,, Ethyl-tertiary-amyl-ketone. 
CH,/ 


This is a liquid with an odor like that of camphor, and boils at 145-150°. When 
oxidized with chromic acid it decomposes into acetic acid and dimethylethyl acetic 


acid, (Hs)2c.co,H. 
gts / 
The higher glycols have received very little attention. 


AMINES OF THE DIVALENT RADICALS. 


The di-, like the mono-valent alkyls, can replace two hydrogen atoms in two 
ammonia molecules and produce primary, secondary, and tertiary diamines. These 
are di-acid bases, and are capable of forming salts by direct union with two 
equivalents of acids. They are prepared by heating the alkylen bromides with 
alcoholic ammonia to 100° (p. 157) in sealed tubes :— 2 

NH 
C,H,Br, -- 2NH, = CH yr, 


i 2 
ameciene mroeide. Ethylene Diamine. 


| / CoN 
2C,H,Br, + 4NH, = N—C,H,—N.2HBr + 2NH,Br, 
\N H/7 


Diethylene Diamine. 


/ GAN ; 
3C,H,Br, + 6NH, = N—C,H,—N.2HBr + 4NH,Br. 
\CH,/ 


Triethylene Diamine. 


To liberate the diamines, the mixture of their HBr-salts is distilled with KOH 
and the product then fractionated. 

Another very convenient method for the preparation of diamines is the reduction 
of alkylen dicyanides (p. 313) with metallic sodium and absolute alcohol (see 
p- 159 and Berichte, 20, 2215) :— 


CH,.CN CH,.CH,.NH, 
d + 4H, = . 
H,.CN CH,.CH,.NH, 
Ethylene Cyanide. Tetramethylene Diamine. 


In the primary and secondary diamines the amid-hydrogen (by action of alkyl 
iodides) can be further substituted by alkyls, whereas the tertiary diamines unite 
with the alkyl iodides to ammonium iodides. 

Further, the diamines unite directly with water, forming ammonium oxides :-— 


/NH NH | 
GH yx? + H,0 = GHC NH’ >°- JV 


312 ORGANIC CHEMISTRY. 


These compounds are very stable, and only lose water when distilled over KOH. 
They part with water when acted upon with acids and yield diamine salts, 


Acid derivatives result from the action of acid chlorides upon the 
diamines. The formation of the dibenzoyl compounds, «. g., 
C.H,(NH.CO.C,H;)., on shaking benzoyl chloride and sodium 
hydroxide with the diamines, is employed for the detection of the 
latter (Berichte, 21, 2744). 

The separation of ammonia from the diamines gives rise to the 
imines, which may be compared to the acid-imides. They also 
appear together with the diamines in the reduction of the alkylen 
cyanides (see above), and are directly obtained from the diamines 
upon heating their HCl-salts (Berichte, 18, 2956) :— 


CH,.CH,NH, — CH,CH, 
oO ‘NH + NH,. 
CH,.CH,.NH,  CH,.CH,/ 


These émines are identical with the i idevicniesaanenids of the 
pyrrol and pyridine bases. 


Of the many diamine derivatives formed by these methods, we may cite the 
following :— 


Ethylene Diamine, CC wie, is a colorless liquid, boiling at 123°. It 
2 


reacts strongly alkaline, and has an ammoniacal odor. It is also produced when 
nascent hydrogen (tin and HCl) acts upon dicyanogen (p. 265) :— 


CN CH,.NH, 
[gels Se ; 
CN CH,.NH, 


Nitrous acid converts it into ethylene oxide, ethylene glycol being very probably 
first formed (p. 161) :— 


CH,.NH, CH. 
| +N,O, = | yo + 2H,O + 2N,. 
CH,.NH, Ci, 


Ethylene diamine, like the ortho-diamines of the benzene series, combines with 
ortho-diketones, ¢.¢., phenanthraquinone and benzil, to form tetrahydropyrazin- 
derivatives (Berichte, 20, 267). It also unites with the benzaldehydes and benzo- 
ketones (Berichie, 20, 276; 21, 2358). 

Diacetyl-diethylene Diamine, C,H,(NH.C,H,0),, is produced by the ac- 
tion of acetic anhydride upon ethylene “diamine. It consists of colorless needles, 
melting at 172°. When this compound is heated beyond its melting point, water 
splits off, and there follows an inner condensation that leads to the formation of an 
amidine base (p. 293) (Berichte, 21, 2332) :— 


ig hoi iemuunit Oe __ CH, .NH 
\C.CH, + CH,.CO,H. 
CH,.NH.CO.CH, ss aes 


Diacetyl- diethylene Hubvleie-sthengl 
Diamine. Amidine. 


PENTAMETHYLENIMINE, 313 


The derivatives of other acids, as well as the propylene diamine and trimethylene 
derivatives, react similarly. These amidine bases are intimately related to the gly- 
oxalines. 

Ethylene-ethenyl Amidine, C,H,:N,H:C,H,, or Ethylene acetamidine, isa 
white crystalline mass very readily soluble in water. It melts at 88°, and boils 
about 223°. 

On heating its HCl-salt, a molecule of NH, escapes from ethylene diamine, and 


CH 
there results ethylene imine, j ‘NH (see above), which is apparently identical 
‘H 
with the base spermine, C,H;N (Berichte, 20, 444). 
NB CH,.NH.CH, 
Di-ethylene Diamine, C,H, Cais l , containing a 
\NH” CH,.NH.CH, 


chain of six members, is to be regarded as hexahydro-pyrazine (piperazine). It is 
formed in the action of ethylene bromide on ethylene diamine. It is a liquid, boil- 
ing at 172° (Berichte, 20, 444). 
CH,.CH.NH, 
Propylene Diamine, | , from propylene bromide and alcoholic 
CH,.NH, 
ammonia, is a liquid, boiling at 117°-120°. Its diacetyl derivative yields an ami- 
dine base when heated, /CH,.NH 
Trimethylene Diamine,CH, 2". 432, from trimethylene bromide, boils at 
\.CH,.NH, 


135°-136°. By the action of trimethylene bromide upon potassium phthalimide, 
a derivative of y-brompropylamine, CH, Br.CH,.CH,.NH,, is produced. This loses 
if CHAN. 


water, and apparently yields ¢rimethy/lene-imine, CH,< CH /NH (Berichte, 21, 
tied -CH,.CH,.NH, 
Tetramethylene Diamine, C,H,(NH,),. = | , is obtained from 
: CH,.CH,.NH, 


ethylene cyanide by the action of nascent hydrogen (see above), and by the action 
of hydroxylamine upon pyrrol, C,H,NH, accompanied by further reduction (Be- 
richte, 22,1968). It is identical with the putrescine (Berichte, 21, 2938), which 
has been isolated from decaying matter. It is a liquid with a peculiar odor. It 
fumes in the air, and boils at 156°-160°. It solidifies on cooling to a crystalline 
mass, melting at 24°. There is always present with the diamine a slight quantity 
of tetramethylen-imine, C,H,:NH (see above), which can be directly obtained by 
heating the HCl-salt of the diamine. It is identical with pyrrolidine or tetrahydro- 
pyrrol, 

Pentamethylene Diamine, C;Hjo(NH,), = cH,< CH CH NH® obtained 
by the reduction of trimethylene cyanide, C,H,(CN),, is a thick liquid, with an 
odor resembling that of piperidine. It boils at 178°-179°, and solidifies in the 
cold. Its specific gravity at 0° is 0.9174 (Berichte, 18, 2956; 19, 780). It is 
identical with cadaverine (p. 316), a ptomaine isolated from decaying corpses (Be- 
richte, 20, 2216 and Ref. 69). 

Neuridine, C;H,,N, (Berich/e, 18, 86), formed by the decay of fish and meat, 
is isomeric with pentamethylene diamine. /CH,.CH 

Pentamethylenimine, C;H,,N — CHO OH 


cyanide, and also from its HCl-salt, is identical with piperidine-hexahydropyridine 
(Berichte, 18, 2956). CH,.CH.CH,.NH, 
8-Methyl-tetramethylene Diamine, | , from pyrotartaric 
- CH,.CH,.NH, 
acid nitrile, CH,.C,H,(CN),, boils at 172°-173°, and by splitting off NH,, yields 


\NH, from trimethylen- 


314 ORGANIC CHEMISTRY. 


CH,.CH.CH, 
8-Methyl Pyrrolidine, | ‘SN, boiling at 103° (Berichte, 20, 1654). 
CH,.CH,” 
CH,.CH(CH,) 
a-Methy]l Pyrrolidine, | >wNH, is produced by the reduction of 
5 ee 
y-amido valeric acid. It boils at 97° ii 22, 1866). 
CH,.CH(CH,).N 


: os -CH(CH,).NH, 
phenylhydrazone of acetonyl acetone. It boils at 175°. On splitting off NH,, 
it becomes (1.4)-Dimethyl Pyrrolidine, boiling at 107° ( Berichte, 22, 1859). 


Diamido Hexane, * is formed in the reduction of the di- 





By permitting the tertiary monamines to act upon ethylene bromide we obtain 
the bromides of ammonium bases :— 


(C,H,;),N + C,H,Br, = i A iy iN. Br. 


The bromine attached to the nitrogen of these compounds can be readily re- 
placed, whereas, the other bromine atom is more intimately combined. Silver 
nitrate ¢ produces the nitrate of triethyl- bromethy!.- ammonium :— 


C,H 
Se she det w.o. NO,. 


And by the action of moist silver oxide, the bromine atom in union with carbon 
is also attacked, HBr separates, and the group, CH,Br.CH,, is changed to the 
vinyl group, CH,:CH. In this manner we get the ¢rzethyl-vinyl-ammonium base 


CH, 2H5)s Lon: 





OXYETHYL BASES OR HYDRAMINES. 


When ethylene oxide and aqueous ammonia act upon each other, I, 2 and 3 
molecules of ethylene oxide unite with 1 molecule of ammonia, and form the 
bases :— 
pd LEED Rha Ethylene Hydramine. 

ad CH OH CH? >NH Diethylene 
CH,(OH).CH,\ . 
CH,(OH).CH,—N Triethylene  “ 
CH,(OH).CH, / 


The HCl-salts of these bases are produced by the action of ethylene chlor- 
hydrin, CH,Cl.CH,.OH, upon ammonia. The bases are separated by fractional 
crystallization of their HCl-salts, or platinum double salts. They are thick, 
strongly alkaline liquids, which decompose upon distillation. 


ce 


OXYETHYL BASES OR HYDRAMINES. 315 


The alkylen oxides and their chlorhydrins also combine with the amines. Such 
oxyalkyl bases may be obtained from the allyl amines by addition of water (by the 
action of H,SO, (Berichte, 16, 532). The bases obtained from the secondary 
amines are a/kamines or alkines (Berichte, 15, 1143) :— 


(C,H,),NH + CH,CI.CH,.0H = (C,H,),N.CH,.CH,OH + HCl. 
Triethyl Alkamine. 


" When digested with organic acids and hydrochloric acid, these oxyethyl bases 
yield (by replacement of the hydrogen of OH by acid radicals) ester-like com. 
pounds, termed Alkeines (see Tropeine). 

Oxy-ethylamine, CH,OH.CH,.NH,, amido-ethyl alcohol, is produced when 
vinylamine is evaporated with nitric acid (Berichte, 21, 2668). | 

Oxy-ethylmethylamine, CH,OH.CH, NH.CH,, results from ethylene chlor- 
hydrin and methylamine when they are exposed to a temperature of 110°. It is 
liquid, boiling at 130-140°: 

Oxy-ethyldimethylamine, CH,OH.CH,.N(CH,),, has been obtained in the 
decomposition of morphine (Berichte, 22, 1115). It boils at 128—130°. 

Dioxy-ethylamine, CH OH CH? NH = C,H,,NO,, imido-ethyl alcohol, 
is formed in the action of ammonia upon ethylene oxide and glycol chlorhydrin. 

If this compound be heated to 160° with hydrochloric acid and distilled with 
caustic potash it loses water, and yields an zmner anhydride, C,LH,NO :— 


CHO) .CH nice. cu Glas. 
CH,(OH).CH, 7" = ONCE 


Dioxy-ethylamine. Morpholine. 


This contains a closed, six-membered nucleus, consisting of four C-atoms, one 
O-atom, and one N-atom. It is the tetrahydro-derivative of Para-azoxine, 
C,H,NO. It has been called morpholine, as it is very probable that an analogous 
atomic grouping exists in morphine. 

Alkylized morpholines, C,H,N(R)O (Berichte, 22, 2081), are produced in an 
analogous manner from the dioxy-ethyl alkylamines, [CH,(OH).CH,],NR. 

The bases obtained from the tertiary amines are especially interesting. Choline 
is one of them. It is quite important physiologically. 


OH J 


Choline, C,H,,NO, = CH N(CH,),.OH, oxyethyl-trimethyl 
ammonium hydroxide. This was first discovered in the bile (hence 
called choline or bilineurine). It is quite widely distributed in the 
animal organism, especially in the brain, and in the yolk of egg, in 
which it is present as /ec’thin, a compound of choline with glycero- 
phosphoric acid and fatty acids. It is present in hops, hence occurs 
in beer. It is obtained, too, from sinapin (the alkaloid of Sinapis 
alba), when it is boiled with alkalies (hence the name sincalin). 
Choline is artifically prepared by heating trimethylamine with 
ethylene oxide in aqueous solution :— 


Vv /CH,.CH,.OH. 
(CH,),N + CH,O + H,O = (CH),NC Gy"? J 


316 ORGANIC CHEMISTRY. 


Its hydrochloride is produced by means of ethylene chlor- 
hydrin eee ay 
(CH,),N + CH,Cl.CH,.OH = (CH), he Gen 


Choline deliquesces in the air and crystallizes with difficulty. It 
possesses a strong alkaline reaction and absorbs CO,. Its platinum 
double salt, (C;H,,ONCl),.PtCl, crystallizes in beautiful reddish- 
yellow plates, insoluble in alcohol. 


Isocholine, CH,.CH(OH).N(CH,),.0H, isomeric with choline, is obtained by 
introducing CH, into aldehyde-ammonia (Berichte, 16, 207). Muscarine, C,H, 
(OH),.N(CHg,)3.OH, is an oxycholine. It is found in fly agaric, and is formed 
by oxidizing choline with HNO,. 

When choline is heated with hydriodic acid, we obtain the compound, (CH;,), 
NY peat This moist silver oxide converts into vinyl-trimethyl-ammonium 


hydroxide :— 
N / CH:CH 
\OH 


This base resembles choline ; it has also been obtained from the brain substance, 
and bears the name Neurine. It is very poisonous. It is produced when cho- 
line decomposes, or upon boiling it with baryta water. It occurs with the 
ptomaines—alkaloids of decay, partly poisonous and partly non-toxic. This decom- 
position is due to pathogenic bacteria, and the first product is choline, then sezr7- 
dine, C;H,,N, (p. 313), and trimethylamine. Later, cadaverine, C,H,,N,, 
identical with pentamethylene diamine (p. 313), putrescine, C,H,,N,, identical 
with tetramethylendiamine, and saprine, C,H,,N,, appear, and with them the toxic 
oxygen bases mydatoxine, C,H,,NO,, and mydine, C,H,,NO. Mytilotoxine, 
C,H,,NO,, has been prepared from a poisonous mussel. It is similar to curara 
(see Brieger, Berichte, 20, Ref. 68, upon ptomaines). 


(CH); ? = C,H,;,NO. 


Betaine (oxyneurine, lycine), C;H,,NO,, is allied to choline. 
It must be considered as trimethyl glycocoll (see this). It is 
obtained by the careful oxidation of choline, when the primary 
alcohol group, CH,.OH, is converted into CO.OH, and the ammo- 
nium /hydroxide that is first formed parts with a molecule of water 


(see Amido-acids) :— 


™y 


\,/ CH,.CO.OH COO 
(CH) NC On" — (CH,) NC Gt + H,0. 


Trimethyl Glycocoll. 


Its hydrochloride is obtained directly by synthesis, when tri- 
methylamine is heated with monochloracetic acid :— 


v /CH,.CO.OH 
(CH,),N + CH,CLCO.OH = (CH,).NC ; 


and on heating amidoacetic acid (glycocoll), NH,.CH,.COOH, 
with methyl iodide, caustic potash and wood spirit. 


SULPHONIC ACIDS OF THE DIVALENT RADICALS. 317 


Betaine occurs already formed in the sugar-beet (Beta vulgaris), 
hence, is present in the molasses from the beet. It crystallizes from 
alcohol with one molecule of water in shining crystals, which deli- 
quesce in the air, has an alkaline reaction and a sweetish taste. At 
100° it loses one molecule of water. When boiled with alkalies it 
decomposes, liberating trimethylamine. 


PHOSPHORUS BASES. 


A number of diphosphines are derived from phosphine; they are perfectly 
analogous to the diamines (p. 157). 
When triethylphosphine acts upon ethylene bromide we obtain :— 


(C,H,),P + C,H,Br, = (C,H;), 
Triethyl-bromethyl- 
phosphonium Bromide. 
Br 
i (CaHp)oPK 
and 2(C,H,),P + C,H,Br, = CH, 
(CoH5)sPC 


p/ C2H,Br 
Br z 


Hexethyl-ethylene-diphosphonium 
Bromide. 


The phosphonium bases are set free by the action of silver nitrate or oxide upon 
the preceding compounds. 
Triethyl arsine, As(C,H),, forms similar derivatives with ethylene bromide. 


- 





SULPHONIC ACIDS OF THE DIVALENT RADICALS (p. 152). 


Methene Disulphonic Acid, CH 130° 4 Methionic Acid, is obtained by 
acting on acetamide or methyl cyanide with fuming sulphuric acid. The acid 
forms long, deliquescent needles. The darium salt, CH,(SO;),Ba + 2H,0, 
occurs in pearly leaflets, and is sparingly soluble in water. Barium chloride pre- 
cipitates it from a solution of the acid. The free acid is very stable and not 
decomposed when boiled with HNO,. 


Hydroxymethene Sulphonic Acid, CH Cae. SO,H” or oxy-methyl sulphonic 


acid, CH,(OH).SO,H, is formed when SO, acts upon methyl alcohol, and the 
product is boiled with water. Very likely a compound is first produced in this 
reaction which is analogous to ethionic acid (p. 319). It crystallizes with difficulty 
and is very stable. The éarium salt crystallizes in small anhydrous plates. 

In addition to the preceding acid we have oxymethene disulphonic acid, 


CH(OH) $0" ry and methine trisulphonic acid, CH(SO,H),. 


Ethylene Disulphonic Acid, C,H RGSS is is produced by oxidizing glycol 
mercaptan and ethylene sulphocyanate with concentrated nitric acid; by acting 


‘ 


» 


318 ORGANIC CHEMISTRY. 


upon alcohol or ether with fuming sulphuric acid ; and by boiling sthglese bromide 
with a concentrated solution of potassium sulphite : — 


/SO,.0K 


C,H Br, + 2KSO,.0K = C,H4¢ 667 6K 


4+ 2KBr. 


The acid is a thick liquid, readily soluble in water, and crystallizes with difficulty. 
When it yields crystals these fuse at 94°. The darium salt,C,H,(SO;),Ba, crys- 
tallizes from water in six-sided plates. Ethylene Diculzhiste Acid, C,H, 
(SO,H),, results from the reduction of ethylene disulphonic acid. 


CH,.OH 
Hydroxyethylene Sulphonic Acid, | , Isethionic 
Cr. SO rn 
Acid, oxyethysulphonic acid, C,H,(OH).SO,;H, is isomeric with 
ethyl sulphuric acid, SO,H(C,H;), and is produced by oxidizing 
nantes with HNO,; by the action of 
nitrous acid upon taurine (below) :— 


monothioethylene glycol, C,H 


/NH 50, 


by heating ales chlorhydrin with os sulphite :— 


OH OK 
C HCC 4+ KSO,K=C HAC 0, x kG: 


and further by boiling ethionic acid (p. 319) with water. 


Preparation.—Conduct the vapors of SO, into strongly cooled, anhydrous 
alcohol or ether, dilute with water and then boil for several hours. The fluid will 
contain isethionic, sulphuric, and some methionic acids. It is next saturated with 
barium carbonate, and the barium sulphate removed by filtration. When the so- 
lution is evaporated barium methionate crystallizes out first, and after further con- 
centration barium isethionate (Berichte, 14, 64, and Annalen, 223, 198). 


Isethionic acid is obtained as a thick liquid, which solidifies when 
allowed to stand over sulphuric acid. Being a sulphonic acid, it is 
not decomposed when boiled with water. Its salts are very stable 
and crystallize well. 


The dartum salt is anhydrous. The ammonium salt forms rhombic plates, 
which fuse at 135°, and at 210-220° it changes to di-isethionic acid (Berichte, 14, 
65). Lthylisethionate, C,H,4(OH).SO,.C,H,, boils at 120°, and is formed in the 
distillation of the diethyl sulphuric ester (p. 149; see Berichte; 15,947). Chromic 
acid oxidizes the isethionic acid to sulpho-acetic acid. 


PCl, converts the acid or its salts into the chloride, C,H KH cp 2 liquid, 
: es 


boiling at 200°. When it is boiled with water it is converted into chlorethyl- 
sulphonic acid, CH,Cl.CH,.SO,H (Annalen, 223, 212). 


TAURINE.—ETHIONIC ACID. 319 


CH,.NH, 
Taurine, C,H,NSO,, Amido-ethylsulphonic acid, | : 
CH,.SO,H - 
occurs as taurocholic acid, in combination with cholic acid, in the 
bile of oxen and many other animals, and also in the different ani- 
mal secretions. It can be artificially prepared by heating chlor- 
ethylsulphonic acid, CH,Cl.CH,.SO;H (from isethionic acid with 
PCl;), with aqueous ammonia and by the union of vinylamine (p. 
163) with sulphurous acid, when they are evaporated together :— 


C,H,NH, + SO,H, = CHC $0, (Berichte, 21, 2667). 


Taurine crystallizes in large, monoclinic prisms, insoluble in 
alcohol, but readily dissolved by hot water. It melts and decom- 
poses about 240°. 

Taurine contains the groups NH, and SO,H, and is, therefore, 
both a base and a sulphonic acid. But as the two groups neutralize 
each other the compound has a neutral reaction. It can, however, 
form salts with the alkalies. It separates unaltered from its solution 
in acids (see Glycocoll). 3 . 

Nitrous acid converts it into isethionic acid (p. 318). Boiling 
alkalies and acids do not affect it, but when fused with caustic 
potash it breaks up according to the equation :— 


NH 
CHC so + 2KOH =C,H,KO, + SO,K, + NH, + H,. 


By introducing methyl into taurine we obtain tauro-betaine, analogous to 


, +g 
betaine (p. 316): (CH,),.N¢“g"«S0,. 

Carbyl Sulphate, C,H,S,0, (Annalen, 213, 210), is formed when the vapors 
of SO, are passed through anhydrous alcohol. It is the anhydride of ethionic 
acid :— 


CH,—O—SO,—\ 4 CH,—O—SO,.0H 
CH,—so,—_ : SCH,SO,.0H: 
Carbyl Sulphate. Ethionic Acid. 


It is also produced in the direct union otf ethylene with two molecules of SO,. 
It is a deliquescent, crystalline mass, fusing at 80°. With water it yields Ethionic 
Acid, C,H,@g gf» The constitution of the latter would indicate it to be 
both a sulphonic acid and primary sulphuric ester. It is therefore dibasic, and on 
boiling with water readily yields sulphuric and isethionic acids :— 


c,H,225%H 4 no 7,H,Z 


OH 
+\s0,H 4\s0,H + 804Hs. 


320 ORGANIC CHEMISTRY. 


Ethidene Sulphonic Acids. The following grouping is intended to express 
the relations of the sulphonic acids of this group with those of ethylene and the 


corresponding carboxylic acids :— 


CH,.0H 


/OH 
CAH: 
H,.CO,H eae 
Ethylene Lactic Acid. Ethidene Lactic Acid. 
CH,.OH yOH 
| CH »-CHX so H 
CH,.SO,H . : 
Isethionic Acid. Ethidene-hydroxy-sulphonic Acid. 
CH 30. 
9-503 CH,.CHY SOsH 
CH,.SO,H kee 
Ethytene Disulphonic Ethidene-disulphonic 
Acid. Acid. 
CH,.CO,H 
pias 3 cHicad on 
H,.CO,H Paieies oe 


Ethylene Dicarboxylic Ethidene Dicarboxylic 
Acid Acid 


Succinic Acid. Isosuccinic Acid. 


The compounds formed by the union of aldehydes with alkaline sulphites 
(p. 189), are viewed as salts of ethidene-hydroxy-sulphonic acid :— 


is /OH 
CH,.CHO + SO,KH = CH VEY Sok. 
The fotassium salt is anhydrous and forms needles; the sodium salt, C,H, 
(OH).SO,Na + H,0O, consists of shining leaflets. When these are heated with 
water they decompose into aldehyde, water and sulphites. 


Ethidene Chlorsulphonic Acid, CH, CHGS) Ww a-chlorethyl sulphonic acid, 
3 


is obtained by heating ethidene chloride to 140° with aqueous neutral sodium sul- 
phite. The acid is quite stable; its salts crystallize well. The sodium salt 
forms pearly leaflets. ; 

Ethidene Disulphonic Acid, CH,.CH(SO,H),, results when thioaldehyde, or 
thialdine, is oxidized with MnO,K, It forms very stable salts (Berichte, 12, 682). 

When ethyl iodide acts upon its silver salt.the product is the diethyl ester, 
CH,.CH(SO,.C,H;),. This is an oil, insoluble in water and caustic soda. The 
hydrogen of its CH-group can be exchanged for sodium by the action of sodium 
alcoholate and then by alkyls. Herein it resembles sulpho-acetic ester and malonic 
ester, (p. 262) (Berichte, 21, 1551). 


ALDEHYDE ALCOHOLS. 


These contain both an alcoholic hydroxyl group and the aldehyde group CHO, 
hence their properties are both those of alcohols and aldehydes (p. 296). The 
addition of 2 H-atoms changes them to glycols, while by oxidation they yield the 
oxy-acids. 


KETONE-ALCOHOLS. 321 


(1) Glycolyl Aldehyde, CH,(OH).CHO, may be considered the first aldehyde 
of glycol, and glyoxal (p. 324) the second or dialdehyde. 


(2) Aldol, C,H,O, = CH;.CH(OH).CH,.CHO, f-oxybutyr- 
aldehyde. ‘This is obtained by letting dilute hydrochloric acid act 
upon crotonaldehyde (p. 199) and acetaldehyde:— . 


CH,.CHO +: CH,.CHO = CH,.CH(OH).CH,.CHO. 


A mixture of acetaldehyde and dilute hydrochloric acid, prepared in the cold, is 
permitted to stand 2-3 days, at a medium temperature, until it has acquired a 
yellow color. It is then neutralized with sodium carbonate, shaken with ether, 
the latter evaporated, and the residual aldol distilled in a vacuum (Berich/ée, 14, 
2069). 


Aldol is a colorless, odorless liquid, with a specific gravity of 
I.120 at o°, and is miscible with water. Upon standing it changes 
to a sticky mass, which cannot be poured. Aldol distils in a vacuum 
undecomposed at too°; but under atmospheric pressure it loses 
water and becomes crotonaldehyde :— 

CH,.CH(OH).CH,.CHO = CH,.CH:CH.CHO + H,0. : 

As an aldehyde it will reduce an ammoniacal silver nitrate solu- 
tion. Heated with silver oxide and water it yields S-oxybutyric 
acid, CH;.CH(OH).CH,.CO,H. 


On standing it polymerizes into paraldol, (CjH,O,)n, which melts at 80-90°. 
Should the mixture of aldehyde and hydrochloric acid used for the preparation of 
aldol stand for some time, water separates, and we obtain the so-called dia/dan, 
C,H,,0,. This melts at 139°, and reduces ammoniacal silver solutions. 

Ammonia converts aldol in ethereal solution into aldol-ammonia, C,H,O,.NHs, 
a thick syrup, soluble in water. When heated with ammonia we get the bases, 
C,H,,NO,, C,H,,NO (oxytetraldin, p. 199) and C,H,,N (collidine). With aniline 
aldol forms methyl quinoline. 


KETONE-ALCOHOLS. 


These compounds contain both the ketone and alcohol groups. A simpler desig- 
nation for them is 4efo/s. They are distinguished, with reference to the relative 
position of the two groups, as a-, B-, y-, or (1.2)-, (1.3)-, etc., ketols (compare 
diketones, p. 325) (Berichte, 22, 2114). Being ketones, the ketols unite with the 
primary alkaline sulphites, with phenylhydrazine, etc. . 

Acetyl Carbinol, Methyl Ketol, Acetol, CH,.CO.CH,.OH, is only known 
in aqueous solution. It is obtained from monobromacetone by the action of silver 
oxide or potassium carbonate, and by fusing cane and grape sugar with caustic 
alkali (Berichte, 16, 837). Acetol, its ethyl ether, and its esters may be formed 
from the corresponding propargylic compounds by hydration with HgBr, (p. 87) :— 


CH:C.CH,.0H ++ H,O = CH,.CO.CH,.OH. 
27 


322 ORGANIC CHEMISTRY. 


Its solution reduces alkaline copper solutions even in the cold. The ethy/ 
ether, C,H;0.0.C,H,, boils at 128°. It is produced by the action of sodium 
upon chloracetic acid. Its phenylhydrazone yields an indol derivative when heated 
(Berichte, 21, 2649). The acetyl ester, C,H,O.0.C,H,0O,is obtained from chlor- 
acetone, CH,.CO.CH,Cl, by heating the latter with potassium acetate and alcohol. 
It boils at 172°, and is readily soluble in water. The denzoyl ester, C,H;0.0.C,H,;0, 
melts at 24°. The esters reduce warm alkaline copper solutions, forming a-lactic 
acid (Berichte, 13, 2344) :— 


CH,.CO.CH,.0H + 0 = CH,.CH(OH).CO.OH. 
Acetol. a-Lactic Acid. 


Acetol combines with 2 molecules of phenylhydrazine and forms the osazone, 
CH,.C(N,H.C,H,).CH(N,H.C,H,) (see the osazones, and Serichze, 21, Ref. 
98). In this respect it resembles the glucoses. 

Homologous Acetols, R.CO.CH,.OH, have been obtained as ethers from the 
halogen derivatives of alkylized acetoacetic esters (Berichte, 21, 2648). 

Acetyl-methyl Carbinol, C,H,0,— CH,.CH(OH).CO.CH,, or Dimethyl 
Ketol, corresponds to benzoin of the aromatic series. It is prepared by reducing 
diacetyl (p. 326) with zinc and sulphuric acid. It is a liquid, boiling at 142°. It 
is miscible with water, and reduces Fehling’s solution. It yields the osazone of 
diacetyl (Berichte, 22, 2214) when heated with phenylhydrazine. 

The following is a y-, or (1.3)-Ketol :— 

Acetopropyl Alcohol, C,H,,O, = CH,.CO.CH,.CH,.CH,OH, is obtained from 
bromethyl acetoacetic ester, CH,.CO.CH 6676 og (from acetyl trimethylene 
carboxylic ester), upon boiling with hydrochloric acid. It is a mobile liquid, 
of peculiar odor, and boils at 208°. It does not reduce either an ammoniacal 
silver solution or Fehling’s solution. When slowly distilled it separates into water 
and an anhydride (a pleasant-smelling liquid, boiling about 75°). The latter can 
be considered a methyl-dihydrofurfurane, C,H;(CH;)O. Acetopropyl alcohol 
yields a hydrazone anhydride with phenylhydrazine. Chromic acid oxidizes it to 
leevulinic acid (Berichte, 21,1196; 22, Ref. 572). 

Hydrobromic acid converts the alcohol into drom-propyl-methyl ketone, CH,.CO. 
CH,.CH,CH,Br. This, like the y-diketones (p. 328), yields a pyrrol derivative when 
heated with ammonia (Berich/e, 19, 2844). 

Acetobutyl Alcohol,C,H,,O, = CH;.CO.C,H,.CH,.OH, is obtained by boiling 
brom-propyl acetoacetic ester, GH, CO.CHE Gotcwe  2 with hydrochloric 
acid (Berichte, 18, 3277); also from acetyl tetramethylene carboxylic ester (Be- 
richte, 19, 2558). It is a liquid, very soluble in water, alcohol and ether, and has 
an odor resembling that of camphor. It boils about 155°. It does not reduce either 
an ammoniacal silver solution, or Fehling’s solution. Sodium amalgam converts 
it into d-hexylene glycol (p. 310); while chromic acid oxidizes it to y-aceto- 
butyric acid. Boiling HBr-acid converts it into drom-butylmethyl ketone, CHsg. 
CO.C,H,.CH,Br. This is a liquid, boiling at 216°. It forms a pyridine derivative 
(tetrahydropicoline) (Berichte, 19, 2844), when heated with ammonia. In this 
respect it is like the d-diketones. 

Diacetone Alcohol, C,H,,O, = CH,.CO.CH,.C(CH,),OH, is obtained from 
diacetonamine (p. 208) by the action of nitrous acid. A liquid, miscible with water, 
alcohol and ether. Specific gravity = 0.930 at 25°. It boils at 164°. Mixed 
with sulphuric acid it parts with water and becomes mesityl oxide (p. 208). 


KETON-ALDEHYDES. 323 


KETON-ALDEHYDES. 


Pyroracemic Aldehyde, CH,.CO.CHO, Acetyl-formyl or Methyl Glyoxal, 
is obtained by boiling isonitroso-acetone (p. 206) with dilute sulphuric acid (this is 
analogous to the formation of the a-diketones, p. 325). Hydroxylamine is split 
off in this reaction (see the oximes, p. 202) :— 


CH,.CO.CH:N.OH + H,O = CH,.CO.CHO + NH,.0H; — 


a volatile yellow oil. It reduces an ammoniacal silver solution. It forms a hydra- 
zone very readily (Berichte, 20, 3218). It yields an osazone, C,,H,,N,, with 
2 molecules of phenylhydrazine; the same compound is obtained from acetol 
(p. 321). (Berichte, 21, Ref. 98). 

B-Keton-aldehydes, general formula R.CO.CH,.COH, are synthetically pre- 
pared by the interaction of ketones, R.CO.CH,, and formic acid esters, in the 
presence of sodium alcoholate. The sodium compounds first result (Claisen, Be- 
richte, 20, 2191; 21, Ref. 915; 22, 3273) :— 


R:CO.CH, + CHO.O.C,H, + NaO.C,H, = R.CO.CHNa.CHO + 2C,H,OH. 


Formic Ester. 


The ketones R.CO.CH,R react similarly with these esters, but not those of the 
type R.CO.CHR,. This is explained by assuming that an earlier union occurs 
between the acid ester and sodium ethylate (Berichte, 22, 533). 

The keton-aldehydes, R.CO.CH,.CHO, and R.CO.CHR.CHO, like the 6-di- 
ketones, R.CO.CH,.CO.R, are acid in their nature. The hydrogen of the groups 
CH, and CHR is readily replaced by metals. They dissolve in alkaline carbo- 
nates to form salts, ¢. g., R.CO.CHNa.CHO. They produce green-colored pre- 
cipitates with copper acetate (Berichte, 22, 1018). Ferric chloride imparts a deep 
violet or red color to their alcoholic solutions (Berichte, 22, 3277). They readily 
yield oximes, anilides, benzene azo-derivatives (Berichte, 21, 1699), hydrazones, 
pyrrazoles, isoxazoles, etc. 

The keton-aldehydes, R.CO.CH,.CHO, are very unstable when free. They 
condense readily. Their sodium and other salts are, however, very stable. The 
monoalkylic keton-aldehydes, R.CO.CHR.CHO, are so constituted that they can- 
not sustain analogous condensation, hence they are stable when in a free condi- 
tion, and can generally be distilled (Berichte, 22, 3274). 

Acetyl aldehyde, CH,.CO.CH,.CHO, formyl acetone, from acetone and 
formic ester, is a liquid, boiling near 100°. Its odor resembles that of acetoacetic 
ester and of acetone. Ferric chloride colors it a deep red. It readily condenses, 
even in solution, to triacetyl benzene :— : 


3CH,.CO.CH,.CHO = C,H,(CO.CH,), + 3H,0. 


It forms methyl-phenyl-pyrrazole with phenylhydrazine (Berichte, 21, 1144). 

Propionyl Aldehyde, C,H..CO.CH,.CHO = C,H,0O,, formyl methyl-ethyl 
ketone, results from methyl-ethyl ketone and formic ester. It yields ethyl-phenyl 
pyrrol with phenylhydrazine. 

Propionyl-propionic Aldehyde, C,H, ,0, — C,H,.CO.CHC CHa formyl 
diethyl ketone, from diethylketone, is stable when free (see above). It consists of 
crystals having a peculiar odor. They melt at 40°, For additional keton-alde- 
hydes consult Berichte 22, 3277. 


324 ORGANIC CHEMISTRY. 


DIALDEHYDES. 


J The only known dialdehyde of the fat series is glyoxal. 


Glyoxal, C,H,O, = CHO.CHO, Diformyl, is the dialdehyde 


of ethylene glycol, while glycolyl aldehyde (p. 321) represents the 


first or half aldehyde :— ; 
CH,OH CH,OH CHO 


| 
7H,0OH CHO CHO 
Glycol. . Glycolyl Aldehyde. Glyoxal, 


Glyoxal, glycollic acid and glyoxylic acid are formed in the careful 


_ oxidation of ethylene glycol, ethyl alcohol, or acetaldehyde with 


x 


nitric acid. 


In preparing glyoxal, alcohol, or betfer, aldehyde and fuming nitric acid are 
placed, layer after layer, in narrow glass cylinders, using a funnel tube for the 
introduction of the acid. Let the whole stand for 5-6 days (Berichte, 14, 2685). 
The residue obtained by evaporation of the mixture to syrup consistence contains 
chiefly glyoxal, with a little glycollic acid and glpoxylic acid. These can be 
removed in the form of calcium salts. To obtain the glyoxal, the residue is directly 
treated with a concentrated solution of primary sodium sulphite, when the double 
salt with glyoxal (see below) will crystallize out (Berichte, 17, 169). 

On evaporating the solutions the glyoxal is obtained as an amorphous, non-vola- 
tile mass. It deliquesces in the air. It is very soluble in both alcohol and ether. 
In this condition it is probably a polymeric modification (C,H,O,),, because 
methylglyoxal (p. 323) and dimethyl glyoxal (p. 326) are very volatile (Berichte, 
21, 809). The alkalies convert it, even in the cold, into glycollic acid. 

In this change the one CHO group is reduced, while the other is oxidized 
(compare benzil and benzilic acid) :— 


CHO CH,OH 


| “+ H,O= 
CHO CH,OH. 


As a dialdehyde it unites directly with 2 molecules of primary sodium sulphite, 
forming the crystalline compound, C,H,O,(SO,HNa), + H,O. It also reduces 
ammoniacal silver solutions. 

With ammonium cyanide and hydrochloric acid, glyoxal forms diamido-succinic 
acid (p. 190). It also yields a dioxime with two molecules of hydroxylamine ; 
this is the so-called Glyoxime, CH(N.OH).CH(N.OH) (p. 207). This is also 
produced when hydroxylamine acts upon trichlorlactic acid (Berichte, 17, 2001). 
It is soluble in water, alcohol and ether. It crystallizes in rhombic plates, melts 
at 178°, and sublimes without difficulty. It has a faintly acid reaction and forms 
salts with the bases. 

_ As to the deportment of other dialdehydes towards hydroxylamine see Berichie, 
20, 507. 
See Berichte, 21, Ref. 636, for the compen of glyoxal with malonic and aceto- 

acetic esters, 

Glyoxal combines with 2 molecules of phenylhydrazine and yields— 

CHIN, F.C, .H, 
Glyoxal Diphenyl Hydrazine, | . This derivative can also 
CH:N,H.C,H,; 


DIKETONES. 325 


be prepared from trichlorlactic acid (Berichte, 17,2001). It crystallizes in needles 
or leaflets, melting at 170°. Its HCl-salt is a yellow-colored compound (Berich/e, 
19, Ref. 303). 

Glyoxal and orthophenylene diamines unite and form quinoxaline derivatives 
(see these). 

Concentrated ammonia yields two bases with glyoxal: Glycosin, C,H,N,, of 
unknown constitution, and in larger quantity, Glyoxaline, C,H,N,, the parent 
“substance of the glyoxalines (oxalines), or amidazoles ((-diazoles) (see these). 


. /CHO CHO 
Malonyl Aldehyde, CH, CHO! and Succinyl pacha , have 
\ H}.CHO 


not been obtained. They are the aldehydes of tri- and tetramethylene glycols. 
CH,.CH(N.OH) 
Succinyl Aldoxime, | , results from the action of hydroxyla- 
CH,.CH(N.OH) e 
mine upon pyrrol. It yields tetramethylene diamine when reduced with metallic 
sodium (p. 313) (Berichte, 22, 1968). 


DIKETONES. 


The diketones contain two ketone groups, — CO. The relative 
position of these groups determines them to be either a-, #-, or 
y-diketones, etc. Peculiar characteristics distinguish these classes. 

(1) a-Diketones, R.CO.CO.CH3. 

The a-, (or 1.2)-dikefones have their two CO-groups united 
directly to each other. In the aromatic series they are called ortho- 
diketones (see these). They may be regarded as diketo-substituted 
ethanes. Hence, the name af-diketo-butane for the compound, 
CH,.CO.CO.CH, (see p. 201) ; or they can be viewed as compounds 
of two acid radicals (that cannot exist uncombined) (p. 246) :— 


CH,.CO. CH, CO. : 
CH,.CO” C,H,.CO” 
Diacetyl. Acetyl-propiony]l. 


The a-diketones are prepared by boiling the isonitrosoketones 
(same as acetyl formyl from isonitrosoacetone, p. 323) with dilute 
sulphuric acid (p. 206) (v. Pechmann, Berichte, 20, 3213) :— 


CH,.CO.C(N.OH).CH, + H,O = CH,.CO.CO.CH, + NH,.OH. 


The solutions obtained by the action of nitrous acid upon mono-alkyl-acetoacetic 
esters may be used for this purpose, instead of the prepared nitrosoketones (Ber- 
ichte, 21, 1411). At times nitrous acid effects the decomposition more rapidly than 
sulphuric acid (Berichte, 22, 532, 527). , 

The a-diketones are yellow-colored, volatile liquids. They possess a penetrating 
odor. They yield monoximes with one molecule of hydroxylamine. These com- 
pounds are also called etoximes (Berichte, 21, 2994). With 2 molecules ot 
hydroxylamine they form the dioximes (glyoximes or acetoximic acids, p. 203). 
These can form anhydrides (see benzildioxime or diphenylglyoxime). The 
a-diketones with 1 molecule of phenylhydrazine yield monohydrazones (or keto- 


326 ORGANIC CHEMISTRY. 


hydrazones), and with 2 molecules of phenylhydrazine the dihydrazones, called 
also osazones.* 

The osazones are bright red, crystalline compounds: When digested with 
alcohol and ferric chloride they produce reddish-brown colorations, soluble in 
ether (reaction of Pechmann). Oxidation takes place and the osofetrazones 
result :— 

CH,.C:N,H.C,H, CH,.C:N.N.C,H, 
+O0= + H,0O. 
CH,.C:N,H.C,H, CH,.C:N.N.C,H,; 


These split off one phenyl group and pass into the osotriazones (Berichte, 21, 
2751). 

sl hydrazoximes, é. g., CH,.C(N.OH).C(N,H.C,H;).CH;, diacetyl hydrazox- 
ime, are compounds of the diketones with 1 molecule of hydroxylamine and 1 
molecule of phenylhydrazine. They form when phenylhydrazine acts upon the 
mon-oximes, or hydroxylamine upon the mono-hydrazones (or ketohydrazones) 
(Berichte, 21, 2994). 

' The a-diketones are characterized and distinguished from the '-, and y-ketones 
by their ability to unite with the orthophenylene diamines (similar to glyoxal). In 
this way they are condensed to the guinoxalines (see these) :-— 


All compounds containing the group —CO.CO—, «. g., glyoxal, pyroracemic 
acid, glyoxylic acid, alloxan, dioxytartaric acid, etc., react similarly with the 
-o-phenylene diamines. The glyoxa/ines are the products of the union of the 
a-diketones with ammonia and the aldehydes. a-Diketones, containing a CH,- 
group, together with the CO-group, sustain a rather remarkable condensation when 
acted upon by the alkalies. Qzinogens are first produced, and later the guinones 
(Berichte, 21, 1418; 22, 2215) :— 


CH,.CO.CO.CH, CH,.C.CO.CH, CH,.C.CO.CH 
l yield | and | \ 
- CH,.CO.CO.CH, CH.CO.CO.CH, CH.CO.C.CH,. 
2 Molecules Diacetyl. Dimethyl-quinogen. p-Xyloquinone. 


(1) Diacetyl, CH,.CO.CO.CH,, Diketobutane, Dimethyl diketone, from 
isonitrosomethylacetone or methyl acetoacetic ester (p. 209) (Berichte, 21, 1411), 
has also been obtained from oxalyldiacetic acid (ketipic acid) by the splitting-off 
of the carboxyls upon the application of heat (Berichte, 20, 3183). It is a.yel- 
low liquid, with an odor like that of quinone. It boils at 87-89°. It dissolves 
rather readily in water, and is miscible with both alcohol and ether. Sulphurous 
acid decolorizes the yellow solution. HCl-hydroxylamine precipitates the dioxime, 
C,H,(N.OH), ; this melts at 234°. The monophenylhydrazone,C,H,O(N,H.C,H;), 
is also formed from methyl acetoacetic acid and benzene diazochloride. It melts 
at 133°. The dihydrazone, C,H,(N,H.C,H;), (see above), melts at 242°. It has 
been obtained from the hydrazone of pyroracemic acid (Berichte, 21, 549). 





* The a-aldehyde alcohols and a-keton alcohols (p. 321) yield similar osazones 
with 2 molecules of phenylhydrazine. An atom of oxygen from the air acts at 
the same time (just as with the osazones of the glucoses), 


* 


DIKETONES. 327 


Two molecules of CNH convert diacetyl into dicyanhydrin, C Ser oy 
(see p. 202). The latter yields dimethyl racemic acid (Berichte, 22, Ref. 137). 

Tetrachlor-diacetyl, CHCI,.CO.CO.CHCL,, results in the action of potassium 
chlorate upon chloranilic acid (together with tetrachloracetone, p. 205). It crys- 
tallizes in yellow plates, melting at 84°. It yields a quinoxaline derivative with 
o-phenylenediamine, and a dihydrazoné with phenylhydrazine (Berich/e, 22, Ref. 
809; 23, Ref. 20). 

Tetrabrom-diacetyl, C,H,Br,O, (Berichte, 23, 35) and Dibrom-diacetyl, 
(CH,Br.CO),, are produced. by the action of bromine upon diacetyl. 

(2) Acetyl-propionyl, C,H;.CO.CO.CH,;, Methyl-ethyl-diketone, from iso- 
nitroso-ethylacetone, or ethyl acetoacetic ester, is very similar to diacetyl. It boils 
at 108° (Berichte, 22, 2117). 

Acetyl-butyryl or Methyl- propyidiietone) C,H, CO.CO.CHs, Acetyl-i -iso- 
butyryl, etc., as well as the mixed a-diketones of the ‘paraffin and aromatic series, 
are analogous compounds (Berichte, 22, 2127). 


(2) 8- (or 1.3)-Diketones, R.CO.CH,.CO.R. ¥ 

In these compounds the two carbonyls are separated by an inter-. 
vening C-atom. They are frequently formed by the breaking down 
of acidyl-acetoacetic esters (see benzoyl acetone). The usual course 
is analogous to the reaction by which the keton-aldehydes (p. 323) 
are produced. It consists in the interaction of acetic esters and 
ketones in the presence of sodium ethylate, or better, metallic sodium 
(Claisen, Berichte, 22, 1009; 23, Ref. 40) :— 


CH,.CO.CH, ++ C,H,.0.CO.CH, = CH,.CO.CH,.CO.CH, + C,H,.OH. 


Ethyl! Acetate. Acetyl Acetone. 


The 3-diketones, like the -ketonaldehydes (p. 323) have an acid character. 
An H-atom-of the CH,-group can be replaced by metal§ (this is similar to the’ 
f-ketonic esters). They are, therefore, soluble in caustic alkalies, forming alkali 
salts, and with copper acetate they generally yield precipitates of copper salts 
(Berichte, 22,1017). Ferric chloride imparts an intense red color to their alco- 
holic solution. They combine with 1 molecule of hydroxylamine with the separa- 
tion of two molecules of water. The products are the remarkable oxime-anhy- 
drides. These belong to the so-called oxyazoles (see these, and Berichle,*21, 
2178). 

With phenylhydrazine the 8-diketones (and all other compounds containing the 
groups —CO.CH ,.CO—) yield pyrrazole compounds (see these), _Methylphenyl- 
hydrazine, however, converts them into hydrazones (Berichte, 22, Ref. 671). 

Acetyl-acetone, C;H,O, = CH,.CO.CH,.CO.CH,, Diacetylmethane, (CH). 
CO),CH,, was first prepared by digesting acetyl chloride with AICI, (BerichZe, 22, 
1009). It is most easily obtained by the action of metallic sodium upon acetone 
and acetic ester (Berichte, 23, Ref. 40). It is a colorless liquid, boiling at 137°, 
and very readily soluble in ether. It dissolves in the caustic alkalies, and splits: up 
into acetone and acetic acid. Its copper salt, (C;H,O,),Cu (see above), is precipi- 
tated as a blue-colored, crystalline precipitate. ‘Phenyihydrazine converts it into 
dimethylphenyl pyrrazole, and with diazobenzene-chloride yields an azo-derivative 
(Berichte, 21, 1699). 

Acetyl. methyl. ethyl Ketone, CH,.CO.CH,.CO.C,H, ==. C,H,,0,, acetyl- 
propionyl methane, from methylethyl ketone and acetic ester, boils at 158°. Its 
sp. gr. is 0.9538. 

Acetyl-methylpropyl Ketone, C,H,,O, = CH,.CO.CH,.CO.C,H,, acetyl- 
butyryl methane, boils at 161° (Berichte, 22, 1055): 


- 
¥ 


328 ORGANIC CHEMISTRY. 


Diacetylacetone, COx CH COCH” is a @ triketone. It apparently is formed 
2° . 3 


from dimethylpyrone (Berichte, 22, 1570). 
CO.CH,.CO.CH, 
Oxalyldiacetone, | , is an a@-tetraketone. It is produced 
CO.CH,.CO.CH, ; 
when sodium ethylate acts upon oxalic ester and acetone. It melts at 121° and 
dissolves easily in alcohol and ether. Ferric chloride colors it a brownish red 
(Berichte, 21, 1141). 


3. y-Diketones, R.CO.CH,.CH,.CO.R. 

These correspond to the paraquinones of the aromatic series (see 
these). They are not capable of forming salts, hence are not soluble 
in the alkalies. They form mono- and di-oximes with hydroxy]l- 
amine, and mono- and di-hydrazones with phenylhydrazine; these 
are colorless. The readiness with which the ;-diketones form 
pyrrol, furfurane, and thiophene derivatives is characteristic of 


hem 

Say Acetonyl] Acetone, A gt tah de So Weekes Ld ok in ttn Ch,, 
diacetylethane, is obtained from pyrotritartaric acid, C,;H,O, (see 
this), and from acetonyl acetoacetic ester (p. 336), upon heating to 
160° with water (Berichie, 18, 58), and from isopyrotritartaric acid, 
and diacetylsuccinic ester, when they are allowed to stand in con- 
tact with sodium hydroxide (Berichte, 22, 2100). A liquid with 
an agreeable odor. It is miscible with water, alcohol and ether. 
It boils at 188° C. 


It unites to a doxime with 2 molecules of hydroxylamine. This new derivative 
crystallizes in Shining leaflets, melting at 136°. It is also produced by the action 
of hydroxylamine upon (1.4)-dimethylpyrrol (Berichée, 22, 3177). With 2 mole- 
cules of phenylhydrazine it yields a di-hydrazone, melting at 120°. Monophenyl- 
hydrazone, by the loss of 2 molecules of water, passes into a pyrrol derivative 
(Berichte, 22,170). Dimethyl pyrrol is produced on heating acetonyl acetone 
with alcoholic ammonia (Paal, Berichte, 18, 58, 367) :-— 


yee 
cH CREE, ee _a= “xe! 4 2,0. 


3 
Dimethyl Pyrrol. 


All compounds containing two CO-groups in the (1.4) position react similarly 
with ammonia and amines. Such are diaceto-succinic ester and leevulinic ester. 
All the pyrrol derivatives formed as above, when boiled with dilute mineral 
acids, have the power of coloring a pine chip an intense red. This reaction 
is, therefore, a means of recognizing all (1.4)-diketone compounds (Berzchze, 19, 


46). 


These derivatives react similarly with amidophenols and amido- 
acids (Berichte, 19, 558). 


ALDEHYDE ACIDS. ; 329 


When heated with phosphorus sulphide acetonyl acetone yields 
dimethyl thiophene (Paal, Berichte, 18, 2251):— 


CH, 
CH,.CO.CH, CH = 
| 4+ SH, = S + 2H,0. 
CH,.CO.CH, CH = Cé 
peat 


3 
Dimethyl Thiophene. 


All the ;y-diketones or (1.4)-dicarboxyl compounds, ¢. g., the 
y-ketonic acids'(p. 343), yield the corresponding thiophene deriva- 
tives upon like treatment (Berichie, 19, 551). | 

The direct removal of one molecule of water from acetonyl 
acetone (by distillation with zinc chloride or P,O;) affords dimethyl 
furfurane (Berichte, 20, 1085) :— 


CH, 
CH,.CO.CH, CH=C~é ! 
l = | yo 4+ H,0. 3 
CH,.CO.CH, CH= C& 
CH 


3 
Dimethyl Furfurane. 


Other y-diketone compounds react in a similar manner (Knorr, 
Berichte, 17, 2756). 

In all these conversions of acetonyl acetone into pyrrol, thio- 
phene, and furfurane derivatives it may be assumed that it first 
passes-from the diketone form into the isomeric or tautomeric form 
of the unsaturated dihydroxyl (p. 54) :— 


CH,.CO.CH, CH = CC Gr? 
| yields | /OH °? 
CH,.CO.CH, CH = CCG. 


and from this, by replacing the 20H groups with S, O, or NH, 
the corresponding furfurane, thiophene and pyrrol compounds are 
produced (Berichte, 19, 551). 


(1.5) or d-Diketones. 

Derivatives of this class are produced when benzaldehyde acts upon esters of 
diazoacetic acid (Berichte, 18, 2372) and upon acetoacetic ester (Berichie, 18, 
2583). They do not yield pyridine derivatives with ammonia. 


ALDEHYDE ACIDS. 


These are the compounds containing both the CHO and the 
CO,H groups. Their properties are both those of the aldehyde and 
the acid. ‘The only member of this class in the fat series is G/- 
oxylic Acid. ; : 

28 


330 ‘ORGANIC CHEMISTRY. — 


i CHO CH(OH), 
Glyoxylic Acid, C,H,O, = | Or: CFO, == 
CO,H CO.OH 

glyoxalic acid. ‘The aldehydes frequently yield hydrates by com- 
bining with one molecule of water; these derivatives are regarded 
as dihydroxyl compounds (see chloral hydrate, p. 196). Glyoxylic 
acid exhibits similar behavior. The free crystalline acid has the 
formula, C,H,O;.H,O = C,H,O,; all its salts are obtained from it. 
Hence, we must consider it a dihydroxyl compound, which may be 
designated a dioxy-acetic acid. By withdrawal of water, the alde-: 
hyde group is produced, and the acid conducts itself as a true alde- 
hyde acid. 

Glyoxylic acid is obtained by oxidizing glycol, alcohol and alde- 
hyde (p. 324). It is most readily prepared by heating dichlor- and 
dibrom-acetic acid to 120° with water :— 


CHCl,.CO,H + 2H,O = CH(OH),.CO,H + 2HCl. 


It is a thick liquid, readily soluble in water, and crystallizes in 
rhombic prisms by long standing over sulphuric acid. The crystals 
have the formula, C,H,O,. It distils undecomposed with steam. 


As a monobasic acid it forms salts with one equivalent of acid. When dried at 
100°, the salts have the formula, C,H,MeO,. The ammonium salt alone has the 
formula, C,H(NH,)O,. The calcium salt, (C,H,O,),Ca, crystallizes with one 
and two molecules of water (Berichte, 14, 585), and is sparingly soluble in water 
(in 140 parts at 18°). Lime water precipitates an insoluble basic salt from its solu- 
tion. The silver salt, C,H,AgQO,, is a white, crystalline precipitate. 

Again, glyoxylic acid manifests all the properties of an aldehyde. It reduces 
ammoniacal silver solutions with formation of a mirror,and combines with primary 
alkali sulphites. When oxidized (silver oxide), it yields oxalic acid; by reduction 
(zine and water) itforms glycollicacid: CHO.CO,H + H, = CH,(OH.)CO,H. 
On boiling the acid or its salts with lime water, or alkalies, glycollic and oxalic 
acids are produced (Berichte, 13, 1392) :— 


CHO CH,.OH CO.OH 
2 | -t. H eV == | : a | ; 
CO.OH CO.OH CO.OH 


This is analogous to the transposition of aldehydes to alcohol and acid (p. 189). 
When hydrocyanic and hydrochloric acids act upon glycollic acid, a like transposi- 
tion ensues. 

Phenylhydrazine unites with glyoxylic acid to phenyl-hydrazine-glyoxylic acid, 
CH(N,H.C,H,).CO,H (Berichte, 17, 577). 

Homologous (3-aldehydic acids (their ester$) are produced (analogous to the /3- 
ketonic esters, p. 338) by the action of sodium, or sodium ethylate, upon a mixture 
of formic ester and acetic ester (or other esters) (Piutti, Berichte, 20, 537; W. 


Wislicenus, Berichte, 20, 2930) :— . 
CHO.0.C,H, + CH,.CO,.C,H, = CHO.CH,.CO,.C,H, + C,H,.OH. 
Formic Acetic Formyl! Acetic 


Ester, Ester, Ester. 


KETONIC ACIDS. 331 


Formyl Acetic Acid, CH COL HH ™ay be called the halfaldehyde of malonic 


acid, CH,(COOH),. Its ethyl ester, from acetic and formic esters, is very unstable. 
It condenses immediately (analogous to the condensation of acetyl aldehyde to 
triacetyl benzene (p. 323) to the ester of trimesinic acid :— 


3CHO.CH,.€O,.C HH. == :C.H(CO..C.,), + 3hO 
(Berichte, 21, 1146). 





KETONIC ACIDS. 


These contain both the groups CO and CO,H; they, therefore, 
show acid and ketone characters with all the specific properties 
peculiar to these. In conformity with the manner of designating 
the mono- and di-substituted fatty acids (pp. 223 and 224), we 
distinguish the groups a-, #- and ;- of the ketonic acids. These 
differ from each other by various peculiarities :— 


R.CO.CO,H R.CO.CH,.CO,H R.CO.CH,.CH,.CO,H. 
a-Ketonic Acids. B-Ketonic Acids. ae. Ketoni¢ AAtidé: 


The a- and y-acids are quite stable, even in a free condition. ‘This 
is only the case with the f-acids when in the form of esters. If they 
are set free from these they readily decompose (p. 323). 

The names of the ketonic acids are usually derived from the fatty 
acids, inasmuch as the acid radicals are introduced into these 


(p. 213)3 ¢. S5— 


CH,.CO.CO,H CH,.CO.CH,.CO,H, etc. 
Acetyl-formic Acid. Acetyl-acetic Acid. 


According to a more recent suggestion of A. Baeyer, these acids 
should be viewed as efo-substitution products of the fatty acids, 
being formed by the substitution of oxygen for 2H in 1 the CH,- 
group (Berichte, 18, 160); hence the names :— 


CH,.CO.CO,H CH,.CO.CH,.CO,H, ete. 
a- aesoropioate Acid, B-Ketobutyric Acid. 


In accord with their ketonic nature, they unite with alkaline sul- 
phites to form crystalline compounds, from which alkalies or acids 
again set them free (Berichte, 17, Ref. 568). They form oximes 
or isonitroso fatty acids (p. 214) with hydroxylamine, and with 
phenyl-hydrazine pheny]l- hydrazo-fatty acids. Nascent hydrogen 
converts all the ketonic acids into the corresponding divalent oxy- 
acids. In this change the ketonic group becomes a secondary alco- 
hol group :— 


CH, CO. CO,H + H, = CH ;-CH(OH). CO oH: 
® eiuetie Acid. 


332 ORGANIC CHEMISTRY. 


1. a-Ketonic Acids—R.CO.CO,H. 

In this class the ketone group CO is in direct union with the 
acid-forming carboxyl group, CO,H. We can view them as com- 
pounds of acid radicals with carboxyl, or as derivatives of formic 
acid, HCO.OH, in which the hydrogen linked to carbon is replaced 
by an acid radical—hence the designation acetyl carboxylic acid or 
acetyl formic acid for the acid, CH;.CO.CO,H. The first name 
indicates, too, the general synthetic method of formation of these 
acids from the cyanides of acid radicals (p. 247), which, by the 
action of concentrated hydrochloric acid, are changed to the cor- 
responding ketonic acids :— 


CH,.CO.CN + 2H,0.+ HCl = CH,.CO.CO,H + NH,Cl. 
Acetyl Cyanide. Acetyl Carboxylic Acid. 


(1) Pyroracemic Acid, a-Ketopropionic Acid (acetyl car- 
boxylic acid), C;H,O; = CH;.CO.CO,H, was first obtained in the 
distillation of racemic acid, tartaric acid and glyceric acid. It is syn- 
thetically prepared from a-dichlorpropionic acid, CH}3.CCl,.CO,H 
(p. 225), when heated with water and silver oxide, and from acetyl 
cyanide by the action of hydrochloric acid (see above). Further, 
by the action of concentrated hydrochloric acid upon acetyl cya- 
nide. Its formation in the oxidation of ordinary lactic acid with 
potassium permanganate, and by the decomposition of oxalacetic 
ester, is rather remarkable. 


For its preparation heat tartaric acid in an iron pan until it chars and swells up. 
After cooling, the mass is broken into pieces, placed in a retort and distilled over 
a free flame (Anunalen, 172, 142). A large yield (about 60 per cent.) is reached 
by distilling tartaric acid with potassium bisulphate (Berichte, 14, 321). The 
formation of pyroracemic acid from tartaric acid (racemic acid and glyceric acid) :— 

CH(OH).CO,H CH, 
= + CO, + H,0O, 
CH(OH).CO,H CO.CO,H 


is quite similar to the transpositions cited on page 134. 


Pyroracemic acid is a liquid, soluble in alcohol, water and ether, 
and has an odor quite similar to that of acetic acid. It boils at 
165-170°, decomposing partially into CO, and pyrotartaric acid 
(2C,H,O;, = C;H,O, + CO,). This change is more readily effected 
if the acid be heated to 100° with hydrochloric acid. 


The acid reduces ammoniacal silver solutions with the production of a silver 
mirror, the decomposition products being CO, and acetic acid. When heated with 
dilute sulphuric acid to 150° it splits up into CO, and aldehyde, CH,.COH. This 
ready separation of aldehyde accounts for the ease with which pyroracemic acid 
enters into various condensations, ¢. g., the formation of crotonic acid by the action 


* 


KETONIC ACIDS. 333 


of acetic anhydride (p. 238), and the condensations with dimethyl aniline and 
phenols (Berichte, 18, 987, and 19, 1089). 

Pyruvic acid is monobasic. Its salts crystallize with difficulty. Its zinc salt, 
(C,H,O,).Zn + 3H,0O, is a crystalline powder, soluble with difficulty in water. 
All the salts are colored red by ferric chloride. 

When the acid or its salts are heated with water, or if the acid be set free from 
its salts by mineral acids, it passes into a syrup-like, non-volatile mass. 

Pyruvic acid forms crystalline compounds with the acid alkaline sulphites. 
It resembles the ketones in this respect. Nascent hydrogen (Zn and HCl, or HI) 
changes it to ordinary a-lactic acid, CH ,.CH(OH).CO,H. PCl1, converts it into the 
chloride of a-dichlorpropionic acid, CH,.CCl,.COCI (p. 225). Pyroracemic acid, 
in aqueous, ethereal or acid solution, unites very readily with phenyl hydrazine to 
form CH,.C(HN,.C,H,).CO,H, a crystalline solid, melting at 182° with decom- 
position (Berichte, 21, 987). This reaction will serve for the detection of minute 
quantities of the acid (Berichte, 16, 2242). With hydroxylamine it yields a-iso- 
nitrosopropionic acid (p. 224). It combines with CNH, like all ketone compounds, 
and forms an oxycyanide (p. 202), from which a-oxyisosuccinic acid is obtained. 
Pyruvic acid also condenses readily to benzene derivatives (p. 208). Thus, uvitic 
acid, C,H,O,, results when the acid is heated with barium hydrate. Ammonia, 
however, produces uvitonic acid (by the decomposition of the imido-pyroracemic 
acid, which is first formed)—a pyridine derivative. It readily furnishes condensa- 
tion products with hydrocarbons of the benzene series (Berichte, 14, 1595, and 16, 
2071). It also unites with anilines and amido-acids (Berichte, 19, 2554). 

It combines with bromine, forming a crystalline, unstable addition product, 
C,H,O,Br,. Substitution products result by heating the acid with bromine and 
water to 100°; dibrom-pyruvic acid, CBr,H.CO.CO,H, crystallizes with 2H,O 
in large, rhombic plates. It loses its water of crystallization when exposed, and 
melts at 89°. Zribrom-pyruvic acid, CBr,.CO.CO,H or CBr,.C(OH),.CO,H, 
is formed by heating a-lactic acid with bromine and water. It has two molecules 
of water of crystallization, and consists of brilliant leaflets which lose water at 100°, 
and then fuse at 90°. When heated with water or ammonia, it breaks up into 
bromoform, CHBr,, and oxalic acid. 

(2) Propionyl-carboxylic Acid, C,H,;.CO.CO,H, a-Ketobutyric Acid, is 
obtained from propionyl cyanide. It is very similar to pyruvic acid, and can only 
be distilled under diminished pressure. Nascent hydrogen converts it into a-oxy- 
butyric acid. 

(3) Butyryl-carboxylic Acid, C,H,.CO.CO,H, is derived from butyryl 
cyanide, and boils at 180-185° with slight decomposition. It decomposes readily 
into CO, and butyric acid. 

(4) Trimethyl-Pyroracemic Acid, (CH,),.C.CO.CO,H, results from the 
oxidation of pinacoline (p. 210) with potassium permanganate. It melts at 90° 
and boils at 185° (Berichte, 23, Ref. 21). 


2. 8-Ketonic Acids, 

In the £-ketonic acids the ketone oxygen atom is attached to the 
second carbon atom, counting from the carboxyl group forward. 
These compounds are very unstable when free and when in the form 
of salts. Heat decomposes them into carbon dioxide and ketones. 
Their esters, on the other hand, are very stable, can be distilled 
without decomposition, and serve for various and innumerable syn- 
theses. 


334 ORGANIC CHEMISTRY. 


The first acid of this class is :— 

Aceto-acetic Acid, C,H,O, = CH;.CO.CH,.CO,H, £-Keto- 
butyric Acid. We can regard this as acetic acid in which a hydro- 
gen atom of methyl is replaced by acetyl, CH;.CO, or as acetone, 
in which carboxyl has taken the place of a hydrogen atom—hence, 
the designation acetone carboxylic acid. To obtain the acid, the 
esters are saponified zz the cold by dilute potash, or the barium salt 
is decomposed with sulphuric acid, and the solution shaken with 
ether (Berichte, 15, 1781 ; 16, 830). Concentrated over sulphuric 
acid, aceto-acetic acid is a thick liquid, strongly acid, and miscible 
with water. When heated, it yields carbon dioxide and acetone :— 


CH,.CO.CH,.CO,H = CH,.CO.CH, + CO,. 


Nitrous acid converts it at once into CO, and isonitroso-acetone (p. 206). Its 
salts are not very stable. It is difficult to obtain them pure, and they sustain 
changes similar to those of the acid. Ferric chloride imparts to them, and also to 
the esters, a violet-red coloration. Occasionally the sodium or potassium salt is 
found in urine (Berichte, 16, 2314). 


The stable aceto-acetic esters, CH;.CO.CH,.CO,R, are produced 
by the action of metallic sodium upon acetic esters. In this reac- 
tion the sodium compounds constitute the first product (Geuther, 
1862; Frankland and Duppa) :— 


CH, CH, 
2 | me Na, = l 
CO.0.C,H, O.CHNa.CO.0.C,H, + C,H,.ONa + H,. 


By similar treatment acetic methyl ester yields the sodium com- 
pound of methyl aceto-acetic ester (see below). The free esters 
result upon treating their sodium compounds withacids. They are 
obtained pure by distillation. ‘The aceto-acetic esters are liquids, 
dissolving with difficulty in water. They possess an ethereal odor. 
They can be distilled without decomposition. Like the free acid, 
they break up into carbon dioxide, acetone and alcohols, when 
heated with alkalies or acids :— 


CH,.CO.CH,.CO,R + H,O = CH,.CO.CH, + CO, + R.OH. 


The formation of aceto-acetic ester is probably such that there first results a so- 
dium aceto-acetic ester, CH,Na.CO,.C,H,, which in turn reacts with a second 
molecule of the acetic ester, a molecule of alcohol, separating at the same time (see 
Berichte, 18, 3460) :— 


CH,.CO,.C,H; + CH,Na.CO,.C,H, = CH,.CO.CHNa.CO,.C,H, + C,H,OH. 


It may be, however, that an addition of sodium ethylate to aceto-acetic ester occurs 
(Claisen, Berichte, 20, 651), and the additional product, CH,.C(OC,H,),.ONa, 
reacts with a second molecule (Claisen, Berichte, 20, 651; 21, 1155). 


— 


KETONIC ACIDS. 335 


Sodium also reacts analogously with propionic ester, forming propio-propionic 
ester (p. 342). 

B-Aldehydic esters (p. 330) are formed if sodium, or sodium ethylate, acts 
upon a mixture of acetic ester (or the ester of any other monocarbonic acid) and 
formic ester, whereas, by using a mixture of ketones and formic esters, aldehyde 
ketones are produced. Diketones result if the mixture consists of ketones and 
acetic esters (p. 327). The oxalic esters and fatty acid esters yield keton-dicar- 
boxylic acids (see oxalacetic acid). All these condensations are analogous. An 
exit of alcohol occurs in each instance. They may well be termed ester-condensa- 
tions. Itis very probable that in every case the first action consists of the addition 
of sodium ethylate (Berichte, 21, 1156; 22, 553). 


The esters of aceto-acetic acid, contrary to expectation, possess 
an acid-like character. They dissolve in alkalies, forming salt-like 
compounds in which a hydrogen atom is replaced by metals. All 
their reactions indicate that it is the hydrogen of the CH, (attached 
to two CO groups) that has the nature of an acid hydrogen. 

We here observe an influence of the negative groups CO upon 
the hydrogen in union with carbon (in the atomic grouping CO. 
CH,.CO) similar to that exercised by the nitro-group in the nitro- 
paraffins (p. 107). 

It matters not whether the carboxyl group be attached to hydro- 
gen, forming the aldehyde or formyl group, or to an alkyl group, 
forming the ketone group, or to an oxyalkyl group, forming a 
carboxyl-ester group :— 


—COH —CO.R —CO.OR 
Aldehyde Group. Ketone Group. Carboxyl-ester Group. 


The union of two such groups to an atom of carbon gives rise to 
six classes of compounds :— 


/COH icy OO / CO.OR 
CH;< CoH CH2< COR CH2< CO.OR 
Dialdehydes. Diketones. Dicarboxylic Esters. 
/CHO /CHO /COR 
CH2< COR CH2< CO.OR .CH2< CO.OR 
Aldehyde Ketones. Aldehydic Acids. Ketonic Acids. 


These are acid in character. Their metallic derivatives are formed 
by the replacement of the hydrogen’ of the CH,- (or CHR-) group. 


The formyl group —CHO exercises the most powerful acid influence. Next in 
acidity is the ketone group —COR, while the ester group —CO.OR is the most 
feeble in its acid nature. Therefore, compounds containing the first group are the 
most acid. The §-diketones and the /-ketonic esters follow in regular succession. 
The entrance of an alkyl into the group CH, greatly diminishes the acid function 
of the homologous compounds (Berichte, 22, 1018). 


The sodium and potassium compounds are obtained pure from 
the aceto-acetic esters by treating the latter with potassium or — 


336 ORGANIC CHEMISTRY. 


sodium, or better, the alcoholates of the latter (in equivalent quan- 
tities) ——T : 


C,H,0,.C,H, + C,H;.ONa = C,H,NaO,.C,H, + C,H,.OH. 


They dissolve readily in water and alcohol, react alkaline and on 
exposure decompose. The decomposition is more rapid on boiling 
with water (similar to the free aceto-acetic esters) (p. 334). Di- 
lute acids liberate the esters. When the latter are dissolved in 
barium hydroxide, corresponding barium compounds are formed, 
from which derivatives of the heavy metals are obtained by double 
decomposition. _Ammoniacal solutions of metallic salts afford the 
same directly from the aceto-esters (Aznalen, 188, 268). Consult 
Annalen, 201, 143, upon the preparation of the dry sodium com- 
pounds. 


In quite a number of different reactions aceto-acetic ester conducts itself as if it 
possessed the constitution indicated by the formula of its isomeride 8 oxy-crotonic 
ester, CH,.C(OH):CH.CO,.C,H,. Hence many writers give the ester this con- 
stitution (Geuther, Berichze, 21, Ref. 295). The sodium salt is represented by the 
formula CH,.C(ONa):CH.CO,.C,H, (A. Michael, Berichte, 21, Refs. 530 and 
573). Usually the unsaturated hydroxylform, C(OH):CH.,, rearranges itself to the 
- ketone form (p.134). Yet, it appears, the reverse sometimes occurs (Berichie, 17, 
2621). The two forms may therefore be considered pseudomeric or tautomeric 
(Berichte, 19, 730; 20, 651; 21, 1084). 


Different monovalent radicals can be substituted for the metal in 
the sodium aceto-acetic esters. Thus by the action of the alkyl 
iodides (or bromides), sodium iodide separating, we get :— 


CH /CH 


/ CRs 
OOS CHICH,).CO..C, 1, SS CHIC 13.00, Call.. 
Methyl Aceto-acetic Ester. Ethyl Aceto-acetic Ester. 


In these mono-alkylic aceto-acetic esters another hydrogen atom 
can be replaced by sodium, by the action of the metal or sodium 
ethylate :— 
coZ CHeis 
\CNa(CH,).CO,.C,H;. 
Sodium Methyl Aceto-acetic Ester. 
If alkyl iodides be again permitted to act upon these last deriva- 
tives, a second alkyl group may be introduced, yielding dialkylic 
aceto-acetic esters, e.g. :— 


COC Ech ),CO,.C,H cof cH 
Dimethyl Aceto-acetic Ester. ie crc, H, ) -CO,.C,H;. 


Methyl-ethyl Aceto-acetic Ester. 


KETONIC ACIDS. 337 


To execute these syntheses, it is not necessary to prepare pure sodium com- 
pounds. To the aceto-acetic ester dissolved in 10 times its volume of absolute alco- 
hol, add an equivalent amount of sodium and then the alkyl iodide, after which 
heat is applied. To introduce a second alkyl, employ again an equivalent quantity 
of the sodium alcoholate and the alky] iodide (Amma/en, 192, 153). In some cases 
sodium hydroxide may be substituted for sodium ethylate in these syntheses (Azn- 
nalen, 250, 123). 


On heating the mono-or dialkylic aceto-acetic esters with alkalies 
in dilute aqueous or alcoholic solution, or with barium hydroxide, 
they decompose after the manner of aceto-acetic esters (p. 334), 
forming ketones (alkylic acetones) (ketone decomposition) :— 

CH CH 
COC CCH) H.CO,.C,H, 4+ 2KOH = COL GH’. cut CO,K,+ C,H,.0H, 
Methyl Acetone. 
/CH, 


CH 
\.C(CH,),CO,.C,H, * ( 


<cuicn,), +CO,K,+C,H,.OH. 


Dimethyl! Acetone. 


CO 2KOH — CO 


At the same time another splitting-off takes place, by which the 
alkylic acetic acids, 7. ¢., the higher fatty acids (p. 212) are pro- 
duced along with acetic acid (acid decomposition) :— 

CH, CH, 
+ 2KOH = | CH) OO Fert: C,H;.0H. 
CO.OK 


otassium Propionate. 


cog 
CH(CH,).CO,.C,H, 
Potassium Acetate, 

Both of these reactions, in which decomposition occurs (the splitting-off of ke- 
tone and of acid), usually take place simultaneously. In using dilute potash or 
caustic baryta, the ketone-decomposition predominates, whereas, with very concen- 
trated alcoholic potash, the same may be asserted in regard to the acid-decompo- 
sition (J. Wislicenus, duna/len, 190, 276). The splitting-off of ketone, with elimi- 
nation of CO,, occurs almost exclusively on boiling with sulphuric or hydrochloric 
acid (1 part acid and 2 parts water). In this case, ketones, or with the dibasic 
ketonic acids, ketone monocarboxylic acids are produced (Anna/en, 216, 133). 
The aceto-acetic esters undergo a decomposition similar tothe splitting-off of acid 
if they are heated alone to 250°, or with sodium ethylate free from alcohol, when, 
instead of acetic acid, we obtain dehydracetic acid, CJH,O,. 


The aceto-acetic esters are changed by nascent hydrogen (sodium 
amalgam) into the corresponding f-oxy-acids (of the lactic acid 
series) (p. 331) :— 

CH,.CO.CH,.CO,.C,H, -+ H, + H,O = CH,.CH(OH).CH,.CO,H + C,H,.OH. 
Aceto-acetic Ester. B-Oxybutyric Acid. > 

They are saponified at the same time. As ketones, they also 
unite with CNH, forming oxycyanides (p. 202), which hydrochloric 
acid converts into oxydicarboxylic acids :— 


CH,.CO CH CC Ee CH,.C(OH).CO,H 
| yields | \ an 
CH,.CO,.C,H, CH,.CO,.C,H, H,.CO,H. 


Aceto-acetic Acid. Oxycyanide. Oxypyrotartaric ‘Acid. 


338 ORGANIC CHEMISTRY. 


In the aceto-acetic esters, the hydrogen of the group CO.CH,,.CO can be directly 
replaced by chlorine and bromine. The products, like 


CH,.CO.CCI,.CO,.C,H, and CH,.CO.CCI(CH,).CO,.C,H,, 


Dichloraceto-acetic Ester, Chlormethylaceto-acetic Ester. 


suffer changes with alkalies and acids analogous to those sustained by the aceto- 
acetic esters (see above). Thus, from dichloraceto-acetic esters are obtained 
dichloracetone, CH,.CO.CHCI,, and dichloracetic acid, CHCl,.CO,H; and from 
chlormethylaceto-acetic ester result chlormethyl-ethyl ketone, and a-chlorpropionic 
acid, CH,.CHCI.CO,H, ete. 

All the aceto-acetic esters combine with hydroxylamine to form esters of the 
corresponding -isonitroso-fatty acids (p. 214). Nitrous acid changes them to the 
isonitroso-derivatives, CH,.CO.C(N.OH).CO,R, which readily break up into 
isonitroso-acetone and CO, and alcohols (see below). The aceto-acetic esters with 
one alcohol radical decompose directly into isonitroso-acetones (p. 206). 

The aceto-acetic esters combine with the diazo-compounds (Berichte, 21, 549) 
of the benzene series, and are capable of forming various condensation products 
(with aldehydes, etc.). 





Benmyi Acéto-acetic’ ‘Ester; CH,.CO:-CH,CG,.C.H; — 
C5H,.O;, Aceto-acetic Ester, is formed by the action of sodium upon 
ethyl acetic ester (p. 254). It also results when acetone-dicarbonic 
ester splits off a CO,R-group. It is a pleasantly smelling liquid, of 
Sp. gr. 1.0526 at 20°, boils at 180.8° and distils over with steam. 
The ester is only slightly soluble in water, and has a neutral reaction 
(that of the methyl ester is acid). Ferric chloride colors it violet. 

Boiling alkalies or acids convert the ester into acetone, carbon 
dioxide and alcohol: 


Preparation of Ethyl Aceto-acetic Ester.—6o parts metallic sodium are gradu- 
ally dissolved in 2000 parts pure ethyl acetic ester. The excess of the latter is dis- 
tilled off. On cooling the mass solidifies to a mixture of sodium aceto-acetic ester 
and sodium ethylate. The mass remaining liquid is mixed with acetic acid (50 per 
cent.) in slight excess. The oil separated and floating on the surface of the water 
is siphoned off, dehydrated with calcium chloride, and fractionated (Anza/en, 186, 
214 and 213, 137). Forthe preparation of the dry sodium compound, see Anna- 
len, 201, 143. j 

The sodium compound, C,H,NaO,.C,H,, crystallizes in long needles, and is 
made by heating ethyl acetic ester with sodium ethylate :— 


- 2C,H,0,.C,H, + C,H,.ONa = C,H,NaO, + 2C,H,.OH. 


The copper salt, (C,H,O,),Cu, (Preparation, Berichte, 19, 21), is precipitated in 
the form of a bright green powder. 

Heated alone or with sodium ethylate, it yields ethyl acetic ester and dehydra- 
cetic acid. 

The pyron-group is then formed. ‘The action of sulphuric acid causes aceto- 
acetic ester to pass into'a condensation product, from which the isomeric iso-dehy- 
dracetic acid, C,H,O,, splits off. Phosgene, COCI,, and copper aceto-acetic ester 
yield dimethyl pyron-dicarboxylic ester (Berichte, 19, 22 and 20, 151). 


KETONIC ACIDS. 339 


Aceto-acetic ester becomes f-oxybutyric acid under the action 
of sodium amalgam. It forms an oxycyanide with CNH, from 
which oxypyrotartaric acid is formed (p. 337). PCI; replaces the 
oxvgen of the CO-group by 2 atoms of chlorine. The chloride, 
CH,.CCl,.CH,.CO.Cl, readily splits off hydrochloric acid and yields 
two chlor-crotonic acids (p. 239). Fuming nitric acid changes 
it to isonitroso-acetic ester (p. 222). 


Chlorine (or sulphuryl chloride, SO,Cl,) and bromine convert aceto-acetic ester, . 
or its copper derivative, into a-mono-, and di-substitution products. The CH,-group 
is first attacked (Berichte, 21, Ref. 831; 22, Ref. 680; Annalen, 253, 168). 

a-Chlor-aceto-acetic Ester, CH,.CO.CHCI.CO,.C,H,, is an oil with a very 
penetrating odor. It boils at 193°. In the action of chlorine, the y-chloraceto— 
acetic Ester, CH,Cl.CO.CH,.CO,.C,H,, is said to be produced simultaneously 
with the a-product. It boils at 188°. It yields citric acid with potassium cyanide 
(Berichte, 22, Ref. 255). 

a-Brom-aceto-acetic Ester, CH,.CO.CHBr.CO,.C,H,, (see above), is an oil 
with piercing odor. It boils at 210°-215°. It attacks the eyes strongly. 

a-Dichloraceto-acetic Ester, CH,.CO.CCIl,.CO,.C,H,, is a pungent-smelling 
liquid, boiling at 205°. Heated with HCl it decomposes into a-dichloracetone, 
CH,.CO.CHCI1,, alcohol and CO, ; withalkalies it yields acetic and dichloracetic 
acids (Berichte, 16, 1553). 

a-lodo aceto-acetic Ester, CH,.CO.CHI.CO,.C,H;, is produced when 
iodine acts upon copper aceto-acetic ester. It is a green-colored oil. It forms a 
pyrazolon-derivative with phenylhydrazine (253, 194). 

Isonitroso-aceto-acetic Ester, CH,.CO.C(N.OH).CO,.C,H,, is formed on 
dissolving ethyl aceto-acetate in dilute potash, adding a solution of potassium ni- 

trite (I molecule NO,K) and acidifying with dilute sulphuric acid (Berichée, 15, 
' 1326). Shining leaflets or prisms readily soluble in alcohol or ether; they melt 
at 53°, and decompose when heated (p. 338). It has an acid reaction, dissolves 
in alkalies with a yellow color and is colored an intense red by phenol and sul- 
phuric acid (p. 107). Hydroxylamine forms di-iso nitroso-butyric ester, CH,. 
C(N.OH).C(N.OH).CO,.C,H,, with it (Berichte, 17, 821). 

Ammonia converts aceto-acetic ester into paramido-aceto-acetic ester, C, H,,NO,., 
which may be regarded either as 3 Imido-butyric Ester, CH,.C(NH).CH,. 
CO,.C,H,, or as 8-Amidocrotonic Ester, CH,.C(NH,):CH.CO.C,H, (Anua- 
len, 226, 294). It crystallizes in bright leaflets, melts at 34°, and boils at 210°- 
215°, with partial decomposition. When distilled, it passes into a /ué¢done deriva- 
a (Berichte, 20, 445), while it forms hydrocollidine dicarboxylic ester with alde- 

yde. 

Aceto.-acetic ester also unites with methylamine and diethlyamine (eviche, 18, 
619). With aniline it yields phenyl-imido butyric acid (see this), which easily 
passes over into quinoline derivatives. With amidines, pyrimidine compounds re- 
sult (Berichte, 18, 759). Acetamide and aceto-acetic ester form aceto-$-imido- 
butyric ester (Berichte, 18, Ref. 141). Pyrazolon-derivatives are formed by union 
with phenylhydrazine (see these). 

Nitrous acid converts §-imidobutyric ester into zsmzdo-7sonitroso-butyric ester, 
CH,.C(NH).C(N.OH).CO,.C,H,;. This is a yellow oil. When reduced with 
zinc dust, it condenses to dimethyl-pyrrol-dicarboxylic ester (Berichte, 17, 1638). 
Zinc chloride condenses it to a 4etine derivative (see Ketines). 


340 ORGANIC CHEMISTRY. 


Methyl Aceto-acetic Ester, CH,.CO.CH,.CO,.CH,, is formed from methyl 
acetate (p. 338). It boils at 170°, and is colored a dark cherry-red by ferric 
chloride. Otherwise it is perfectly similar to the ethyl ester. 


: /7CH, 
Methyl Ethyl Aceto-acetic Ester,CO Ve (CH,)H. CO,.C,H, 


= C,H,,0; (p. 336), (a-aceto-propionic ester). This boils at 186° 
and has a specific gravity of 1.o1 at 12°. Potash readily decom- 
_ poses it into methyl acetone, carbon dioxide and alcohol. By the 
acid-decomposition it yields propionic acid. ee methyl aceto- 
acetic acid, obtained by saponification of the ester with alkalies in 
the cold, is very similar to aceto-acetic acid (p. 336). 


; Te /CH Lag : 
Dimethyl Aceto-acetic, Ester, CONC(ICH) Cope He. =a CH,O,, isan 


oil, nearly insoluble in water, of sp. gravity 0.991 at 16°. It boils at 190°. Boil- 
ing aqueous potash does not affect it. Alcoholic potash, however, or baryta water, 
changes it to dimethyl acetone, carbon dioxide, and alcohol. By the acid-decom- 
position it yields isobutyric acid, (CH,),.CH.CO,H. The free acid is crystalline, 
but very unstable. CH, 

Ethyl Aceto-acetic Ester, COC CHIC, H,).CO,.C,H,’ is sparingly soluble in 


water. It boils at 195°. Its specific gravity equals 0. 998. at 6°. Ferric chloride 
colors it blue. Boiled with aqueous potash, it decomposes into ethylacetone, 
carbon dioxide, and alcohol. In the acid-decomposition it forms normal butyric 
acid. 

Diethyl Aceto-acetic Ester, COE H,),.CO, C, H, = C,)H,,0s, is insolu- 
ble in water, boils at 210-212°, and has a specific gravity ‘at 0° of ©. 974. Aqueous 
potash has no effect upon it, while with alcoholic potash or baryta waterit yields 
diethyl ketone, CH,.CO. CH(C, H;),. By the acid-decompodsition (with sodium 
ethylate) diethylacetic acid results. The free diethyl-aceto-acetic acid is liquid, 
and when distilled, yields CO, and ade acetone. 


CH, 
Methyl-ethyl Aceto. acetic Ester, COL EHH, (C, H,).CO,.C,H, = C.H,,0;, 


boils at 198°. By decomposition it furnishes methyl-ethyl acetone and methyl- 
ethyl acetic acid (p. 229). 
For other mixed alkyl aceto-acetic esters consult Anmalen, 226, 206. 


: CH : : 
Allyl Aceto-acetic Ester, COC CHIC.H,).CO,.C,H,= C,H,,Os, is obtained 


by the action of allyl iodide upon sodium aceto-acetic ester. It boils at 206°; its 
specific gravity is 0.982 at 17.5°. Ferric chloride gives a carmine-red coloration. 
When it decomposes, allyl acetone and allyl acetic acid are produced (p. 241). 
Sodium amalgam changes it into Saas oe acid. - By the addition of more 
allyl, we obtain— 


: ; ee é 
Diallyl aceto-acetic Ester, cog cae H,),-CO,.C,H,, which: boils at 206°, 


and decomposes into diallyl acetone and diallyl acetic acid. 

By the action of propyl iodide, isopropyl iodide, isobutyl iodide, amyl iodide, 
benzyl chloride, C,H;.CH,Cl, etc., higher aceto-acetic esters have been formed, 
from which, by decomposition, higher ketones and fatty acids resulted, and were 
converted into higher oxy-acids by the addition of H,. 

The following is an a-y-ketonic ester :— 


Acetonyl-aceto-acetic Ester, CH,.CO.CH,.CHZ CO.CH, 


<.CO,.C,H,’ is produced 


KETONIC ACIDS. 341 


by the action of chloracetone, CH,.CO.CH,Cl, upon aceto-acetic ester. It forms 
pyrotritaric ester (Berichte, 17, 2759) with fuming hydrochloric acid. On heating 
the ester with water to 160° C. acetonyl acetone results. 





By the action of chlorcyanogen upon sodium methyl aceto-acetic ester the follow- 
ing derivatives are produced :— 

Methyl Cyan-acetoacetic Ester, CH,.CO.CH(CN).CO,.CH;. This can 
be prepared from methyl cyanacetic ester when acetyl chloride acts upon its sodium 
compound (Berichte, 21, Ref. 187; 22, Ref. 207). It is crystalline, readily solu- 
ble in alcohol and ether, and melts at 46°. Its reaction is acid. Its salts crys- 
tallize well. 

Ethyl Cyan-acetoacetic Ester, CH,.CO.CH(CN).CO,.C,H;, from ethyl 
cyanacetic ester, melts at 26°. 

Methyl and ethylaceto-acetic esters yield corresponding cyanogen products, CH,. 
CO.C(CN)R.CO,.C,H,;. These are insoluble in alkalies (Berichte, 22, Ref. 407). 





The hydrogen in the aceto-acetic esters may also be replaced by 
acid radicals, by letting the acid chlorides act on the sodium com- 
pounds, suspended in ether. Thus arise the dketon-monocarboxylic 
esters. Acetyl chloride forms :— 


Acetyl Aceto-acetic Ester, C,H,0.CH(C,H,O).CO,.C,H; or Diaceto-acetic 
Ester,ci1"CQ, »CH.CO,GH, It boils with partial decomposition at 210°, and 
is broken up by water, even at ordinary temperatures, into acetic acid, aceto-acetic 
ester and CO, (Anna/en, 226, 210). Sodium ethylate displaces an acetyl group in it, 


. . . . me rt H O’\. _ 
forming aceto-acetic ester and sodium aceto-acetic ester : CH,O - CH.CO,.C,H; + 


C,H,;-ONa = C,H,0.CHNa.CO,.C,H, + C,H,0.0.C,H,;. Acetyl-methyl-aceto- 

acetic ester and acetyl-ethyl-aceto-acetic ester, (C,H,O),C(C,H,).CO,.C,H;, are 

produced in an analogous manner. 

eer tae P CH,.CO \ ; 
oyl aceto-acetic Ester, i CO CH.CO,.C,H,, obtained from aceto- 
¥ 
acetic ester by benzoyl chloride, breaks up, when boiled with sulphuric acid, into 
benzoyl acetone, CH,.CO.CH,.CO.C,.H, (Berichte, 16, 2239), and CO,. 


The following is a monobasic Diketonic Acid :— 

Aceto-pyroracemic Acid, C;H,O, — CH,.CO.CH,.CO.CO,H, or Acetone 
Oxalic Acid. Its ethyl ester results when sodium ethylate acts upon acetone and 
oxalic ester. It boils at 214° (Berichte, 20, 2189). Ferric chloride imparts a dark 
red color to it. Copper acetate precipitates the green copper compound (C;H,O,), 
from its alcoholic solution. The acid, liberated from the ester, condenses quite 
readily to symmetrical oxytoluic acid (Berichte, 22, 3271). Asa B-diketone com- 
pened (CO.CH,.CO), acetone-oxalic ester manifests all the reactions peculiar to 
this class. 


Acetophenone, C,H;.CO.CH;, by treatment analogous to that 


just described above, passes into the ester of benzoyl pyroracemic 
acid, C;H;.CO.CH,.CO.CO,H (see this). 


342 ORGANIC CHEMISTRY. 


Acid residues can also be introduced into the aceto-acetic esters, 
by allowing esters of substituted fatty acids to act upon the sodium 
compounds. ‘The esters of the ketone dicarboxylic acids are ob- 
tained in this way. Chlorformic ester produces 


Aceto-malonic Ester, CH,.CO.CH”% CO). CH; Chlor- 


acetic ester, CH,Cl.CO,.R, yields Oe anne 
Aceto-succinic Ester, CH;.CO. CHL CO.R a These 


dibasic ketonic acids will be discussed after the oxy-acids. Di- 
CH,. CO: CH:CO, C,H; 

acetyl succinic Ester, | , a rather remark- 
CH;.CO.CH.CO,.C,H, 

able body, produced by the action of iodine upon sodium aceto- 

acetic ester, properly belongs in the same section. 


Sodium also facilitates the conversion of propionic ester into a-propionyl-propio- 
nic ester (Berichte, 20, 1320 and Annalen 239, 386) :— 


CH,.CHNa CH,CH.CO.CH,.CH, 
l tO DOC CE Cio | ; 
CO,.C,H, CO,.C,H, + C,H,.ONa. 
2 Molecules Propionic Ester. a- Peoskonyt- propionic Ester. 


On the other hand normal butyric ester, isobutyric ester and isovaleric ester, when 
acted upon by sodium, do not yield analogous compounds, but the oxy-alkyl de- 
rivatives of higher fat-acids (Berichte, 22, Ref. 22). The action of ferric chloride 
upon fatty acid chlorides is a common synthetic method for the preparation of 
higher 3-ketonic acid esters. In this reaction the chlorides of the ketones are first 


formed: 2C,H,.CO.Cl = CyH,.CO.CHY Coty + HCl. When treated with 
water they split off CO,, and become ketones (p. 200). With alcohol they are 
converted into esters of eg ketonic acids (Hamonet, Berichte, 22, Ref. 766) :— 


/CH, 
<coec,H, + HCl 
a-Propionyl-propionic Acid. 


C,H,.CO. cH Cot +. + C,H,.OH = C,H,.CO.CH 


a-Propionyl-propionic Ester, C,H,.CO. CHK Co; C,H, Prepared by both 
methods, is an agreeably smelling liquid, boiling at 199°; its specific gravity at 0° 
is 0.995. Sodium alcoholate and ethyl iodide do not convert it into ethyl propi- 
- onyl-propionic ester, but into the decomposition products of the latter—propionic 
ester and methy! ethyl acetic ester. Sodium amalgam converts it into the corres- 
ponding oxy-acid, which passes into methyl propyl acetic acid by reduction (p. a 
CH,.CO.CH.CO,.C,H 
Succinyl-succinic Ester, C,,H,,O, = | | j 
C,H;.CO,.CH. CO.CH, 
may be similarly obtained from succinic ethyl ester by the action of sodium or so- 
dium alcoholate. This new compound is doubtless a quino-tetrahydro-dicarboxy- 
lie ester, and will be considered under the benzene derivatives. 


KETONIC ACIDS. ee 


3. y-Ketonic Acids. | 

These have the ketone oxygen atom attached to the third carbon 
atom from the carboxyl group (p. 331) and are distinguished from 
the acids of the 8-variety by the fact that they are stable in a free 
condition even when heated. By the addition of two hydrogen 
atoms they yield y-oxy-acids, which immediatély pass into lactones 
(see these). 


When distilled, the y-ketonic acids split off water and pass into unsaturated 
lactones (Berichte, 18, 2263). This transposition may be explained by assuming 
that the tautomeric form of the y-lactone is to be ascribed to the y ketone acids 
(Annalen, 226, 225) :— 








CH,.CO.CH,.CH, CH,.C(OH).CH,.CH, CH,.C:CH.CH, 
or | | yields | 
COOH O CO O CO. 
Levulinic Acid. Angelica Acetone. 


&-Aceto-propionic Acid, C;H,O, — CH;.CO.CH,.CH,.CO,H, 
Levulinic Acid, 7-Ketovaleric Acid. This is isomeric with methyl 
aceto-acetic acid, which may be designated a-aceto-propionic acid 
(p. 340). It is obtained from aceto-succinic ester (p. 342) on 
boiling with hydrochloric acid or baryta water, and from cane sugar, 
levulose, starch, and apparently from all the carbohydrates (Ber- 
ichte, 19, 707) on boiling them with dilute hydrochloric or sulphuric 
acid. 


Preparation.—Heat 500 grs. of sugar dissolved in 1 litre of water with 250 
grs, of crude concentrated hydrochloric acid until the separation of brown humus 
substances ceases. The solution is then concentrated, repeatedly extracted with 
ether, and the levulinic acid, remaining after the evaporation of the ethereal solu- 
tion, is purified by distillation ina vacuum. A yield of about 8 per cent. of acid 
is obtained in this way (Annalen, 227, 99). 

A more advantageous -method is to boil starch with hydrochloric acid (Berichte, 
20,1775). The yield of acid is about 13 per cent. It is obtained commercially 
by heating cane sugar with dilute hydrochloric acid (Berichte, 19, 2572). 


Levulinic acid dissolves very readily in water, alcohol and 
ether, and crystallizes in scales, melting at 33.5°. The acid boils 
with slight decomposition at 239°. Traces of moisture lower the 
melting point. The molecular refractions of the free acid and its 
esters confirm the idea of its being a ketonic acid (p. 60). 


In accordance with this view it yields y-isonitrosovaleric acid (p. 228) with 
hydroxylamine, It unites with phenylhydrazine acetate to form phenylhydrazine- 
levulinic acid, C,H;.N,H:C(CH,).CH,.CH,.CO,H. This passes into an anhy- 
dride, C,,H,,.N,O, when heated to 166° (Berichte, 22, Ref.673). It melts at 108°. 
The hydrazone yields y-amidovaleric acid by reduction (p. 319). 

The calcium salt, (C,H,O,),Ca + 2H,0, forms delicate needles; the darium 
saltisa gummy mass. The sz/zver sa/t is a characteristic, crystalline precipitate, 
dissolving in water with difficulty, The methyl ester, C;H,(CH,)Osg, boils at 
191°, the ethyl ester at 200°. 


344 ~ ORGANIC CHEMISTRY. 


When heated to 150-200° with hydriodic acid and phosphorus, 
levulinic acid is changed to normal valeric:acid. By the action of 
sodium amalgam sodium ;-oxyvalerate is produced. The acid 
liberated from this becomes valerolactone. Dilute nitric acid con- 
verts leevulinic acid (analogous to the oxidation of ketones, p. 203) 
into acetic and malonic acid and again into succinic acid and car- 
bon dioxide. 


Leevulinic acid unites with potassium cyanide, forming the J/actone cyanide, 
CH,.C(CN).CH,.CH, 
ad | , from which a-methyl-glutaric acid is obtained by hydro- 

O O 
. chloric acid (Berichte, 19, 3269). 

Two angelica lactones, C;H,O, (a and £8), are produced on distilling leevulinic 
acid. Water separates at the same time. The a-derivative yields $-bromlevu- 
linic acid by the addition of hydrobromic acid. 

6-Bromlevulinic Acid, CH,.CC.CHBr.CH,.CO,H, obtained from the 
lactone (see above), melts at 59°. Its e¢hy/ ester is produced in the bromination of 
leevulinic ester,and boils at 240°. It yields diaceto-glutaric ester (Berichie, 19, 
47) with sodacetoacetic ester. Warming with sodium hydroxide converts the 
6-bromlzevulinic acid into hydroxy-levulinic acid and aceto-acrylic acid (see below) 
(Berichte, 20, 425). Aniline converts brom-lzvulinic acid into dimethyl-indol, as 
all compounds with the group —CO.CH Br—react analogously (Berich/e, 21, 3360). 

B-Aceto-butyric Acid, CH,.CO.CHC Gi".00,1 = C,H,,0,, -methy! 
aceto-propionic acid, is obtained from a-methyl aceto-succinic ester (p. 342). It 
boils at 242° and becomes crystalline at—12°. The ethyl ester boils near 205°. 
The isomeric— 

B-Aceto-isobutyric acid, Ha iO Gee Scueo,n — C,H,,0,, a-methy]- 
leevulinic acid, from $-methyl aceto-succinic ester, boils at 248°. Its ethyl ester 
boils at 207°. 

Nitric acid oxidizes both acids to CO, and methyl succinic acid (pyrotartaric 
acid). Consult.Berichte, 23, 622 upon the lactone formation of the alkyl-levu- 
linic acids, 








6-Ketonic Acid. 

y-Aceto-butyric Acid, CH,.CO.CH,.CH,.CH,.CO,H = C,H,,.Ox, is ob- 
tained from the ester of aceto-glutaric acid (p. 341) by the withdrawal of CO,. 
It melts at 13° and boils at 275°. Sodium amalgam converts it into a salt of 
d-oxycaproic acid, which yields a d-lactone (Amma/en, 216, 127). 


UNSATURATED KETONIC ACIDS. 


B-Aceto-acrylic Acid, CH,;.CO.CH:CH.CO,H, is derived from -bromlzvu- 
linic acid (see above) upon digestion with a soda solution. It crystallizes from 
alcohol in brilliant needles melting at 125° C. It combines with phenylhydrazine 
( Berichte, 21, 2937) and with bromine, forming in the latter case dibrom-levu- 
linic acid.. Ammonia converts this into tetramethyl pyrazine (dimethyl ketine) 
(Berichte, 20, 426). 

8-Trichlor-aceto-acrylic Acid, CCl,.CO.CH:CH.CO,H, is very probably 
Trichlorphenomalic Acid. This is obtained from benzene by the action of potas- 


ALCOHOL- OR OXY-ACIDS. 345 


sium chlorate and sulphuric acid (Anna/en, 223,170). It crystallizes from water 
in shining leaflets, melting at 131°. It breaks up into chloroform and maleic acid 


when boiled with barium hydroxide. 7eo.CH, 
Ethidene Aceto-acetic Acid, CH,.CH:C -—  . The ethyl ester re- 
\CO,H 


sults from the action of hydrochloric acid upon aldehyde and aceto-acetic ester. 
A liquid with penetrating odor, and boiling at 211°. - Caustic potash decomposes 
it (Annalen, 218, 172). 

A series of homologous acids, CnH yn—4O,, has been prepared from the bromi- 
nated alkyl aceto-acetic esters by the action of: alcoholic potash, or by heating them 
alone or with water. These have been called pentinic, tetrinic acids, as ete. 
(Demarcay), 

Tetrinic Acid melts at 189° and boils at 262°. It takes on a violet saib upon 
the addition of ferric chloride, 

Pentinic Acid melts at 126.5° and is colored cherry-red by ferric chloride. 

The two compounds appear, however, not to be carboxylic acids, but are more 


properly £etolactones of the formula R.CHE | (see Berichte, 21, 2603; 
22, 243). CO—CH, 

The Oxy -tetrinic Acid, C,H,O,, from tetrinic acid, is identical with mesaconic 
acid ( Berichte, 21, Ref. 180). i 


The sulpho-carboxylic acids are analogues of the keton-carboxylic acids. es 
form a-, 3-,and y-derivatives :— 


C,H,.SO,.CO,8 .C.H,.S0,.CH,CO,H CH USs0.CH.CH, COL, 


Phenyl sulphe-firwia Ethyl sulpho-dcetic Acid: “Ethyl salpho-propiosic ‘Acid. 
cid. ; 


These are prepared by the action of the sulphinates, R.SO, Na, upon the esters 
of chiorfatty acids, e. g., chlorformic ester, CICO,R, chloracetic ester, etc. (Berichte, 


21, 89, 992). 





ALCOHOL- OR OXY-ACIDS. 
/ OH 
\ CO,H. 

Acids of this series, with the empirical formula, C,H,,0;, show 
a twofold character in their entire deportment. Since they contain 
a carboxylic group, they are monobasic acids with all the attaching 
properties and transpositions of the latter ; the OH-group linked to 
the radical bestows upon them all the properties of the monohydric 
alcohols. They may, therefore, be designated alcohol acids (corre- 
sponding to the ketonic acids, p. 331, and the aldehyde acids, p 
329). They were formerly called divalent or dihydric (diatomic) 
acids, as they contained two hydroxyl groups (an alcoholic and an 
acid) and could be obtained by oxidizing the dihydric alcohols 
(p. 297). At present they are mostly termed oxy- or hydroxy-faity 


“0 


C,H, 


346 ORGANIC CHEMISTRY. 


acids, because of their origin from the fatty-acids by the replace- 
ment of a hydrogen atom by OH :— 


ORE os 
C,H,.CO,H and CHA C,H 
Propionic Acid. Oxypropionic Acid, 


This view of them is especially well adapted for the nomenclature 
of the acids (p. 348). 

The following are the chief methods of producing the oxy- 
acids :— . 

1. The transposition of the mono-halogen fatty acids with silver 
oxide, boiling alkalies, or even water :— 


CH,Cl.CO,H + KOH = or Sere se. 
2 


Monochloracetic Acid. Oxy-acetic Acid. 


The conditions of the reaction are perfectly similar to those observed in the 
conversion of the alkylogens into alcohols (p. 119). The a-derivatives yield 
a-oxy-acids; the §-derivatives are occasionally changed to unsaturated acids by the 
splitting-off of a haloid acid (p. 235), while the y-compounds form y-oxy-acids, 
which subsequently pass into lactones. y-Halogen acids are converted directly 
into lactones by the alkaline carbonates. 


The oxy-acids can be reconverted into fatty acids by heating 
them with hydriodic acid (p. 94) :— 


CH,(OH).CO,H + 2HI — CH,.CO,H + H,O +1,, 
or are first changed to monobrom-acids with hydrobromic acid :— 
: CH,(OH).CO,H + HBr = CH,Br.CO,H + H,0, 


and the product reduced with nascent hydrogen. 

2. Some fatty acids have OH directly introduced into them. 
This is accomplished by oxidizing them with KMnO, in alkaline 
solution :— 

(CH,),-CH.CO,H + O = (CH,),.C(OH)CO,H. 
Isobutyric Acid. a-Oxyisobutyric Acid. 


Only acids containing the tertiary group CH (a so-called tertiary H-atom) are 
adapted to this kind of transposition (Anmalen, 208@60, 220, 56). Nitric acid 
effects the same as MnO,K (Berichte, 14,1782; 15, 2318). 


3. The action of nascent hydrogen (sodium amalgam, zinc and 
hydrochloric acid) upon the ketonic acids and their esters (p. 331) :— 


CH,.CO.CO,H + H, = CH,.CH(OH).CO,H. 
Racemic Acid. a-Oxypropionic Acid. 


4.. By the action of nitrous acid upon amido-acids :— 


CH,(NH,).CO,H + NO,H = CH,(OH).CO,H + N, + H,0. 
Arttido-Acéiic Acid. Oxyacetic Acid. 


ALCOHOL- OR OXY-ACIDS. 347 


This reaction is perfectly similar to that observed in the conver- 
sion of amines into alcohols (p. 161). The intermediate products 
are the diazofatty acids, and on en them with water or dilute 
acids oxyacids result (see these). 

5. Careful oxidation of the glycols with dilute nitric acid or 
platinum sponge :— 


CH,.OH CH,.OH 
| a O, v3 | BF H,0, 
CH,.0H CO.OH 
Glycol. Glycollic Acid. 
CH,.CH.OH CH, -CH.OH 
| Be! tome | + H,0. 
CH,.OH CO.OH.. 
a-Propylene Glycol. a-Lactic Acid. 


6. By allowing hydrocyanic acid and hydrochloric acid to act 
upon the aldehydes and ketones. At first oxycyanides are pro- 
duced (p. 202), after which hydrochloric acid changes the cyanogen 
group into carboxyl :— 

CH,.CHO + NCH = CH,.cH¢ 24 ana 
: sera SO | 
TA? / OH 
CH, .CH< < oN + 2H,O = CH »CH< co. yu t+ NHs- 
a- Daigoresicne Acid. 

In preparing the oxycyanides, the aldehydes or ketones are heated under pres- 
sure, with the equivalent amount of hydrocyanic acid (from 20-30 per cent.). Or 
we can add pulverized potassium cyanide to the ethereal solution of the ketone, 
and follow it with the gradual addition of concentrated hydrochloric acid (Berichte, 
14, 1965; 15, 2318). The concentrated hydrochloric acid changes the cyanides 
to acids, the amides of the acids being at first formed in the cold, but on boiling 
with more dilute acid they sustain further change to acids. Sometimes the change 
occurs more readily by heating with a little dilute sulphuric acid. 


The glycol chlorhydrins (p. 302) undergo a like alteration 
through the action of potassium cyanide and acids :— 
CH,.(OH).CH,Cl + CNK = CH,(OH).CH,.CN + KCl and 
CH,.(OH).CH,CN + 2H,O = CH,(OH).CH,.CO,H + NH,. 
B-Oxypropionic Acid. 

7. A method of ready applicability in the synthesis of oxyacids 
consists in permitting zinc and alkyl iodides to act upon diethyl 
oxalic ester (Frankland and Duppa). This reaction is like that in 
the formation of tertiary alcohols from the acid chlorides by means 
of zinc ethyl, or of the secondary alcohols from formic esters (p. 121) 
—1 and 2 alkyl groups are introduced into one carboxyl group 
(Annalen, 185, 184) :— 

CO.0.C,H, CH) = OH Bax OH 
yields 


| 
CO.0.C,H, bo.o.c, HH; ‘cH, a cb: C,H, 
Oxalic Ester. *Dimethy4-oxsilic Ester. 


348 ORGANIC CHEMISTRY. 


If we employ two alkyl iodides two different alkyls may be intro- 
duced. 

The acids obtained, as indicated, are named in accordance with 
their derivation from oxalic acid, but it would be more correct to 
view them as derivatives of oxy-acetic acid or glycollic acid, 
CH,(OH).CO,H, and neten é. g., dimethyl-oxalic acid, as 
dimethyl-oxyacetic acid. P 


8. The fatty acids are formed from alkyl malonic acids, CRR’(CO,H),, by the 
withdrawal of one carboxyl group (p. 212), and the oxy- fatty acids are obtained 
in a similar manner from alkyl oxymalonic acids or tartronic acids :— 


CROH)C ¢ ime OHS CRH(OH).CO,H. 


Alkyl- be mon Alkyl-oxy-acetic Acid. 


The tartronic compounds are synthetically prepared from malonic acid esters, 
SP. CHS Co! ce H® by first introducing the alkyl group (see malonic acid), 
then replacing the second hydrogen of CH, by chlorine, and finally saponifying 
the alkylic monochlor-malonic ester with baryta (Berichte, 14, 619). The suc- 
cessive transformations correspond to the formulas :— 


/CO,.CH, £C02CH, CRS COCHs ana CR(OH)CO2H 


Ps. CO CH. mCO, CH, \.CO,.CH, , CO, H 


CHR 





The possible isomerides of the dihydric acids are best derived 
from their corresponding monobasic acids, by replacing a hydrogen 
atom in the latter by OH. 
~ Only one oxy-acid can be derived from acetic acid, viz., glycollic 
acid, CH,.OH.COOH. From propionic acid, CH;.CH,.CO,H, 
we can obtain two oxy-acids. Five isomerides agree with the for- 
mula, C TOs = a | Cea three of them are derived from 
normal butyric acid, CH,.CH,.CH,.CO,.H, and two from isobu- 
tyric acid, (CH;),CH.CO,H, etc. 

The above compounds are named like the substituted fatty acids 
(p. 223), Z. €., aS a-, B-, -y, etc., oxy-acids :— 

.CH(OH).CO,H CH,(OH).CH,.CO,H 
“eSayprovine Acid. B-Oxypropionic Acid. 


H,(OH).CH,.CH,.CO,H 
y-Oxybutyric Acid, 


CH. CH.\ 
F CH? »C(OH).CO,H CH, (OH) >CH-COH. 
_ a-Oxyisobutyric Acid. B-Oxyisobutyric Acid, 


The a- and *f-oxy-acids exist free, while the y-acids are only 
known in their salts and acids. When liberated from the latter 
they immediately give up a molecule of water and pass into their 


ALCOHOL- OR OXY-ACIDS. 349 


anhydrides, the lactones. Various other peculiarities distinguish 
them (p. 350). 





The oxy-fatty acids containing one OH group are, in consequence, 
more readily soluble in water, and less soluble in ether than the 
parent acids (p. 297). They are less volatile, and as a general thing, 
cannot be distilled without undergoing a change. 

Their chemical properties fully accord with their structure, by 
which they are both acids and alcohols. The acid hydrogen (of 
the carboxyl group) can be easily replaced by metals and hydro- 
carbon residues, thus giving rise to normal salts and esters :— 


CH,.0H CH,.0H 
| and | 
CO.OK CO.0.C,H,. 

The remaining OH-group deports itself like that of the alcohols. 
Alkali metals and alkyls may replace its hydrogen. Acid radicals 
and NO, are substituted for it by the action of chlorides of mono- 
basic acid radicals (like C,H,O.Cl), and a mixture of concentrated 
nitric and sulphuric acids :— 

Cy, HO ana 31,980 
Aceto-lactic Acid. Nitro-lactic ‘Acid. 

Both these reactions are characteristic of the hydroxyl groups of 
the alcohols (p. 302). 

PCI, replaces the two hydroxyl groups by chlorine :— 


/OH ey. 
Glycollic Acid. Glycolyl Chloride, or 
Chloracetyl Chloride. 


The chlorine in union with CO is very reactive -with water and 
alcohols, yielding free acids and their esters; in the case cited, 
monochlor-acetic acid, CH,Cl.CO,H, and its esters result. The 
remaining chlorine atom is, on the contrary, firmly united, as in 
ethyl chloride. 

The various esters of the dihydric acids exhibit similar rela- 
tions :— 


/OH /0.C,H /O0.C,H 
aS CO. CH CAS co. CB COC 
Ethy! Glycollic Ethyl Glycollic Ethyl Etho-glycollic 
Ester. Acid. Ester. 


Alkalies cause the alkyl combined with CO, to separate, forming 


ethyl glycollic acid, Choe “ : 
See Berichte, 15, 162, upon the formation of esters of the oxy- 
acids. i 


350 ORGANIC CHEMISTRY. 


In the preceding transpositions all the oxy-acids react similarly, 
but in those following they exhibit variations influenced by the 
position of the OH group. 

Their varying behavior when oxidized is characteristic, especially 
when chromic acid is employed as the oxidizing agent (p. 203). 

The primary oxy-acids, containing the primary alcohol group, 
CH,.OH, may have the latter converted into aldehyde, and car- 
_ boxyl groups (p. 117), and the products will then be aldehyde-acids 
and dicarboxylic acids. ‘Thus, from glycollic acid are derived 
glyoxylic and oxalic acids :— 


CH,.OH CHO CO.OH 
l yields | 
CO,.OH CO.OH CO.OH. 
Glycollic Acid. Glyoxylic Acid. Oxalic Acid. 


The secondary oxy-acids, with the secondary alcoholic group, 
>CH.OH, can yield ketones, which, however, pass very readily 
into other compounds (p. 333). The a-oxy-acids, too, lose carboxyl 
when boiled with a chromic acid mixture. In them the CO,H and 
OH groups are attached to one carbon atom. Should the latter be 
linked to two hydrocarbon residues, ketones and carbon dioxide are 
produced :— 

GH? »C(OH). CO,H+0= cH’ > 


ES Acid. Rostens: 


G CO +CO, + H,0O; 


whereas, if it be in combination with only one such group, alde- 
hydes are first formed :— 


CH,.CH(OH).CO,H 4+ 0 — CH,.CHO + CO, + H,0; 
a-Oxypropionic Acid. Aldehyde. 


and these can then be further oxidized to acids. 


The a-oxyacids undergo a like decomposition when heated with dilute sulphuric 
or hydrochloric acid (or by action of concentrated H,SO,). Their carboxyl group 
is removed as formic acid (when concentrated H SO, is employed, CO and H,O 
are the products) :— 


(CH,),C(OH).CO,H + H,O = (CH,),CO + HCO,H, 
CH,.CH(OH).CO,H + H,O = CH,.CHO + HCO,H. 


Another alteration is sustained by the a-oxy-acids at the same time; it, however, 
does not extend far. Water is eliminated and unsaturated acids are produced. 
This change is easily effected when PCl1, is allowed to act on the esters of a-oxy- 
acids (p. 235). 

When the f-oxy-acids are heated alone or with acids, water is withdrawn and 
unsaturated acids are almost the sole products (p. 346) :— 


CH,(OH).CH,.CO,H = CH,:CH.CO,H + H,0. 
feOaseirobionic Acad: Acrylic Acid. 





ALCOHOL- OR OXY-ACIDS. 351 


Anhydrides of the Oxy-acids.—The anhydrides of the oxy-acids may be pro- 
duced in three ways. If two molecules of the acids unite so that the water can be 
withdrawn from the carboxyl groups, the true or real acid anhydrides are formed. 
These are perfectly analogous to the anhydrides of the fatty acids (p. 248). Ifthe 
water should arise from the alcohol hydroxyls, then the products are a/cohol auhy- 
drides or anhydridic acids :-— 


CH,.OHCH,.OH CH;—O—CH, 
| and | | 
CO—O—CO, CO.OH  CO.OH. 
Acid Anhydride, Alcohol Anhydride, 
Glycollic Anhydride. Diglycollic Acid. 


The acid anhydrides of the oxy-fatty-acids have not yet been prepared. The. 
alcohol anhydrides, like diglycollic acid, correspond perfectly to the ethers and 
sometimes appear on heating the oxy-acids. As a general thing they are prepared 
according to the same methods as the ethers of the alcohols. Thus diglycollic acid 
(and some glycollic acid) is obtained from monochloracetic acid, CH ,Cl.CO, H, by 
the action of bases (lime water or lead oxide); further, dilactic acid (its esters) is 
made from a-chlorpropionic ester and sodium lactic ester :— 


CH,.CHCI CH(ONa).CH, CH,.CH—O—CH.CH, 
| ee = 
CO,R CO,R OR COR 
a-Chlorpropionic Sodium Lactic Dilactic Ester. 
Ester. Ester. 


These ether acids (anhydridic acids), like the alcohol ethers, break up into 
oxy-acids on heating them with hydrochloric acid to 100°. 

In the ¢ird class of anhydrides, the ester anhydrides, the reaction is between 
the hydroxyl groups of carboxyl and the alcohol (p. 251). Should zwo molecules 
of the oxy-acid react we may have the single and double ester formation. Thus, 
glycollic acid forms a first and second anhydride :— 


CH,.OH COOH CH,—O—CO CH,—O—CO 
| +") yield | | and | Be 
CO.OH CH,.0H CO.OH CH,.OH CO—O—CH, 
2 Molecules Glycollic Acid. rst Anhydride 2d Anhydride 
Glycollic Anhydride. Glycolide. 


From lactic acid (a-oxy-propionic acid), C,H,O,, we get lactic anhydride, 
C,H,,O,, and the so-called Lactide,C,H,O, (p. 358). Only the a-oxy-acids 
are capable of entering this simple and double “ ester anhydride formation” by 
the union of two molecules. Heat hastens the reaction (occurs on standing in the 
dessicator). Conversely the ester anhydrides when heated with water absorb it 
and the oxy-acids are regenerated. 


Should the anhydride formation occur within one and the same 
molecule of the oxy-acids, we get what are designated J/actones 
(fittig, Annalen, 208, 111; 216, 27; 226, 322) :— 


CH,.CH,.0H CH,.CH 


2 
| —H,0= SO. 
CH,.CO.0H : du..co = 
y-Oxy-butyric Acid. y-Butyrolactone, 


The y- and 0-oxy-acids (from mono- and dicarboxylic acids) 
especially are adapted to this lactone formation, hence we distinguish 


352 ‘ ORGANIC CHEMISTRY. 


y- and d-lactones (Annalen, 216, 127). In the first we have a 
chain of four, in the second a chain of five carbon atoms closed by 
oxygen. This resembles the union in the anhydrides of the dibasic 
acids. Generally the lactones are liquids, easily soluble in water, 
alcohol and ether. They show neutral reaction, possess a faintly 
aromatic odor, and can be distilled without decomposition. The 
alkaline carbonates precipitate them from their aqueous solution in 
the form of oils. The ;-lactones are characterized by great 
stability. They are partially converted into oxy-acids by water, 
but this only occurs after protracted boiling, whereas those of the 
é-variety gradually absorb water at the ordinary temperature and 
soon react acid (Berichte, 16, 373). Boiling alkaline carbonates 
convert lactones into oxy-acid salts. The caustic alkalies effect this 
more readily. If the oxy-acids are freed from their salts by the 
mineral acids they at once break up into water and lactones. Heat 
hastens the conversion. 
The y-lactones can be obtained :— 

\ (1) By boiling the y-halogen fatty acids with water, or with 
caustic alkalies, and then liberating them with mineral acids. The 
lactones are produced even in the cold by the action of the alkaline 
carbonates (p. 346). 


Many j-derivatives, ¢. ¢., y-chlorbutyric acid (p. 226), decompose directly into 
lactone and HCl (Berichte, 19, Ref. 13) when distilled. 


| (2) By digesting the unsaturated acids, in which the double union 
occurs in the (8:7) or (7: 4)-position, with hydrobromic or sul- 
phuric acid (diluted with 1 volume H,O); or by their distillation 
(Berichte, 16, 373; 18, Ref. 229) :— 
CH,:CH.CH,.CH,.CO,H — CH,.CH.CI1,.CH, 
Allyl Acetic Acid. | | 
O O. 


Valerolactone. 





(3) By the action of sodium amalgam upon the y-ketonic acids, 
and the decomposition of the sodium salts by mineral acids (see 
above). Unsaturated lactones are formed upon distilling 7-ketonic 
acids (Berichte, 18, 2263), ¢. g., the two angelica lactones (p. 343) 
from leevulinic acid :— 


CH,.CO.CH,.CH,.CO.OH yields CH,.C:CH.CH, and CH,:C.CH,.CH, 


| 
O—CO O——CO 


4. Finally, by the distillation of lactone carboxylic acids (split- 
ting-off of CO,), whereby the isomeric unsaturated acids are also 
produced, owing to a rearrangement of the atoms. 

Some lactones have their lactone union severed, and the elements - 


OXY-ACIDS. 353 


of a halogen hydride added, through the action of HI, or by heat- 

ing with hydrochloric or hydrobromic acid. The products i in this 
case are y-halogen fatty acids (Berichte 19, Ref. 165) :— 

CH,.CH,.CH, 

| + HI =CH,I.CH,.CH,.CO,H. 

O 





With other lactones this transposition does not occur except in 
the presence of alcohol. Then the esters of the halogen fatty 
acids are formed (Berichte, 19, 513). ‘The lactones are reduced to 
fatty acids upon boiling with hydriodic acid.. Ammonia converts 
them into the amides of the y-oxyacids, which rapidly regenerate 
the lactones. Valerolactone, for example, unites with potassium 
cyanide to form y-cyanvaleric acid, CH;.CH(CN).CH,.CH,.CO,H 
(p. 344 and Berichte, 19, Ref. 439). The lactones do not react 
with phenylhydrazine. 

é-Caprolactone is the only known member of its class (p. 365). 


Besides the y and d-oxyacids some /- oxyacids (of the benzene series) are capa- 
ble of yielding corresponding lactones (Berichte 16, 3001; 17, 415). These 
§-lactones are much less stable, pass readily into their corresponding oxyacids, and 
split off carbon dioxide with ease. The existence of an a-lactone seems also to 
have been demonstrated (Berichte, 15, 579). 


The divalent groups, attached to the two hydroxyl groups, in the 
oxy-acids, are often called radicals :— 


CH. 2 CH,.CH__ 
| 

CO =: CO__ 

Glycolyl. Lactyl. 





OXY-ACIDS C,H,,O,. 
Carbone: Acid. — CH,O, = co” OH 


esate 3 \ OH 

Oxyacrtc sf CoHOy = CHC C6 a 
Crypropionie Acts} COs = CaIN C6 
spices Acids C,H,0,; = CHC Co-n 
Oxyvaleric “ C;H,,.0; ae aes OOH: 


etc., etc. 


1. Carbonic Acid, CH,0,—oxyformic acid—is the lowest member of the 
series. It cannot exist free, and its character varies considerably from those of 


the rest. From its symmetrical structure, COL OF and the fact that no differ- 


ence exists in the OH groups, this compound is a dibasic acid, although very feeble. 
30 


354 ORGANIC CHEMISTRY. 


Therefore it and its numerous derivatives will be treated later, after the other 
dihydric acids. 


2. Glycollic Acid, C,H,O, = CH,(OH).CO,H. 

Glycollic, or oxyacetic acid, is obtained according to the 
methods given as follows: from ethylene glycol, from monochlor- 
or brom-acetic acid, and from amido-acetic acid, CH,(NH,). 
CO.H, by means of nitrous acid. It is produced, also, when nas- 
cent hydrogen (zinc and sulphuric acid) acts upon oxalic acid :— 


CO.OH CH,.0H 

| + #8, = | + H,0; 

CO.OH CO.OH 
by oxidizing ethyl alcohol with nitric acid at ordinary temperatures 
(with glyoxal and glyoxylic acid, p. 330); from glycosin and its 
derivatives, and from glycerol by the action of silver oxide 
(Berichte, 16, 2414). 


The best method of preparing the acid is to boil chloracetic acid with alkalies 
or calcium carbonate. The calcium salt first formed is decomposed with an 
equivalent amount of oxalic acid and the filtrate concentrated (Berichée, 16, 


2954). 


Glycollic acid is a thick syrup, which gradually crystallizes upon 
standing over sulphuric acid. The crystals melt at 80° and deli- 
quesce in the air. It dissolves easily in water, alcohol and ether. 
When distilled it decomposes with formation of epee meidenyde 


(p. 192). 


Its alkali salts are very deliquescent. The calcium salt, (C,H,O,),Ca, with 
3 and 4 H,0, is sparingly soluble in cold water (1 fag in 8 parts H,O at 10°), 
and crystallizes in needles. The s/ver salt, (CoH 30,Ag), + H,0, is also 
rather insoluble. The e/Ay/ ester, CH,(OH). CO,. ot Bs is a liquid, possessing a 
specific gravity equal to 1.03, and boils at 150°. 


Alcohol and acid radicals can replace the hydrogen in alcohol- 
hydroxyl of glycollic acid. 

The acid derivatives are formed :— 

(1) On heating glycollic acid with monobasic acids :— 


ri /OH ee OO 
CH,¢ ¢9, 4 + C2H,0.0H = CH, ¢o47° + HO: 


2 
: Acetoglycollic Acid. 
or by acting upon esters of the acid with acid chlorides :— 


/ OH /Q.C,H,O 


Boece tT CsCl = Cisse eee 


(2) By action of the alkali salts of acids upon esters of monochlor-acetic acid :— 


ec: + HCL. 


CH,CL.CO,.C)H, + €,H,0.0K = Blair + KC. 
gees 
Potassium Benzoate. eee Glycollic 
ter. 





OXY- ACIDS, 355 


We obtain the alcohol derivatives when sodium alcoholates act on monochlor- 
acetic acid :— ee 
0.C, Fi, 


CH,Cl.CO,Na + C,H,.0Na= CHC Co, Na 4+ NaCl, 
Ethyl Glycollic Acid. 
: ‘ /0.CH, 1; re : ; 
Methyl Glycollic Acid, CH3< ¢o H boils at 198°; ethyl glycollic acid, 
CH,(O0.C,H,).CO,H, at 206°. Both are very stable, and boiling alkalies do not 
decompose them. 


The ether-esters, like CBX ac , result when chloracetic 


esters are acted upon by sodium alcoholates. For their boiling 
points see Berichte, 17, 486. 


Thioglycollic Acid, CHC co HW is both an acid and a mercaptan. It is 
2 


obtained from monochloracetic acid and potassium sulphydrate; from thiohy- 
dantoin (see this), and its phenyl derivatives, when they are heated with alkalies 
(Annalen, 207, 124). It is an oil, which is readily soluble in water, alcohol and 
ether. Heat decomposes it. On adding ferric chloride to the acid solution, then 
neutralizing with ammonia, we obtain a purple-red coloration. Thioglycollic acid 
behaves like a dibasic acid, forming primary and secondary salts. This is due to 
the SH group imparting the properties of the mercaptans. The darium salt, 


CH, Go, Ba + 3H,0, dissolves with difficulty in water. 


The acid (its alkali salts), on exposure to the air, oxidizes to— 
Dithiodiglycollic Acid, $,/ pi peed pl It may also be produced by oxi- 
8+Y > °2\ CH,.CO,H’ x Pp y 

dation with ferric chloride, or by the action of iodine upon potassium thioglycollate 
(Berichte, 19, 114). It is crystalline and fuses at 100° C. 

Thiodiglycollic Acid, S“ GH, .COsH results from the action of chloracetic 

Bly » °\ CH,.CO, H? 
acid upon potassium sulphide. It crystallizes in plates and melts at 129°. Potas- 
sium permanganate oxidizes it to sulphodiacetic acid, $05 Ga Con: The lat- 
” 

ter exhibits a deportment analogous to that observed with aceto-acetic acid, in that 
its CH,-group is very reactive (Berichte, 18, 3241 and p. 307). 

Thioglycollic acid, and also thioacetic acid (p. 262), like the mercaptans (p. 306), 

unite with the aldehydes, ketones and ketonic acids to form compounds of the 
S.CH,.CO,H aad Se 

type, R,.C me SCH rs CO, yy: Boiling concentrated hydrochloric acid resolves them 

into their components (Berichte, 21, 478). 

Thiocyanacetic Acid, CH eo Ht Sulphocyanacetic Acid, is formed 
by the action of chloracetic acid upon KCN S. Itisathick oil. Its ethyl ester, 
from chloracetic ester, boils about 220° C. 

On boiling the latter (or thiohydantoin) with concentrated hydrochloric acid, 


rhodanacetic acid, CH % set is formed. This acid should probably be viewed 
2 


: * 
356 ORGANIC CHEMISTRY. 


CH,—S 
as pseudo-dioxythiazole, | ‘Sco ( Berichte, 22, Ref. 19). Large leaflets, 
C 


: O—NH~ 
melting at 128°. It forms a benzylidene compound with benzaldehyde (Beriche, 
22, Ref. 333). SH 


Rhodanic Acid, CH Age SCN? the mixed anhydride of thioglycollic (see 


above) and sulphocyanic acids, is obtained by the action of CNS(NH,) upon chlor- 
acetic acid. It consists of yellow prisms or plates, and melts at 169°*with decom- 
position. Upon digestion with baryta water it splits up into thioglycollic and 
hydro-sulphocyanic acids (Berichte, 19,114; 22, Ref. 334). It,in all probability, 


2—S A 
represents a ¢hioxythiazole, | CS. 
CO—NH” 





Anhydrides of Glycollic Acid. 

Glycollic Anhydride, C,H,O; — CH,(OH).CO.0.CH,.CO,H, the first 
ester anhydride of glycollic acid (p. 354), is produced on heating glycollic acid to 
100°. It is a solid, insoluble in alcohol, water and ether. It melts at 128-130°. 
Boiling water changes it to glycollic acid. 


CH,—O—CO 
Glycolide, C,H,0O, = - - —the second ester anhydride of gly- 
CO—O— CH, 


collic acid (p. 354)—is obtained by strongly igniting glycollic acid (to 250°) or 
tartronic acid, and by heating potassium or silver glycollate (Berich/e, 14, 577). 
It forms a powder almost insoluble in water, and melts at 220°. It returns to 
glycollic acid when boiled with water. When heated with ammonia it yields 


glycolamide, CH Co. NH.’ which boils at 120°. Formerly glycolide was sup- 
posed to be an ester anhydride (p. 351) with the formula, CH, > The 
present double formula is assigned it from its analogy to lactide (p. 359). 

Diglycollic Acid, C,H,O,, the alcohol anhydride of glycollic acid (p. 351), 
is formed on boiling monochloracetic acid with lime, baryta, magnesia, or lead 
oxide (also with glycollic acid), and in the oxidation of diethylene glycol, 
OC See (p- 30 ith nitric acid and platinum sponge. When sepa- 

\.CH,.CH, .OH p. 304), with nitric aci p ponge. Pp 
rated from its rather insoluble calcium salt with sulphuric acid, diglycollic acid 
crystallizes in rhombic prisms, which melt at 148°. Boiling alkalies do not alter 
it. It is only when heated with concentrated hydrochloric acid to 120° that it 
breaks up into glycollic acid. Theacid is dibasic, yielding primary and secondary 
salts. 


_| 3. Lactic Acids, or Oxypropionic Acids, C,H,O,. . 
There are two possible isomerides :— 
CH,.CH(OH).CO,H and CH,(OH).CH,.CO,H 
Oxy nto ionic Acid. Bay pro ionic Acid. 
Ethidene Lactic Acid. Ethylene Lactic Acid. 
(1) Ethidene Lactic Acid, Ordinary Lactic Acid of Fer- 
mentation, CH;.CH(OH).CO,.H, is formed by a peculiar fer- 
mentation of sugar (milk sugar, cane sugar), gum and starch, in the 


Se 


7 ae 


ad 


¥ ‘ 
OXY-ACIDS. 357 


presence of albuminoid substances (chiefly casein). It is, therefore, 
contained in many substances which have soured, ¢, g., in sour milk, 
in sour-kraut, pickles, also in the gastric juice. The lactic fermen- 
tation occurs by the action of a particular, organized ferment, at 
temperatures from 35-45°. Excess of free acid arrests it, but it is 
renewed, if the acid be neutralized by alkalies. 

The acid is artificially prepared by the methods already described, 
p. 347 :—from a-chlor- or brom-propionic acid by boiling with alka- 
lies; from a-propylene glycol by oxidation with nitric acid ; from 
alanine, CH;.CH(NH,).CO,H, by means of nitrous acid, and by 
the action of nascent hydrogen upon racemic acid. Other methods 
consist in heating grape sugar and cane sugar with water and 2-3 parts 
barium hydrate, to 160°, and a-dichloracetone, CH;.CO.CHCI.,, 
with water to 200°. 


Preparation.—Lactic acid is usually obtained by the fermentation of cane sugar. 
2 Kilograms of cane sugar and 15 grams of tartaric acid are dissolved in 17 litres 
of water, and the solution allowed to stand several days. Then add 100 grams 
decaying cheese, previously macerated in 4 litres of sour milk, and 1200 grams _ 
zinc-white, and let the mixture ferment at 40°-45° for 8-10 days (longer fermenta- 
tion changes the lactic into butyric acid). The entire mass is next brought to 
boiling, filtered, and the filtrate strongly concentrated. The zinc lactate which 
separates out is decomposed by H,S, the zinc sulphide removed by filtration, and 
the filtrate containing the lactic acid evaporated on the water bath. To separate 
the lactic acid produced in this manner from the mannitol (formed simultaneously) 
dissolved by it, shake the residue with ether, which will not dissolve the mannitol. © 


Fermentation lactic acid is a thick syrup, with a specific gravity 
1,215, but it cannot be obtained crystallized. It is miscible with 
water, alcohol and ether, and absorbs moisture when exposed to 
the air. Placed in a dessicator over sulphuric acid it partially de- 
composes into water and its anhydride. When distilled it yields 
lactide, aldehyde, carbon monoxide and water. 

It is optically inactive. Penicillium glaucum converts its ammo- 
nium salt into active sarcolactic acid (Lewkowitsch, Berichte, 16, 
2720). 

Heated to 130° with dilute sulphuric acid it decomposes into 
aldehyde and formic acid (p. 350); when oxidized with chromic 
acid, acetic acid and carbon dioxide are formed. Heated with 
hydrochloric acid, it changes to a-brompropionic acid: 


CH,.CH(OH).CO,H + HBr = CH,.CHBr.CO,H + H,0. 
Hydriodic acid at once reduces it to propionic acid. 


The sodium salt, C,H,O,Na, is an amorphous mass. When heated with metal- 
lic sodium, the alcoholic hydrogen is replaced, and we get the disodium compound : 


O.N 
C,H,O,Na, = CH,.CHC Co Na 


358 ORGANIC CHEMISTRY. 


The calcium salt, (C,H;O;),Ca + 5H,O, crystallizes in hard warts, consisting 
of concentrically grouped needles. It is soluble in ten parts cold water, and is 
very readily dissolved by hot water and alcohol. 

The zine salt, (C,H,O,),Zn + 3H,0, crystallizes in shining needles, which 
dissolve in 58 parts cold and 6 parts hot water, The zon salt, (C,H;O,),Fe 
+ 3H,O, is very sparingly soluble in water, and yields crusts consisting of deli- 
cate needles. It is also obtained by boiling whey with iron filings. The salts of 
lactic acid are called /actates. 


Ethyl Lactic Ester, CH,.CH(OH).CO,.C,H,, is formed when lactic acid and 
anhydrous alcohol are heated to 170°. It is a neutral liquid, which boils at 156°. 
It is soluble in water, and rapidly decomposes into lactic acid and alcohol. When 
potassium and sodium act upon the ester, they replace alcoholic hydrogen, and if 
the product be treated with ethyl iodide we obtain :— 

Ethyl Etholactic Ester, CH,.CH Co 464 . This is formed also on heating 
a-chlorpropionic ester (or lactyl chloride) with sodium ethylate :— 


/0.C,H; 
\.CO,.C,H, 


It boils at 156°, and is insoluble in water. When the ester is boiled with caustic 
soda ethyl-lactic acid is produced. 


Lthyl Lactic Acid, CH,CHC Go, as, A strongly acid sytup, yielding crys- 
2 


CH,.CHCLCO,.C,H, + C,H,.ONa = CH,.CH + NaCl. 


talline salts, which revert to the diethyl ester when acted upon with ethyl iodide. 
Hydriodic acid breaks it up into lactic acid and ethyl iodide :— 


/0.C,H me /OH 
cota’ + HI= CH, CHC 66, 4 


Aceto-lactic Acid, CH. CHC o. a ae occurs together with sarcolactic acid in 
2 


CH,.CH + C,H;,I. 


beef extract. It results from the interaction of lactic acid, as well as of sarcolactic 
acid, with acetic acid. Its amorphous zinc. salt distinguishes it from the other 
lactic acids (Berichte, 22, 2711). 

On adding lactic acid to a mixture of nitric and sulphuric acids (p. 349) it dis- 


solves, forming mitrolactic acid, CH, CHC C5. mo A yellow liquid, slightly 
soluble in water. It decomposes readily. Its specific gravity equals 1.35. 
Lactyl Chloride, CH. CHC 66 cp a-chlorpropionyl chloride, is obtained by 
the distillation of dry lime lactate (1 part) with PCl, (2 parts). It is imperfectly 
separated from the PC],O which is formed at the same time. With water it yields 


a-chlorpropionic acid ; with alcohol a-chlorpropionic ester. Lactic acid is regen- 
erated when the chloride is heated with alkalies. 


ANHYDRIDES OF LACTIC ACID. 


Lactic Anhydride, C,H,,0,, is the first ester anhydride of lactic acid (p. 351). 
It is formed when lactic acid is heated to 130°, or when it stands over sulphuric 
acid; further, by the action of potassium lactate upon a-brompropionic acid :— 


CH,.CH.OH CO,H CH,.CH.OHCO,H 


see 80 | | + KBr. 
CO.OK CHBr.CH, CO—O—CH.CH, 


———————— 


ANHYDRIDES OF LACTIC ACID. 359 


It is an amorphous powder, almost insoluble in water. The alkalies imme- 
diately convert it into lactic acid. 
; CH,.CH—O--CO 
Lactide, C,H,O, = : : 
CO—O—CH.CH, 
obtained by distilling lactic acid, or by passing dry air through the acid heated to 
150°. It crystallizes from alcohol in rhombic plates, melting at 124.5° and boiling 
at 255°. It dissolves slowly in water with gradual formation of lactic acid. The 
vapor density agrees with the formula, C,H,O, (Berichte, 7,755). It was for- 


, the second ester anhydride, is 


merly believed that it was “an inner anhydride,”’ i in Le: 
CH,—CH—O—CH.CH, 
Dilactic Acid, C,H,,O; = : The diethyl ester is 
CO,B > COUR. 


produced on heating a-brompropionic ester with sodium lactic ester (p. 351), in 
alcoholic solution. It boils at 235°, and when heated above 100° with water, 
breaks up into lactic acid and alcohol. 


Substituted Lactic Acids :— 

B-Chlorlactic Acid, CH,Cl.CH(OH).CO,H = C,H,ClO,, is formed by the 
oxidation of epichlorhydrin and a-chlorhydrin, CH,Cl.CH(OH).CH,.OH, with 
concentrated HNO,; by the addition of hypochlorous acid to acrylic acid (together 
with a-chlorhydracrylic acid (p. 362) :-— 

CH,:CH.CO,H yields CH,Cl.CH(OH).CO,H and’ CH,(OH).CHCI.CO,H ; 

Acrylic Acid. B-Chlorlactic Acid. a-Chlorhydracrylic Acid. 


and by the addition of HCl to epihydrinic acid (glycidic acid) :— 


gs a 4. HCl = CH,Cl.CH(OH).CO,H. 

Brom- and iod- acetic acids are obtained in the same manner (Serichie, 14, 
937). The first melts at 89°-g0°, the second at 100°-101°. -Chlorlactic acid 
is also formed from monochloraldehyde by the action of hydrocyanic and hydro- 
chloric acids (p. 347). 

8-Chlorlactic acid crystallizes from water in large transparent plates or prisms, 
and melts at 78°-79°. Silver oxide converts it into glyceric acid; when reduced 
with hydriodic acid it becomes -iodpropionic acid. Heated with alcoholic 
potash it is again changed to epihydrinic acid (see above), just as ethylene oxide 
is obtained from glycolchlorhydrin (p. 300). 

Dichlorlactic Acid, CHCI,.CH(OH).CO,H, is obtained from dichloraldehyde 
through the cyanide (p. 347). It forms deliquescent plates, melting at 77°. It 
reduces ammoniacal silver solutions. 


Trichlorlactic Acid, CCl,;.CH(OH).CO,H, is made by heat- 


ing chloralcyanhydrin, OGL. CH ee (p. 196), with concentrated 


hydrochloric acid (Berichte, 17, 1997). It is a crystalline mass, 
melting at 105°-110°, and soluble in water, alcohol and ether. 
Alkalies easily change it to chloral, chloroform and formic acid.” 
Zinc and hydrochloric acid reduce it to dichlor- and mono-chlor- 


360 ORGANIC CHEMISTRY. 


acrylic acids (p. 237). Its ethyl ester melts at 66°-67°, and boils 
at 235°. The best method of preparing. it consists in heating 
chloralcyanhydrin with alcohol and sulphuric acid (or HCl, Be- 
richte, 18, 754). 


Because trichlorlactic acid yields chloral without difficulty, it is converted quite 
readily, by different reactions, into derivatives of chloral and glyoxal. It forms 
glyoximes with hydroxylamine, and glycosin with ammonia (p. 325, and Berichte, 
18, 754). 

When trichlorlactic acid is heated to 1 50° with excess of chloral, we obtain 
trichlorethidene-trichlorlactic ester :— 


/OH a fOr 
CCl;.CH< ¢0.0H + CHO.CCI, = OE 0 Oe + H,O. 
_ The same body, C,H,CIl,0,, called Chloralide, was at first prepared by heat- 
ing chloral (1 part) with fuming sulphuric acid (3 parts) to 105°. It crystallizes 
from alcohol and ether in large prisms, is insoluble in water, melts at 114°—115° 
and boils at 272°-273°. When heated to 140° with alcohol, it breaks up into 
trichlorlactic ester and chloral alcoholate. - Chloral also unites with lactic and 
other oxy-acids, like glycollic, malic, salicylic, etc., forming the so-called chlora/- 
ides (Annalen, 193, 1). 

Tribromlactic Acid, CBr,.CH(OH).CO,H, from bromal cyanhydrin, melts 
at 141°-143° and unites with chloral and bromal to corresponding chloralides and 
bromalides. 

a Thio-lactic Acid, CH,.CH(SH).CO,H, Thio-dilactic Acid, 

/ CH(CH,).CO,H aed sna ge, / CH(CH,).CO,H 

SC CHICH CoH and Dithiodilactic Acid, S.C CHICH'}.COoH are ob- 
tained from a-chlorpropionic acid by methods analogous to those employed with 
thioglycollic acids (p. 318). They can also be prepared from racemic acid by the 
action of hydrogen sulphide. Racemic acid yields alkyl-thio-oxypropionic acids, 
with the mercaptans :— 


CH,CO Ap ie | : 
| +C,H,SH = CH;,. ie "6°"5 (Berichte, 18, 262). 
i a CO,H. 


Cystein is probably an amtdo-thiolactic acid, CH,.C (Ga ).co,H. It is 
2 


obtained from cystin by reduction with tin and hydrochloric acid. A crystalline 
powder, very soluble in water, and yielding an indigo-blue color with ferric chlo- 
ride. In the air it rapidly oxidizes to cystin ( Bertch/e, 18, 258, and 19, 125). 
Cystin, C,H,,N,0,5,, probably dithio-diamido-dilactic acid, 
$< CCH 0 ONHY?.COLE? occurs in some calculi and urinary sediments. It 
forms colorless leaflets. It is insoluble in water and alcohol, but dissolves in acids 
and alkalies. 
The Mercapturic Acids (Aerichte, 18, 258) are probably acetyl compounds 
of alkyl-thio-lactic acids. 





4 


/ Sarco-lactic or Paralactic Acid isa peculiar modification of 
fermentation lactic acid. It is present in different animal organs, 
especially in the juice of the flesh. Liebig’s Beef Extract furnishes 


ETHYLENE LACTIC ACID. 361 


it. In all its transpositions it behaves like ordinary lactic acid, 
hence we must accept the same chemical structure for it. The 
existence of the two modifications is explained by the asymmetry of 
a carbon atom in the acid (p. 63). Sarco-lactic acid is distin- 
guished from the ordinary variety by turning the plane of polariza- 
tion to the right (the ordinary acid is inactive) and by differences 
in its salts. When heated. to 130° it yields lactic anhydride (p. 
358), which water changes back to ordinary lactic acid. 


Its calcium salt, (C,H;O,),Ca, contains four molecules of water, and is more 
sparingly soluble in water than that of ordinary lactic acid. The zéwc salt con- 
tains two molecules of water, yields shining, thick prisms and is more soluble (1 
part in 17 parts H,O at 15°) in water than the zinc salt of ordinary lactic acid. 





2. Ethylene Lactic Acid, or Hydracrylic Acid, CH,(OH). 
CH,.CO,H, f-oxypropionic acid, is obtained from f-iodpropionic 
acid on heating it with moist silver oxide, or on boiling» with 
Water o-—— 


CH,I.CH,.CO,H + AgOH = CH,(OH),CH,.CO;H + Agl; 
B- bedoesighinic Acid; B- Daverapianie ‘Reid. 


by the careful oxidation of £-propylene glycol (p. 308), or by con- 
version of the same into chlorhydrin and #-chlorpropionic acid :— 


CH,.OH CH,Cl CH,Cl CH,.0H 
| | 
CH; CH, CH, >and “CH, ¢ 
| | | | 
CH,.OH CH,.0OH = -CO.OH CO.OH 
by the action of CNK and HCl upon ethylene chlorhydrin :— 
CH,.0H CH,.0H CH,.0H 
| yields | and | . 
CH,Cl CH,.CN CH,.CO,H 


and from ethylene oxide through the agency of CNH and HCl. 
The formation of the acid from acrylic acid by heating with aqueous 
sodium hydroxide to 100° is also very interesting. 

The free acid yields a non-crystallizable, thick syrup. When 
heated alone, or when boiled with sulphuric acid (diluted with 1 
part H,O), it loses water and forms acrylic acid nents the name 
hydracrylic acid, p. 350):— 


CH,(OH).CH,.CO,.H = CH,:CH.CO,H + H,0. 
Hydriodic acid again changes it to f-iodpropionic acid. It yields 
oxalic acid and carbon dioxide when oxidized with chromic acid or 
nitric acid. 


362 ORGANIC CHEMISTRY. 


The sodium salt, C,H,O,Na, is indistinctly crystalline, and melts without 
change at 142-143°. It loses water at 150°, and forms sodium acrylate. The 
calcium salt, (C,H,O,),Ca + 2H,O, forms large rhombic prisms, loses its water 
of crystallization at 100°, and fuses at 140-145° without decomposition. Heated 
to 190° it parts with water and becomes calcium acrylate. The zinc salt, 
(C,H,O,),Zn + 4H,0, crystallizes from a moderately concentrated solution, in 
large, shining prisms, and dissolves in an equal part of water at 15°. If the solu- 
tion is very concentrated it will only crystallize with difficulty. The zinc salt is 
soluble in alcohol, whereas the latter precipitates zinc a-lactate and paralactate. 

a-Chlorhydracrylic Acid, CH,(OH).CHCI.CO,H, from acrylic acid, is a 
liquid, and is converted into hydracrylic acid by nascent hydrogen; it yields gly- 
cidic acid with the alkalies, 


4. Oxybutyric Acids, C,H,O; = C,;H,(OH).CO,H. 

Four of the five possible oxybutyric acids are known :— 

(1) a-Oxybutyric Acid, CH;.CH,.CH(OH).CO,H, is obtained 
by boiling a-brombutyric acid with moist silver oxide or caustic 
potash, and from propionic aldehyde with hydrocyanic and hydro- 
chloric acids. It is crystalline and deliquescent in theair. It melts 
at 43-44°. ‘The zinc salt, (C,H,O;).Zn + 2H,O, crystallizes from 
water in white leaflets, sparingly soluble in cold water. When 
oxidized with chromic acid, the acid decomposes into propionic 


acid and CO,. 


(2) B-Oxybutyric Acid, CH,.CH(OH).CH,.CO,H, is formed by the action 
of sodium amalgam upon aceto-acetic ester (p. 338), by the oxidation of aldol (p. 
321) with silver oxide, and from a-propylene chlorhydrin, CH,.CH(OH).CH,Cl, 
(p. 308) by the action of CNK and subsequent saponification of the cyanide. It is 
a thick, non-crystallizable syrup, which volatilizes with steam. The Ca- and Zn- 
saliés are amorphous and readily soluble in water. When heated the acid decom- 
poses (like all S-oxy-acids, p. 350) into water and crotonic acid, CH,.CH:CH. 
CO,H. An optically active 6-oxybutyric acid has been isolated from diabetic urine 
(Berichte, 18, Ref. 451). 


(3) y-Oxybutyric Acid, CH,(OH).CH,.CH,.CO,H, is not 
very stable in a free condition, because it readily breaks up, like all 
y-oxy-acids (p. 351) into water and its inner anhydride butyrolac- 
tone, C,H,O,. The acid (its salts) is obtained by letting sodium © 
amalgam act on succinyl chloride, C,H,(CO.Cl),., and from the 
bromhydrin of f£-propylene glycol (p. 308) by means of CNK and 
the after-saponification of the cyanide, and from butyrolactone car- 
boxylic acid (see this), by the splitting-off of CO, (Berichte, 16, 
- 2592); by the distillation of y-chlorbutyric acid (p. 352); and from 
the reaction product of ethylene chlorhydrin and aceto-acetic ester 
by decomposing it with baryta (Berichie, 18, Ref. 26). Butyrolac- 
tone, obtained from its salts, is a neutral, thick liquid, boiling at 
203° ; its specific gravity equals 1.130 at 20°. It is miscible with 
water, and is precipitated by soda. 


OXYVALERIC ACIDS. 363 


(4) «Oxyisobutyric Acid, Gy? >C(OH).CO,H, was first ob- 
3 


tained by the actionof CNH and HClon acetone (p. 203), hence 
called acefonic acid :— 


CH \./OH 


CH, j 
ap 4, yields CH, 7C\.CO,H. 


CH, / 


It is further obtained from acetone chloroform (p. 205); from ox- 
alic ester by the action of CH,I and Zn (see p. 347), hence termed 
dimethyloxalic acid, or better, dimethyl-oxyacetic acid; from a- 
bromisobutyric acid on boiling with baryta water :— 


(CH,),CBr.CO,H + H,O = (CH,),C(OH).CO,H + HBr: 


from f-isoamylene glycol by oxidation with nitric acid (p. 310) 
(hence called butyl lactic acid), and from isobutyric acid, C,H,O., 
by oxidizing with potassium permanganate (p. 227). Oxy-isobutyric 
acid crystallizes in prisms and is very soluble in water and ether. 
It sublimes at 50°, in long needles, melts at 79° and distils at 212°. 
Methacrylic acid is formed when PCI, acts on its esters (p. 240). 
When oxidized with chromic acid, it breaks up into acetone and 
carbon dioxide. 


The barium salt, (C,H,O,),Ba, consists of easily soluble shining needles. 
The zinc salt, (C,H,O,),Zn + 2H,0, crystallizes in microscopic, six-sided 
plates, sparingly soluble in water. 

(5) B-Oxyisobutyric Acid, CH,.OH.CH(CH,).CO,H, has not been ob- 


tained. 


5. Oxyvaleric Acids, C;H,,O, = C,H,(OH).CO,H. 


(1) a-Oxyvaleric Acid, CH,.CH,.CH,.CH(OH).CO,H, has been obtained 
from normal a-bromvaleric acid and from -normal butyric aldehyde. It forms 
table-like crystals, melting at 28—29° (Berichie, 18, Ref. 79). Fo oe 

(2) y-Oxyvaleric Acid, CH,.CH(OH).CH,.CH,.CO,H, like all the y-oxy- 
acids, decomposes when separated from its salts into water and its inner anhydride, 
valerolactone, C;H,O, (p. 352). The Jatter is prepared directly from y-brom- 
valeric acid (from allyl acetic acid, p. 241), on heating it with water-above 100°. It 
may be obtained more readily by acting on {-aceto-propionic acid (levulinic acid, 
P- 343), with sodium amalgam and water. Sulphuric acid is added to the solu- 
tion and the latter shaken with ether. Valerolactone is a colorless liquid which 
does not solidify at —18°, and boils at 206-207°. It is miscible with water, form- 
ing a neutral solution from which it is reprecipitated by alkaline carbonates. 
When boiled with alkalies, baryta or lime it forms y-oxyvalerates. It yields suc- 
cinic acid when oxidized with nitric acid (Anma/en, 208, 104). 

(3) a-Oxyisovaleric Acid, (CH,),.CH.CH(OH).CO,H, is obtained from a- 
bromisovaleric acid and from isobutyraldehyde, (CH, ),CH.CHO, by means of CNH 
and HCl. It crystallizes in large rhombic plates, which melt at 86° and volatilize 


: 
: 
’ 


364 ORGANIC CHEMISTRY. 


at 100°. Its ethyl ester, boiling at 175°, is obtained from oxalic ester by zinc and 
isopropyl iodide. Heated with sulphuric acid it decomposes into isobutyraldehyde 
and formic acid, and when oxidized with chromic acid it yields isobutyric acid 
and CO,. Heated to 200° it affords an anhydride, (C;H,O,), (?) (p. 358), resem- 
bling lactide. It melts at 136°. 

(4) B-Oxyisovaleric Acid, (CH,),C(OH).CH,.CO,H, is formed on oxid- 
izing dimethyl-allylcarbinol (p. 121) with chromic acid, or isopropyl acetic acid, 
(CH,),.CH.CH,.CO,H, with an alkaline KMnO, solution (p. 346). It is a 
liquid which is not volatile with steam. Chromic acid oxidizes it to acetone, acetic 
acid and carbon dioxide. CH, \ 

(5) Methyl-ethyl Oxyacetic Acid, CH /C(OH).CO2H, a-methyl-a-oxy- 


butyric acid, is obtained from methyl-ethyl acetic acid (p. 229), by oxidation with 
a solution of potassium permagganate; from oxalic ester by means of CH,I, 
C,H,I and zinc; and from methyl-ethyl ketone by means of CNH and HCl. It 
is crystalline, melts at 68°, and sublimes at 100°. Hydriodic acid reduces it to 
methyl-ethyl acetic acid, while CrO, oxidizes it to methyl-ethyl ketone and CO,. 
Its ethyl ester boils at.165°. CH3\ 

(6) a-Methyl-3-oxybutyric Acid, Uren) CCH, is obtairied 


from methyl aceto acetic ester, CH,.CO.CH(CH,).CO,.C,H,; (p. 340). Itisa 
liquid, which decomposes, when distilled or if heated with HI, into water and 
methyl crotonic acid. 

6. Oxycaproic Acids, C,H,,O, = C,;H,,(OH).CO,H. 

(1) a-Oxycaproic Acid, CH,.(CH,),.CH(OH).CO,H, is probably the so- 
called leucic acid, obtained from leucine by the action of nitrous acid. 

It is crystalline, melts at 73°, and sublimes near 100°. The oxycaproic acid 
obtained from bromcaproic acid appears to be different. This compound melts at 
60-62° (Berichte, 14, 1401). 

(2). y-Oxycaproic Acid, CH,.CH,.CH(OH).CH,.CH,.CO,H, like a y-oxy- 
acid, decomposes when free into water and its lactone, Caprolactone, C,H,,O,. 
The latter is obtained from bromcaproic acid (from hydrosorbic acid and HBr, p. 
245), on heating the latter with water (Auna/en, 208, 66), and from arabinose- 
carbonic acid, C,H,,0,, by reduction with hydriodic acid (Berichte, 20, 339). 
It is a liquid, boiling at 200°, and dissolves in 5-6 volumes H,O at 0°. On heat- 
ing, caprolactone again separates. Nitric acid oxidizes it to succinic acid. 

(3) 6-Oxycaproic Acid, CH,.CH(OH).(CH,),.CO,H, is formed from }- 
aceto-butyric acid (p. 344). It furnishes a d-lactone (p. 353), which melts at 18°, 
and boils at 230°. It forms a neutral solution with water, but this becomes acid 
after some time. 

(4) y-Oxyisocaproic Acid, (CH,),.C(OH).CH,.CH,.CO,H. When free, 
this breaks up into. water and the corresponding lactone, Isocaprolactone, 
C,H,,O,. The latter appears in oxidizing isocaproic acid with KMnO, or 
HNO,; by the distillation of terebic acid (see this), and in the transposition of 
pyroterebic acid (p. 241), when heated alone or with hydrobromic acid (Annazez, 
208, 55):— : 





(CH,),C.CH,.CH, 
(CH,),C:CH.CH,.CO.OH yields l 
3)2 2 a 6 CO 
Pyroterebic Acid. : isocaprolactone. 


Isocaprolactone melts near 7°, boils at 206-—207°, and is soluble in double its 
volume of water at 0°. When the solution is heated, it becomes turbid and the 
lactone separates. Dilute nitric acid oxidizes a CH, group in caprolactone (also 
in valerolactone) to carboxyl (Berichte, 15, 2324). 


AMIDES OF THE DIHYDRIC ACIDS. 365 


(5) y-Oxy-a-methylvaleric Acid, CH,.CH(OH).CH,.CHY 66, 4, and 
2 > 
its lactone, a-Methylvalerolactone, or symmetrical caprolactone, 
CH ,.CH°CH,.CH.CH, 
, are obtained from (-aceto-isobutyric acid (p. 344), by 
O — CO 
the action of nascent hydrogen, and by reducing saccharin, C,H,,O,, with hy- 
driodic acid (Berichte, 16, 1821). The lactone boils at 206°, and dissolves in 20 
volumes of water. Further heating with HI, changes it to methyl-propyl acetic 
acid (p. 230). ' 

(6) y-Oxy-B-methylvaleric Acid, CH,.CH(OH).CH(CH,).CH,.CO,H, 
and its lactone, 8-methyl valerolactone, are obtained from (-aceto-butyric acid (p. 
344). The lactone boils at 210°. 

(7) Oxyheptylic Acids, C,H,,0,. 

The heptolactone, C,H,,O,, corresponding to y-oxyheptylic acid, is formed 
on reducing teracrylic acid, C,H,,O, (p. 241), with hydrobromic acid, just as 
iso-caprolactone is obtained from pyroterebic acid (see above). Heptolactone 
melts at 11°, and boils at 220°. It dissolves in 12 volumes of water at 0°. 

Many other higher oxy-fatty acids have been obtained from oxalic ester by 
means of propyl iodide, amyl iodide, etc., and zinc, and also from the higher 
aceto-acetic esters, by the use of sodium amalgam. The unsaturated acids, a/ly/ 
oxyacetic acid, C,H,.CH(OH).CO,H, and diallyl oxyacetic acid, (C,;H,),C(OH). © 
CO,H, are produced in a similar manner. 





UNSATURATED OXY-ACIDS, CnH,n—,03. 


But few of this class are known. 

(1) Oxyacrylic Acid, C,H,O, = CH(OH):CH.CO,H, appears to form 
upon boiling {-chloracrylic ester with baryta. It is very unstable, and passes 
rapidly into malonic acid. 

(2) Oxycrotonic Acid, C,H,O,, is not known in a free condition. The 
alkylized 8-oxycrotonic acids :— 


CH,.C(O.CH,):CH.CO,H and CH,.C(0.C,H,):CH.CO,H, 
Methyloxycrotonic Acid. Ethyloxycrotonic Acid. 


have been prepared from /-chlorcrotonic and chlorisocrotonic acids by the action 
of sodium methylate and ethylate. - Both are crystalline, insoluble in water and 
very readily sublimed. The first melts at 128°, the second at 137°. 

(3) Oxyangelic Acid, C;H,O,. The lactones of the y- and d-oxy acids 
have been obtained by the distillation of lzevulinic acid (p. 343). 


AMIDES OF THE DIHYDRIC ACIDS. 


In the dihydric acids both the alcoholic and acid hydroxyl group can be re- 
placed by the amid-group, NH,. In the first instance amic or amido-acids result, 
while in the second case we get the isomeric acid amides (p. 255). The zmzdes 
result by substituting the divalent acid radicals for two of the hydrogen atoms of 
ammonia (p. 353) :— 


OH NH 


CH,7 


CH,Z 2 
2\. CO.NH, 2\ COOH 
Glycolamide. NH Glycolamidic Acid. 
F< 
CH,.CH co = 


Lactimide, 


366 ORGANIC CHEMISTRY. 


1. Amides. 


Glycolamide, C,H,NO, = CH Be NH.” is directly produced on heating 
. 2 


glycolide (p. 356) with dry ammonia, or from acid ammonium tartronate when 
heated to 150°. It crystallizes in needles, melting at 120°, possesses a sweet taste, 
and dissolves easily in water, but with difficulty in alcohol. When boiled with 
alkalies it breaks down into glycollic acid and ammonia. 


Lactamide, C,H,NO, = CH CHA Cs ai , is obtained by the union of lac. 
7 2 


tide with ammonia, and upon heating ethyl lactic ester with ammonia. It forms 
crystals, readily soluble in water and alcohol, and melts at 74°. Boiling alkalies 
break it up into lactic acid and ammonia. 

Lactimide, C,H;NO = C,H,O:NH, is produced by. heating alanine, 


CH, CHC G6, ip in a current of HCl to 180-200°. It consists of colorless 
2 
leaflets or needles, which melt at 275°, and dissolve readily in water and alcohol. 


2. Amic or Amido-Acids. 
Here the alcoholic hydroxyl is replaced by the group NH, :— 


CH,.0H > CH,.NH, 
| and | ‘ 
CO.OH CO.OH 

Glycollic Acid Glycolamidic Acid. 


It is simpler to view them as amido-derivatives of the mono- 
basic fatty acids, produced by the replacement of one hydrogen 
atom in the latter by the amido-group :— 


CH, CH,.NH, 
| | 
CO.OH CO.OH 
Acetic Acid. “ Amidoacetic Acid. 


Hence they are usually called amido-fatty acids. The firm union 
of the amido-group in them -is a characteristic difference between 
these compounds and their isomeric acid amides. Boiling alkalies 
do not eliminate it (similar tothe amines). Several of these amido- 
acids occur already formed in animal organisms. Great physio- 
logical importance attaches to them here. They have received the 
name a/anines or glycocolls from their most important representa- 
~ tives. 

The general methods in use for preparing the amido-acids 
are :— 

(1) The transposition of the monohalogen fatty acids when heated 
with ammonia (similar to the formation of the amines from the 
alkylogens, p. 157) :— 


CH,Cl.CO,H + 2NH, = CH,(NH,).CO,H + NH,Cl. 


Monochlor-acetic Acid. Amido-acetic Acid. 


AMIDES OF THE DIHYDRIC ACIDS. 367 


(2) The reduction of nitro- and isonitroso-acids (p. 214) with 
nascent hydrogen (Zn and HCl) :— 

CH,(NO,).CH,.CO,H + 3H, = CH,(NH,).CH,.GO,H + 2H,0. 
B-Nitropropionic Acid. B-Amido-propionic Acid, 

(3) Transposition of the cyan-fatty acids (p. 262) with nascent 
H(Zn and HCl, or by heating with HI), in the same manner that 
the amines are produced from the alkyl cyanides (p, 159) :— 

CN.CO.OH ++ 2H, = CH,(NH,).CO,H. 


Cyanformic Acid. Amido-acetic Acid. 


Cyanformic acid and glycocoll are formed from dicyanogen by 
the same method. 

(4) A synthetic method consists in heating the aldehyde-ammo- 
nias with hydrocyanic acid and hydrochloric acid (p. 190) :— ~ 


/NH 
\ OH 


The amido acids are then obtained on boiling the products with 
hydrochloric acid. 


cn..cad Sis conn = oh catty no. 


\CN 


A more advantageous method consists in converting the cyanides of the aldehydes 
(p. 190) into amid-cyanides by means of alcoholic ammonia (in equivalent quan- 
tity) :— 

/ OH 
\CN 


/ CN 


CH,.CH NH, 


4+ NH, = CH,.CH + H,0, 


and saponifying these with hydrochloric acid (Berichte, 14, 1965). In this man- 
ner the ketones can also be changed through the cyanides (p. 255) to amido- 
acids :— a : 


NH, 


(CH,),CO forms (CHs),C7 Co fr 


The aldehydes, too, can be converted into amido-acids by means of ammonium 
cyanide (Berichte, 14, 2686). 

(5) The conversion of the unsaturated acids upon heating them to 100° with 
ammonia. This seems to be a very common method. ‘Thus, crotonic acid, by this 
treatment, becomes 3-amido-butyric acid (p. 372). Aspartic acid results in a simi- 
lar manner from fumaric and maleic acids (Berichze, 21, Refs. 86 and 523). 


As the amido-acids contain both a carboxyl and an amido-group, 
they are acids and bases (amines). They yield salt-like derivatives 
with metallic oxides and with acids, and are capable also of directly 
combining with certain salts. Since, however, the carboxyl and 
amido-groups mutually neutralize each other, the amido-acids show 
neutral reaction, and it is very probable that both groups combine 

to produce an ammonium salt :— 


Vv 
ONE, 20H CHC SEs SO. 


is pam © 58 Sa ,co*/ 


368 ORGANIC CHEMISTRY. 


The existence and method of producing trimethyl glycocoll or 
betaine would indicate this (p. 316). A separation of the two 
groups would again occur in the formation of the salts. 


The hydrogen of the CO.OH group can be replaced by alcohol radicals with 
formation of es¢evs, which are, however, unstable. On the other hand, the hydro- 
gen of the amido-group can be replaced by both acid and alcohol radicals. The 
acid derivatives appear when acid chlorides act upon the amido-acids or their 
esters :— 

cH. 7 NH 


: yu /NH.C,H,O 
2\ CO,H 


2\ CO,H + HCl; 
Acetyl Amido-acetic Acid. 


+ C,H,0.Cl=C 


whereas the alcohol derivatives are obtained by the action of the amines on sub- 
stituted fatty acids :-— 


CH,Cl.CO,H + NH(CH,), = CHA Cyan” 4+ HCl. 
2 


Dimethyl Glycocoll. 

The amido-acids arescrystalline bodies with usually a sweet taste, 
and are readily soluble in water. As a general thing, they are 
insoluble in alcohol and ether. Consult Berichte, 18, 388, upon 
active and inactive amido acids. ‘They are not affected by boiling 
alkalies, but when fused they decompose into salts of the fatty acids 
and into amines or ammonia. By dry distillation (with baryta 
especially) they yield amines and carbon dioxide :— 


Ns 
CH,.CHC 60 44 CH ica NH, COL 
Ethylamine. 
Nitrous acid converts them into oxy-acids :— 
7 /NH CO egake CVEL 
CH,< ¢o,44 + NO.H = CH, Co, + Na + HO. 
Glycollic Acid. 


When potassium nitrite is allowed to act on the hydrochlorides 
of the esters of the amido-acids, esters of the diazo-fatty acids (p. 
373) are produced. Their formation serves as a test for even 
minute quantities of the amido-acids ( Berichte, 17, 959). Ferric 
chloride yields a red color with all the amido-acids. Acids dis- 
charge the same. 


By continuing the introduction of methyl into the amido-acids it is possible to 
entirely split off the amido-group. Unsaturated acids result. Thus, a-amidopro- 
pionic acid yields acrylic acid, and a-amido-butyric acid yields crotonic acid (er- 
ichte, 21, Ref. 86). ~ 

‘Amido-anhydrides are produced by the elimination of water from the amido- 
acids. They correspond to the ester anhydrides (p. 351). When this change 
occurs with glycocoll and glycollic acid (p. 351) two molecules unite (Berichie, 21, 
Ref, 254, and 22, 793) :— 


/NH—CO\ 


\e6—nN Cs: 


aGH Os ts yield CH 
Givcecols 


7 


AMIDES OF THE DIHYDRIC ACIDS. 369 


The y- and d-amido-acids are capable of forming amido-anhydrides by inner con- 
densation. In this respect they are analogous to y- and d-oxy-acids. This new 
class of compounds has been designated /actams (compare the lactams of the 
aromatic series). They contain closed chains of five and six members. Thus, 
y-amido-butyric acid yields pyrrolidon (belonging to the pyrrol series) (Berichée, 
22, 3338; 23, 8838) :— 


CH,.NH CH,.NH 
Ce Pern ee ee 


\cH,.CO,H \CH,.CO 


d-Amido-valeric acid, CH,(NH,).CH,.CH,.CH,.CO,H, is similarly converted 
into oxy-piperidine, C,H, NO (or piperidon). 


Taurine, described p. 319, belongs to the amido-acids. 


» 





Glycocoll, C,H;NO, 
Alanine, C,H,NO, 
Propalanine, C,H,NO, 
Butalanine, C,H,,NO, 
Leucine, C,H,,NO.. 


1. Glycocoll, Amido-acetic Acid, C,H;NO, = CH,(NH,).CO, - 


H, is produced in the decomposition of various animal substances, 
like hippuric acid, glycocholic acid or glue (hence the name 
glycocoll: glucus, sweet; kolla, glue), when they are boiled with 
alkalies or acids. It is obtained synthetically: by heating mono- 
chloracetic acid with ammonia ; by conducting cyanogen gas into 
boiling hydriodic acid :— : 


CN CH,.NH, 
| + 2H,0 + 2H, = { + NH,; 
CN CO.OH 


furthermore, by the action of zinc and hydrochloric acid upon 
cyancarbonic ester (p. 377) in alcoholic solution :— 


CN CH,.NH, 
4+ 2H, +H,O= | + C,H,.0H; 
CO,.C,H, co, 

and finally, by letting ammonium cyanide and sulphuric acid act 
upon glyoxal, CHO.CHO (p. 324), when the latter probably at first 
yields formaldehyde, CH,O (Berichte, 15, 3087). Alanine is analo- 
gously formed from acetaldehyde and ammonium cyanide. 


In preparing glycocoll, pour 2 parts of concentrated sulphuric acid over finely 
divided glue (1 part), let stand several days, then add 8 parts of water and boil 
for some time, with occasional addition of water to replace the evaporated steam. 
Next, neutralize with chalk, filter and concentrate the filtrate. The glycocoll 
obtained in this manner is crystallized from hot, dilute alcohol, to free it of any 
adherent leucine. : & 


3t 


V 


37° ORGANIC CHEMISTRY. 


A simpler procedure employs hippuric acid, CH, oor (benzoyl gly- 
cocoll). The latter is boiled with concentrated HCl (4 parts) for about one hour, 
allowed to cool, the separated benzoic acid filtered off, and the filtrate concentrated. 
The resulting glycocoll hydrochloride is boiled with water and lead oxide, the 
lead chloride filtered off and the excess of Pb precipitated by H,S. In evaporat- 
ing the filtered solution glycocoll crystallizes out. 

Glycocoll is also obtained by warming monochloracetic acid with dry ammonium 
carbonate (Berichte, 16, 2827). 

It is most easily prepared by heating phthalylglycocoll ester, C,H,O,:N.CH,. 
CO,.C,H, (from phthalimide and chloracetic ester), to 200° with hydrochloric acid 
(Berichte, 22, 426). 


Glycocoll crystallizes from water in large, rhombic prisms, which 
are soluble in 4 parts of cold water. It is insoluble in alcohol and 
ether. It possesses a sweetisl taste, and melts with decomposition 
at 232-236°. Heated with baryta it breaks up into methylamine 
and carbon dioxide ; nitrous acid converts it into glycollic acid. 
Ferric chloride imparts an intense red coloration to glycocoll solu- 
tions; acids discharge this, but ammonia restores it. 


Glycocoll yields the following compounds with hydrochloric acid: C,H,;NO,. 
HCl and 2(C,H,;NO,).HCl. The first is obtained with an excess of hydrochloric 
acid. It crystallizesin long prisms. The mztrate, C,H,;NO,.HNOsg, forms large 
prisms. 

An aqueous solution of glycocoll will dissolve many metallic oxides, forming 
salts. Of these the copper salt, (C,H,NO,),Cu + H,O, is very characteristic, 
It crystallizes in dark blue needles. The sz/ver salt, C,H,NO,Ag, crystallizes 
on standing over sulphuric acid. The combinations of glycocoll with salts, ¢. ¢., 
C,H;NO,.NO,K, C,H,NO,.NO,Ag, are mostly crystalline. 


The ethyl ester, CH af CO °c HW (Berichte, 17, 957), is an oil with an odor 
g°~atts 


resembling that of cacao, and boiling at 149°. It is very unstable and readily 
becomes an anhydride (CH,(NH)CO), (Berich/e,16, 755). On leading HCl gas 
into glycocoll and absolute alcohol, the HCl-salt is formed; this melts at 144°. 
The hydrochlorides of the methyl and propyl esters, etc. (Berichte, 21, Ref. 253), 
are produced in a similar manner. 

Glycocoll Anhydride, (CH,.CO.NH), (?), forms upon evaporating glycocoll 
ester with water. It crystallizes from hot water in large plates. When these are 
rapidly heated they sublime in needles. If heated slowly, they become brown at 
245° and melt at 275° (Berichte, 22,793). 


Glycocollamide, CHC CO NH , amidoacetamide, is produced when glycocoll 
AN EEG 


is heated with alcoholic ammonia to 160°. A white mass which dissolves readily 
in water, and reacts strongly alkaline. The HC\l-salt results on heating chloracetic 
ester to 70° with alcoholic ammonia. NH.CH 
Methyl-glycocoll, C,H,NO, = CH, G9 i»: Sarcosine, is obtained in 
2 


the action of methylamine upon monochloracetic acid (p. 368), and is also pro- 
duced when creatine and caffeine are heated with baryta. It crystallizes in 
rhombic prisms, which dissolve readily in water but with difficulty in alcohol. It 
melts at 210-220°, decomposing into carbon dioxide and dimethylamine, yielding 
at the same time an anhydride, (C,H;NO),, which melts at 150° and boils at 350° 


AMIDES OF THE DIHYDRIC ACIDS. 371 


( Berichte, 17,286). It forms salts with acids; these have an acid reaction. Ignited 

with soda-lime it evolves methylamine. Nitrous acid changes it to the nitroso- 

compound, CH,“ Sia goed aa Sarcosine yields methylhydantoin with cyanogen 
pound, 2\ CO,H : z vine yang 


chloride. 
Trimethylglycocoll, cae NKCAls)s5, is betaine, described p. 316. 


Ethyl-glycocoll, C,H,NO, = CHX Co, ails, is obtained by heating mono- 
2 


chloracetic acid with ethylamine. It consists of deliquescent leaflets; it unites 
with acids, bases and salts. /N(CyH;), 


Diethyl-glycocoll, CH CO it ,is derived from monochloracetic acid 
2 


and diethylamine. It consists of deliquescent crystals which sublime under 100°. 

Aceto-glycocoll, CHGen. ey, aceturic acid, is obtained by the action 
of acetyl chloride upon glycocoll silver, and of acetamide upon monochloracetic 
acid. It consists of small needles, which dissolve readily in water and alcohol, 
and char at 130°. It conducts itself like a monobasic acid. (Compare phenyl- 
acetonic acid, Berichte, 21, Ref. 715.) 


Glycocoll may be viewed as ammonia with one hydrogen atom replaced by the 
monovalent group, —CH,.CO,H. It is plain that two and three hydrogen atoms 
in NH, may be replaced by this group :— 


/ CH,.CO,H 
NH,.CH,.cO,H NH/CH:CO,H Nn“ cH’ co.H 
'  Glycolamidic PO eee \ CH,.CO H. 
Acid 's ove me Ms beige ¢ fr r2ge mi 

cid. 


These compounds are formed, together with glycocoll, on boiling monochloracetic 
acid with concentrated aqueous ammonia. The solution is concentrated, filtered 
off from the separated ammonium chloride, and boiled with lead oxide. On cool- 
ing, the lead salt of triglycolamidic acid separates out, while glycocoll and lead 
diglycolamidate remain dissolved. To remove the last compound, hydrogen sul- 
phide is added to the solution, and the filtrate boiled with zinc carbonate. Zinc — 
diglycolamidate separates out, while glycocoll remains dissolved. 

Di- and triglycolamidic acids are crystalline compounds, forming salts with 
bases and acids; the first is dibasic, the second tribasic. Diglycolamidic acid 
yields a nitroso-compound with nitrous acid. 


2. Amidopropionic Acids, C,H,NO, = C,H;(NH,)O,. 

(1) a-Amidopropionic Acid, CH,;.CH(NH,).CO,H, Alanine, 
is derived from -a-chlor- and brom-propionic acid by means of 
ammonia, and from aldehyde ammonia by the action of CNH 
and HCl (p. 367). Aggregated, hard needles, with a sweetish 
taste. ‘The acid dissolves in 5 parts of cold water and with more 
difficulty in alcohol ; in ether it is insoluble. When heated it com- 
mences to char about 237°, melts at 255° and then sublime It is 


372 ORGANIC CHEMISTRY. 


partially decomposed into ethylamine and carbon dioxide. Nitrous 
acid converts it into a-lactic acid. e 


(2) B-Amidopropionic Acid, CH,(NH,).CH,.CO,H, is obtained from -iod- 
propionic acid and /-nitropropionic acid (p. 224). It crystallizes in rhombic 
prisms which dissolve readily in water. When heated it melts at 180° and sub- 
limes with partial decomposition. Its copper compound is far more soluble than 
that of the isomeric alanine. ; 





3. Amidobutyric Acids, C§H,(NH,)O,. 

a-Amidobutyric Acid, CH,.CH,.CH(NH,).CO,H, Propalanine, is obtained 
from brombutyric acid. It crystallizes in little leaflets or needles and is very 
soluble in water. 

B-Amidobutyric Acid, CH,.CH(NH,).CH,.CO,H, is apparently produced 
when crotonic acid is heated with ammonia (p. 367). 

y-Amidobutyric Acid, CH,(NH,).CH,.CH,.CO,H, can be obtained from 
phthalimide-trimethylene cyanide (Aerichte, 22, 3337). It is very readily soluble 
in water. It melts at 183°, and breaks down into water and pyrrolidon (p. 369). 

a-Amidoisobutyric Acid, (CH;),C(NH,).CO,H, is made from acetonyl-urea 
on heating with hydrochloric acid, and is obtained from acetone by means of 
CNH, NH, and HCl (p. 367). It is also produced in the oxidation of diaceto- 
namine with chromic acid (together with amido-isovaleric acid, p. 208). It 
crystallizes in large rhombic plates, and sublimes without decomposition near 220°. 





4. Amido-valeric Acids, C,H,(NH,)O,.—a-Amido-isovaleric Acid, 
CH,.CH,.CH,CH(NH,).CO,H, is formed on treating butyraldehyde with 
hydrocyanic and hydrochloric acids. It consists of shining prisms, which sublime 
without fusing. It is also produced by the oxidation of conine (Berichée, 19, 

OO). ‘ 

; i mibiadiaterit Acid, CH,.CH(NH,).CH,.CH,.CO,H, results from the 
decomposition of phenyl hydrazone-levulinic acid (p. 343) by sodium amalgam 
(Berichte, 22, 1860). It is crystalline, melts at 193° and forms an anhydride, 
which is a pyrroline derivative. Boiling alkalies and baryta convert it again into 
the acid. 

d-Amidovaleric Acid, CH,(NH,).(CH,),.CO,H (Homopiperidic Acid), is 
produced when piperidine is oxidized. It forms shining leaflets, melts at 158°, 
and breaks down into water and oxy-piperidine, C,H,ONH. The latter is 
resolved, by acids or alkalies, into the amido-acid. The latter is an indifferent 
_ compound, but oxy-piperidine is a powerful poison (Berichte, 21, 2235). 


a-Amido-isovaleric Acid, (CH,),.CH.CH(NH,).CO,H, Bu- 
talanine, occurs in the pancreas of the ox, and is produced by the 
action of ammonia upon bromisovaleric acid. It consists of shining 
prisms which sublime without fusing. It dissolves with more diffi- 
culty than leucine in water and alcohol. 


B-Amido-isovaleric Acid, (CH,),C(NH,).CH,.CO,H, is obtained by the 
wee tg the nitro-acid (p. 228); it melts and sublimes at 215°. 


DIAZO-ACIDS. 373 


(5) a-Amido- -caproic Acid, CH;. (CH,)s. CH(NH,). COs, 
Leucine, occurs in different animal j juices, in the pancreas, and i is 
formed by the decay of albuminoids, or when they are boiled with 
alkalies or acids. Artificial leucine prepared from bromcaproic 
acid and valeric aldehyde appears to be an isomeride of the pre- 
cedin 

fencine crystallizes in shining leaflets, which have a fatty feel, 
melt at 170° and sublime undecomposed when carefully heated. 
Rapid heating breaks it up into amylamine and CO,. _ It is soluble 
in 48 parts of water at 12° and in 800 parts of alcohol. 

The leucines derived from different sources differ in their optical 
behavior. The synthetic variety (from brom-caproic acid and 
valeric aldehyde) is inactive. Penicillium glaucum causes this 
variety to ferment, and it is then transformed into the levorotatory 
variety. Boiling baryta water changes this again into the inactive. 
Therefore, when albuminoids are decomposed by boiling baryta 
water the product is inactive leucine. Active levo-leucine results 
if the decomposition be effected with hydrochloric acid (Berichte, 


17, 1439; 18, 2984). 
Nitrous acid converts it into leucic acid (p. 364). Fused with potash it decom- 


poses into ammonium and potassium valerates. When oxidized with lead peroxide 
we get valeronitrile, C;H,,.CN. 





DIAZO-ACIDS. 


Acids of this class, like diazo-acetic acid, CHN,.CO,H, contain 
the diazo-group N, =, consisting of two nitrogen atoms, instead of 
two hydrogen atoms. ‘They are similar to the diazo-derivatives of 
the aromatic series, but not wholly likethem. When liberated from 
their salts, by mineral acids, they immediately sustain decomposi- 
tion.. They are rather stable when existing as esters or amides. 

The esters of the diazo-acids are obtained by the action of potas- 
sium nitrite upon the hydrochlorides of the amido-fatty acid esters 
(p. 370) (Curtius, 1883; Berichte, 16, 2230) :— 
HC1(H,N)CH,.CO,.C,H, + KNO, = CH(N,).CO,.C,H, + KCl + 2H,0. 


Hydrochloride of Elycocoll Paster. Diazo-acetic Uster, 


The diazo-acids are very volatile, yellow-colored liquids, with peculiar odor. 
They distil undecomposed with steam, or under reduced pressure. ‘They are 
slightly soluble in water, but mix readily with alcohol and ether. The hydrogen 
of their CHN,-group can be replaced by alkali metals. This change may be 
effected by the action of alcoholates. It shows that they possess a feeble acid 
nature. Aqueous alkalies gradually saponify and dissolve them, with the forma- 
tion of salts, CHN,.CO,Me. Acids decompose these at once with the evolution 
of nitrogen. 3] 


374 ORGANIC CHEMISTRY. 


Ethyl Diazoacetate, CHN,.CO,.C,H,, boils at 143-144° (under 120 mm. 
pressure) ; its sp. gr. is 1.073 at 23°, When chilled it solidifies, forming a leafy, 
crystalline mass, melting at —24°. It explodes with violence when brought in 
contact with concentrated sulphuric acid. A blow doesnot have this effect. Con- 
centrated ammonia converts it into an amide, diazoacetamide, CHN,.CO.NH.,, 
that crystallizes from water and alcohol in golden- yellow plates or prisms, The 
crystals become non-transparent at 112°, and melt at 114° with decomposition. 

The diazo-compounds of the marsh gas series are especially reactive. They 
split off nitrogen, and its place is taken either by wo monovalent atoms or radicals. 

The diazo-esters are converted, by boiling water or dilute acids, into esters of 
the oxy-fatty acids. (glycol acids) :— 


CHN,.CO,.C,H, + H,O = CH,(OH).CO,.C,H, + N,. 
Aster of Glycallic Acid. 


_ This reaction can serve for the quantitative estimation of the nitrogen in diazo- 
derivatives. Alkyl glycollic esters are produced on boiling with alcohols :— 


CHN,.CO,.C,H, + C,H,.OH = CH,(0.C,H,).CO,.C,H, + N,; 


a small quantity of aldehyde is produced at the same time. 
Acid derivatives of the glycollic esters are obtained on heating the diazo-com- 
pounds with organic acids :— 


CHN,.CO,.C 2H. + C,H ,0.0H = CH,(0.C, H ,0).CO, C,H; +N 
Ristic Acid. “Aceto-glycollic Ester. 
The haloid acids act, even in the cold, upon the diazo-compounds. The pro- 
ducts are haloid fatty acids :— 


CHN,.CO,.C,H, + HCl = CH,C1,CO,.C,H, + N,. 
The halogens produce esters of dihaloid fatty acids :— 
CHN;, COCC AM 4 Toee Cet CO OC M, + N.. 


Bkisdowcetic Exter. 


Diazo-acetamide is changed, in a similar manner, to di-iodo-acetamide, CHI,. 
CO.NH,. By titration with‘iodine it is possible to employ this reaction for the 
quantitative estimation of diazo-fatty compounds (Berichze, 18, 1285). 

The esters of the diazo-fatty acids unite with aldehydes to form esters of the 
ketonic acids, e. g., benzoylacetic ester, C,H,;.CO.CH,.CO,.C,H, (Berichte, 18, 
1371). They produce peculiar acid esters by their ‘anion with the benzenes. 
These compounds are isomeric with the esters of the phenyl fatty acids (Berichte, 
21, 2637) :— 


Cito 1- CON CO.C 4 = C,H;.CH,:CO,.C.H, + N,. 


The diazoacetic esters and the esters of the unsaturated acids (acrylic, cinnamic, 
fumaric) combine to additive products, which crystallize well :— 


CH, CH 

| <}-N,CH.CO,R = | — \N,:CH.CO,R. 
RO -C. Gia Diazoacetic Ester. RO, C.CH wa 
Acrylic Ester. : Aectpiie Wadouvetic Ester. 


On the application of heat nitrogen is split off, and an ester of trimethylene 
carboxylic acid results :— 


CH, CH 

*\N; :CH.CO,R = | ° SCH.CO,R. 
RO,.C.CH / RO,CCH 

.% 


o4 rimetteylene dicicboxyiie Ester, 


CARBONIC ACID AND DERIVATIVES. 375 


In a similar manner cinnamic ester yields phenyl-trimethylene-dicarboxylic ester, 
and fumaric ester,C,H,(CO,R),, trimethylene-tricarboxylic ester, C,H,.(CO, R); 
(Berichte, 21, 2637; 23, 701). The compound with acetylene dicarboxylic ester 
( Berichte, 22, 842) conducts itself differently. 

The esters of anilido- fatty acids result from the union of the anilines with diazo- 
esters. They revert to the amido-acids upon reduction (with zinc dust and glacial 
acetic acid). Hydrazine-fatty acids are intermediate products. These are not 
very stable (Berichte, 17, 957). 

a-Diazo-propionic Ester, CH;.CN,.CO,.C,H,, is similarly obtained from 
the hydrochloride of alanine ethyl ester (p. 371). It is a yellow oil. It behaves 
very much like diazo-acetic ester (Berichie, 22, Ref. 104) (sgg-this). Diazosuc- 
cinic acid is a dibasic diazo-acid. 

Triazo Compounds. 

Triazo-acetic Acid (Triazo-trimethylene-tricarboxylic acid), C,H,N, 
(CO, H),, is formed (as sodium salt) when concentrated sodium hydroxide acts upon 
diazo-acetic ester. It contains three molecules of water, and crystallizes in orangé- 
yellow, shining plates. When rapidly heated they melt at 152° (Berichte, 22, 
Ref. 133). The acid is almost insoluble in cold water, ether and benzene, but 
soluble in alcohol and glacial acetic acid. Its sodium salt is sparingly soluble. 
The e¢hy/ ester melts at 110°. Ammonia converts its ester_into triazo-acetamide. 
The acid is resolved into oxalic acid and hydrazine ( Berichte, 22, Ref. 134); when 
digested with water or mineral acids :— 


C,H,N,(CO,H), + 6H,O = 3C,H,0, + 3N,H, 


Consult the Jour. pr. Chemie, 39, 107, upon the constitution of the diaza: and 
triazo-derivatives (Berichte, 22, Ref. 196). 


CARBONIC ACID AND DERIVATIVES. 


The acid only exists in its salts (p. 353), and may be-regarded 
as oxyformic acid, HO.CO.OH. Its symmetrical structure distin- 
guishes it, however, from the other oxy-acids containing three atoms 
of oxygen. It is a weak ddasic acid and constitutes the transition 
to the true dibasic dicarboxylic acids—hence it will be treated 
separately. 

Carbon Monoxide, CO, and Carbon Dioxide, CO,, the 
anhydride of carbonic acid, have already received mention in 
inorganic chemistry. Paper moistened with a solution of palla- 
dious chloride is blackened by CO, hence it may be employed as a 
reagent for this latter compound. 

Carbonyl Chloride, COCIl,, Phosgene Gas, is formed by the 
direct union of CO with Cl, in sunlight (they combine very slowly 
.in diffused light); by conducting CO into boiling SbCl,, and by 
" oxidizing chloroform (2 parts) with a mixture of concentrated sul- 
phuric acid (50 parts) and potassium bichromate (5 parts) :— 


2CHCl, + 30 = 2COCl, + H,O + Cl,. ra 


376 ORGANIC CHEMISTRY. 


The simplest course is to conduct CO and Cl, over pulverized and cooled bone 
charcoal (Paterno). Instead of condensing the gas it may be collected in cooled 
benzene. To remove excess of chlorine the COCI, is passed over heated anti- 
mony. 


Carbonyl chloride is a colorless gas with suffocating odor, and on 
cooling is condensed to a liquid which boils at +-8°. Water at once 
breaks it up into CO, and 2HCl. 

When phosgene gas is allowed to act upon anhydrous alcohols, 
the esters of chlorcarbonic acid are formed :— 


1 
COCI, + C,H;.0H = COL Gc, yu, + Hel. 
They are more correctly termed esters of chlorformic acid, 
CClO.OH (p. 219). These are volatile, disagreeable-smelling 
liquids, decomposable by water. When heated with anhydrous 
alcohols they yield the neutral carbonic esters. 


The methyl ester, CC1O.0.CH.,, boils at 71.4°, the ethyl ester, CCIO,.C,H;. 
at 94°, the propyl ester, at 115°, the isobutyl ester, at 128.8°, and the isoamy] 
ester, at 154° (Berichte, 13, 2417). 

The amide of chlorcarbonic acid, cog called urea chloride, is produced 
by the interaction of phosgene gas and ammonium chloride at 400° (Berichte, 20, 
858; 21, Ref. 293) :-— 


COCl, + NH,.HCl = COM NH, + HCl. 


It is a liquid with penetrating odor. It solidifies in needles, which melt at 50° 
and boil at 61°—62°, when it dissociates into hydrochloric acid and isocyanic acid, 
HCNO. The latter partly polymerizes to cyamelide. Urea chloride suffers a like 
‘change on standing. Water or moist air decomposes it into carbon dioxide and 
ammonium chloride. It reacts violently with amines, forming substituted ureas :—- 

Cl NH.C,H 
COC NH, + C,H,.NH, = COC NH, 
With the benzenes and phenol ethers it yields acid amides: COCI.NH, + C,H, 
= C,H,.CO.NH, + HCl (Berichte, 21, Ref. 214). 


Alkyl Derivatives, A/éy/ Urea Chlorides, CO¢ Nur: result from the action 


of COCI, upon the HCl-amines at 250-270° C. (Berichte, 20, 118, 858; 21, Ref. 
293) — 


4. HCL. 


va 


cocl, + NH,.C,H,.HCl = COC NHC, H, 


4+ 2HCl. 


These are badly-smelling compounds boiling apparently without decomposi- 
tion, yet they suffer dissociation into hydrochloric acid and pe aaa acid esters, 


CO.NR, which reunite on cooling: CO.NR + HCl = ROC sie: The reac- 


tions of the alkyl urea chlorides are perfectly analogous to those of urea chloride 
itself. 
They re decomposed into CO, and HCl. amines by water, and with amines 


— 


ETHYL CARBONIC ACID 377 


they yield alkylized ureas. They form carbamic and allophanic esters with alco- 
hols (Berichte, 21, Ref. 293). The benzenes convert them into alkylamides of 
the carboxylic acids (see above). When distilled with lime they pass into isocy- 
anic esters (see above). cl 

Ethyl Urea Chloride, COX NH. C,H,? also obtained from ethylisocyanate and 
hydrochloric acid, boils at 60-61°. * Methyl Urea Chloride, COON. CH,’ crys- 
tallizes in large leaflets, melts about 90° and boils with dissociation (see above) at 

° 


93-94 - 
Dimethyl Urea Chicride, Cog Eli H as, dimethyl-carbamic chloride (p. 384), 


is produced by the action of dimethylamine upon COCI, olved in benzene. 
It boils at 150° C. Water decomposes it into CO, and thylamine hydro- 
chloride. /N(C,H;) 

Diethyl Urea Chloride, CO Cl 2°" 5/2, is obtained from diethyl oxamic acid, 


(C,H,),N.CO.CO,H, by means of PCl,. It boils at r9g0-195°. 
Ethyl Cyancarbonic Ester, COG : Aa or abigegae ester, is obtained 
by distilling oxamic ester with P,O,, or better with PCl, 
CO.NH, CN 


CO.0.C,H, CO.0.C,H, 


It is a pungent-smelling liquid, boiling at 115-116°. It is insoluble in water, 
but is gradually decomposed by the latter into CO,, CNH and alcohol. Zinc and 
hydrochloric acid convert it into glycocoll (p. 366). Concentrated hydrochloric 
acid decomposes it into oxalic acid and ammonium chloride. Bromine or anhy- 
drous HCl, at 100°, converts it into a crystalline, polymeric modification, melting 
at, 165°, and transformed by the. action of alkalies in the cold into salts of para- 
cyancarbonic acid, ¢. g., (CN.CO,K),. 

The methyl ester, CN.CO,.CH,, boils at 100-1019. 


The primary esters of carbonic acid are not stable in a free 
condition. The potassium salt of Ethyl Carbonic Acid, 


COL OK , separates in pearly scales on adding CO, to the 


alcoholic solution of potassium alcoholate. Water decomposes it 
into potassium carbonate and alcohol. 
The xeutral esters appear when the alkyl iodides act on silver 
carbonate :— 
CO,Ag, + 2C,H,I = CO,(C,H,), + 2Agl; 


also by treating esters of chlorformic acid with alcohols, whereby 
mixed esters may also be obtained :— 
fC “ an/ OH 
COf 6.cH, + C2Hs-0H = COC G ciy,* + HCL 
Methyl-ethy! Carbonate. 


It is also true, that, with application of heat, the higher alcohols are able to ex- 
pel the lower alcohols from the mixed esters :— 


/O.C,H L On JOC 
COX O.cH,* + C2Hs-OH = CO 0.2 H 4 CH LO. 
Methyl Ethyl Ester, Diethyl Ester. Ps 


32 


378 “ORGANIC CHEMISTRY. 


Hence, to obtain the mixed ester, the reaction must occur at a lower temperature. 

As regards the nature of the product, it is immaterial as to what order is pursued 
in introducing the alkyl groups, z, e., whether proceeding from chlorformic ester, 
we let ethyl alcohol act upon it, or reverse the case, letting methyl alcohol act 
upon ethyl chlorformic ester; the same methyl ethyl carbonic acid results in each 
case (Berichte, 13, 2417). This is an additional confirmation of the like valence 
of the carbon affinities, already proved by numerous experiments made with that 
direct object (with the mixed ketones) in view. 


The neutral carbonic esters are ethereal smelling liquids, insoluble 
in water. Excoayns dimethyl and the methyl-ethyl] ester, all are 
lighter than wa With ammonia they first yield carbamic esters 
and then urea. When they are heated with phosphorus pentachloride, 
an alkyl group is eliminated, and in the case of the mixed esters this 
is always the lower one, while the chlorformic esters constitute the 
product :— 


Coc. Wg COC Gc. 1, + PCI,O + CH,Cl. 
bio | 


Methyl Carbonic Ester, CO,(CH,)., is produced from chlorformic ester 
by eee with lead oxide. It boils at 91°. The methyl ethyl ester, 
CO ome c. H, , boils at 109°. Theethyl ester, CO,(C,H,),, is obtained from ethy| 
oxalate, é ,0 4(C,H;),, on warming with sodium or sodium ethylate (with evolu- 
tion of CO, aD boils at 126°. The methyl propyl ester, CO,(CH,)(C,H,), boils 
at 130°. 

The ethylene ester, CO,C, Hy, glycol ee obtained from glycol and COCI,, 
melts at 39°, and boils at 236°, 


CO 


Carbon mono-sulphide, sainlegbes to carbon monoxide, is 
unknown. 

Carbon Oxysulphide, COS, occurs in some mineral springs, 
and is formed in various ways, as, for example, by conducting sul- 
phur vapor and carbon monoxide through red hot tubes. It is 
most easily prepared by heating potassium thiocyanate with sulphuric 
acid, diluted with an equal volume of water: CN.SH + H,O = 
CSO + NH; (Berichte 20, 550). 

- In order to obtain it pure, conduct the gas into an alcoholic 
potash solution, and decompose the separated potassium ethyl thio- 
carbonate, ona (p. 382), with dilute hydrochloric acid. 

Carbon oxysulphide is a colorless gas, with a faint and peculiar 
odor. It unites readily, and forms an explosive mixture with air. 
It is soluble in an equal volume of water. It is decomposed by the 
alkalies according to the following equation :— 


COS + 4KOH = CO,K, + K,S + 2H,0. 
Thiocarbonyl Chloride, CSCl,, is produced when chlorine acts upon carbon 


disulphide, and when the latter is heated with PC], in closed tubes to 200°: CS, 
-+ PCkK = CSCI, + PCI,S. 


TRI-THIOCARBONIC ACID. 379 


It is most readily obtained by reducing perchlormethylmercaptan, CSCI, (p. 
142), with stannous chloride, or tin and hydrochloric acid (Klason, Berichte, 20, 
2380; Billeter, 21, 102) :— 


CSCI, + SnCl, = CSCI, + SnCl,. 


This is the method employed for its production in large quantities. 

It is a pungent, red-colored liquid, insoluble in water, and boiling at 73°; its sp. 
gr. is 1.508 at 15°. On standing exposed to sunlight, it is converted into a poly- 
meric, crystalline compound, C,S,Cl, = CI.CS.S.CCl,, methyl perchlor-dithio- 
formate, which melts at 116°, and at 180° : reverts to the ae (Berichte, 21, 


7). : 
Thiocarbonyl chloride converts secondary amines (I 
sulpho-carbamic chlorides (p. 386) :— 


Cl 
CSCI, + NH(C,Hs)C.Hs = CS< nc. ,)¢,H,° 


Asecond molecule of the amine produces tetra-alkylic thioureas (Berichte, 21,102). 


ecule) into dialkyl 


Carbon Disulphide, CS., is obtained by conducting sulphur 
vapor over ignited charcoal. It is a colorless liquid, with strong 
refractive power, boils at 47°, and at o° has a specific gravity of 
1.297. It is obtained pure by distilling the commercial product 
over mercury or mercuric chloride; its odor is then very faint. 
It is almost insoluble in water, but mixes with alcohol and ether. 
It serves as an excellent solvent for iodine, sulphur, phosphorus, 
fatty oils and resins. In the cold it combines with water, yielding 
the hydrate 2CS, + H,O, which decomposes again at —3°. 


Carbon disulphide, in slight amount, is detected by its conversion into potassium 
xanthate. This is accomplished by means of alcoholic potash. The copper salt 
is obtained from the potassium compound, The production of the bright-red com- 
pound of CS, with triethyl phosphine (p. 169, and Berich/e, 13, 1732) is a more 
delicate test. 

Dry chlorine gas converts CS, into sulphur monochloride and thiocarbonyl 
chloride, CSCl,. By the addition of chlorine we obtain CSCl, — CC1,.SCl, per- 
chlormethyl mercaptan, a yellow liquid, which becomes CC],.SO,Cl (p. 153) when 
oxidized, Zinc and hydrochloric acid convert CS, into trithiomethylene (p. 193): 


Carbon disulphide can be called the sulphanhydride of tri-thio- 
carbonic acid, CS;H,. It is perfectly analogous to CO,, and unites 
with metallic sulphides, forming tri-thiocarbonates. 

Tri-thiocarbonic Acid, CS,H, = Cae. Hydrochloric acid 
precipitates this as a reddish-brown, oily liquid, from solutions of its 
alkali salts. The sodium salt, CS,Na,, separates in the form of a 
thick, red liquid when alcohol and ether are added to a solution of 
sodium sulphide containing carbon disulphide. This salt is readily 
dissolved by water. The barium salt, CS,Ba, is a yellow crystalline 
powder, obtained by shaking aqueous BaS with CS,. 


380 ORGANIC CHEMISTRY. 
oe ZAS.C pees : 
Ethyl Trithiocarbonate, CS\s CH” is formed when an alcoholic solution 


of ethyl iodide acts upon sodium trithiocarbonate. It is a yellow oil, insoluble in 
water, and boils at 240°. It forms red-colored, crystalline derivatives with two 
atoms of chlorine or bromine. These regenerate the ether when treated with water. 
The methyl ester, CS(S.CH,),, boils at 204-205°. The action of ethylene bromide 


upon the sodium salt yields the e/hy/ene ester, at: Z C,H 45 large, yellow crys- 


tals, melting at 36.5°. These dissolve readily in ether, but with more difficulty in 
alcohol. When oxidized with dilute nitric acid the ester becomes ethylene-dithiocar- 
bonic ester, COS, oA ac forms plates, melting at 31°. 

Ethyl-trithiocar c Acid, CSM oe ,is not known in a free condition. 
The potassium salt, CSC ext 5, is produced by the direct union of carbon-di- 


sulphide, with potassium mercaptide, C,H,;.SK. 





Dithiocarbonic acid, COS,H,, may have one of two formulas :— 


/SH ASH 
COf SH CS¢ OH: 
Dithiocarbonic Acid. Thiosulphocarbonic Acid.* 


The free acids are not known; dialkyl esters, however, do exist. 
Thiosulphocarbonic acid is capable of forming esters or ether acids 


of the type Spe ass called xanthic acids :— 


/O.CH, : /O0.C,H 
CO SH ; CS SH OB 
Methyl Xanthate. i Ethyl Xanthic Acid. 


The esters of dithiocarbonic acid, CO(SH),, result when COCI, acts upon the 
mercaptides :— 


COCI, + 2C,H,.SK — CO(S.C,H,), + 2KCl; 


and when thiocyanic esters (p. 278) are heated with concentrated sulphuric 


acid :— 
2CN.S.CH, + 3H,0 = CO(S.CH,), + CO, + 2NH,. 


They are liquids with garlicky odor. Alcoholic ammonia decomposes them 
into urea and mercaptans :— 


CO(S.C,H,), + 2NH, = COC NH 4 2C,H,.SH. 


The methyl ester, CO(S.CH,),, boils at 169°; the “pec ester, CO(S.C,H;)., 
at 196°. 





* To distinguish the isomerides the sulphur joined with two valences to carbon 
is called see/pho-, the monovalent sulphur, ¢hzo. 


THIOCARBONIC ACID. 381 


The xanthates, R.O.CS.SM’, are produced by the combined 
action of CS, and caustic alkalies in alcoholic solutions :— 


CS, + KOH +,CH,OH = CS@ Qi" + 1,0. 
Potsbaln Methylxanthate. 
Cupric salts precipitate ye//ow copper salts from solutions of the 
alkaline xanthates. By the action of alkyl iodides upon the salts 
we obtain the esters :—— 


~0.CH /O.CH 
CS gk ° + GHI = Cs £2. CR 


résticaen "Xunthic Ester. 

The latter are liquids, not soluble in water. Ammonia breaks 
them up into mercaptans and esters of sulphocarbamic acid (p. 
385) :— 

/O0.C,H 
\S.C,H, 


With alkali alcoholates, mercaptan and alcohol separate, and 
salts of the alkyl thiocarbonic acids (p. 382) are formed (Berichte, 
13; 530): ayes 


/O.C,H 
oi. 3.cH. 


cs 5 NH, = CSCNH * + GH,SH. 


C,H;.0H 
GH, SK 


/O.CH, 


5 + CH,OK + H,O = ¢ SK. 


4 OD 


Xanthic Acid, or ethyl oxydithiocarbonic acid, C,H;.0.CS.SH. A heavy 
liquid, not soluble in water. It decomposes at 25° into alcohol and CS,. 
Potassium Xanthate, C,H;.0.CS.SK, forms on mixing alcoholic potash with 
carbon disulphide. It consists of silky needles, which dissolve very readily in 
water, and are quite insoluble in alcohol. The salts of the heavy metals are in- 
soluble in water, and are obtained from the potassium salt by double decomposition. 
The copper salt is yellow; it decomposes on drying. 
S.CS 0.C,H,; 
Xanthic Disulphide, | , is produced on adding an alcoholic solu- 
Ss ; 


tion of iodine to the potassium salt (p. 251). Insoluble, shining needles, melting 
at 28°. 


When ethyl chloride acts upon potassium xanthate, we get the ethyl ester, 
C,H,.0.CS.S.C,H,, a colorless oil, boiling at 200°. 

The remaining alkyl oxydithiocarbonic acids are perfectly similar to xanthic 
acid. Ethyl-methyl xanthic ester, CH,O.CS.S.C,H,, and methyl xanthic ester, 
C,H,.0.CS.S.CH,, both boil at 184°. They are distinguished by their behavior 
toward ammonia and sodium alcoholate (see above), 


Carbonic acid, containing one sulphur atom, may exist in two 
isomeric forms (p. 380) :— 


CS On me. ore 


\ SH. 
Sulphocarbonic Thiocarbonic 
Acid, Acid. 


382 ORGANIC CHEMISTRY. 


Both acids are incapable of existing free, but they yield isomeric 
dialkyl esters. Thiocarbonic acid can, like xanthic acid, yield 
/ 0.C,H; 

Noe 


Sulphocarbonic Acid. Its ethyl ester, CS(O.C,H,).,, is produced by the 
action of sodium alcoholate upon thiocarbonyl chloride, CSCl,, and in the dis- 
tillation of S,(CS.0.C,H,), (see above). It is an ethereal smelling liquid, boil- 
ing at 161-162°. With alcoholic ammonia the ester decomposes into alcohol and 
ammonium thiocya N.S.NH,; alcoholic potash converts it into alcohol and 
potassium ethyl thi ate. /0.C,H 

Ethyl Thiocarbonic Acid. The Aotassium salt, COX sk 2 


from xanthic esters and alcoholic potash (p. 381), and in the union of carbon 
dioxide with potassium mercaptide, C,H,.SK. It crystallizes in needles and 
prisms, which readily dissolve in water and alcohol. With ethyl iodide the potas- 


2 aoe > which can be prepared 


ether-thiocarbonates of the type, CO 





5, is obtained 


sium salt forms ethy/ thioxycarbonate, CO 


from chlorcarbonic ester, COC1.0O.C,H,, and sodium mercaptide. It boils at 156°. 
Alkalies decompose it into carbonate, alcohol and mercaptan. Such esters can 
also be prepared by acting upon the zinc mercaptides with esters of chlorcarbonic 
acid (Berichte, 19, 1228). 





“ 


AMIDE DERIVATIVES OF CARBONIC ACID. 


Carbonic acid is dibasic, and forms amide derivatives similar to 
those of the dibasic dicarboxylic acids :— 


ANH AN 
COC OH” COL NH? 
Carbamic Acid. 6 Casbamide: 
/ OH Lah 
HNC. ‘on CO = NH. 
Imido-carbonic Acid. Carbimide. 


Carbamic Acid, H,N.CO.OH, Amidoformic Acid, is not 
known in a free state. It seems its ammonium salt is contained in 
commercial ammonium carbonate, and is prepared by the direct 
union of two molecules of ammonia with carbon dioxide. It isa 
white mass which breaks up at 60° into 2NH, and CO,, but these 
combine again upon cooling. Salts of the earth and heavy metals 
do not precipitate the aqueous solution; it is only after warming 
that carbonates separate, when the carbamate has absorbed water 
and becomes ammonium carbonate. When ammonium carbamate 
is heated to 130-140° in sealed tubes, water is withdrawn and urea, 
CO(NH,)., formed. 

The esters of carbamic acid are called urethanes; these are 
obtained by the action of ammonia at ordinary temperatures upon 
carbonic esters :— 


CO PPC 


AN 
0 o.cH? + NH, = CO OCH, 4 C,H,.0H; 


oS 


AMIDE DERIVATIVES OF CARBONIC ACID. 383 


and in the same manner from. the esters of chlorcarbonic and cyan- 
carbonic acids :— 


/NH, 


A Cl aa 

OX. qeat. + Bs = Sect. 4.7 
ACN Oe ee 

COC 6.c,H, + 2NHs = COCO Gig, + CNH, 


Also by conducting cyanchloride into the alcohols :— 


/NH 
CNCI + 2C,H,.0H =COl 9 G27, + CHCl; 


and by the direct union of cyanic acid with the alcohols :-— 


ti Roae «| 
CO.NH + C,H,.0H = OH 
When there is an excess of cyanic acid employed, allophanic esters are also pro- 
duced. ' 
The urethanes are crystalline, volatile bodies, soluble in alcohol, ether and water. 
Alkalies decompose them into CO,, ammonia and alcohols. They yield urea when © 
heated with ammonia :— 


/NH, 


NH 
£0.C2 (Ss.4. Con: 


CO (NH, 


H, + NH, = CO 
Conversely, on heating urea or its nitrate with alcohols, the urethanes are re- 
generated. /NH 
Methyl Carbamic Ester, COX 0 CH , methyl urethane, crystallizes in | 


plates, which melt at 52°, and boil at 177°. The ethyl ester, CO(NH,).0.C,H,, 
also called urethane, consists of large plates, which melt at 47—50°, and boil at 
180°. The propyl ester melts at 53°, and boils at 195°. The zsoamyl ester crys- 
tallizes from water in silky needles, which melt at 60°, and boil at 220°. The a//y/ 
ester, CO(NH,).0.C,H,, is a solid, melting at 21°, and boiling at 204°. 


Alcohol radicals can replace the hydrogen of NH, in carbamic 
acid. The esters of these alkylized carbamic acids are formed, like 
the urethanes, by the action of carbonic or chlorcarbonic esters 
upon amines; and on heating isocyanic esters (p. 274) with the 
alcohols to 100° :— 

NH.C,H 
CO:N.C,H, + C,H,.0H = COC 6c. 5; 
also, by the interaction of the chlorides of alkyl urea and the alco- 
hols :— . 
/OC,H 


/Cl ee 
CO R + CzH,.OH = COC nat 


CNH 5 4+ HCl. 


Methyl Etho-carbamic Ester, CH,.HN.CO.O.C,H,, boils at 170°. 
Ethyl Etho-carbamic Ester, (C,H,)HN.CO.O.C,H,, boils at 175°. 


384 | ORGANIC CHEMISTRY. 


Derivatives of carbamic acid with divalent radicals are produced by the union of 
esters of the acid with aldehydes :— Py 

Ethidene Urethane, CH,.CH(HN.CO.O.C,H,),, from urethane and acetal- 
dehyde, crystallizes in shining needles, melting at 126° C. 

Chloral Urethane, CCl s-CH.CFN.C0.0.C,H,? from urethane and chloral, 


melts at 103°. ; ' 
Cyanamido-carbonic Acid, CO<Gu Cyancarbamic acid. Its salts 


are formed by the addition of CO, to salts of cyanamide :— 
N(Na).CN 
2CN.MINa + CO, = COX oes PON Cnn. 


The esters of this acid result by the action of alcoholic potash upon esters of cyan- 
amido-dicarbonic acid, CN NCCC A The latter are produced by allowing 
the esters of ¢hlorcarbonic acid to react with sodium cyanamide (_ Jour. pr. Chem., 
16,146). The chloride of carbamic acid, COM Gr * has been described as the 
amide of chlorcarbonic acid (p. 376). Its alkylic derivatives, or alkyl urea chlor- 
ides (p. 376) may also be termed a/ky/ carbamic acid chlorides. 





Imido-carbonic Acid, HNC. Or 

The esters of this acid are obtained by reducing the esters of chlorimido-car- 
bonic acid (see above) with potassium arsenite. They are alkaline liquids, with am- 
moniacal odor, miscible with water, and again separated upon the addition of caustic 
alkalies. They are very unstable, distil with decomposition, and are decomposed 
by acids into ammonia and esters of carbonic acid. ‘They give off the odor of car- 
bylamine, CN.C,H,;, when heated with zinc dust. They unite with amide deriva- 
tives and at the same time split off the imide.group. 

Their combinations with orthophenylene-diamines and ortho-amido-phenols (Be- 
richte, 19, 862 and 2650) are quite interesting. /O.C,H 

The esters of Chlorimido-carbonic Acid, CIN:C 0.C_H” are produced in the 

a**5 


action of esters of hypochlorous acid (p. 155) upon a concentrated potassium cya- 
nide solution. They are solids, with a peculiar penetrating odor, and distil with 
decomposition. Alkalies have little effect upon them, while acids break them up 
quite easily, forming ammonia, esters of carbonic acid and nitrogen chloride. 

The ethyl ester, CIN:C(O.C,H,),, melts at 39°, and the methyl ester, CIN:C 
(0.C,H,),, at 20°. Y/NR 

The chlorides of dialkylic sulpho-carbamic acids, CS \Cl 2, are produced by 


the action of thiophosgene upon secondary amines (p. 378). 


Cyanic acid (p. 271) is probably the imide of carbonic acid— 
Carbimide, CO:NH. 


AMIDE DERIVATIVES OF CARBONIC ACID. 385 


Perfectly analogous amides are derived from the thio-carbonic acids. 
Dithiocarbamic Acid, cst oH is a reddish oil, obtained by decomposing 


the ammonium salt with dilute sulphuric acid. It breaks up very readily into thio- 
cyanic acid and hydrogen sulphide :— 


ANH, _ 
OX sa, = CN.SH + SH,. 
Water decomposes it into cyanic acid and 2SH,. The ammonium salt 
cs< enh , forms yellow needles or prisms, and is produced in the action of 
alcoholic ammonia upon CS,. 

By heating this salt together with aldehyde we obtain the compound, H,N.CS. 
S.N (CH,.CH), = C,H,,)S,N., carbothialdine. This is also obtained on 
mixing CS, with alcoholic aldehyde-ammonia (Berichte, 11, 1384). It consists of 
large, shining crystals, and when boiled with acids decomposes into ammonia, 
carbon disulphide and aldehyde. 

The dithiourethanes are the esters of the above acid. They arise when the 
thiocyanic esters are heated with HS (compare phenyl dithiocarbamic acid) :— 


aio ne 
CN.S.C,H, + H,S = <S.C.o, 
They are crystalline compounds, soluble in alcohol and ether, and are decom- 
posed into ammonium thiocyanate and mercaptans, when treated with alcoholic 
ammonia. 
The ethy/ ester melts at 41-42° and the. propyl ester at 97°. Both crystallize in 
shining leaflets. 
Alkyls may replace hydrogen of NH, in dithiocarbamic acid. The amine 
salts of these compounds are obtained on heating CS, with alcoholic solutions of 
the primary and secondary amines :— 


NHC. Hi; 

CS, + 2C,H,.NH, = CSC S(NH..CH,) 

Boiling aqueous soda eliminates ethylamine from this salt and produces sodium 
ethyl dithiocarbamic acid, OR ong 2 The free:acid obtained from: this-is 
an oil which solidifies to a crystalline mass. When its amine salts are heated to 
110°, dialkylic thio-ureas are produced (p. 395) :— 


/NH.C,H ee ARE 
CSINH CH) OR NBC 
Diethyl Sulphocarbamide. 


If the aqueous solution of the salts obtained from the primary amines be digested 
with metallic salts, ¢.¢., AgNO,, FeCl, or HgCl,, salts of ethyl-dithiocarbamic 
acid are precipitated :— 


/NH.C,H Ne ECL 
CS< S(NH..C,H,) + A8NOs = CSC gag * * + (NH,-C,H,)NO. 
These yield the mustard oils when boiled with water (p. 279) :— 
acs¢ NM-C2Ms _ 2Cs:N.C,H, + Ag,S + SH 
\SAg — :N.C,H; + Ag,S + 2° 


The salts obtained from the secondary amines do not yield mustard oils 
( Berichte, 8, 107). 


386 ORGANIC CHEMISTRY. 


Monosulphur carbamic acid can occur in two isomeric forms in its esters :— 


ANH Ss “NH 
Sulphocarbamic Ester. Thiocarbamic Ester.* 


(1): The esters of sulphocarbamic acid—thiourethanes—are formed when 
alcoholic ammonia acts upon the xanthic esters (p. 381) :— 


/S.C,H af RE 
CSG Cr + NH = CSCO .¢? 


They are crystalline compounds, which decompose into mercaptans, cyanic acid 
and cyanuric acid on heating. Alcoholic alkalies decompose them into alcohols 
and thiocyanates, CNSK. 

The ethyl ester of sulphocarbamic acid is slightly soluble in water and melts at 
38°. The methyl ester melts at 43°. 

The esters of a/kylic sulphocarbamic acids are obtained when the mustard oils 
are heated to 110° with anhydrous alcohols :— 


CS:N.C,H, -++ C,H,;.0H = C 


u, + CoH,.SH. 


¢ /NH.GH, 
SOC! 


They are liquids with an odor like that of leeks, boil without decomposition and 
break up into alcohols, CO,, H,S and alkylamines, when acted upon with alkalies 
or acids. 

Ethyl Etho-sulphocarbamic Ester, C,H;.NH.CS.O.C,H,, boils at 204—208°. 
Allyl sulphocarbamic ester, C,H;.NH.CS.O.C,H,, from ‘allyl mustard oil, boils at 
210-215°. 

(2) The esters of thiocarbamic acid are obtained by conducting hydrochloric 
acid gas into a solution of CNSK (or of alkyl sulphocyanates, Berichte, 19, 1083) 
in alcohols (together with esters of sulphocarbamic acid—/ourn. pract. Chem., 
16, 358); and by the action of ammonia upon the dithiocarbonic esters, 
CO(S.C,H,),, and chlorthioformic esters :— 


/NH, 
\S.C,H; 


These are crystalline compounds, which are dissolved with difficulty in water, 
and decompose when heated. ; 

The methyl ester, NH,.CO.S.CH,, melts at 95-98°. The ethyl ester melts at 
108°( 102°). /NH 

Ammonium Thiocarbonate, CON S.NH,? is prepared by leading COS into 


/ Cl fee 
00< S.c,H, + 2NHs = 60 + NH,Cl. 


alcoholic ammonia. It is a colorless, crystalline mass, which acquires a yellow 
color on exposure to the air, owing to the formation of ammonium sulphide. When 
heated to 130° it breaks up into hydrogen sulphide and urea. 


: OR / NH, 
Carbamide, Urea, CH,N,O = CO. NH; 


This was discovered in urine in 1773, and was first synthesized 
by Wohler in 1828. It occurs in various animal fluids, chiefly in 





* Tmidothiocarbonic acid, HN:CZ oie , is isomeric with these acids. It is only 


~ known in its phenyl derivatives (see phenyl] isothiourethane). 


CARBAMIDE—UREA. 387 


the urine of mammals, birds, and some reptiles. It may be pre- 
pared artificially in various ways: (1) by evaporating the aqueous 
solution of ammonium isocyanate, when an atomic transposition 
occurs (Wohler) :— 


CO:N.NH, yields co¢ NE 


\NH,? 1% 
(2) by the action of ammonia upon carbonyl chloride or carbonic 
esters :— 

COCcl, + 2NH, = coé NH + anc, 


\NH, 7 
SOC,H Li ony oe ‘ 
COL 9.@2H® + 2NH, = COM Nyy? + 2C,H5-0H ; 


(3) by heating ammonium carbamate or thiocarbamate to 130- 
140° :— 


NH /NH 
COCO. Nit, = COC Ny? + H,03 


It is further produced in the action of alkalies upon creatine and 
allantoin ; in the oxidation of uric acid, guanine and xanthine, and 
when small quantities of acids act upon cyanamide (p. 288):— 


/NH, 
\NH,’ 


Préparation from Urine. Urine is evaporated to a thick syrup, and when 
cool concentrated nitric acid (or, better, oxalic acid) is poured over it. The sepa- 
rated, brown-colored nitrate is repeatedly crystallized from dilute nitric acid, in 
order to obtain it pure; it is then dissolved in water, heated with barium carbonate, 
and the filtrate evaporated to dryness. The urea is extracted from the residue with 
absolute alcohol. 

The best synthetic method is its preparation from ammonium cyanate. Mixed 
aqueous solutions of potassium cyanate and ammonium sulphate (in equivalent 
quantities) are evaporated; on cooling potassium sulphate crystallizes out and is 
filtered off, the filtrate being evaporated to dryness, and the urea extracted by means 
of hot alcohol. The following gives good practical results: 28 parts of anhydrous 
yellow prussiate of potash are fused with 14 parts of manganese dioxide. The 
fused mass is dissolved in water, 20% parts of ammonium sulphate are added, and 
the entire solution is then evaporated to dryness. The urea is extracted from the 
residue with alcohol. 

The easiest course to pursue in order to obtain the urea is to conduct ammonia 
into fused phenyl carbonate, CO(O.C,H,), (Berichte, 17, 1286). 


CN.NH, + H,O = CO 


Urea crystallizes in long, rhombic prisms or needles, which have 
a cooling taste, like that of saltpetre. It dissolves in 1 part of cold 
water and in 5 parts of alcohol ; it is almost insoluble in ether. It 
melts at 132°, and above that temperature breaks up into ammonia, 
ammelide, biuret and cyanuric acid. When urea is heated above 
100° with water, or when boiled with alkalies or acids, it decom- 
poses into its constituents :— 


CO:N,H, + H,O = CO, + 2NH,. 


388 ORGANIC CHEMISTRY. 


Nitrous acid decomposes urea, in the same manner that it decom- 
poses all other amides :— i 


H 
COC NH + N,0; — CO, + 2N, + 2H,0. 

Urea, like glycocoll, forms crystalline compounds with acids, bases and salts. 
Although it is a diamide it combines with but one equivalent of acid (one of the 
amido-groups is neutralized by the carbonyl group). 

Urea Nitrate, CH,N,O.HNO,, crystallizes in shining leaflets, which are not 
very soluble in nitric acid. The AC7-salt, CH,N,O.HCI, is formed when dry 
HCl-gas is conducted over urea; it is a yellow oil, decomposing on exposure to 
the air. The oxalate, (CH,N,O),C,H,O, + 2H,O, is precipitated by oxalic 
acid from an aqueous solution of urea in the form of thin leaflets, which are not 
readily soluble in water. 

The compound with mercuric oxide, CH,N,O0.2HgO, is a white precipitate, 
obtained on adding potassium hydroxide and mercuric nitrate, Hg(NO,),, to 2 
urea solution. Jercuric chloride produces a white precipitate, which assumes a 
yellow color when washed with water, and has then the ~.mposition expressed by 
the formula, CH,N,0.3HgO. Silver oxide yields a crystalline, gray compound, 
(CH,N,O),.3Ag,0. 

On evaporating a solution containing both urea and sodium chloride, the com- 
pound, CH,N,O.NaCl -+- H,0O, separates in shining prisms. Large rhombic 
prisms of CH,N,O.AgNO, crystallize from a concentrated solution of urea and 
silver nitrate. 

Mercuric nitrate precipitates compounds of variable composition from aqueous 
urea; a volumetric method for estimating the latter is founded on this fact. 





—¥ 


Isuretine, oH Naty: is isomeric with urea; it is produced by the direct 
union of hydroxylamine, NH ,O, with CNH (p. 294). 


Hydroxy-urea, oleae Ons is obtained by mixing aqueous 
hydroxylamine nitrate with potassium isocyanate. It is readily 
soluble in water and alcohol, but is thrown out of these solutions in 
rhombic leaflets by ether. It melts at 128—-130°. 


COMPOUND UREAS. 


By this term we designate all compounds derived from urea by 
the replacement of hydrogen in the amido-groups by alcohol or 
acid radicals. 

1. A/kylic ureas are produced according to the same reactions 
which yield urea, substituting, however, amine bases for ammonia 
or isocyanic esters for cyanic acid :— 


NH.C,H, 
CO:NH + NH,.C,H, = COC NT,” 


Ethyl Urea: 


COMPOUND UREAS. 389 
: as /NH.C,H 
CO:N.C,H; + NH,.CH, = COs wH.CH:™ 
Methyl-ethyl Urea. 


_- a. /NHLC,H, 
CO:N.C,H, +NH(CzH5)2 = COC N(CH. 


Triethyl Urea, 

This is the reaction with the primary and secondary amines, but 
not with the tertiary amines. 

Alkylic ureas are formed, too, when isocyanic esters are heated 
with water—CO,, and amines being produced ; the latter unite with 
the esters :— 

CO:N.C,H, + H,O = NH,.C,H, + CO, and 


NH.C,H, 
CO:N.C,H, + NH,.C,H, = COON H?, 


They are also obtained by the action of urea chloride and alkyl- 
urea chlorides (p. 376) upon amines :— 


/NH NH 
COC S) 241 NH,.C,H, = COC NHC,H, 4+ HCl, 
anes 4+ .NH,R = COM NHR 4+ HCl. 


Ureas of this class are perfectly analogous to ordinary urea so far 
as properties and reactions are concerned. ‘They generally form 
salts with one equivalent of acid. They are crystalline salts, with 
the exception of those containing four alkyl groups. On heating 
those with one alkyl group, cyanic acid (or cyanuric acid) and an 
amine are produced. The higher alkylized members can be dis- 
tilled without decomposition. Boiling alkalies convert them all 
into CO, and amines :— 


co/NH.CH 


(nu, °+H,0 =CO, + NH, + NH,.CH,. 


Methyl Urea, Cee , results on heating methyl aceto-urea (from aceta- 
2 


mide by the action of bromine and caustic potash, p. 391 and Berichte, 15, 409) 
with potassium hydroxide (Berichte, 14, 2734). It consists of prisms melting at 


102°. Sodium nitrite converts its nitrate into nitroso-methyl urea, CO(NH,). 


N(NO).CH,. By reduction this yields methylhydrazine (p. 167). 
Ethyl Urea, On forms large prisms, melting at 92°. They dis- 
. 2 
solve readily in water and alcohol. Nitric acid does not throw them out of aque- 
ous solution. /NH.C,H : 
_ a@-Diethyl Urea, COC 'NH.C.H, , crystallizes in long prisms, melting at 112°, 
| ; 5 ; 
and boiling undecomposed at 263°. Nitrous acid (or KNO, upon the sulphate) 


: : NH.C,H eae 3 
changes it to itrosodiethyl urea, COL 3 (NO).C, He: This is a yellow oil, that 


solidifies on cooling, and melts at + 5°. By reduction, it yields an amido-deriva- 
_ tive, which breaks up into CO,, ethylamine, and ethyl hydrazine (p. 167). 


390 ORGANIC CHEMISTRY. © 


$-Diethyl Urea, NC? H.).» 18 formed when potassium cyanate acts upon 
g*t5)2 


diethylamine sulphate, Colorless crystals, melting at 70°. 


Triethyl Urea, COC N(CH.) , melts at 63°, and distils at 223°; it is very 


soluble in water, alcohol and ether. 


Tetraethyl Urea, co” NC aHs)2, is produced on conducting COCI, into a 
: ‘ ed: \N(C,H5). 
solution of diethylamine in benzene :— 


© eH), 
COCI, + 2NH(C,H,), = COC nic?’ + 2H. 


This liquid boils at 210-215°, and has an odor resembling that of peppermint. 
It is soluble in acids, but is reprecipitated by alkalies. 

Allyl Urea, et ia aa is obtained from allyl cyanic ester and ammonia, 
or from allylamine sulphate and potassium cyanate. It consists of beautiful prisms, 


melting at 85°. : 
Diallyl Urea, COCNH CH Sinapoline, is formed when allyl isocyanic 


ester is heated with water (p. 389) :— 
NH.C,H 
2CO:N.C,H, + H,O = COC NH CH’ + €CO,; 

or by heating mustard oil with water and lead oxide. Diallyl-thio-urea is first 
formed, but the lead oxide desulphurizes it (p. 395). Diallyl-urea crystallizes in 
large, brilliant leaflets, melting at 100°. They do not dissolve readily in water, 
and have an alkaline réaction. 

Ethylene Urea, Ol Sa ae is produced on heating ethyl carbonate to 


180°, together with ethylene-diamine. Needles, melting at 131°, and readily solu- 
ble in both water and hot alcohol. 


Ethylene Diurea, ae NH Oe is produced upon heating ethylene dia- 
\ NH, 
mine hydrochloride with silver cyanate. It dissolves with jdifficulty in alcohol, 


but readily in hot water. It melts at 192°, with decomposition. 
Ethylated ethylene ureas are similarly formed :— 


NH.C,H /NH 
co” 25 2 
SAN “OSNIGH Ac 4 
co/ NH Cp yl 
\ NHG,H; \NH, 
From Cyanic Ester and From Cyanic Acid and. 
Ethylene Diamine. Diethyl Ethylene Diamine. 


Derivatives of urea with aldehyde radicals exist. They are produced at ordi- 
_ mary temperatures by the union of urea with aldehydes; water is eliminated (Zer- 
ichte, 22, Ref. 579). ‘NH\ 

Methylene Urea, COC NH Jody is formed from urea and concentrated 
. formic aldehyde. White, granular crystals. 
Ethidene Urea, COC Ni CH.CH, is not very soluble in water, and melts 


at 154°. Chloral Urea, CO(NH),:CH.CCIl,, crystallizes in leaflets, which melt 
at 150° with decomposition. . 
When boiled with water these compounds break up into aldehydes and urea. 


GLYCOLYL UREA. 391 


CH,—O 
Ethylene-pseudo(iso)-Urea, d 


Se CH,—O < 
C:NH C.NH,, 4 

Pate , or 2 meee g» 1S 
oe ont ethylene urea. It is a derivative of hypothetical iso- or pseudo-urea, 
HO. CONE (compare isothiourea (p. 394), and ethylene pseudo-thiourea (p. 396). 
It is produced by the action of brom-ethylamine hydrobromide (p. 163) upon 
potassium cyanate. It is a basic oil, which solidifies with difficulty (Berichte, 22, 
1451). 

Propylene-pseudo Urea, C,H,:CON,H,, is quite analogous. It results from 
HBr-propylamine and potassium cyanate, as well as from allyl urea, by a molecu. 
lar rearrangement induced by hydrobromic acid (Berichte, 22, 2990). 


2. DERIVATIVES OF UREA WITH ACID RADICALS, OR UREIDES. 


The derivatives of the monobasic acids are obtained in the action 
of acid chlorides or acid anhydrides upon urea. By this procedure, 
however, it is possible to introduce but one radical. The com- 
pounds are solids ; they decompose when heat is applied to them, 
and do not form salts with acids. Alkalies cause them to separate 
into their components. 


Acetyl Urea, COM BES C gHs D5 is not very soluble in cold water and alcohol. 
It forms long, silky nae ‘which melt at 112°. Heat breaks it up into acetamide 
and isocyanuric acid. Chloracetyl urea, H,N CO.NH.CO.CH,Cl, from urea and 
chloracetyl chloride, crystallizes in fine needles, which decompose about 160°. 


Bromacetyl urea dissolves with difficulty in water. When heated with ammonia 


it changes to hydantoin (see above). 


Methyl Acetyl Urea, COC. che 20. is obtained from methyl urea upon 
digesting it with acetic anhydride, and by the action of bromine and potassium 
hydroxide upon acetamide (p. 160). It dissolves very readily in hot water, crys- 
tallizes in large prisms and melts at 180°, 


Diacetyl Urea, COC NEC HO” results when COCI, acts on acetamide, 
. 3 


NH,.C,H,O, and sublimes in needles without decomposition. 
Derivatives of Urea with Divalent Acids :— 


Glycolyl Urea, C,H,N,O,, Hydantoin, is produced by heat- 
ing bromacetyl urea with alcoholic ammonia :— 


/NH.CO.CH,Br NH.CO Ps 


el. HCH, a & 
and from allantoin, and from alloxanic acid by heating with yar: 
odic acid. It crystallizes from hot water and alcohol, in ne 
which melt at 216°, and show a neutral reaction. When bo 
with baryta water, it passes into As coats acid :— 


cod | + H,0 = cof. 
\NH.CH, ss CH,CO.OH. 
Glycolyl Urea. Glycoluric Acid. 


392 ORGANIC CHEMISTRY. 


Nitrohydantoin, C,H,(NO,)N.O,, is produced when very strong nitric acid 
acts upon hydantoin. It melts at 170°. The alkyl hydantoins react in like 
manner (Berichte, 21, 2320; 22, Ref. 58). 

Glycoluric Acid, C,H,N,O,, Hydantoic Acid, was originally obtained from 
uric acid derivatives (allantoin, glyco-uril, hydantoin), but may be synthesized by 
heating urea with glycocoll, to 120° :— 


/NH, 7 NH, /7NH, 
Powe Ts. Con = = COC NH CH.cG.8 6 ee 
or by digesting glycocoll sulphate with potassium isocyanate :— . 


/NH, 
\.NH.CH,.CO,H. 


Hydantoic acid is very soluble in hot water and alcohol. It crystallizes in large, 
rhombic prisms. It is a monobasic acid, whose salts are generally very readily 
soluble ; when heated with hydriodic acid they yield CO,,NH, and glycocoll. 


CO:NH + NH,.CH,.CO,H = CO 





Hydantoin contains a closed or ring-shaped nucleus of five members, consisting 
of three C-atoms and two nitrogen atoms. In this respect it resembles the glyox- 
alines or imido-azoles. The hydantoin ring is, however, not very stable, owing 
to the presence of two CO-groups. The alkylic hydantoins are derived by the 
replacement of the hydrogen atoms of the CH,- and the two NH-groups. They 
are known as a-, §- and y-derivatives, and are-represented as follows :— 


The a-derivatives may be synthesized by heating the cyanhydrins of the aldehydes 
and ketones (p. 203) with urea (see a-phenyl-hydantoin, and Berich/e, 21, 
2320) :— 


JEN Joo: .NH 
R.CHE + H,N.CONH,=RCH( | 4 NH,. 
OH NH.CO 
a-Alkyl-hydantoin. 


p- -Methyl- hydantoin, C sH,(CH,)N, O,, was first obtained from creatinine, 


and is also formed when sarcosine (p. 370) is heated with urea :— 
yn N(CH,).CH, 

00% 6 *NH(CH:).CH, = COZ |, + NH. + H,0, 
te l O 


CO,H 


~ or by heating the sarcosine with cyanogen chloride (Berichte, 15, 211). It forms 
soluble’ prisms which melt at 157°, and sublime in shining needles. It forms 
metallic derivatives on boiling with silver or mercury oxide, when the hydrogen of 
the imid-group suffers replacement. 

§-Ethyl-hydantoin, C,H,(C,H;)N,O,. It is formed like the preceding, 
and crystallizes in rhombic. plates which melt at 100° and sublime readily. 

a-Lactyl Urea, C,H,N,O,, a-Methyl-hydantoin. It is formed from alde- 
hyde ammonia along with alanine (p. 371), if cyanide of potassium, containing 


ALLOPHANIC ACID. 393 | 


potassium isocyanate, be used in its preparation. It is very likely that then the 
alanine (a-amidopropionic acid) first produced acts upon the cyanic acid (as in the 
formation of hydantoic acid) (Berichte, 21, 516) :— 


NH,.CH.CH, NH.CH.CH, 
CO:NH + l = co ¢ + H,0. 
CO.OH ‘“\NH.CO 
a-Amido-Propionic Acid. Lactyl Urea. 


It has one molecule of H,O, and crystallizes in large, rhombic prisms, which 
effloresce on exposure. It melts, at 140-145°, and sublimes with partial decom- 
position. Boiled with baryta it absorbs water and forms a-Lacturic Acid, 


COC Ne hee which melts at 155°. 
2 


yNH-O(CH ete 
Acetonyl Urea, C.H,N,O, = CO | 
\NH—CO 

toin, the ureide of a-oxyisobutyric acid, (CH,),.C(HO).CO,H, is obtained like 
the preceding compound, on heating acetone and potassium cyanide hy tegtrhi 
potassium isocyanate) with fuming hydrochloric acid. It is very soluble in water, 
and crystallizes in large prisms, which melt at 175° and sublime in needles. When 
heated to 160° with fuming hydrochloric acid, it breaks up into a-oxyisobutyric 
acid, NH, and CO,. Boiling baryta water converts it into acetonyluric acid, 
H,N.CO.NH.C(CH,),.CO,H, which fuses at 155-160°. 


, a-Dimethyl-hydan- 





The ureides of the dibasic acids and those of glyoxylic acid, CHO.CO,H, will 
receive attention under the uric acid derivatives. We will yet mention those of 
carbonic acid: allophanic acid, biuret and carbonyl diurea. 


: ; ~ / NH ‘ . 
Allophanic Acid, COS NH.CO,H’ is not known in a free state. Its esters 


are formed when chlorcarbonic esters act upon urea :— 


“NH aA Ne 
CO. NH, + CClO.0.C,H,; = COS NH.CO,.C,H, 
or by leading cyanic acid vapors into the anhydrous alcohols: 2CO:NH + C,H,;.0H 
= NH,.CO.NH.CO,.C,H;. At first carbamic acid esters are produced (p. 383) ; 
these combine with a second molecule of cyanic acid and yield allophanic esters 
(Berichte, 22,1572). The action of urea chloride upon alcohols (p. 376) proceeds 
in a similar manner. The first products are carbamic esters. These unite with a 
second molecule of the chloride and produce allophanic esters: Cl.CO.NH, + 
H,N:CO.C,H, —H,N.CO.NH.CO,.C,H, (Berichte, 21, Ref. 293). The allo- 


+ HCl; 


phanic esters are crystalline, dissolve with difficulty in water, and, when heated, 


split up into alcohol, ammonia and cyanuric acid. The allophanates are obtained 
from them by means of the alkalies or baryta water. They show an alkaline reac- 
tion and are decomposed by carbonic acid. On attempting to free the acid by 
means of mineral acids, it at once breaks up into CO, and urea. 4 
Ethyl Allophanic Ester, NH,.CO.NH.CO,.C,H,, is obtained when hydfochlorie 
acid acts upon a solution of potassium isocyanate dissolved in alcohol. ‘Shining 
needles, melting at 190-191°. The propyl ester melts at 155°. . 


Allophanamide, CO< NH.CO.NH,’ Biuret, is formed on heating the allo-.. 


Se 
phanic esters with ammonia to 100°, or urea to I50-160° :— 
/NH 5 pan7Ne 
2CO\ wo, = COV wH.co.nu, + As. 


33 


394 ORGANIC CHEMISTRY. 


It is readily soluble in alcohol and water, and crystallizes with 1 molecule of 
water, in the form of warts and needles. When anhydrous, biuret melts at 190°, 
and decomposes further into NH, and cyanuric acid. The aqueous solution, con- 
taining KOH, is colored a violet red by copper sulphate. Heated in a current of 
HCl, biuret decomposes into NH,, CO,, cyanuric acid, urea and guanidine. 

Carbonyl Diurea, C,H,N,O,, is formed on heating urea with COCI, 
100° :— 

/NH / NH.CO.NH\, 
\NH, ts Re 5 5 


It is a crystalline powder, not readily dissolved by water. Heat converts it into 
ammonia and cyanuric acid. 


2CO 21 COCIl, = CO CO + 2HCl. 


Thio-urea, Sulphocarbamide, Se . Itis obtained by 
2 
heating ammonium thiocyanate to 170°, when a transposition, 
analogous to that occurring in the formation of urea, takes place 
(p- 387) :— 
/NH, 


CS:N.NH, yields CSC 3373 


and by the action of hydrogen sulphide (in presence of a little 
ammonia), or ammonium thiocyanate upon cyanamide :— 

/ NH, 

\NH,’ 

Preparation.—Heat dried ammonium thiocyanate to 180° for several hours. 


_ The mass is then treated with an equal weight of hot water and the filtered solu- 
tion allowed to crystallize (Annalen, 179, 113): 


CN.NH, + SH, =CS 


Sulphocarbamide crystallizes in fine, silky needles, or in thick, 
rhombic prisms, which dissolve easily in water and alcohol, but 
with difficulty in ether ; they possess a bitter taste and have a neu- 
tral reaction. They melt at 169° (Berichte, 18, 461) and decom- 
pose at higher temperatures. When sulphocarbamide is heated with 
water to 140° it again becomes ammonium thiocyanate. — If boiled 
with alkalies, hydrochloric acid or ga dab acid, it decomposes 


he according to the equation :— 


% CSN,H, + 2H,O = CO, + 2NH, + H,S. 


‘Nitrous acid eliminates nitrogen. Silver, mercury, or lead oxide 
ae “f ter will convert it, at ordinary temperatures, into cyanamide, 
Hi} and on boiling into dicyandiamide (p. 289). 





a The Sacha isothio- urea or imido-thiocarbamic acid, HN = SH? ys 


isomeric with thio urea. It is, however, only known in its derivatives (p. 396 and 
phenyl-isothiourea). Both are probably tautomeric and change into each other, 
while their alkyl derivatives are isomeric (p. 54, and Berichée, 18, 3103; 21, 


1859). 


DERIVATIVES OF UREA WITH ACID RADICALS. 395 


Thio-urea combines with 1 equivalent of acid to form salts. The m7trate, 
CSN,H,.HNO,, occurs in large crystals. Auric chloride and platinic chloride 
throw down red colored double chlorides from the concentrated solution. - Silver 
nitrate precipitates (CSN,H,),.Ag,O + 4H,O, and mercuric nitrate, (CSN,H,), 
3HgO + 3H,0O (see Berichte, 17, 297). 





Compound Sulphocarbamides, in witch hydrogen is replaced by alcohol radi- 
~ are formed :— 
(1) On heating the mustard oils (p. 279) with amine bases :— 


CS:N.C :H, + NH, = Cana? aH, 


Ethyl Sulphocarbamide, 
CS:N.C,H, + NH, CH, = CSC NCH, 5, ? 
Ethyl-methyl Sulphocarbamide. 
(2) By heating the amide salts of the alkyl dithiocarbamic acids (p. 385) :-— 
NH.C,H,; NH.C,H, 
CS<s(NH;.C;H,) ~ “°SNEEC,H, * “2 


The sulphocarbamides regenerate amines and mustard oils by distillation with 
P,O,, or when heated in HCl-gas :— 


NH(C,H,) 
Cc 3,,°{ == CS:N.C.H, th. Gate: 
Ethyl Sulphocarbamide, CS<NH,” € oH; crystallizes in needles, melting ee 


at 106°. _NH. CH 

Diethyl Sulphocarbamide, CSCNH. CHY’ consists of large crystals, not 
very soluble in water. It melts at 77°. NH. CH, 

Methyl Ethyl Sulphocarbamide, SNE. C, H, , is derived from ethyl 
mustard oil and methylamine. It melts at 54°. 

The sulphur in the alkylic sulphocarbamides may be replaced by oxygen if 


these compounds are boiled with water and mercuric oxide. Those that contain 
two alkyl groups yield the corresponding ureas :— 


NH.C,H NH.C,H 
CSO NH Sr aR gis adie COC NE. Gu = Hes, 


whereas the mono-derivatives pass into alkylic cyanamides (and melamines) after — 


parting with hydrogen sulphide (p. 289) :— pe es 
CSC NH, ‘GH; _ N:C.NH.C,H; + SH,. , seer Se 


On digesting the dialkylic sulphocarbamides with mercuric oxide and amines, 
oxygen is exchanged forthe imid- group and guanidine derivatives appear (p. 295) * — 


NH.C,H, /NH.C,H, ss 


cs = ot NH oe + Hg0 = CaN.GH, * 4 HgS + H,0. 
\ NHLGH, = 


3**5 
Consult Berichte, 23, 283, upon the different SE 


396 ORGANIC CHEMISTRY: 


Allyl Sulphocarbamide, CSC NH Aeglth 


union of allyl mustard oil with ammonia :— 


5, Thio-sinamine, is formed by the 


/NH.C,H; 
in tee 


It forms shining prisms, with bitter taste, and melts at 74°. It decomposes at 
higher temperatures. It is readily soluble in water, alcohol and ether; combines 
with one equivalent of acid, and forms salts with acid reaction. Water decom- 
poses them. Allyl cyanamide and triallyl-melamine are produced on boiling with 
mercuric oxide or lead hydroxide (p. 289). For the constitution of the dialkyl 
sulphocarbamides compare a aiid cite, ania and Berichte, 23, 271. 


Ethylene Sulphocarbamide, cs? oo H,, is obtained from ‘ethylene- 
Pp \.NH 4 72""4 y 


diamine and carbon disulphide (Berichée, 5, 242). It is crystalline, and melts at 
194°. It does not combine with acids. orice 

ia pseudo(iso) Sulphocarbamide, d Pa :NH or 

CH,—NH 

| ne NH,, is isomeric with the preceding. "It is a derivative of pseudo- 
CH, and 
sulphocarbamide (p- 391). It is obtained from HBr-ethyleneamine (p. 163) and 
potassium thiocyanate. Bromethyl-sulphocarbamide, CH,Br.CH,.NH.CS.NH,, 
is formed at first and splits off hydrobromic acid. Ethylene pseudo-suiphocarba- 
mide is a base with strong basic properties. Its salts crystallize well. Alkalies 
separate it from these in the form of an oil. This in time solidifies and then melts 
at 85° (Berichte, 22, 1141). 

Propylene-pseudo-thio-urea, C,H,:CSN,H,, from brompropylamine and 
potassium thiocyanate, is perfectly similar. It ‘also results from allyl thiourea by 
action of hydrobromic acid (Berichée, 22, biG 23, 964). 


CS:N.C,H, + NH, = CS 





Acetyl sulphocarbamide and Thiohydantoin are considered as acid derivatives 
of sulphocarbamide. ‘The latter is undoubtedly a derivative of the isomeric iso- 
thiocarbamide (p. 394). 

‘ ANH, /NH, ; 

Acetyl Sulphocarbamide, CSC NH! C,H,0, mec tiN Ksc? H,0” is 


obtained from thio-urea by heating it with acetic anhydride. Its formation from 
cyanamide (carbodiimide, p. 288) and thio-acetic acid argues for the second 
formula :— 


AN 
CN.NH, + C,H,0.SH = NEEC( 3G H,0° 


err Iterystallizes from hot water in prisms; these melt at 165°. 
The so-called Thio- or Sulpho-hydantoin, C,H,N,SO, is not constituted 
according to the formula I, corresponding to that of hydantoin (p. 391), but 
_ according to 2:— 
» NH.CO NH.CO 


, 
t CS ~ . | and2,HN:C” | * 
: or \NH. CH, eo A ay 
i Glycolyl Thio-urea. Glycolyl Tenthloviren: 





* Real sulphohydantoins (of the formula 1) have been prepared in the benzene 
series (see phenyl sulphhydantoin and Berichte, 17, 425). 


GUANIDINE DERIVATIVES. 397 


The grouping (Axna/en, 207, 121) in this instance is analogous to that shown 
by the isothio-amides (p. 260) and the phenyl isothiourethanes (p. 396). 

The closed, five-membered ring in thiohydantoin and in ethylene pseudo-thio- 
urea consists of three C-atoms, one N-atom, and one S-atom. It is known as the 
Thiazoline-ring. It is closely allied to thiazole derivatives (see these). 

Sulphohydantoin is obtained when chloracetic acid and its anhydride act on 
sulphocarbamide; or (analogous to the formation of acetylsulphocarbamide) by 
evaporating an aqueous solution of cyanamide and thioglycollic acid (p. 355), when 
the sulphohydantoic acid (see below), produced at first, parts with a molecule of 
water :— 

NH.CO 
HCL > bo te He 
2 


/ ie 
CN.NH, + he i — HN: eae 


Sulphohydantoin crystallizes from hot water in long needles, and decomposes 
near 200°. When boiled with baryta water it decomposes into thioglycollic acid 
and dicyandiamide. Unlike the thio-ureas, it is not desulphurized when boiled 
with lead oxide or mercuric oxide and water. 

Boiling acids convert it into mus¢tard-otl acetic acid, with elimination of NH,. 

Isonitrosohydantoin (erichte, 19, Ref. 14) is produced by the action of 
nitrous acid upon it. NH 


Sulphohydantoic Acid, C,H,N,SO, = HN:C¢ NH2 is obtained 
a eNarOs \.S.CH,.CO,H, 


by heating sulphocarbamide with sodium chloracetic acid. It is a crystalline 
compound, not very soluble in water. It resembles the amido-acids in having a 
neutral reaction, but dissolves in alkalies and acids with production of salts. When 
heated with acids it reverts to thiohydantoin. 


GUANIDINE DERIVATIVES. 


Guanidine, like urea, is capable of yielding acid derivatives 
(p. 296), but few of them, however, are known. Creatine and 
creatinine, compounds of great significance physiologically, belong 
in this class and are derived from glycocyamine. 


Glycocyamine, cai aN 302, guanidoacetic acid, is obtained by the direct 


union of glycocoll with cyanamide :— 
ANH 
CNN. 1 cH 7 eee eee 
\.CO,H 
\NH—CH,.CO,H. ae 
Cyanamide. Glycocoll. Glycocyamine. eg SE 


On mixing the aqueous solutions it separates after a time in granular c ystals. 
It is soluble in 120 parts cold water and rather readily in hot water; while it is 
insoluble in alcohol and ether. It forms crystalline compounds with acids and 
bases. When boiled with water and lead peroxide, or with dilute sulphuric.acid, 
it breaks down into guanidine, oxalic acid and carbon dioxide. hires: 

8-Guanidopropionic Acid, C,H,N,O, (alacreatine, CN,H,.CH,.CH,. 
CO,H), is homologous with the preceding, and is obtained in a similar manner 
from cyanamide and {-amidopropionic acid. It decomposes at 205°. Isomeric 
a-guanidopropionic acid melts at 180°. : 


398 ORGANIC CHEMISTRY. 


Glycocyamidine, C,H,N,0O, glycolyl guanidine, bears the same relation to 
glycocyamine as hydantoin °to ‘hydantoic acid (p. 391). Its hydrochloride is pro- 
duced when glycocyamine hydrochloride is heated to 160° :— 


/NH, /NH—CO 
C=NH =—C=NH | +H,0. 
\ NH—CH,—CO,H \ NH—CH, 


The free base crystallizes in deliquescent lamin, having an alkaline reaction. 
PtCl, precipitates its hydrochloride. 
The methy] derivatives of glycocyamine and glycocyamidine are :— 





NH co 
NHC’ NH = CZ | 
Bes a —CO,H ‘\N(CH,)—CH 
Creatine. Creatinine. 


Creatine, C,H,N,O,, methyl glycocyamine, occurs in the animal 
organism, especially in the juice of muscles, It may be artificially 
prepared, like glycocyamine, by the union of sarcosine (methyl 
glycocoll) with cyanamide :— 


NH.CH, NH, 
CN.NH, + | _ = NE:C% 
H,.CO,H \N(CH,)—CH,—CO,H 


To obtain creatine, exhaust finely divided flesh with cold water, boil the solution 
to coagulate the albumen, precipitate the phosphoric acid in the filtrate with baryta 
water and evaporate the liquid, then let it crystallize. 


Creatine crystallizes with one molecule of water in glistening 
prisms. Heated to 100°, they sustain a loss of water. It reacts 
neutral, has a faintly bitter taste and dissolves rather readily in 
boiling water; it dissolves with difficulty in alcohol, and yields 
crystalline salts with one equivalent of acid. 


When digested with acids, creatine loses water and becomes creatinine (see 
above), and with eet water it falls into urea and sarcosine :— 
NH(CH,) 
NH: em ie HO = 00g | : 
N(CH,)—CH,—CO,H \NH,  CH,.CO,H. 


Ammonia is liberated at the same time and methyl hydantoin (p. 392) is formed. 
~»>>When its aqueous solution is heated with mercuric oxide, creatine becomes oxalic 
acid and methyl guanidine. Ammonia and methylamine are disengaged when it 

i igttued with soda lime. 
a 


Creatinine, C,H,N,O, methyl glycocyamidine, occurs con- 

“ -stantly in urine (about 0.25 per cent.), and is readily obtained 
from creatine by evaporating its aqueous solution, especially when 
acids are present. It crystallizes in rhombic prisms and is much 
more soluble than creatine, in water and alcohol. . It is a strong 
base which can expel ammonia from ammonium salts and yields 


Meats) TS A eer 


ee ane con 


DIBASIC ACIDS. 399° 


well crystallized salts with acids. Its compound with zinc chloride, 
(C,H,N;O),.ZnCl,, is particularly characteristic. Zinc chloride 
precipitates it from creatinine solutions as a crystalline powder, 
dissolving with difficulty in water. 


Bases cause creatinine to absorb water and become creatine again. Boiled with 
baryta water it decomposes into methyl hydantoin and ammonia :— 


a NH—CO\ Jee CO 
NIC GNICH )--CH,)) 31? ot a. gm 


When boiled with mercuric oxide it breaks up like creatine into methyl-guanidine 
and oxalic acid. . 

When creatinine is heated with alcoholic ethyl iodide, the ammonium iodide of 
ethyl creatinine, C,H,(C,H,)N,O.I, is produced. Silver oxide converts this 
into the ammonium base, C,H,(C,H;)N,0.OH. 





DIBASIC ACIDS, C,H», 20, 


Oxalic Acid .C,H,0O,:== (GOs) 

Malonic 66 ' CHO, == CERO 
Succinic Acids C,H,O, = C,H,(CO,H), 
Pyrotartaric Acid C;H,O, = C,;H,(CO,H), 


Adipic “ C,H,,0,— C,H,(CO,H),, ete. 


The acids of this series contain two carboxyl groups, hence are 
dibasic. "They are produced according to methods analogous to 
those employed with the monobasic acids, by a repetition of the 
formation of the carboxyl group. 

The most important general methods are :— 

(1) By oxidation of oxy-fatty acids, in which OH is linked to 


Qe 


CH,.0H CO.OH 
| +0,= d + H,0O. 
CO.OH O.OH 
Glycoliic Acid. Oxalic Acid. 


(2) By oxidation of the corresponding dihydric alcohols :— 


CH,.OH CO.OH 
20, -- 2H,0. 
CH,.0OH CO.OH J 
Oxalic Acid. P 


(3) Conversion of monohalogen substituted fatty-acids into cyan- 


derivatives, and boiling the latter with alkalies or acids (pp. 21% : 
and 282):— 


CH,.CN co, 
| + 2H,0 = CH,” + NH;,. 
CO.OH \co,H 
Cyanacetic Acid. -  Malonic Acid. 


400. ORGANIC CHEMISTRY: 


(4) Conversion of the halogen addition products of the alkylens, 
C,,H,,,, into cyanides and the saponification of the latter :— 


CH,.CN CH,.CO,H 
| +4H,0 = | 4 2NH,. 
CH,.CN CH,.CO,H 


Only the halogen products having thetr halogen atoms attached to 
two different carbon atoms can be converted into dicyanides. 

(5) A very general method for the synthesis of dibasic acids is 
founded upon the transposition of aceto-acetic esters. Acid resi- 
dues are introduced into the latter and the products decomposed 
by. concentrated alkali solutions (p. 341). Thus from aceto- 
malonic ester we get malonic acid .— 


PCO. Ce 
\CO,.C,H; 


/CO,H, 


CH,.CO.CH »< €O2H} 


yields CH 


and from aceto-succinic ester, succinic acid :— 


//PHyCO,.CaHs CH,.CO,H 
: CH,.CO.CHE yields | ; 
CO,.C,H, CH,.CO,H 


(6) Ina perfectly similar manner, higher dibasic acids can be 
prepared from malonic esters, CH,(CO,R),. One hydrogen atom 
of CH, is replaced by sodium and then the alkyls introduced by 
means of the alkyl iodides :— 

a oR 
CHNaC 65°" fh yields CH(CH,)< Go? Rete. 


Sodium Malonic fester. Methyl] Malonic or Tsosnecinic Ester. 


In these monoalkylic esters the second hydrogen atom can be 
replaced by sodium and alkyls :— 


¥CO.R CH,\ /CO, R 
\CO,R yields CH. / C <.CO,R? etc. 
Peck S$ Malonic Ester. 


CNa(CH,) 


The free acids are obtained by saponifying the esters with 
alkalies. 


28, Umprae these syntheses the malonic ester is mixed with the theoretical 


amount of sodium dissolved in absolute alcohol (10 volumes), the alkyl iodide 

added, and heat applied until the alkaline reaction disappears. After expelling 

bo igh the excess of alcohol, the ester is precipitated with water (in preparing the dialkyl 

~ derivatives 2 equivalents of sodium alcoholate and alkyl iodide are added. Anuna/len, 

204,129). Tri- and poly- -carboxylic acids may likewise be obtained by the introduc- 

tion of acid esters (by means of chloracetic ester, etc. (p. 341 and Berichte, 15, 1109). 

The synthesis of the alkyl derivatives may also be effected by means of the alkyl 

iodides and zinc (Berichte, 20, 203). Allyl iodide reacts similarly with zinc 
(Berichte, 21, Ref. 181). 


DIBASIC ACIDS. 401 


The dibasic acids are also formed on oxidizing the fatty acids 
C,H,,,O., the acids of the oleic acid series, and the fats with nitric 
acid. Potassium permanganate oxidizes some hydrocarbons, C,H,,, 
to dibasic acids. s 





The acids of this series are solids, crystallizable, and generally 
volatile without decomposition. ‘They are mostly soluble in water 
and have a strong acid reaction. The melting points of the normal 
dicarboxylic acids exhibit the same regularity observed with the 
fatty acids (p. 215), z. ¢., the members containing an even number 
of carbon atoms melt higher than those with an odd number 
(Berichte, 10, 1286). The melting points of both series fall with 
increasing carbon content (Berichte, 18, Ref. 59). 

At higher temperatures those members which are capable of yield- 
‘ing anhydrides part with water and pass into such compounds, 
whereas, the others, having both carboxyl groups attached to one 
carbon atom, decompose more or less readily into CO, and mono- 
basic fatty-acids (p. 211). Thus, from oxalic acid we get formic 
acid, from malonic acid, CH,(CO,H),, acetic acid, from isosuccinic 
acid, CH;.CH(CO,H)., propionic acid, etc. Similarly, malonic 
acid, and mono-alkyl malonic acids, R.CH(CO,H),, are decom- 
posed, at the ordinary temperature, by concentrated nitric acid, 
with the evolution of two molecules of carbon dioxide, while the 
dialkyl malonic acids, R,C(CO,H),, and succinic, pyrotartaric and 
the unsaturated acids, fumaric and maleic, etc., are unattacked by 
cold nitric acid (Berichte, 18, Ref. 146; 19, Ref. 337). 

Having two carboxyls, the dibasic acids can form neutral and 
acid salts, likewise neutral and acid esters or ether-acids (similar to 
sulphuric acid) :— 


/CO,.C,H /CO,.C,H 
©2H4< co,.C,H, Cee 
Neutral Ester. Primary Ester. 


The best method to use in making the neutral esters is to dissolve 
the acid in alcohol, and while applying heat lead in a stream of | 
hydrogen chloride gas; on adding water the ester is precipitated, 
and may then be purified either by distillation or crystallization. 


See Berichte, 14, 2630, for the ester formation of dibasic acids (p. 251). 


With the dibasic acids the anhydride formation takes place within 
one molecule and leads to the formation of z#zmer anhydrides ; 
those resulting from the union of two molecules are not known (p. 

34 


402 ORGANIC CHEMISTRY. 


351). The anhydrides are obtained by either heating the acids (see 
above), or by the action of PC], (1 molecule) :— 


/CO,H a /CON 
CHAK Co*y + PCs = CHC Go >O + PCO + 2HCl. 
Succinic Acid. Succinic Anhydride, 


In many cases the analogous action of chlorides of the fatty acids, ¢. 2., acetyl 
chloride, on the free acids or their silver salts, is better adapted to the preparation 
of anhydrides (Berichte, 13, 1844) :— 

c 

CAL On ri ee ete ee CHK GoD? + C,H,0.0H + HCL. 

It is a singular fact that anhydrides cannot be prepared from 
oxalic acid, C,O,H,, malonic acid, CH,(CO,H),, isosuccinic acid, 

CH;.CH(CO,H),, etc., whereas succinic acid, normal pyrotartaric 
acid, also maleic and phthalic acids are capable of such formations. 
It seems, then, that anhydrides are only possible with dicarboxylic 
acids (p. 352) in which there is a chain of four or five carbon atoms.” 

The members obtained from succinic acid, by the entrance of 
_alkylens, are more inclined to the formation of anhydrides accord- 
ing to the number of methyl groups they may contain (Berichte, 

23, 101 and 620). 

- The anhydrides of this series are perfectly analogous in properties 
and transpositions to those of the fatty acids; they slowly dissolve 
in water, more readily on heating, with regeneration of their acids. 

When two molecules of phosphorus pentachloride are permitted 
to act on the dicarboxylic acids chloranhydrides of the acids are 
formed :— 


CO.Cl 


£00.08 4 spc, — CHC Coc + 2PCl,0 + 2HCl. 


C2H4< co.0H 
These behave in all respects like monovalent acid chlorides. 

The divalent residues joined to the two OH’s are termed the 
radicals of the dicarboxylic acids, ¢. g., C,O,, oxalyl, CH,(CO),, 
malonyl, C,H,(CO)., succinyl. 


The amides are similar to those of the monobasic acids (p. 255). Both acza 
amides or antic acids, and the real diamides exist :— 


/CO.NH /CO.NH 
4 ©2Hu< Co.0H C244 CO.NH,: 


pI Succinamic Acid. Succinamide. 
“tls peg 


* Malonic acid, succinic acid, and others, can be distilled without decompo- 
sition under reduced pressure. Adipic acid, CgH,,O,, is the first member of the 
series that can be distilled at the ordinary pressure without sustaining decomposition 
(Berichte, 22, 816). - ; 





DIBASIC ACIDS. 403 


The cmides are derived by substituting divalent acid radicals for two hydrogen 
atoms in one molecule of ammonia (Azma/en, 215, 172) :— 
CoH 6 NH, Succinimide. 
The amide compounds may also be derived from the primary and neutral am- 
monium salts by the withdrawal of water :— 


Acid Ammonium Salt — H,O yields Amic Acid. 
- oe « —2H,O0 *  Imide. 
Neutral eS — SEP. eae: : 


By withdrawing 4 molecules of H,O from the neutral salt the acid nitriles or 
cyanides of the divalent alcoholic radicals result (p. 265) :— 


/CO.O.NH /CO.NH “CN 
C2H4< CO.0.NH, CH. CO.NH, C2HaC cn: 
Ammonium Salt. Amide. Nitrile. 


_The possible cases of isomerism correspond with those of the 
C,H,, hydrocarbon groups ; the two COOH groups may be at- 
tached to two different carbon atoms or to a single carbon atom. 
Isomerides of the first. two members of the series— 





are not possible. For the third member two structural cases 
exist :— 
CH,.CO,H 


and CH, CHE Go "Hp 
CH,.CO,H 2 
Ethylene Dicarboxylic Acid, Ethidene Dicarboxylic Acid, 
Succinic Acid. Isosuccinic Acid. 


There are four possible isomerides with the formula CEs“ perass 
2 
etc. Many acids are named from malonic acid; this accords with: 
their synthesis and is quite practicable (p. 400). 


are. 


nee ONCE en oes I en ae ee 


1. Oxalic Acid, C,0O,H, (Acidum oxalicum), occurs in many 
plants, chiefly as potassium salt in the different varieties of Oxads 
and Rumex. ‘The calcium salt is often found crystallized in plant 
cells; it constitutes the chief ingredient of certain calculi. The 
acid may be prepared artificially by oxidizing many carbon com- 
pounds with nitric acid, or by fusing them with alkalies. It is 


* 


404 ORGANIC CHEMISTRY.’ 


formed synthetically by rapidly: heating sodium formate above 
440° :— 


CHO.ONa 
CHO.ONa = + Hy; 


by oxidizing formic acid with nitric acid (Berichte, 17, 9); by 
adding water to cyanogen :— 


CN CO.O.NH, 
| +4H,0= | > 
CN CO.O.NH, 


and by conducting carbon dioxide over metallic sodium heated to 
350—-360° :— 
2CO, + Na, = C,0,Na,. 

Formerly, the acid was obtained from the different oxalis species or by oxi- 
dizing sugar with nitric acid. At present it is prepared on an immense scale by 
fusing sawdust (cellulose) with a mixture of KOH and NaOH (equal parts) in 
iron pans and maintaining a temperature of 200-220°. The brown fusion is 
extracted with water and boiled with milk of lime. The separated calcium salt 
is decomposed with sulphuric acid and the filtrate evaporated to crystallization. 

The ease with which sodium oxalate is produced from sodium formate (above), 
and the latter from CO and NaOH (p. 217) would make it appear possible to 
obtain the acid on a commercial scale by these reactions (Berichte, 15, 1508). 


Oxalic acid with the formula, C,H,O, + 2H,O = C,(OH),, crys- 
tallizes in fine, transparent, monoclinic prisms, which effloresce at 
20° in dry air and fall to a white powder. It is soluble in g parts 
of water of medium temperature, and quite easily in alcohol. The 
hydrated acid melts at ro1° if rapidly heated, and the anhydrous 
at 189° (Berichte, 21, 1901). When carefully heated to 150° the 
anhydrous acid sublimes undecomposed ; rapidly heated it decom- 
poses into formic acid and carbon dioxide :— 


C,H,0, = CH,O, + CO,. 

Oxalic acid decomposes into carbonate and hydrogen by fusion 
with alkalies or soda-lime (p. 218):— 
C,0,K, + 2KOH = 2C0, K, + H,. 
_ Heated with concentrated sulphuric acid it yields carbon monox- 
_ ide, dioxide and water :— 

Md =, C,H,O, = CO, + CO + H,0. 

Nascent hydrogen (Zn and H,SQ,) converts it into glycollic acid. 


~The oxalates, excepting those with the alkali metals, are almost insoluble in — 
water. 
The neutral potassium salt, C,{0,K, +- H,O, is very soluble in water, and parts 
with its water of crystallization at 180°. The acid salt, C,0,HK, dissolves with 


ESTERS OF OXALIC ACID. © 405 


more difficulty, and occurs in the juices of plants (of Oxalis and Rumex). Potas- 
sium quadroxalate, C,O,KH, C,0,H, + 2H,0, forms triclinic crystals, soluble 
in 20 parts of water at 20°.” Commercial salt of sorrel consists generally of a 
mixture of the acid and the super-salt. 

' Neutral Ammonium Oxalate C,0,(NH,), + H,0O, consists of shining, 
rhombic prisms, and is easily soluble in water. When heated it becomes oxamide, 
which further decomposes into C 2N2, CO,, CO and NH,. Actd ammonium 
oxalate, C,0,H(NH,), yields oxamic acid on heating. The calcium oxalate, 
C,0,Ca + H. 2O, is formed ina crystalline state in plant cells; it is precipitated 
as a white crystalline powder (quadratic octahedra) on the addition of an oxalate 
to a warm solution of a calcium salt. (A salt with 3H,O separates from very 
dilute and cold solutions.) Calcium oxalate is insoluble in water and acetic acid, 
but is dissolved by the mineral acids. It parts with its water of crystallization at 
200°. The st/ver salt, C,0,Ag,, explodes when quickly heated. 


ESTERS OF OXALIC ACID. 


Oxalic Methyl Ester, C,0,(0.CH,),, is obtained by distilling oxalic acid (1 

part) or potassium oxalate (2 parts) with methyl alcohol (1 part) and sulphuric 

acid (1 part); or by boiling anhydrous oxalic acid with methyl alcohol. It forms 

sey rhombic plates, which are easily soluble in water and alcohol; possesses an 

aromatic odor, melts at 51° and distils at 163°. Water, especially when boiling, 
decomposes it into oxalic acid and methy] alcohol. 

CO.O.CH, 
The acid ester (methyl oxalic acid), dae , is very unstable, and is found 


in the mother-liquor from the neutral ester. 

Oxalic Ethyl Ester, C,0,(0.C,H,),, is an aromatic-smelling liquid, oe Sp. 
gr. 1.0793 at 20° and boils at 186°. It dissolves with difficulty in water, and is 
gradually decomposed by it into oxalic acid and ethyl alcohol. It is produced by 
distilling equal parts of salt of sorrel, alcohol and sulphuric acid. The following 
method yields it more readily. Anhydrous oxalic acid (3 parts) is dissolved on the 
water bath, in absolute alcohol (2 parts), and the solution then introduced into a 
tubulated retort and heated to 100°. Gradually raising the- temperature to 130°, 
the vapor of 2 parts absolute alcohol is conducted into the liquid; water and alco- 
hol distil off. The oxalic ester is separated from the residue by fractional distil- 
lation (Berichie, 18, Ref. 221). 

It forms oxamide and alcohol when shaken with aqueous ammonia; dry ammo- 
nia converts it into oxamic ester. Potassium ethyl oxalate, C,0,< oe 
mixed with C,0O,K,, is precipitated by adding alcoholic potash to a solution of 
oxalic ester. The same salt is formed when monochloracetic ester is heated with 
KNO,. It is a crystalline powder, which decomposes above 140°. Free ethyl 
oxalic acid is obtained by heating anhydrous oxalic acid with absolute alcohol, 
and distils undecomposed at 117° under 15 mm. pressure. Distilled under ordi- 
nary atmospheric pressure it decomposes into CO,, formic ester and oxalic ester. 
See Berichte, 19, 1442; 22, 1807, for homologous alkyloxalic acids. ~~ 


POCI1, converts potassium ethyl oxalate into chloroxalic ester, C 02 OCH, H,. 
A better method is to heat oxalic ester with PCl, until no more ethyl chloride is 
disengaged :— ; 
CO.0.C,H; CO.Cl 
ee + PCI, = | + POC], + C,H,Cl. 
CO.0.C,H, CO.0.C,H,; 


406 | | ORGANIC CHEMISTRY. . 


The first product is di-ethyl dichlorglycollic ester, which, upon distillation, sepa- 
rates into C,H,Cl and chloroxalic ester :— 


CLOCc.H, CoG 
| cas dy. HCl 
CO.0.C,H,; CO.0.C,H, 


This course is very convenient for the preparation of the ester of chloroxalic acid 
(Berichte, 19, 2159). The action of PCl; upon the homologues of oxalic ester is 
similar (Berichte, 19, 1443, Ref. 806). 

When separated from the POCI, by fractional distillation, ethyl oxalyl chloride 
is a pungent-smelling liquid, boiling at 131.5°. It fumes strongly in the air and 
rapidly decomposes into oxalic acid. It sinks in water and gradually passes into 
oxalic acid, hydrochloric acid and alcohol. It reacts very energetically with alco- 
hols and forms neutral esters. By further heating with PCl,, it is slowly changed 
to trichloracetic ester. 

The Isoamyl Ester, C,O0,(0.C,;H,,),, is obtained by heating amyl alcohol 
with oxalic acid. It is a thick oil which boils at 262°, and smells like bedbugs. 
Phosphorus pentachloride converts it into amyl oxalyl chloride, COs o.c H 

sada: | 
an oil which partly decomposes on the application of heat (Berichée, 14, 1750) ; 
diamyl dichlorglycollic ester (Berichte, 19, 1443) is an intermediate product. 

The Allyl Ester, C,0,(0.C,H,),, obtained by the action of allyl iodide on 
silver oxalate, boils at 206-207°, and has a specific gravity of 1.055. 





AMIDES OF OXALIC ACID. 


Oxamide, C,0,(NH,)., separates asa white, crystalline powder, 
when neutral oxalic ester is shaken with aqueous ammonia. It is 
insoluble in water and alcohol. It is also formed when water and 
a trace of aldehyde act on cyanogen, C,N,, or by the direct union 
of hydrocyanic acid and hydrogen peroxide (2CNH -++ H,O, = C, 
O,N,H,). Oxamide is partially sublimed when heated, the greater . 
part, however, being decomposed. When heated to 200° with 
water, it is converted into ammonium oxalate. 


Hydrorubianic Acid (p. 265) may be considered as Dithio-oxamide, C,S, 
_ (NH,),, or isothio-oxamide, C,(SH),(NH,)>. 


The substituted oxamides containing alcohol radicals are pro- 
duced by the action of the primary amines upon the oxalyl esters, 


% f / NH.CH ANH.C,H 
Pees 720s. NUCH. ©2024 NHC.H,’ 
Dimethyl Oxamide. Diethyl Oxamide. ri 


These compounds are more soluble in hot water and alcohol than 
oxamide, and distil without decomposition. The first melts at 210°. 
The alkalies break them up into oxalic acid and amines. 


OXAMIC ACID. 407 


When two molecules of PC], act upon dimethyl or diethyl oxamide the oxygen 
atoms are replaced by chlorine. The resulting amid+chlorides (p. 258) — 


CCl,.NH.CH, CCl,.NH.C,H, 
| and d , 
CCl,.NH.CH, Cl,.NH.C,H, 


readily part with three molecules of HCl and yield chlorinated bases: chloroxal- 
methylin, C§H,CIN,, and chloroxalethylin, C,H,CIN,. Both are very alkaline 
liquids, soluble in water ;.the first boils at 205°, the second at 217—218°. On heat- 
ing them with hydriodic acid and amorphous phosphorus we get bases that do not 
contain chlorine; Oxalmethylin, C,H,N,, and Oxalethylin, C,H, ,N,; the first 
is identical with methyl glyoxaline, the second with ethyl glyoxalethylin (p. 325). 
Oxamic Acid, CON OH is obtained from its ammonium salt, which is pro- 
duced by heating acid ammonium oxalate, or by boiling oxamide with ammonia, 
and then liberating the acid with hydrochloric acid (Berichte, 19, 3229). It is 
most easily obtained by boiling oxamethane with ammonia (Berichte, 22, 1569). 
It is a crystalline powder, that dissolves with difficulty in cold water, and melts at 
173°. It is monobasic and forms crystalline salts. It passes into acid ammonium 
oxalate when heated with water. 
Its esters result from the action of alcoholic, or dry ammonia upon the esters of 
oxalic acid :— 
/O0.C,H 
C,02< 0.C,H, 


! NH 
+ NH,= COX 6.CH, + C,H,.OH. 


Ethyl Oxamic Ester (Oxamethane), CO 6.eH , consists of shining, fatty- 


feeling leaflets. It melts at 114-115° and boils at 200°. PCI, converts it into the 
amid-chloride, CC\,(NH,).CO.O.C,H, (see above), a crystalline compound, which 
reverts to oxamethane, when exposed to moist air. HCl separates when heat is 
applied and the product is cyancarbonic ester, CN.CO.O.C,H;. Isomeric bodies, 
alkylic oxamic acids, are obtained by heating salts of the primary amines of 


oxalic acid. Ethyloxamic acid, COX OH gre crystallizes in six-sided plates 


and melts at 120°. /N(C,Hs) 
Ethyl Dietho-oxamic Ester, C02, a 4.” (Diethyloxamethane), boils at 254° 
and is produced by the action of diethylamine upon oxalic esters. It regenerates 


diethylamine on distilling with potash. A method for separating the amines (p. 
158) is based on this behavior. 


Oxalimide, SNH, is obtained from oxamic acid by the aid of PCI, or PC1,O. 
O 


It dissolves with difficulty in cold water, and crystallizes in shining needles from 
hot water. Boiling water decomposes it into oxalic acid and oxamide. Aqueous 
ammonia converts it into oxamide (Berichte, 19, 3229). 

Cyanogen is the nitrile of oxalic acid (p. 263). 


The oximido-ether is produced when HCl acts upon cyanogen in 
alcoholic solution :— 


CN C(NH).O.C,H, 
| - + 2C,H,OH = 
CN C(NH).O.C,H, 


408 ORGANIC CHEMISTRY. 


This is analogous to the formation of the imido-ethers (p. 292) 
from nitriles. 
Alcoholic ammonia converts the product into oxamidine, 
C(NH).NH, 
(Berichte, 16, 1655). 
C(NH).NH, 
C(N.OH).NH, 
Oxaldiamid-oxime, | , the dioxime of — is formed when 
C(N.OH).NH, 
‘ammonia acts upon oximido-ether, or hydroxylamine (2 2 molecules) upon cyano- 
gen, CN.CN, upon cyan-aniline, or hydrorubianic acid (p. 265). It crystallizes, 
from alcohol, in white needles, melting at 196°. It exhibits all the properties of 
the amidines, and dissolves in acids and alkalies ( Berich/e, 22, 2942 and 2946). 





(2) Malonic Acid, C;H,O, = CH,(COOH),, occurs in the 
_ deposit found in the vacuum pans employed in the beet sugar 
manufacture. It is obtained by the oxidation of malic acid (and 
hydracrylic acid) with chromic acid :— 


CO,H 
CH,.CO,H , | : 
| + 0, = CH, + CO, + H,O; 
CH(OH).CO,H Ne 
CO,H 


by the decomposition of malonyl urea (barbituric acid, see this) 
with alkalies, and by the oxidation of propylene and allylene with 
potassium permanganate. It may be prepared, too, by boiling 
5 Sgyacis acid (p. 262) with alkalies or acids :— 


7 CN 


CO,H 
2 Co,H + 2,0 = CH,~ 4+ NH,. 


w, Ss 2< CO,H 


Prepa?ation.—100 grams of chloracetic acid, dissolved in 200 grams of water, 
are neutralized with sodium carbonate (110 grams), and to this 75 grams of pure, 
pulverized potassium cyanide are added, and the whole carefully heated, after 
solution, upon a water-bath. The cyanide produced is saponified either by con- 
centrated hydrochloric acid or potassium hydroxide (Berichte, 13, 1358, and 
Annalen, 204,125). To obtain the malonic ester directly, evaporate the cyanide 
solution, cover the residue with absolute alcohol and lead HCl gas into it (Azna- 
len, 218, 131). 


~ Malonic acid crystallizes in large tables or laminz. It is easily 
soluble in water, alcohol and ether, and melts at 132°. At higher 
. temperatures it decomposes into acetic acid and carbon dioxide. 
The ethyl ester is similarly broken up into CO, and acetic ester 
when it is heated with water to 150° Bromine in aqueous solution 
converts it into tribromacetic acid and CO,. Its darium salt, 


MALONIC ACID. : 409 


(C,;H,O,)Ba + 2H,O, forms silky, shining needles. The calcium 
salt, (C;H,0O,Ca) ++ 2H,0, dissolves with difficulty in. cold water, 
hence is precipitated by calcium chloride from neutral solutions. 
Silver nitrate precipitates the sz/ver salt, C;H,Ag,O,, as a white, 
crystalline compound. 


The malonic es¢ers are obtained by dissolving the acid in alcohol, and conduct- 
ing HCl-gas into the solution (see above). 

The methyl ester, CH,(CO,.CH,)., boils at 175-180°. The ethyl ester boils at 
195°: its specific gravity at 18° is 1.068. This compound is useful in performing 
various syntheses (see above). By the action of sodium ethylate upon it the 
Na-compounds, CHNa(CO,.C,H,), and CNa,(CO,.C,H,;), (Berichte, 17, 
2783), result. Upon heating sodium malonic ester to 145° a condensation of 3 
molecules occurs, with a splitting off of 3 molecules of alcohol, and there 
remains the ester of trisod-phloroglucin tricarboxylic acid (a derivative of ben- 
zene) ( Berichte, 18, 3458) :-— 


3CHNa(CO,.C,H,), = C,0,Na,(CO,.C,H,), + 3C,H,.OH. 


The amide of malonic acid (CH,.(CO.NH,),), formed from malonic ester and 
ammonia, consists of crystals, and melts at 170° (Berichte; 17, 133). 


Malononitrile, CH, eee methylene cyanide, is obtained by distilling cyanace- 


tamide, CN.CH,.CO.NH,, with P,O;. A crystalline mass, melting at 30° and 
boiling at 218° C. Silver nitrate precipitates CAg,(CN), from the aqueous solu- 
tion (Berichte 19, Ref. 485). ; 

As in the aceto-acetic esters, so in the malonic esters, the hydrogen of the methy- 
lene group (CH,) can be replaced by alkali metals (p. 400). Malonic ester 
unites with formaldehyde to produce propantetracarboxylic ester (Berichie, 19, 
1054). Consult Berichte, 20, Refs. 504, 552, upon the action of sodmalonic 
esters upon unsaturated acids. 

When iodine acts upon sodmalonic ester the product is an ester of ethane-tetra- 
carboxylic acid. The disodium compound, under like treatment, would yield 
ethylene-tetracarboxylic ester, C,(CO,R),4. 

When nitrous acid is conducted into the solution of the sodium compound of 
the ethyl ester, isonitrosomalonic ester, C(N.OH)(CO,.C,H,),, is formed. 
This is a yellow oil which decomposes when heated. «= Its specific gravity at 15° 
is 1.149. Saponification with alkalies liberates isonitrosomalonie acid, 
C(N.OH)(CO,H),. This is also formed by the action of hydroxylamine 
(Berichte, 16, 608, 1621) upon violuric acid (see this) and mesoxalic acid, 
CO(CO,H),. It is easily soluble in water, crystallizes in shining needles, and 
melts near 126°, decomposing at the same time into hydrocyanic acid, carbon 
dioxide and water, Nitromalonic Ester, CH(NO,)(CO,.C,H;), forms when 
malonic ester dissolves in concentrated nitric acid. It dissolves in ammonia and 
forms an ammonium salt (Berichte, 23, Ref. 62). Amidomalonic Acid, 
CH(NH,).(CO,H),, is obtained from it by reduction with sodium amalgam. This 
new acid is readily dissolved by water, and when warmed passes into glycocoll, 
CH,(NH,).CO,H and CO,. The amide of amidomalonic acid is obtained from 
chlormalonic ester (Berichte, 15, 607). 

Chlormalonic Ester, CHCI(CO,.C,H,), is obtained by conducting chlorine 
into warm malonic ethylate. It boils at 222°. When saponified with excess of 
caustic alkalies it yields oxymalonic acid (tartronic acid), CH.OH.(CO,H),. The 
addition of one molecule of sodium ethylate to its solution produces at first sodium 
chlormalonic ester, CNaCl(CO,R),. The alkylogens convert this into chlorinated 


41ToO ORGANIC CHEMISTRY. 


alkyl malonic esters (Berichte, 13,2159). The latter yield higher oxydicarboxylic 
acids, R.C(OH)(CO,H), (Amualen, 209, 232), when saponified with excess of 
caustic alkalies. 

Two molecules of sodium alcoholate convert it into the sodium salt of chdor- 
malonic acid, which crystallizes in shining prisms that melt at 133°, and at 180° 
decompose into CO, and monochloracetic acid (Berichte, 15, 605). 

Monobrom-malonic Acid, CHBr(CO,H),, is produced in slight quantity 
when malonic acid is treated with bromine. It consists of deliquescent needles. 
Silver oxide converts it into oxymalonic acid (tartronic acid). 

Dibrom-malonic Acid, CBr,(CO.OH),, is formed when bromine (dissolved 
in chloroform) is allowed to act upon malonic acid. Deliquescent needles, which 
melt at 126° and then decompose. Heated with baryta water it changes to dioxy- 
malonic acid (mesoxalic acid). 

Cyanmalonic Ester, CH(CN)(CO,R),, results from the action of cyanogen 
chloride upon sodium malonic ester (Berichte, 20, Ref. 563), or acetyl chloride 
upon sodium cyanacetic ester. It is~a pungent-smelling liquid which boils with 
decomposition ina vacuum. It has avery acid reaction, and decomposes-the alka- 
line carbonates, forming salts, like CNa(CN)(CO,R), (Berichte, 22, Ref. 567). 





/CO,H 
S. succinic Acids, C,H,O, — C At CO, HH 
CH,.CO,H* cO,H 
CHCHC. 2 ; 
CH;.CO,H CO. H 
Ordinary Succinic Acid. Isosuccinic Acid. 


vi. Succinic Acid, or ethylene dicarboxylic acid, occurs in 
amber, in some varieties of lignite, in resins, turpentine oils and in 
animal fluids. It is formed in the oxidation of fats with nitric acid, 
in the fermentation of calcium malate or ammonium tartrate and 
in the alcoholic fermentation of sugar. 
It is synthetically prepared :— 

‘ (1) By boiling ethylene cyanide (from ethylene bromide) (p. 303) 

with alkalies or acids :— 


. CH,.CN  CH,.CO,H 


2 
| + 4H,0 = | + 2NH,; 
CH,.CN CH; COU 


/ (2) By converting #-iodpropionic acid (p. 224) into cyanide 
and decomposing the latter with alkalies or acids :— 


“CN /CO,H 
Dees CH. CG 1 S20 CHL cy .CO,H 


* Considered stereochemically, succinic acid must have the axial-symmetric 
HO,C.CH, 
configuration, . The plane-symmetric form is unstable, and is 
CH,.CO,H 
CH,.CO 


only f.xed in succinic anhydride, | So 
CH,.CO” 


+ NH;; 





SUCCINIC ACID. AII 


(3) By the action of nascent hydrogen upon jnnientc and maleic 
acids :— 
/ CO,H 


/CO,H | - 
\ CO, H 


be «\CO,H? 


+H,=CH 


(4) By reducing malic acid (oxysuccinic acid) and tartaric acid 
(dioxysuccinic acid) with hydriodic acid (p. 41) :— 


CH,.CO,H CH,.CO,H 
l + 2HI= | +H,O +1, 
CH(OH).CO,H CH,.CO,H 
Malic ‘Acid. Succinic Acid. 
CH(OH).CO,H CH,.CO,H 
4HI = | + 2H,O + 2I,. 
CH(OH).CO,H CH,.CO,H | 


Tartaric Acid. 


Malic acid undergoes a like reduction in the fermentation of its 
calcium salt. 

(5) By the decomposition 6 aceto-succinic esters (p. 400), and 
from ethene-tricarboxylic acid by the elimination of carbon dioxide. 


Preparation.—Distil amber from an iron retort; evaporate the distillate and 
purify the residual, brown crystalline mass, by crystallization from dilute nitric 
acid. The acid is easily prepared by letting calcium malate ferment. Water 
and rancid cheese are added to crude calcium malate and the mixture let stand 
at a temperature of 30-40° for several days. Subsequently the succinate of cal- 
cium, obtained in this manner, is decomposed with sulphuric acid, the gypsum 
filtered off and the filtrate evaporated to crystallization. Consult Berichte, 14, 214, 
upon the production of succinic acid by the fermentation of ammonium tartrate. 


Succinic acid crystallizes in monoclinic prisms or plates, and has 
a faintly acid, disagreeable taste. It melts at 180° (185°) and dis- 
tils at 235°, at the same time decomposing. partly into water and 
succinic anhydride. At the ordinary temperature it dissolves in 20 
parts of water. It dissolves with more difficulty in alcohol. Ether 
will extract nearly all of the acid from its aqueous solution. 

Uranium salts decompose aqueous succinic acid in sunlight into 
propionic acid and CO,. The galvanic current acts as indicated 
by the equation (p. 87) :— 


C,H,(CO,H), = C,H, + 2CO, + H,. 


It (also the alkyl succinic acids) forms fluorescein dyes when heated with resor- 
cinol and sulphuric acid. 

The salts with the alkali metals are readily soluble in water. The Aotassium 
salt, C,H,O,K, + 3H,O, forms deliquescent needles. The calcium salt, 
C,H <0. «Ca, separates with 3 molecules of H,O from a cold solution, but when 
it is deposited from a hot liquid it contains only 1H,O. It dissolves with diffi- 
culty in water. When ammonium succinate is added to a solution containing a 
ferric salt, all the iron is precipitated as reddish-brown basic ferric succinate. 

Ethyl Succinic Ester, C,H,(CO,.C,H,),, is obtained in the action of hydro- 


412 ORGANIC CHEMISTRY. 


chloric acid upon an alcoholic solution of succinic acid. It is a thick oil, insoluble 
in water and boils at 216°. : 

Its specific gravity at 0° is 1.072. Sodium converts it into ethyl succino-succi- 
nate. 

Methyl Succinic Ester, C,H,(CO,.CH,),, has been obtained from silver suc- 
cinate and methyl iodide, as well as from succinyl chloride and sodium methylate. 
It melts at 19°, and boils at 80°, under a pressure of 10 mm, 

Ethylene Succinic Ester, C,H ROD 4) 1S produced by heating suc- 

2 . 
cinic acid and ethylene glycol to 200°. It fuses at 90°, and decomposes upon dis- 
tillation. 


Succinic Anhydride (succinyl oxide), CHK G9 20. is produced in the dis- 


tillation of succinic acid, or more readily by heating it with 1 molecule of PC, ; 
further, by heating succinic acid with acetyl chloride (p. 402). It crystallizes in 
needles or prisms from alcohol or ether, melts at 120° and distils at 250°, When 
boiled with water, it reverts to succinic acid. 

Two molecules of PC], convert succinic acid into— 

; 5 CO.Cl CCl ; 

Succinyl Chloride, CHK CO.Cr or CHK 66 10 (Berichte, 22, 3184). 
This is an oil, solidifying at 0° and boiling at 190°. It forms succinic dimethyl 
ester with 2 molecules of sodium methylate. By acting with sodium amalgam 
upon an ethereal solution of succinyl chloride and glacial acetic acid, we get 
butyrolactone, C, H, <é5*>° (p. 362), which was formerly considered succinic 
dialdehyde, C,H,(CHO),. 

Zinc ethide converts succinyl chloride into C,H Ket O, y-diethyl- 
butyrolactone, which boils at 230°; it forms salts of the corresponding acid with 
alkalies. : 

Succinamide, CHES NE is produced by shaking succinic ester with 
aqueous ammonia. It is a white powder. It is insoluble in water and alcohol, 
and crystallizes, from hot water, in needles. At 200° it decomposes into ammonia 
and succinimide. 


Ethylene cyanide, C,H,(CN),, (p. 303), is the nitrile of succinic acid. 

Succinimide, CHL 66 DNE. Gentle ignition of the anhy- 
dride in a current of dry ammonia or the distillation of ammonium 
succinate produces this compound. It crystallizes with 1 molecule 
of H,O in rhombic plates, and dissolves readily in water and 
alcohol. It crystallizes from acetone in rhombic octahedra without 
any water. When anhydrous it melts at 126° and boils at 288°. 


Succinimide combines with metallic oxides like those of silver and lead, exchang- 
ing its imide hydrogen for metals, for instance, C,H KG DNAs. The same com- 
pounds are obtained by the double decomposition of the potassium derivative with 
salts of the heavy metals (Anualen, 215, 200). The potassium compound, C,H, 
(CO),NK and C,H,(CO),.K + %H,0O, is formed by adding alcoholic potash to 
an alcoholic solution of succinimide. Ether precipitates it, either as a powder, or 
crystalline mass, The sz/yer salt, C,H,(CO),NAg and C,H,(CO),NAg -} 
144H,0, crystallizes in silky needles. 


PYRROLIDINE. 41% 


These compounds show that succinimide, like other imides, possesses 
an acid character. 

It is not only the carboxyl group that determines the acid char- 
acter of the carbon compounds ; the imide group, NH, also seems 
capable of exchanging hydrogen for metals (forming salts), if it 
be attached to one or two carbonyl groups, CO (as in CO—=WNH, 
cyanic acid, and in CO NED. This is particularly manifest in the 


urea derivatives of the dicarboxylic acids (see these). 


Methyl Succinimide, CHC eh NICHE is obtained by distilling methy]l- 


amine succinate. It crystallizes in leaflets, melts at 66.5° and boils at 234°. 
Ethyl Succinimide, C,H,Z CO DN-GHy crystallizes in broad needles, which 
dissolve easily in water, alcohol and ether. It melts at 26° and boils at 234°. 
On distilling succinimide with zinc dust, oxygen is withdrawn 
and pyrrol, C,H;N (see this), is formed :— 


CH,.CO CH=CH 
l SNH yields | SNH. 
CH,.CO (Cn en: 
Succinimide. Pyrrol. 


Ethyl Pyrrol, C,H,N(C,H;), is obtained in a similar manner from 
ethyl succinimide. ’ 

Pyrrolidine, C,H,N (Berichte, 20, 2215), is formed in the action 
of sodium upon succinimide dissolved in absolute alcohol. 


Succinamic Acid, GE. COOH” is produced by heating succinimide with 


baryta water :— 
/ CO. 433 /CO.NH 
GH co /NH + H,O = CHAS CO,H “ 


It is crystalline, and water decomposes it with ease into succinic acid and 
ammonia. 





See Annalen, 254, 155, upon the Chlorsuccinic Acids. 

Mono- and Dibrom-succinic Acids are formed when succinic acid, bromine 
and water are heated to 150-180° in sealed tubes. The first is the chief product 
when an excess of water is used. The bromine is more readily introduced into 
succinic esters, or succinyl chloride, or the anhydride (p. 221). It is not even 
necessary to use the last two compounds as such; it will suffice to warm the suc- 
cinic acid with amorphous phosphorus and water (Berichte, 21, Ref. 5). 

Monobrom-succinic Acid, C,H,Bré Rees is obtained by the union of 
fumaric or maleic acid with HBr(C,H,O, + HBr — C,H, BrO,) (Annalen, 254, 
161). It crystallizes in warty masses, consisting of minute needles, and is readily 


414 ORGANIC CHEMISTRY. 


soluble in water. It melts at 160°, and decomposes into HBr and fumaric aci:! 
It suffers similar decomposition when heated with water. On boiling with moist 
silver oxide it yields oxysuccinic acid, C,H,(OH)(CO,H), (Malic Acid). Its 
ethyl ester, C,H,Br(CO,.C,H,),, boils at 150-160°, under 50 mm. pressure. 
With KCN, or when distilled at the ordinary temperature, it forms fumaric ester 


(Berichte, 22, Ref. 813). Its anhydride, C,H,Br¢ 
ing the acid with acetyl chloride. It melts at 30°. When distilled it decomposes 
into hydrobromic acid and maleic anhydride. 

Dibrom-succinic Acid, C,H,Br,(CO,H),, results by the direct union of 
fumaric acid with bromine. It may be obtained by heating succinic acid (12 
parts) with bromine (33 parts) and water (12 parts) to 150-180°, until all the 
bromine has disappeared. It is more easily prepared by heating fumaric acid with 
bromine and water to 100° C, (Berichte, 18,676). It consists of prisms which 
are not very soluble in cold water. When heated to 200—235° it breaks up into 
HBr and brom-maleic acid. Boiling water decomposes its salts; the silver salt 
yields dioxysuccinic acid (inactive tartaric acid), the sodium-salt monobrom-malic 
acid, C,H,Br(OH)(CO,H),, and the barium salt, inactive tartaric acid and mono- 
brom-maleic acid, C, HBr(CO,H),. When dibromsuccinic acid is heated with a solu- 
tion of potassium iodide it becomes fumaric acid; boiling water decomposes it into 
HBr and brom-maleic acid. The methyl ester, C,H,Br,(CO,.CH,)., melts at 
62°; the ethyl ester at 68°, and when distilled it suffers decomposition. It forms 
fumaric ester when digested with reduced silver. 

Isodibrom-succinic Acid, C,H,Br,(CO,H),, is isomeric with the preceding. 
It is obtained in slight quantity by adding bromine to succinic acid, but is better 
prepared by the addition of Br, to maleic acid (see this), or by digesting the anhy- 
dride of the latter with water. Itis crystalline and very soluble in water. It melts 
at 160° and decomposes at 180°, or by boiling with water, into HBr and so-called 
brom-fumaric acid (p. 425). Silver oxide and water convert it into brom-fumaric 
and racemic acids (Berichte, 21, 267). Sodium amalgam changes it to succinic 
acid. When warmed with a solution of potassium iodide it passes into fumaric 
acid, 

The esters of this acid are prepared by conducting HCl-gas into the alcoholic 
solution of the acid. They are liquids, and readily decompose when heated. The 
anhydride, C,H,Br,(CO),O, results on heating maleic anhydride, C,H,(CO),O, to 
100° with bromine (dissolved in chloroform). It crystallizes in tables, melts at 
42°, and at 100° decomposes into HBr and brom-maleic anhydride. It readily 
unites with water to yield isodibrom-succinic acid. 

_ Both dibrom-acids are converted by alcoholic potash into acetylene dicarboxylic 
acid, C,(CO,H), (p. 431). 


>O, is produced by heat- 
CO 


It was generally assumed that the two dibrom-acids were derived 
from ordinary succinic acid and corresponded to the formulas :— 


CHBr.CO,H CBr,,CO,H 
b and | 
HBr.CO,H CH,.CO,H 
Dibromsuccinic Isodibromsuccinic 
Acid. Acid. 


Their reactions, however, indicate that both have the first struc- 
tural formula (Berichte, 21, 264, 788). They, therefore, exhibit 
the phenomenon of alloisomerism (p. 50), analogous to that of all 





DIAMIDO-SUCCINIC ACID. 415 


-CHX.CO,H 
the other symmetrical disubstituted succinic acids, | 
(p. 419). CHX.CO,H 


Tribrom-succinic Acid, C,HBr,(CO,H),, is produced when bromine (and 
water) acts upon brom-maleic acid and isobrom-maleic acid; it consists of acicular 
crystals, which melt at 136-137°. The aqueous solution decomposes at 60° into 
CO,, HBr, and dibromacrylic acid, C,H, Br,O,, which melts at 85°. 

Sulpho-succinic Acid, C,H, { {6 #7'7#, is obtained by dissolving succinic 
acid in fuming sulphuric acid, or by the union of fumaric or maleic acid with pri- 
mary alkali sulphites. Itistribasic. 

C(N.OH).CO,H 
Isonitroso-succinic Acid, d , oximido-succinic acid. Its ethyl 
H,.CO.H 


ester is formed by the action of hydroxylamine hydrochloride upon oxalo-acetic 

ester. It is a colorless oil. Sodium amalgam reduces it to aspartic acid (Berichte, 

21, Ref. 351). The mono-ethyl ester is obtained from the dinitroso- derivative of 

succino-succinic ester. It yields ethylic-asparto-ether acid (Berichte, 22, Ref. 241). 
- C(N.OH).CO,H 

Di-isonitroso-succinic Acid, . ,is formed by acting upon tetra- 
C(N.OH).CO,H 

oxysuccinic acid with hydroxylamine. It crystallizes in prisms and melts with 

decomposition at 128-130° (Berichte, 16, 2985). 


Amido-succinic acid (aspartic acid), C,H,(NH,) (CO,H),, and 
amido-succinamic acid (asparagine), CH,(NH,)¢ CO. NH.’ will 
2° 2 


be described under malic acid, as they bear the same relation to it 
that glycocoll (amido-acetic) bears to glycollic acid. 


Diamido-succinic Acid, GHA(NH,),< Corp is formed from dibromsuccinic 
acid by the action of ammonia, and also results from the diphenylhydrazine deriva- 
tive of dioxy-tartaric acid through the decomposition brought about by sodium 
amalgam (Berichte, 20, 245) :— 


C(OH),.CO,H CH(NH,).CO,H 
: yields | ‘ 
C(OH),.CO,H CH(NH,).CO,H 


It is almost insoluble in the ordinary reagents, but dissolves in mineral acids and 
alkalies, with the formation of salts, which are nearly all decomposed by water. 
It separates from them as a crystalline powder. Rapidly heated, it is almost 
wholly carbonized. As it contains 2 COOH groups and 2 amide groups, it is a 
diglycocoll (p. 367). - ; 

Another diamido-succinic acid has been described. Its ethyl ester was obtained 
by the action of alcoholic ammonia upon dibrom-succinic acid (Berichte, 15, 1848). 

C(N,).CO,.C,H, 

Ethyl Diazo-succinic Ester, | , is obtained from HCl-ethyl 

: CH,.CO,.C,H, 
amido-succinic ester (ester of aspartic acid) by the action of sodium nitrite (p. 
373). It is a dark-yellow oil, which volatilizes in steam with only partial decom- 


416 ORGANIC CHEMISTRY. 


position. Its reactions show it to be wholly analogous to diazo-acetic ester. When 
boiled with water it yields nitrogen and fumaric ester. When heated, it sustains 
a complicated transposition with the formation of the ester of azin-succinic acid 
(Berichte, 18, 1302; 19, 2460). Zinc dust and ammonia convert it into the esters 
of aspartic acid, 

Cyan-succinic Acid, C,H,(CN)(CO,H),, is produced when potassium cyanide 
acts upon brom-succinic ester (p. 262). The hydrogen of the CH-group, in its 
diethyl ester, can be replaced by sodium and alkyls ( Berichie, 22, Ref. 267). 


J (2) Isosuccinic Acid, CH;.CH7 ce e ethidene dicarboxy- 
lic acid, methyl malonic acid, is obtained Gow a-chlor- and brom- 
propionic acids through the cyanide (Berichie, 13, 209) :— 


ACN /CO,H 
\CO, \CO,H 


When ethidene bromide, CH,.CHBr,, is heated with potassium 
cyanide and alkalies, we do not obtain ethidene succinic acid by 
the operation, but ordinary ethylene succinic acid. When malonic 
esters are treated with sodium and methyl iodide they yield iso- 
succinic acid. ‘The latter crystallizes in needles or prisms, and is 
more readily soluble than ordinary succinic acid (in 4 parts H,O). 
It sublimes below 100° in plates, melts at 130°, and by further 
application of heat breaks up into carbon dioxide and propionic 


acid (p. 351) — 
CH,.CH 


CH,.CH W + 2H,O = CH,.CH 4+ NH,. 


CO.OH 
CO. On = — CH,.CH,.CO,H + CO,. 


When heated with water above 100° the result is the same. ‘The 
ethyl ester, CJH,O,(C,H;)., boils at 196°; the methyl ester at 179°. 


Brom-isosuccinic Acid, CH,.CBr(CO,H), is formed on heating isosuccinic 
acid with water and bromine to 1. Large deliquescent prisms, which decom. 
pose readily. 


7 : 3 CO,H 
. Pyrotartaric Acids, C;H,O, = C,Hy¢ Khn. 
4. ry » 5 a4 . *\ CO,H 
Four of these acids are theoretically possible :— 
CH, CH,.CO,H CH, CH, 
| | 
' CO,H 
CH.CO,H CH, or ee and £ CoH: 
| | 
CH,.CO,H CH,.CO,H CHC Go! a CH, 
Pyrotartaric Acid. Glutaric Acid. Ethyl Malouic: Acid. Dimethyl Malonic Acid. 
7, CO,H 


(1) Pyrotartaric Acid, CH;.CH< cH. CO,H? propylene di- 


carboxylic acid, was first obtained in the dry distillation of tartaric 


q 
‘ 
: 
3 
> 





GLUTARIC ACID. 417 


acid (mixed with pumice stone). It may be synthetically prepared 
from propylene bromide, by means of the cyanide— 


/CN /CO,H 
OE CES Ca: On \.CH,.CO,H, 


yields CH,.CH 
or by the action of nascent hydrogen upon the three isomeric 
acids: ita-, citra-, and mesa-conic acids: C,;H,O, + H, = C;, 
H,O,. It is further formed from a- and #-methyl aceto-succinic 
esters (made by introducing methyl into aceto-succinic esters) and 
by acting on aceto-acetic esters with a-brompropionic esters, p. 400; 
from 8-brombutyric acid by means of the cyanide, and by heating 
pyroracemic acid, CH;.CO.CO,H, alone to 170°, or with hydro- 
chloric acid to 100°. ‘The acid consists of small, rhombic prisms, 
which dissolve readily in water, alcohol and ether. It melts at 112° 
and when quickly heated above 200°, decomposes into water and 
the anhydride. If, however, it be exposed for some time to a tem- 
perature of 200-210°, it splits into CO, and butyric acid. It suffers 
the same decomposition when in aqueous solution, if acted upon -by 
sunlight in presence of uranium salts. 


The neutral calcium salt, C;H,O,Ca + 2H,0O, dissolves with difficulty in water. 
The same may be remarked of the acid potassium salt, C;H,KO,. The ethyl ester 
boils at 218°. £CO 

The anhydride, CH,.CH & CH,.CO >O, obtained by heating pyrotartaric acid 





above 220°, is a heavy oil, which boils at 244.9°, sinks in water and gradually 
reverts to the acid (Annalen, 191, 48). Be 


(2) Glutaric Acid, Pik cn coe Normal _ Pyrotartaric 
Acid, was first obtained by the reduction of a-oxyglutaric acid with 
hydriodicacid. It may be synthetically prepared from trimethylene 
bromide (p. 102), through the cyanide; from aceto-acetic ester by 
means of the aceto-glutaric ester (p. 400); from glutaconic acid 
(p. 425), and from propane tetracarboxylic acid, C;H,(CO,H),, by 
the removal of 2CO,. Glutaric acid crystallizes in large mono- 
clinic plates, melts at 97°, and distils near 303°, with scarcely any 
decomposition. Itis soluble in 1.2 parts water at 14°. : 


The calcium salt, C;Hg0,Ca + 4H,O, and barium salt, C,H,0O,Ba + 5H,O, 
are easily soluble in water; the first more readily in cold than in warm water. 
The ethyl ester, C;H,O,(C,H;) 2, boils at 237°. The anhydride, C,H,O;, forms 
on slowly heating the acid to 230-280°, and in the action of acetyl chloride on the 
silver salt of the acid. It crystallizes in needles, melting at 56-57° (after solidifi- 
cation it melts at 36°), and boils near 285°. 


_Glutarimide, C;Hg(CO).NH, results by the distillation of ammo- 
nium glutarate. It crystallizes in shining leaflets and melts at 152°. 


35 


418 ORGANIC CHEMISTRY. 


The vegetable alkaloid piperidine, C;H,.NH, is obtained from it by 
distilling with zinc dust. PCl, and HI convert it into the base 
pyridine, C5H;N, just as succinimide yields pyrrol (p. 413), (Berichte, 
16, 1683). 


(3) Ethyl Malonic Acid, C,H CHC CG? pads obtained from a-brombutyric 
ester, through the cyanide, and by the action ‘of Na and C,H,I upon malonic 
ester. It is very similar to ordinary tartaric acid, melts at 1 IT. 5° "and decomposes 
at 160°, more rapidly at 170°, into butyric acid and CO,. The calcium salt, 
C,;H,O,Ca + H,O, forms prisms, and is more easily soluble in cold than in hot 
water. Its ethyl ester boils at 200°. For sodium- and chlor-ethyl malonic ester, 


see Berichte, 21, 2085. 
(4) Dimethyl Malonic Acid,cry° + S6¢ Co! rpis obtained from a-bromiso- 


butyric ester by means of potassium cyanide ; by introducing methyl into malonic 
ester, and from mesitylenic acid (Berichte, 15, 581). It crystallizes in four-sided 
prisms, and dissolves with difficulty in alcohol, but is rather readily soluble in water. 
It is not as soluble as its isomerides. It sublimes about 120° and melts at 170°, 
decomposing at the same time into CO, and isobutyric acid. The darium salt 
crystallizes in needles; the ca/cium salt is more soluble in cold than in warm 
water. The ethyl ester boils at 195°. 


The isomeric chlorine and bromine substitution products of the pyrotartaric 
acids are produced by the direct addition of HCl, HBr and Br,, to the unsaturated 
isomeric acids, C,H ,O,: itaconic, citraconic and mesaconic acids (p. 429). The 
new derivatives are known as ita-, citra- and mesa-pyrotartaric acids :— 


Itaconic Acid Ita- Cie. 
Citraconic Acid } C5H,O, + Br, = C,H,Br,0, 4 Citra. | D'prompyre 
Mesaconic Acid Mesa- artaric acids. 


Itachlor-pyrotartaric Acid, C,H,CIlO,, is formed by heating itaconic acid with 
fuming hydrochloric acid to 130°. It melts at 145°. When heated with water or 
alkalies it passes into itamalic acid, C;H,(OH)O,. It yields paraconic acid, C,H, 
O,, with silver oxide. 

Citra- or Mesa-chlorpyrotartaric Acid is obtained on treating citraconic 
anhydride with cold concentrated hydrochloric acid, and by heating mesaconic 
acid to 140° with concentrated hydrochloric acid. It crystallizes in plates and 
melts at 129°. When boiled with water it breaks up into HCl and mesaconic 
acid. Boiling alkalies change it into HCl, CO, and methacrylic acid, C,H,O,. 

_ Fuming hydrobromic acid converts citraconic acid, its anhydride and also 
mesaconic acid (at 140°) into the same brompyrotartaric Acid, C,H,BrO,. It 
melts at 148°, and when boiled with water yields CO,, HBr and methacrylic acid. 
Itabrompyrotartaric Acid, from itaconic acid, is not so soluble in water, and 
melts at 137°. 

The ita-, citra- and mesa-dibrompyrotartaric acids, C;H,Br.O,, are dis- 
tinguished by their different solubility in water. The ita- compound changes to 
aconic acid, C;H,O,, when the solution of its sodium salt is boiled; the citra- 
and mesa- compounds, on the other hand, yield brom-methacrylic acid (p. 240). 

Nascent hydrogen causes all these substitution derivatives to revert to ordinary 
pyrotartaric acid. 


aaa, pe eee 


ADIPIC ACID. 419 


5. Acids, C,H,,0, = C HC CORT 

Nine are possible and eight Known : (1) Normal Butandicarboxylic acid or 
Adipic acid. (2) a- and (-Methyl glutaric, acids (isomerides), derived from 
glutaric acid, CHC GH CO: (3) Symmetrical and unsymmetrical dimethyl 
succinic acids and ethyl succinic acid (isomerides) derived from succinic acid, 
CH,.CO,H 

(4) Propyl, isopropyl and methyl-ethyl malonic acids (isomerides), 

CH,.CO,H 
derived from malonic acid. 

Symmetrical dimethyl succinic acid, like other symmetrical disubstituted suc- 

CHX.CO,H 
cinic acids, JS (as dibromsuccinic acid (p. 414), dioxysuccinic acid or 
HX.CO,H 

tartaric acid, diethyl-, methylethyl-, diisopropyl-, diphenyl-succinic acid, etc.), 
exists in two modifications. These have the same structural formulas, and are, 
therefore, to be regarded as alloisomeric (p. 50). Inthe case of dioxysuccinic 
or tartaric acid (see this) there are two active and two inactive forms (one capa- 
ble of division, the other not). They are striking examples of the facts that 
vant’ Hoff endeavors to explain by his theory of asymmetric carbon atoms (p. 
63). The various dialkyl succinic acids also contain asymmetric carbon atoms, 
and show some analogy to fara-tartaric (racemic acid) and az/z- or meso-tartaric 
acids. On this account their isomerism is presumed to be due to the same cause, 
and in consequence the modification with the higher melting point, and dissolving 
with greater difficulty, is known as the Zara form, while the more soluble variety, 
with lower melting point, is known as the azz form (Bischoff, Berichte, 20, 2990; 
21, 2106). This assumption seems rather questionable, as no one has yet suc- 
ceeded in converting any of the dialkyl-succinic acids, which are always inactive, 
into an active form (Berichte, 22, 1819). 

Another explanation, emphasizing the similarity that may be traced between the 
two different modifications of the dialkylsuccinic acids and maleic and fumaric 
acids, calls the one form “ fumaroid,’ and the other “ maleinoid” (Berichie, 21, 
3169). The isomerism is supposed to be due to the same cause that underlies the 
isomerism of fumaric and maleic acids. van’t Hoff attributes it to the “ fixation ” 
of two doubly-linked carbon atoms. This would, then, establish the “ fixation”’ of 
carbon atoms united by single bonds. The result: would be the removal of one of 
the fundamental ideas of the far-reaching theory of van’t Hoff. 

A third attempt to elucidate the existing difficulty is known as the “ Theory of 
dynamical Isomerism” (Berichte, 23, 624). It, probably, finds expression in the 
fact that it seeks to account for isomerides that do not exist (Berichte, 23, 1606). 


(1) Adipic Acid, C,H,.O,, was first obtained by oxidizing fats 
with nitric acid. It is synthetically prepared by heating -iod- 
propionic acid, with reduced silver, to 130-140° :— 


CH,.CH,.CO,H 
2CH,1I.CH,.CO,H + Ag, = L + 2Agl. 
H,.CH,.CO,H 


It is also obtained by the action of nascent hydrogen upon hydro- 
muconic acid, CsH,O, (p. 430), and by oxidizing sebacylic acid 
with nitric acid (along with succinic acid), and by the separation of 


420 ORGANIC CHEMISTRY. 


2CO, from tetramethylene tetracarboxylic acid, C,H,(CO,H),. It 
crystallizes in shining leaflets or prisms, which dissolve in 13 parts 
of cold water, and melt at 148°. 


(2) a-Methyl Glutaric Acid,CH,< Gy + CHL) CO, rp is obtained from methyl 


aceto-acetic ester, by the action of (-iodpropionic ester and the elimination of 
ketone (p. 400), by the reduction of saccharon with hydriodic acid, and by the 
action of KCN upon levulinic acid. It melts at 76°. It yields methylpenthio- 
phene (Berichte, 19, 3270) when heated with P,S,. 

(3) The -acid, CH CHY CH,.CO,H from ethidene dimalonic acid (Anna- 

Ai Plt \.CH, CO, H’ 

len, 218, 161), melts at 86°, and forms an anhydride, which melts at 46° and boils 
at 283°. 

(4) Ethyl Succinic Acid, C,H;.C HC co! as results from ethyl aceto suc- 


cinic ester, by elimination of ketone, also from a- and -ethyl ethane tricarbonic 
ester, C,H,.C,H,(CO,R),, when boiled with sulphuric acid (Berichte, 23, 638). 
It melts ‘at ‘98°. When heated it yields a liquid anhydride, C,H,O,, boiling at 
aa5°., CH,.CO,H 

{5) Unsymmetrical Dimethyl Succinic Acid, , is pro- 

(Cir C,CO,H 
duced from isobutylene tricarboxylic acid, (CH,),.C Come (from malonic 
\CH(CO,H), 
ester and a-bromiso-butyric acid, Berichze, 18, 2350; 23, 636), by splitting off CO, ; 
when copaiva oil is oxidized (Berichte, 18, 3211); and from isobutylene bromide 
by means of the dicyanide (Berichte, 22, 1739). It crystallizes in prisms, melts at 
ps and at higher temperatures, passes into the anhydride, C,H,O,, fusing at 
29°, and boiling at 230°. CH,.CH.CO,H 

(6) Symmetrical Dimethyl Succinic Acid, | : 

CH,.CH.CO,H 
alloisomeric forms, the maleinoid (az/7-) form, and the fumaroid ( para-) modifica- 
tion. These (their esters) are produced as follows : By the elimination of two 
molecules of carbon dioxide from dimethyl ethane tetracarboxylic acid; by the 
saponification of aj-dimethyl-ethane tricarboxylic esters, (CH,),.C,H( CO oR)» 
with hydrochloric or sulphuric acid (Bischoff, Berichte, 22, 389; 23, sie from 
a3-dimethyl aceto succinic ester by the elimination of acid (p. 400); by heating 
a-brompropionic acid, CH,.CHBr.CO,H, with reduced silver (Berichte, 22, 60), 
or more readily by the action of potassium cyanide upon a-brompropionic ester 
(Zelinsky, Berichte, 21, 3160); also by the reduction of dimethyl fumaric acid, 

pyrocinchonic acid (p. 430) with sodium amalgam or hydriodic acid (Berichte, 20, 
27373; 23,644). Bothsymmetrical dimethyl succinic acids are produced in all of 
these syntheses. They are separated by crystallization from water. 

The fara-acid (analogous to racemic and fumaric acids) is soluble in 96 parts of 
water at 14°. It forms needles and prisms, melting at 192°-194°. They sustain 
a partial loss of water upon melting. If the acid be heated for some time to 180° 
200°, it yields a mixture of the anhydrides, C,H,O,, of the para- and anti-acid. 
With water each reverts to its corresponding acid. When acetyl chloride acts on 
the para-acid, its anhydride is the only product. It crystallizes from ether in 
thombic plates, melts at 38°, distils at 234°, and unites with water to form the 
pure para-acid (Berichte, 20, 2741; 21, 3171; 22, 389; 23, 641). 

If the para-acid be heated to 1 30° with bromine, it yields pyrocinchonic acid, 
C,H,O, (p. 430). Both acids, when digested with bromine and phosphorus, 
yield ‘the same brom-dimethyl succinic acid, C,H, BrO,, melting at 91°. Zinc and 


exists in two 


a lity Wt citi ithe, anal 





METHYL ETHYL SUCCINIC ACID. 421 


hydrochloric acid change it to the amzi-acid (Berichte, 22, 66). The ethyl ester of 
the para-acid (from the silver salt) boils at 219°; the methyl ester at 199°. 

The anzi-acid (analogous to anti-tartaric acid and maleic acid) dissolves in 33 
parts of water at 14°. It crystallizes in shining prisms, and fuses, after repeated 
crystallizations from water, at 120-123°. It yields its axhydride, C,H,O,, when 
heated to 200°. This melts at 87°. It regenerates the acid with water. If the 
anti-acid be heated with hydrochloric acid to 190°, it becomes the para-acid. The 
methyl ester boils at 200° ; the ethyl ester at 222°..When the anti-acid is etherified 
with HCl, it yields a mixture of the esters of the anti- and para-acid (Berichte, 22, 
389, 646; 23, 639). , OOM ; 

(7) Methyl-ethyl Malonic Acid, Cc H 7C(CO2H)2, melts at 118°, and 

27-5 
decomposes into CO,, and methyl-ethyl acetic acid. 

(8) Propyl Malonic Acid, C,H,.CH(CO,H),, obtained from malonic acid, 
and by the reduction of dichloradipic acid (Berichte, 18, 852), melts at 96°, and at 
150° decomposes into CO,, and normal valeric acid. 

(9) Isopropyl Malonic Acid, CyH,.CHC Go'yp from sodium malonic ester, 


melts at 87°, and at 175° breaks up into CO, and normal valeric acid. 


6. Acids, C,H,,O, = C,;H,9(CO,H),. /CH,.CH,,.CO,H 
a d : 2-CH,.CO, Sioa 
(1) Normal Pentan-dicarboxylic Acid, CH;< CH,.CH,.CO,H? a-pimelic 
acid, first prepared by oxidizing suberone, C,H,,O (p. 422), by heating furonic 
acid, C,H,O,, with HI, and in the oxidation of fats with nitric acid, can be ob- 
tained synthetically from trimethylene bromide and malonic ester by heating pen- 
tamethylene tetracarboxylic acid, which is the first product of the reaction ( Berichte, 

18, 3249). It consists of large laminz or prisms, melting at 102°—104°. 
(2) B-Ethy! Glutaric Acid,C,H,.CH.C Gi Co ip propylidene diacetic acid, 
from propylidene dimalonic acid (from propionic aldehyde and malonic acid) 


(Annalen, 218, 167), melts at 67°. /CH(CH,).CO,H 
‘ : ; : a) SA att 

(3) edocs Dimethyl Glutaric Acid, CH 2 CH(CH,).CO,H’ is pro- 
duced in two alloisomeric forms when methylene iodide acts upon a-cyanpropionic 
ester. These melt at 103° and 128°. The first (regarded as ¢rimethyl-succinic 
acid ) has also been obtained from methyl malonic ester and a-bromiso-butyric ester 
(Berichte, 22, 2823; 23, 1600). Symmetrical diphenyl glutaric acid has been 
prepared in but one variety (Berich/e, 22, 3289). 

(4) Propyl Succinic Acid, C,H,.CHZ CH2CO2H fom propyl-ethylene 

Py Pehl OO +5 propy!-ethy 

tricarboxylic ester (Annalen, 214, 54), crystallizes in warty masses, and melts at 
g1° 


(5) Isopropyl Succinic Acid, (CH,),.CH.CH/ CH2-CO2H. pimelic Acid, 
3 \CO,H 


was first prepared by fusing camphoric acid, and may be synthetically obtained 

from aceto-acetic or malonic esters (Berichte, 16, 2622; Annalen, 220, 274)« 7-38 

forms crusts, is readily soluble in water, alcohol and ether, melts at 114°, and on 

stronger heating, yields an anhydride, boiling at 250°. 
CH,.CH.CO,H 

(6) Methyl Ethyl Succinic Acid, | , exists in two alloiso- 
C,H,.CH.CO,H 

meric modifications. It results after heating a-methyl-ethyl ethylene tricarboxylic 

ester with sulphuric acid. The gara-acid melts at 168°, and when heated for 


422 ORGANIC CHEMISTRY. 


some time passes into the anhydride of the anti-variety. The avdzz- or meso-acid 
melts at 84°, and yields a liquid anhydride, boiling at 243°. 

(7) Normal Butyl Malonic Acid, C,H,.CH(CO,H),, has been obtained from 
a-bromcaproic acid and potassium cyanide. It melts at 101°, and at 140° decom- 
poses into CO, and caproic acid. ; ; 

(8) Isobutyl Malonic Acid, (CH,),.CH.CH,.CH(CO,H),, from malonic 
ester, melts at 107°. 

(9) Diethyl Malonic Acid, (C,H,;),C(CO,H),, from ethyl malonate, melts 
at 121°, and above 170°, decomposes into CO, and diethyl acetic acid. 

7. Acids, C.H,,O, = C,H,,(CO,H),. 

(1) Suberic Acid, C,H,,O,, probably of normal structure, is obtained by boil- 
ing corks, or fatty oils, with nitric acid (Berichte, 13, 1165). It is soluble in 200 
parts of cold water, readily in hot water, alcohol and ether. It crystallizes in 
needles or plates, melting at 140° and subliming without decomposition. Its 
ethyl ester boils at 280-282°, Hexane, C,H,,, and Suberone, C,H,,0 = 


CH CH CH CO (Annalen, 211, 117), result when its calcium salt is distilled. 
Suberone is a liquid boiling at 180°. Its odor resembles that of peppermint. 


CH,.CH(CH,).CO,H 
(2) aa-Dimethyl Adipic Acid, | , has been prepared by 
CH,.CH(CH,).CO,H 
the action of reduced silver upon 8-bromisobutyric acid. It occurs in two allo- 
isomeric modifications. One melts at 139°, the other is a liquid (Berichde, 23, 
295). 

4 Trimethyl Glutaric Acid, CH Cinch?) co’ is formed, together 
with tetramethyl succinic acid (p. 423), when a-bromisobutyric acid is heated with 
reduced silver. It melts at 97° and sublimes without decomposition. It is not 
volatile with steam. When the acid is heated for some time, or acted upon with 
acetyl chloride, it changes to its anhydride, C,H,,O3, melting at 96°, and boiling 
at 262° (Berichte, 23, 300). \ G,H,.CH.CO,H 

(4) Symmetrical Diethyl Succinic Acid, | , exists, like other 

+ C,H,.CH.CO,H 
symmetrical dialkylsuccinic acids, in two alloisomeric modifications (p. 419). These 
are obtained: By the elimination of 2CO, from diethylethane-tetracarboxylic acid, 
(C,H;).C,(CO,H), (Berichte, 21,2085); by heating xeronic anhydride (p..431) with 
hydriodie acid ( Berzchze, 20, Ref. 416; 21,2105), The diethyl ester results upon 
heating a-brombutyric ester with silver (Hell, Berichte, 22, 67), and upon boiling 
aB-diethyl-ethane-tricarboxylic ester, (C,H;),C,H(CO,R),, with sulphuric acid 
(Berichte, 21, 2089; 23, 650). The para-acid is soluble in 162 parts of water 
at 23°. It crystallizes in needles and melts about 189—192°. It then loses water. 
The azti-acid is soluble in 41 parts of water at 23°, and melts at 129°. Heated 
to 240° the anti-acid forms a liquid anhydride, C,H,,O;, boiling at 246°, and 
reverting to the acid when treated with water. The para-acid, after long heating 
at 240°, also yields the anhydride of theanti-acid. Vice-versd, the amtt-acid is 
changed to the para-acid when heated to 200° with hydrochloric acid or water, 
(Berichte, 21, 2102; 23, 656). 

There is a third diethylsuccinic acid. It is supposed to be symmetrical (Ze- 
richie, 23, 628). It melts at 137.5°. It is very probably ethyl-methyl-glutaric 
acid (Berichte, 23, 1606). CH, :€0; 

(5) Unsymmetrical Diethyl Succinic Acid, | , has been 

: (C,H;),C-CO,H 
obtained from a-diethyl-ethane-tricarboxylic ester. It melts at 86°. It forms an 
anhydride, boiling about 71° (Berichte, 23, 651). 
For two additional ethyl-dimethyl-succinic acids, see Berichte, 23, 1606. 


UNSATURATED DICARBOXYLIC ACIDS. 423 


(CH,),-C.CO,H 
(6) Tetramethyl Succinic Acid, , is formed, together with 
(CH,),.C.CO,H 
trimethyl glutaric acid (p. 422), when a-bromisobutyric acid (or its ethyl ester) is 
heated with silver. It is volatile with steam, It melts about I90-192°. It parts 
quite readily with water and passes into the anhydride, C,H,,0,, melting at 
147°, and boiling at 230° (Berichie, 23, 297). 
(7) n-Pentyl Malonic Acid, C,H,,.CH(CO,H),, from brom-cenanthylic ester 
and potassium cyanide, melts at 82°, It decomposes above 129° and splits off 
CO,. 





C,H,.CH.CO,H 

Symmetrical Diisopropyl Succinic Acid, (?), appears in 

C,H.,.CH.CO,H 
two alloisomerides when a-bromisovaleric acid, C,H,.CHBr.CO,H, is acted upon 
with silver. The one variety volatilizes with steam and melts at 178°. It readily 
passes into an oily anhydride on heating. The other is non-volatile, melts at 197°, _ 
and sublimes undecomposed above 210° (Berichte, 22, 48). 

Higher dibasic acids are produced by oxidizing the fatty acids or oleic acids 
with nitric acid. They always form succinic and oxalic acids at the same time. 
The acids of the series, C,H.» _4O, (p. 244), usually decompose into the acids 
C,H2,O0,, when oxidized with fuming nitric acid. The mixture of acids that 
results is separated by fractional crystallization from ether; the higher members, 
being less soluble, separate out first (Berichte, 14, 560). ° 

Lepargylic Acid, C,H,,O,, Azelaic Acid, is best prepared by oxidizing 
castor oil (Berichte, 17, 2214). It. crystallizes in shining leaflets, resembling 
benzoic acid. It melts at 106°, and dissolves in 100 parts of cold water. 

Sebacic Acid, C,,H,,O,, is obtained by the dry distillation of oleic acid, by 
the oxidation of stearic acid and spermaceti, and by fusing castor oil with caustic 
potash. It crystallizes in shining laminz, which melt at 127°. 

Brassylic Acid, C,,H,,O,, obtained by oxidizing behenoleic and erucic acids, 
melts at 108°, and is almost insoluble in water. 

Roccellic Acid, C,,H,,O,, occurs free in Roccella tinctoria. Prisms melting 
at 132°. 

Cetyl Malonic Acid, C,,H,,0, = C,,H,,.CH(CO,H),, from malonic ester 
and cetyl iodide, melts at 121°, and immediately breaks down into CO, and 
stearic acid. 





UNSATURATED DICARBOXYLIC ACIDS, C,H, —,O,. 


The acids of this series bear the same relation to those of the 
oxalic acid series that the acids of the acrylic series bear to the 
fatty acids. They can be obtained from the saturated dicarboxylic 
acids by the withdrawal of two hydrogen atoms. This is effected 
by acting on the monobrom-derivatives with alkalies :— 


C,H,Br(CO,H), + KOH = C,H,(CO,H), + KBr + H,0; ‘ 
Bromsuccinic Acid. Fumaric Acid, 


Cy ORGANIC CHEMISTRY. 


or, the same result is reached by letting potassium iodide act upon 
the dibrom-derivatives (p. 235). Thus, fumaric acid is formed 
from both dibrom- and isodibrom-succinic acids :— 


C,H,Br,(CO,H), + 2KI =C,H,(CO,H), + 2KBr + I,; 


and mesaconic acid, C,H,(CO,H),, from citra- and mesa-dibrom- 
pyrotartaric acids, C,H,Br,.(CO,H),. Asa general thing the unsatu- 
rated acids are obtained from the eer pory ite acids by the 
elimination of water (p. 235). — 

The esters of these acids are obtained in the condensation of 
malonic esters with aldehydes :— 


CH,.CHO + CH,(CO,R), = CH,.CH:C(CO,R), + H,0. 


Ethidene malonic esters are formed at the same time; from them 
we can get saturated dicarboxylic acids (Avnalen, 218, 156). 

The union is more easily brought about by the action of sod- malonic 
ester (Berichte, 20, Ref. 258, 552). 





The isomerisms of the acids of this series offer peculiar relations, as yet unex- 
plained. The lowest member of the series has the formula C,H,(CO,H),. This 
can be structurally represented in two ways :— 


- CH.CO,H CH, 
(1) || and (2)- || |, C0. H. 

CH.CO,H 
"N60. H 


The first would sel 40 succinic acid, the second to the iso-acid. Two 
acids—maleic and fumaric—with the formula C 2H,(CO,H),,are known. Owing 
to its ability to form an anhydride, maleic acid is supposed to have the first struc- 


_ tural formula. (The supposition that a divalent carbon atom is present in the acid 


offers no explanation for its behavior.) ‘The second formula is then ascribed to 
fumaric. acid. Certain synthetic methods (p. 425) used in forming these acids 
argue: for the preceding views. Yet most of the transpositions suffered would seem 
to ‘show that the acids have the same structural formula. 

This. is evidently a case of alloisomerism (p. 50), which our present structural for- 


ree ites fail to represent. Various hypotheses have been advanced for the explana- 


_ tion of the peculiar isomerism of these two acids (Annailen, 239, 161), but have, 
to some extent, been abandoned, ¢.g., the supposition that the relations existing 
between the acids (fumaric and maleic) were similar to those existing between 
racemic and inactive tartaric acid, has been disproved by a determination of the mole- 
cular weight according to Raoult (Paternd, Berichte, 21, 2156). Another suggestion 

is that the isomerism is due to a difference of structure in the two carboxyl groups, 
and that maleic acid should be viewed as a dioxylactone (zdzd.)._ A more prom- 
ising indication for the solution of these difficulties, seems to lie in the introduction 
of representations upon the spatial relations of the atoms in accordance with the 
view or hypothesis of LeBel and van’t Hoff, lately elaborated by J. Wislicenus (see 
PP- 51, 525 and (Berichte, 20, Ref. 448; 21, Ref. 501). 


UNSATURATED DICARBOXYLIC ACIDS. 425 


This view ascribes to fumaric acid the axial-symmetric, and to maleic acid the 
plane-symmetric configuration, briefly represented as follows :— 


H—C—CO0O.OH HO.OC—C—H 
| and | , 
H—C—CO.OH H—C—CO,H 
Maleic Acid. Fumaric Acid. 


The arrangement of the two carboxyls upon the same (corresponding) side gives __ 
maleic acid the power of forming an anhydride. In fumaric acid the carboxyls - 
oppose each other; an anhydride cannot be formed, 


1. Fumaric and Maleic Acids, C,H. Go'tp are obtained by 
2 


distilling malic acid :— 
C,H;(OH)(CO,H), = C,H,(CO,H), + H,0; 


fumaric acid remains in the residue, while maleic acid and its anhy- 
dride pass over into the receiver (Berichte, 12, 2281). The last 
two are formed in especially large quantities on rapidly heating 
malic acid, whereas, by prolonged heating at 140°-150°, fumaric 
acid is the chief product (Berichte, 18, 676). If maleic acid be 
heated for some time at 130° it changes to fumaric acid ; when the 
latter is distilled it decomposes into water and maleic anhydride. 
Maleic acid is only completely converted into fumaric acid when it 
is heated, either alone, or in aqueous solution, to 200-201°, in a 
sealed tube. Fumaric acid is fully changed to maleic anhydride - 
by heating to 160° with P.O; (Tanatar). For the.conversion of 
maleic into fumaric acid, by means of bromine and hydrobromic 
acid, consult Berichte, 21, Ref. 501, and Annalen, 248, 342. 
Acetylene is obtained by the electrolysis of a concentrated solution 
of the sodium salts of the two acids (p. 87). 


ore SS 


We can obtain maleic acid (its ester) synthetically by heating dichloracetic 
ester, CHCI,.CO,.C,H;, with silver or sodium. Fumaric acid is formed from 
aG-dichlorpropionic acid (which yields a-chloracrylic acid, CH,:CCl.CO,H, p. 
237), by the action of potassium cyanide and caustic potash. Both syntheses 
indicate that the first formula properly falls to maleic acid and the second to 
fumaric (p. 424). This conclusion is contradicted by the formation of maleic acid 
from $-dibrompropionic acid (which yields @ bromacrylic acid, CH,:CBr.CO,H, 
p. 237), by the action of potassium cyanide and potash, and fumaric acid from 
chlorethenyl tricarboxylic ester, C,H,Cl(CO,.C,H,;), (Berichte, 13, 100 and 

; 2163) ; also, by the fact that fumaric acid is formed from dichloracetic and malonic 
: acids (Azmalen, 218, 169). The action of sodium ethylate upon a-bromisobu- 
____tyric acid produces a-ethoxy-isosuccinic acid (see Isomalic Acid). $-Ethoxy-iso- 
succinic ester and methylene malonic ester are produced by the interaction of 
methylene iodide and sodium malonic ester. 4 see 


Fumaric Acid occurs free in many plants, in Iceland moss, in’ 
fumaria officinalis and in some fungi. It is produced by heating ~~ 
dibrom- and isodibrom-succinic acids with a solution of potassium _ 

36 





et 


ee | 


gies — 


426 ORGANIC CHEMISTRY. 


iodide ; and from monobrom- and sulpho-succinic acids by fusion 
with potash. It may be prepared by boiling brom-succiny] chloride 
with water (Berichte, 21, Ref. 5). It is almost insoluble in water. 
“Mineral acids precipitate it from solutions of its alkali salts as a 
white crystalline powder. It crystallizes from hot water in small, 
striated prisms. It has a very acid taste, and dissolves readily in 
alcohol and ether. It melts with difficulty, sublimes at 200°, form- 
ing maleic anhydride and water. Sodium amalgam, hydriodic acid 
and other reducing agents convert it into succinic acid. Metallic 
zinc combines with fumaric acid in the presence of water, forming 
zinc succinate: C,H,O, + Zn = C,H,O,Zn. 

Fuming hydrobromic acid at 100° converts fumaric into mono- 


_bromsuccinic acid. At ordinary temperatures it combines with 


bromine (and water) very slowly, more rapidly on heating to 100°, 
yielding dibromsuccinic acid. When fumaric acid (also maleic 
acid, Berichte,-18, 2713) is heated with caustic soda to 100°, or 
with water to 150-200°, it passes into inactive malic acid, which, 
at 135°, decomposes into water and maleic acid. ‘The esters of 
fumaric and maleic acids pass into alkyloxysuccinic acids (Beviche, 
18, Ref. 536) when heated with sodium alcoholates. On oxidizing 
the acid with MnO,K it yields racemic, whereas, maleic acid forms 
inactive tartaric acid (Berichte, 14, 713). 


With the exception of the alkali, all the salts of fumaric acid dissolve with diff- 
culty in water. The stlver salt, C,H,O,Ag,, is perfectly insoluble; hence, silver 
nitrate will completely precipitate famaric acid from even dilute solutions. 

The esters are obtained from the silver salt by the action of alkyl iodides, and 
by leading HCl into the alcoholic solutions of fumaric and maleic acids (er ichte, 
12, 2283). They are also produced in the distillation of the esters of brom-suc- 
cinic acid, malic acid and aceto-malic acid (Berichie, 22, Ref. 813). They unite 
just as readily as the esters of maleic acid with 2Br (forming esters of dibromsuc- 
cinic acid). 

_ The methyl ester, C,H,(CO,.CHs),, forms white needles, melting at 102°, and 
boiling at 192°. The ‘ethyl ester is liquid, and boils at 218°, It can be obtained 


_ by the action of PCI, upon esters of malic acid. 


Maleic Acid crystallizes in large prisms or plates, is very 


FB cael soluble in cold water, and possesses a peculiar taste. It 


“melts at 130° and distils at 160°, decomposing partially into the 


anhydride and water. Heated for some time at 130°, or boiled 


-with dilute sulphuric acid, or nitric acid, with HBr and’HI, it 
changes to fumaric acid. Nascent hydrogen converts it into ordi- 
nary succinic acid. Metallic zinc dissolves in aqueous maleic acid 
without evolving hydrogen, and forms zinc maleate and acid zinc 


3C,H,O, + 2Zn = C,H,0,Zn + (C,H,O,),H,Zn. 


- Fuming hydrobromic acid combines with maleic acid at o° and 
© yields monobromsuccinic acid ; an equivalent of fumaric acid forms 





UNSATURATED DICARBOXYLIC ACIDS. 427 


at the same time. Bromine (and water) at ordinary temperatures 
converts the acid into isodibrom-succinic and fumaric acids. 


The esters are produced in the same manner as those of the preceding acid. 
Traces of iodine will change them, on warming, into esters of fumaric acid. - The 
latter also result in conducting HCl-gas into the alcoholic solutions of maleic acid. ~ 
Bromine converts them into esters of dibrom-succinic acid; fumaric acid very 
probably appears at first. 

The methyl ester, C,H,(CO,.CH,), is a liquid, and boils at 205°. The ethy/ 
ester boils at 225°. 

Maleic anilide separates when aniline acts upon aqueous maleic acid. All the 
derivatives of this acid react similarly, while fumaric acid and its derivatives do not 
enter such a combination (Berichze, 19, 1375. Compare Annalen, 239, 137). 


Maleic Anhydride—Maleyl Oxide, C.H,0.=GH,< Go DO. 


This is produced by distilling maleic or fumaric acid, or more 
readily by heating maleic acid with acetyl chloride (p. 402); it is 
purified by crystallization from chloroform (Berichte, 12, 2281, and 
14, 2546). It consists of needles or prisms, which melt at 53° (60°) 
and boil at 202° (196°). It regenerates maleic acid by union with 
water, and forms isodibromsuccinic anhydride when heated with 
bromine to 100°. 





Brom-maleic Acid, C,H,BrO,, is produced by boiling barium dibromsuccinate 
or the free acid with water. It consists of prisms, melting at 128°. Brom-fumaric 
Acid, C,H,BrO,, called isobrommaleic acid, is formed, the same as the preceding, 
from isodibromsuccinic acid, or its barium salt, or by the addition of HBr to ace- 
tylene dicarboxylic acid (p. 431). It consists of very soluble leaflets, which melt 
at 179°. 

These two brom-acids conduct themselves toward bromine and HBr the same 
as maleic and fumaric acids. When boiled with HBr brommaleic acid is con- 
verted into bromfumaric acid; its esters, too, change to those of bromfumaric acid 
when they are heated with iodine. Sodium amalgam changes both to fumaric and 
subsequently to succinic acid. By distillation, both yield water and brommaleic 
anhydride, C,HBrO,. The latter readily unites with water, forming brommaleic 
acid (Annalen, 195, 56). 

Dibrom-maleic Acid, C,Br,(CO,H),, is obtained by acting on succinic acid 
with Br, or by the oxidation of mucobromic acid with bromine water, silver oxide. 


or nitric acid. It is very readily soluble, melts at 120°-125°, and readily forms __ 


the anhydride, C,Br,(CO),O, which melts at 115°, and sublimes in needles (Be- 
richte, 13,736). Itshalf-aldehyde is the so-called mucobromic acid,C,H, Br,O,= | 
FCO 


CBr, se CHO ” which results from the action of bromine water upon pyromucic — : 


acid. It crystallizes in glistening lamince, and melts at 120°. When oxidized it 
is converted into dibrom-maleic acid; baryta changes it to malonic, dibrom-acrylic 
and brompropiolic acids. ? 


The dialdehyde of dibrom-maleic acid, CBE CHO? is produced when ines 


ine water acts upon dibrompyromucic acid, C,H,Br,O,. It melts at 88°, and . 
when oxidized yields mucobromic acid. | 


428 ORGANIC CHEMISTRY. 


: CC1.CO 
Dichlormaleic Acid, C,Cl,(CO,H),. Its zwde, || >NH, is obtained 
CC1.CO 


when the perchlorpyrocoll and succinimide (p. 412) are heated in a current of 
chlorine. It consists of needles melting at 179°. Boiling caustic potash converts 
the imide into dichlormaleic acid. This consists of deliquescent needles, which 
on the application of heat pass into the exhydride, C,Cl,(CO),O, which melts at 
120°, When the imide is heated with water CO, splits off and a-dichloracrylic 
acid is produced (Berichte, 16, 2394; 17, 553). Potassium nitrite converts the 
imide into an analogue of nitranilic acid (Berichie, 22, 33). 

PC, converts succinic chloride into two isomeric dichlormaleic chlorides, C,Cl,O, 
from which the acid and anhydride can be obtained (Berichte, 18, Ref. 184): 

The half-aldehyde of dichlormaleic acid is the so-called mucochloric acid, 
pk co This is obtained when chlorine water acts upon pyromucic acid. 


2 
It melts at 125°. Alkalies convert it into formic and a-dichloracrylic acid. 





Methylene Malonic Acid, CHCl Gots (p. 424), is hypothetical and iso- 
2 


meric with fumaric and maleic acids. It cannot be obtained free. Its dze¢hyl 
ester, C,H,O,(C,H;),, is produced when 1 molecule of methylene iodide and 
2 molecules of sodium ethylate act upon I molecule of malonic ethyl ester 
(together with 6-ethoxy-iso-succinic ester, C,H,;.0.CH,.CH(CO,R), (Berichte, 
23, 194; 22, 3294). Under diminished pressure it distils as a mobile, badly- 
smelling oil. If allowed to stand, it soon changes to a white, solid mass, 
(C,H,,0,),. The liquid ester deports itself like an unsaturated compound. It 
unites with bromine. When saponified with alcoholic potash it takes up alcohol 
and becomes f-ethoxy-isosuccinic acid, C,H,.0.CH,.CH(CO,H),. 





a. acias, C.41,0, = C,H,(CO,H),. 

Six unsaturated dicarboxylic acids of this formula are known: ethidene malonic, 
methylene succinic, glutaconic, itaconic, citraconic and mesaconic acid; the struc- 
ture of the last three is yet in doubt. The so-called vinylmalonic acid, obtained 
from ethylene bromide and the ester of malonic acid, is identical with a-trimethy- 
lene dicarboxylic acid, derived from trimethylene. 

Ethidene Malonic Acid, CH,.CH:C(CO,H),, is only known in its ethyl 
ester. This is formed by the condensation-of malonic ester with acetaldehyde 
on heating with acetic anhydride (p. 424). It boils at 220°, and at 118—120° 
under a pressure off 21 mm. When saponified with baryta water it yields an 
oxydicarboxylic acid, C,H;(OH)(CO,H),. It combines with malonic ester on 
heating, and becomes ethidene dimalonic ester. 

‘The condensation of malonic ester with chloral may be effected by heating them 


= with acetic acid anhydride, the product being the diethyl ester of Zrichlor ethi- 


dene malonic acid, CCl,.CH:C(CO,H),, a thick oil, boiling about 160° under 23 
mm. pressure. 

; CH,:C.CO,H 
~ Methylene Succinic Acid, | , is probably £-trimethylene dicar- 
CH,.CO,H 
- boxylic acid (see this), inasmuch as it is produced from malonic ester and a-brom- 
* acrylic ester (Berichte, 20, Ref. 47). 


Glutaconic Acid, CHC Gatco, ae arises in the saponification of the dicar- . h 
° 4 - / 


4 
; 
ol 






UNSATURATED DICARBOXYLIC ACIDS. 429 


boxy-glutaconic ester (obtained from the ester of malonic ester and chloroform, 
Annalen, 222,249). It melts at 132°. Sodium amalgam converts it into glutaric 
acid. 
PCI, converts acetone dicarboxylic acid (p. 435) into Chlorglutaconic Acid, 
cc 4 CH2-CO,H 
\\CH.CO,H 
passing into glutinic acid (p. 432) (Berichte, 20, 147). 


, melting at 129°, and when acted upon by alcoholic potash, 





Citraconic and itaconic acids, judging from their behavior, bear the same rela- 
tions to mesaconic acid that maleic sustains to fumaric acid. They yield anhy- 
drides, whereas mesaconic acid when distilled passes into citraconic anhydride. 

Citraconic and itaconic acids are obtained in the distillation of citric acid. 
Aconitic acid, C,H,(CO,H), (see this), is produced at first and by the subse- 
quent withdrawal of water and CO, it yields itaconic and citraconic anhydrides: 
C,H,O, = C,;H,O, + H,O + CO,. Both anhydrides are present in the filtrate. 
The first yields itaconic acid by union with water (Berichte, 13, 1541.) When free 
itaconic acid is distilled it yields water and citraconic anhydride, which changes to 
the acid on warming with water. If citraconic acid be heated for some time to 
100° or its aqueous solution to 130°, itaconic acid is produced. Boiling dilute 
nitric acid or concentrated haloid acids convert citraconic into mesaconic acid. 

Citra-, ita- and mesaconic acids unite with chlorine, bromine and the halogen 
hydrides, yielding derivatives of pyrotartaric acid (p. 416); the first two acids 
react in the cold; mesaconic acid (like fumaric acid) only on the application of 
heat. Nascent hydrogen converts them all into the same pyrotartaric acid. The 
electrolysis of their sodium salts (p. 87) decomposes them, according to the 
equation :— 


C,H,(CO,H), = C,H, + 2CO0, + H,, 


when ordinary allylene, CH,.C: CH, results from citra- and itaconic acid, and iso- 
allylene (p. 89) from itaconic acid. 

Citraconic Acid, C,;H,O,, is obtained from its anhydride by heating the latter _ 
with water. It crystallizes in glistening prisms, which deliquesce in the air, and 
melt at80°. It breaks up by distillation into its anhydride and water. Citraconic 
Anhydride, C,H,O,, is also formed by heating the acid with acetyl chloride, and 
is obtained by the repeated distillation of the distillate (see above) resulting from 
citric acid. It is an oily liquid which boils at 213—214° with partial transformation 
into xeronic anhydride (see below); it combines to citraconic acid when heated 
with water. : , 

Itaconic Acid, C;H,O,, is best obtained by heating citraconic anhydride with 
3-4 parts water to 150°. It crystallizes in rhombic octahedra, dissolves in 17 parts 
of H,O at 10°, melts at 161° and decomposes when distilled into citraconic anhy- 
dride and water. Itaconic acid gives the maleic acid reaction with aniline (p. 427 
and Berichte, 19, 1383). Itaconic Anhydride, C;H,O,, is prepared from the 
acid on heating with acetyl chloride (Berichte, 13, 1541). It crystallizes from 
chloroform in rhombic prisms, melts at 68° and distils unaltered under diminished 
pressure, but at ordinary pressures changes to citraconic anhydride. It dissolves in 
water with formation of itaconic acid. 2S 

Mesaconic Acid, C;H,O,, is prepared by heating citra- and itaconic acid with’ 
a little water to 200° and may be obtained by evaporating citraconic anhydride with 
dilute nitric acid (Annalen, 188, 73). It dissolves with difficulty in water (47 
parts at 18°), crystallizes in glistening needles or prisms, melts at 202° and at 205° 


_ «, decomposes into citraconic anhydride and water. 


Consult Berichte, 14, 2785, for the esters of citra-, ita-, and mesaconic acids. 





430 ORGANIC CHEMISTRY. 


4. Acids, C,H,0; = C,H,(CO,H),.* 
_ Allyl Malonic Acid, CH,:CH.CH,.CH(CO,H),, is obtained from malonic 
ester by means of allyl iodide. It crystallizes in prisms and melts at 103° (Anua- 
len, 216, 52). Hydrobromic acid converts it into carbovalerolactonic acid, C,H,O, 
(the lactone of y-oxyproprio-malonic acid)-(p. 352) :— 


CO,H CH,.CH.CH,.CH.CO,H 
CH,:CH.CH,.CHé yields l l 
\CO,H O Co 


The latter is a thick liquid, readily soluble in water. When heated to 200° it 
breaks up into CO, and valerolactone (p. 363). : 

Propylidene Malonic Acid, C,H,.CH:C(CO,H),, is produced by the action 
of malonic acid upon propionic aldehyde. It breaks down into carbon dioxide 
and propylidene acetic acid (p. 241), when distilled. 

Hydromuconic Acid exists in a stable and an unstable modification (Berichie, 
23, Ref. 231) :— 


CO, H.CH,.CH:CH.CH,.CO,H and CO,H.CH,.CH,.CH:CH.CO,H. 
Unstable or ABy-acid. Stable or AaB-acid. 





The uzstadle variety is formed in the reduction of dichlormuconic acid, or of mu- 
conic acid (p. 432), and of diacetylene dicarboxylic acid (p. 432). It dissolves 
with difficulty in cold water. It melts at 195°. Potassium permanganate dissolves 
it to form malonic acid. If boiled with sodium hydroxide it is transformed into 
the s/ab/e acid. The latter melts at 169°. Potassium permanganate converts it into 
succinic acid. Sodium amalgam reduces the unstable acid, after its conversion 
into the stable variety, to adipic acid. 
CH CLO. . 
Dimethyl Fumaric Acid or Maleic Acid \| , pyrocinchonic acid, 
H,.C.CO,H 

is only known in its salts and ethers. When separated from the latter it is at once 
transformed into the anhydride,C,H,O,. The latter is obtained by oxidizing 
turpentine oil (together with terebic acid), by heating cinchonic acid, C,H,O,, 
(with separation of CO,), and by heating a-dichlor-, or dibrom-propionic acid, 
CH,.CBr,,CO,H, with reduced silver (Berichte, 18, 826, 835). The anhydride 
crystallizes from water in large pearly laminze, which melt at 96° and distil at 223°. 
The aqueous solution has a very acid reaction and decomposes alkaline carbonates. 
The salts have the formula, C,H,O,Me,; its solutions acquire a dark-red color 
on the addition of ferric chloride. It is oxidized by a chromic acid mixture, and 
yields 2 molecules of acetic acid and 2 molecules of carbon dioxide. By the action of 
sodium amalgam, or by heating with hydriodic acid it is converted into unsymmetri- 
cal dimethylsuccinic acid (p. 420) (Berichte, 18, 838). Pyrocinchonic acid, like 
malic acid, unites with metallic zinc (Berichte, 18, 844). Consult Beriche, 23, 
Ref. 92, upon methylitaconic and methylcitracontic acids. 





a vids. 11,0, == C.H,(CO,H),. 
" Allyl Succinic Acid, CEpCH.C Go att 
carbon dioxide from allyl ethenyl tricarboxylic acid, C,H,.C,H,(CO,H), (Be- 
richte, 16, 335). It crystallizes from alcohol in leaflets, melts at 94° and when 


, results by the withdrawal of 





* Tetramethylene dicarboxylic acid is isomeric with these unsaturated acids. 





DIBASIC ACIDS. 431 


heated above 140° passes into the corresponding anhydride, C, H,O,—an oil boil- 
ing near 250°. Hydrobromic acid converts it into Carbocaprolactonic Acid, ~*~ 
C,H, .O4, the lactone of y-oxypropio-succinic acid :— 


CH,,.CO,H CH,.CH.CH,.CH.CH,.CO,H 

CH,:CH.CH,.CH¢ yields l l : 

CO,H O——— CO 

The latter melts at 69° and distils at 260° without decomposition. 

Teraconic Acid, (CH,),C: CCH CO, HW 3s produced in small quantity 
(together with pyroterebic acid) (p. 241) in the distillation of terebic acid (Anna- 
en, 208, 50), and may be prepared by the action of sodium upon terebic esters 
(Annalen, 220, 254). It melts at 162°, decomposing at the sametime into water 
and its anhydride,C,H,O,. The latter boils near 275° and by its union with 
water regenerates teraconic acid. Hydrobromic acid or heat and sulphuric acid 
cause it to change to isomeric terebic acid (a lactonic acid, see this) anes 226, 





363) :— 
O,H ) /CO H 
(cH) C: al yields (Base \. CH). 
“CH, .CO,H 6 co 
Teraconic ‘Acid. Verebic Actl. 
C,H..C.cO; a 


5. Xeronic Acid, C;H,,0,, or Diethyl Fumaric Acid, 

C,H,.C.CO,H 
(Berichte, 15, 1321), is very much like dimethyl fumaric acid, and when it is freed 
from its salts it immediately decomposes into water and the anhydride, C,H,,O,. 
The latter is produced in the distillation of citraconic anhydride, and is an oil 
which is not very soluble in water. It boils at 242°. It volatilizes in a current of 
steam. It is also obtained from a-dibrombutyric acid, C,H;.CBr,.CO,H, when 
heated with silver (Anmalen, 239, 276). If it is heated with hydriodic acid it suf-_ 
fers reduction to diethylsuccinic acid (p. 422). 





DIBASIC ACIDS, C,H», — <O,. 


C.CO,H 
Acetylene Dicarboxylic Acid, C,H,O, = ||| ,is ebtained when alco- 
2 C.CO,H 


holic potash is allowed to act upon dibrom- and isodibrom-succinic acid (Berichie, 
18, 677; 21, Ref. 658). It crystallizes with two molecules of water, but these 
escape on exposure. The anhydrous acid ¢rystallizes from ether in thick plates, 
and melts with decomposition at 175°. The acid unites with the haloid acids 
to form halogen fumaric acids, C,H, XO, (p. 427). Its esters unite with bromine 
and form dibrommaléic esters. With water they yield oxalacetic acid (Berichée, 
22, 2929). The primary Aotassium salt, Cs,HKO,, is not very soluble in water 
and when heated decomposes into CO, “and potassium propiolate (p. 244). 
Traces of acetylene are produced at the same time. Phenylhydrazine converts 
acetylene dicarbonic ester ay into the phenylhydrazone of oxalacetic ester 


(p. 435). 


432 ORGANIC CHEMISTRY. 


COOH + 
Glutinic Acid, | ‘seo , is obtained by the action of alcoholic potash upon 


chlorglutaconic acid i San It crystallizes from water in minute needles, melt- 
ing at 145-146° with evolution of carbon dioxide. ‘This gas is also liberated 
when the acid is boiled with water. 
CH CH. CO,H 
Muconic Acid, | , is formed when alcoholic potash acts upon 
Hes CHAD) ’ 

. the dibromide of By-hydromuconic acid (p. 430). It melts above 260°. Dzch/or- 
muconic Acid, C,H,Cl,O,4, results when PCl, acts upon mucic acid. It yields 
By-hydromuconic acid with sodium amalgam (Aerichie, 23, Ref. 232). 


Diallyl Malonic Acid, (CeCe is obtained from malonic ester. 
2 


It melts at 133°. Hydrobromic acid converts it into the corresponding a@z/actone, 
which melts at 106° (Azmalen, 216,67), When heated it breaks up into CO, and 
diallyl acetic acid (p. 245). 

Unsaturated Acids :— 

(=-c.CO,H 
Diacetylene Dicarboxylic Acid, C,H,O, = | , is made by the 
C=C.CO,H 
action of potassium ferricyanide upon the copper compound of propiolic acid 
( Berichte, 18, 678, 2269). It dissolves quite readily in water, alcohol and ether, 
crystallizes in needles or plates with 1 molecule H,O, instantly assumes a dark 
red color on exposure to light, and at 177° explodes with a loud report. Sodium 
amalgam reduces it to hydromuconic acid, then to adipic acid and at the same 
time splits it up into propionic acid. The e¢hy/ ester is an oil boiling at 184° 
under a pressure of 200 mm. Zinc and hydrochloric acid decompose it and yield 
propargylic ethyl ether, CH=C.CH,.0.C,H, (p. 136), compare p. 244. 
CA CSC.00 
Tetra-acetylene Dicarboxylic Acid, C,,H,O, = | CO, 
SO. C S400. H 

escapes on digesting the acid sodium salt of diacetylene dicarboxylic acid with 
water, and there is formed the sodium salt of déacetylene monocarboxylic acid, 
which cannot be obtained in a free condition. When ferricyanide of potassium 
acts upon the copper compound of this acid tetra-acetylene dicarboxylic acid is 
formed. This crystallizes from ether in beautiful needles, rapidly darkening on 
exposure to light and exploding violently when heated (erichie, 18, 2271). 
Consult Berichte, 18, 2277, for an experiment made to explain the explosibility 
of this derivative. 





KETONE DICARBOXYLIC ACIDS. 


In this class are included the dibasic acids, which contain ketone 
groups in addition to the two carboxyl groups. ‘They may be syn- 
thesized in the following manner :— 

1. By introducing acid radicals into malonic ester. This is done 
by acting upon the sodium compounds with acid chlorides :— 


CH,.COCI + CHNa(CO,.R), = CH,.CO.CH(CO,R), + NaCl. 


‘Abate gintontc ester. 





KETONE DICARBOXYLIC ACIDS. 433 


2. By the introduction of acid residues into aceto-acetic ester. 
In this case esters of the fatty acids are allowed to act upon the 
sodium derivatives (p. 342) :— 


CH,.CO.CHNa.CO,R 4 Cl.CO,R = CH,.CO.CHC oR + NaCl. 


hlorformic Ester. ; 
Cc Aceto-malonic Ester. 


Chloracetic ester, CH,Cl.CO,.R, under like conditions, yields 
acetosuccinic ester, while f-iodo-propionic ester forms acetoglu- 
taric ester, etc. Many other dibasic acids are produced in an 
analogous manner (Aznalen, 216, 39, 127). 


The £-ketone dicarboxylic acids, formed as above, sustain the same decomposi- 
tions as the 6-ketone monocarboxylic acids (p. 333). Thus, acetosuccinic ester 
when acted upon with concentrated potassium hydroxide, breaks down into acetic 
and succinic acids (acid decomposition) :— 

CH,.CO.CH.CO,R CH,.coO.H 
+ 3H,O = CH,.CO.OH + | + 2ROH, 
CH,.CO,R CH,.CO,H 


Aceto-succinic Ester, 


whereas, if boiled with baryta water, or acids, the ketone decomposition occurs, 
and the products are CO,, and (-acetopropionic acid (lzvulinic acid) :— 


CH,.CO.CH.CO,R 
i eat H,O = CH,.CO.CH,.CH,.CO,R + CO, + ROH. 
‘H,.CO, 


Both decompositions occur simultaneously, as in the case of aceto-monocarboxylic 
ester. 


3. By the condensation of oxalic ester and fatty acid esters 
through the action of sodium or sodium alcoholate. This is 
analogous to the formation of aldehydic and ketonic esters (W. 
Wisticenus, Berichte, 19, 33253; 20, 3392) :— 


CO.OR CO.OR 
l + CH,.CO,R + Na= | + ROH. 
CO.OR Acetic Ester. O.CHNa.CO,R 

Oxalic Ester. Oxalacetic Ester. 


The sodium compounds are first formed. The esters are obtained 
by heating them with acids. 


The esters of all the fatty acids having primary radicals (carboxyl attached to a 
CH,-group, e. g., propionic acid, normal butyric acid), act like the acetic esters. 
Isobutyric acid does not react (Berichte, 21,1156). Propionic ester yields methyl 

CO.OR 
oxalacetic ester, | , ete. 
CO.CH(CH,).CO,R 


Po? em ORGANIC CHEMISTRY. 


In the same way oxalic and lzvulinic esters yield oxal-levulinic ester (Berichte, 
22, 885), and oxalic and succinic esters yield oxal-succinic ester—a ketone tricar- 
boxylic acid. : 


i, Mesoxalic Acid, C,H,0, — CO(CO,H), or C,H,O, = C 
(OH),.(CO,H),, dioxymalonic acid, is formed from amidomalonic 
acid by oxidation with iodine in an aqueous solution of potassium 
iodide ; from dibrom-malonic acid by boiling with baryta water or 
silver oxide :— 

/CO,H 


fe CO ono COM). Corr 


\.CO,H “AHBr; 


and by boiling alloxan (mesoxalyl urea) with baryta water. 


Preparation.—Add barium alloxanate (5 gr.) to water (1 litre) of 80°, then 
quickly heat to boiling (5-10 minutes) and filter. As the solution cools, barium 
mesoxalate will separate in the form of a fine, crystalline powder. It is decom- 
posed with an equivalent quantity of sulphuric acid, the barium sulphate removed 
by filtration, and the solution concentrated at a temperature of 40—50°, until the 
remaining mesoxalic acid solidifies in a crystalline mass, 


Mesoxalic acid crystallizes in deliquescent prisms containing 1 
molecule H,O ; it melts at 115° without loss of water, and at higher 
temperatures decomposes into CO, and glyoxylic acid, CHO.CO,H. 
It breaks up into CO and oxalic acid by the evaporation of its 
aqueous solution. 

As mesoxalic acid contains 1 molecule of water intimately com- 
bined, and as all its salts dried at 110° contain 1 molecule H,O, it 
is considered a dihydroxy] derivative—dioxymalonic acid, C(OH),. 
(CO,H),. Here, as in the case of glyoxylic acid, we observe an 
intimate union of two OH groups with 1 carbon atom, already com- 
bined with negative CO.H groups (p. 331). Again, mesoxalic acid 
deports itself like a ketonic acid (p. 329), inasmuch as, with a loss 
of: water, it unites with primary alkaline sulphites, and when acted 
upon by sodium amalgam in an aqueous solution of 90°, it is 
changed to tartronic acid :— 


/CO,H of /CO,H 
COX €02H + H, = CH(OH)< Co? 


It combines with hydroxylamine to isonitrosomalonic acid 
(p. 409). With phenylhydrazine it forms the phenylhydrazone, 
C(N.NHC,H;)(CO,H),. This is identical with benzene mal6nic 
acid obtained by the action of benzene diazo-salts upon malonic 
acid (Berichte, 21, 118). 

Barium mesoxalate, C(OH) JOOS Be and calcium mesoxalate, are crystal- 

? SCO oe ? ? 


_ line powders, not very soluble in water. The ammonium salt, C(OH),.(CO,. 
NH,),, obtained by evaporating a solution of the acid in ammonium carbonate, 





ACETONE DICARBOXYLIC ACID. 435 


crystallizes in needles. The sz/ver salt, C(OH),.(CO,Ag)., is a white amorphous 
powder, which blackens on exposure to the air, and when boiled with water affords 
mesoxalic acid, silver oxalate, silver and CO,. 

The diethyl ester, C(OH),(CO,.C,H,)., is obtained by the action of C,H,I 
upon the silver salt. It is an unstable oil. It forms a crystalline diamide, 
C(OH),.(CO.NH,),, with/aqueous ammonia. Acetyl chloride converts it into 


the diacetyl compound, C(O.C,H,0). eg? eH? 
long needles, melting at 145°. ie arte 
CO.CO,H 
2. Oxalo-Acetic Acid, C,H,O; =A 
H 


(p. 196), which crystallizes in 


The diethyl ester (analogous 
Pp 874s | 

to acetoacetic ester, p. 431) is formed when sodium acts upon a mixture of oxalic 
and acetic esters, and when acetylene dicarboxylic ester is digested with sulphuric 
acid. The ester is a thick oil. Heat soon decomposes it. When boiled with 
alkalies it breaks down into alcohol, oxalic and acetic acids. Boiling H,SO, 
causes it to undergo the ketone decomposition (p. 337) whereby CO, and pyro- 
racemic acid (CH,.CO.CO,H) are produced. Ferric chloride imparts a deep red 
color to the solution of the ester. 

Oxalo-acetic acid is both an a- and £-ketonic acid (331). The union of the 
ester with phenylhydrazine gives rise to a condensation product—a _ pyrazolon- 
derivative (Berichte, 22, 2929). C(N,H.C,H,).CO,H 

The phenylhydrazine derivative of amido-oxalo-acetic acid, | 

CH(NH,).CO,H 
has been prepared by the reduction of the osazone of dioxytartaric acid (erichie, 


20, 245). 


Bromine converts oxalo-acetic ester into the dibromide, C,H,Br,O,;. This 
undergoes decomposition quite readily (Berichte, 22, 2912). 

3. Acids, CHO... 

(1) Aceto-malonic Acid, CH,.CO.CH(CO,H),. Its ethyl ester is formed 
when chlorcarbonic ester acts upon sodium aceto-acetic ester (Berichte, 22, 2617; 
21, 3567). - It is a mobile liquid, boiling about 240°. It decomposes into CO,, 
acetone and acetic acid when saponified. 


2. Acetone Dicarboxylic Acid, COs ee cae may be 


obtained by warming citric acid with sulphuric acid :— 
CH,.CO,H  CH,.CO,H 
bon).co,H = CO 4 H,O + CO. 
bus, co,H CH,.CO,H. 


Dehydrated citric acid is heated upon a water bath with 2 parts concentrated sul- 
phuric acid until the evolution of CO ceases and that of CO, begins. The rapidly 
cooled mass is then mixed with 2% parts water, when the acid separates as a 
crystalline mass. To obtain the diethyl ester the product of the above reaction 
is at once poured into absolute alcohol (Berichte, 17, 2542; 18, Ref. 468). 


Acetone dicarboxylic acid dissolves readily in water and ether ; 
it crystallizes in colorless needles, melting at 130° when it decom- 
poses into CO, and acetone. The same alteration occurs on boil- 
ing the acid with water, acids or alkalies; aceto-acetic ester is also 


436 ORGANIC CHEMISTRY. 


an intermediate product. The solutions of the acid are colored 
violet by ferric chloride. Being a ketonic acid it unites with 
phenylhydrazine; with HCN it yields an oxy-cyanide (p. 202), 
which is reconverted into citric acid by hydrochloric acid. The 
diethyl ester, C;H,(C,H;),.0; (preparation above) is an oily liquid, 
which can only be distilled under reduced pressure. The 4H- 
atoms of the two CH,-groups in it can be successively replaced by 
alkyls (Berichte, 18, 2289). 


PCl, converts the acid into chlorglutaconic acid (p. 429). Ammonia and the 
diethyl ester combine to form oxyamidoglutaminic ester (Berichte, 18, 2290), 
which condenses further to glutazine (see this)—a trioxypyridine derivative 
(Berichte, 19, 2694). The esters of acetone dicarboxylic acid condense with 
anilines to form esters of oxyquinoline carboxylic acids. Phenylhydrazine yields 
derivatives of oxy-quinizine (-pyrazole) (Berichie, 18, Ref. 469). Metallic sodium 
causes the ester to condense to dioxyphenylaceto-dicarboxylic ester (Berichte, 19, 
1446). CO.CO,H 

(2) Methyl Oxal-acetic Acid, “ , a-oxal-propionic acid. 

H(CH,).CO,H 
Its ethyl ester is obtained from the esters of oxalic and propionic acids. It is a 
colorless oil. Its alcoholic solution is colored an intense red by ferric chloride. 
It decomposes into alcohol, oxalic and propionic acids when boiled with alkalies. 
By the ketone decomposition (boiling with sulphuric acid) it separates into CO,, 
and propionyl carboxylic acid, CH,.CH,.CO.CO,H (p. 342) (Berichte, 20, 3394). 
4. Acids, C,H,O,. 
CH,.CO.CH.CO,H 
(1) Aceto-succinic Acid, . Its ethyl ester is prepared 
CH,.CO,H 
from aceto-acetic ester and chlor-acetic ester. It boils at 244-250°. Ferric 
chloride does not color it. By the acid decomposition it yields acetic and succinic 
acids; by the ketone decomposition the products are CO,, and f aceto-propionic 
acid (p. 343). The hydrogen atom of the CH-group, in the esters, can be re- 
placed by alkyls with the formation of alkyl-aceto-succinic acids (see below). 
CO.CO,H 
(2) Ethyl Oxal-acetic Acid, , a-oxal-butyric acid, is ob- 
C,H, CH.CO,n 
tained as ethyl ester from oxalic and ees esters. Isobutyric ester does not 
react (p. 434). . 
5. Acids, C,H,,0O;. 
(1) Aceto- glutaric Acid, CH ,.CO.CH 


is formed from aceto-acetic ester, and Riise ais ester. It yields acetic and 
glutaric acids in the acid decomposition. 
CH,.CO.C(CH,).CO,H 
(2) a-Methyl Aceto-succinic Acid, | . Its methyl 
CH,.CO,H 
ester is formed from methyl aceto-acetic ester and chloracetic ester; also by 
methylating aceto-succinic ester. It boils at 263°. The acid decomposition con- 
verts it into methyl succinic acid and acetic acid, while by the ketone decompo- 
sition (separation of CO,R) the product is B-aceto-butyric acid (p. 344). 
H,.CO.CH.CO,H 
(3) 6-Methyl Aceto-succinic Acid, , from aceto- 
H(CH a); CO, H 
a ester and a-brom-propionic ester, CH,.CH,Br.CO,R , also boils at 263°, 


on Its ethyl ester 








DIACETO-SUCCINIC ACID. 437 


and in the acid decomposition breaks down into methyl-succinic acid and acetic 
acid. The ketone decomposition yields CO,R and (-aceto-isobutyric acid (p. 344). 


(4) Acetone-diacetic Acid, 0O¢ CH CH CO loses water and becomes 


the y-dilactone, C,H ,O,4 :— 
CH,.CH,.C.CH,.CH, 
§ Box Peri 
CO 8 Be Fr CO 
This is formed when succinic acid is boiled for some time :— 
2C,H,O, = C,H,0O, + CO, + 2H,O 


(Berichte, 22, 681). It melts at 75°, and distils without decomposition under 
reduced pressure. Boiling water, or better, boiling alkalies cause it to become 
acetone diacetic acid, by absorption of water. This acid is identical with propion- 
dicarboxylic qcid, and hydrochelidonic acid. ‘The first is obtained by the action 
of HCl upon furfur-acrylic acid, and the latter by the reduction of chelidonic 
acid. 

Acetone-diacetic acid melts at 143°. Acetyl chloride or acetic anhydride will 
again convert it into the y-dilactone. Hydroxylamine changes it to the oxime, 
C(N.OH)(C,H,.CO,H),, melting at 129°. Its phenylhydrazone, C(N,H. 
C,H,)(C,H,.CO,H)., melts at 107° (Berichte, 22, 682). 








Diketone-dicarboxylic Acids :— 
CO.CH,.CO,H 
1. Oxal-diacetic Acid, C,H,O, = | . Its ethyl ester, like 
CO.CH,.CO,H 

oxal-acetic ester (p. 435), is produced in the action of sodium upon a mixture of 
oxalic ester with two molecules of acetic ester, (Berichte, 20, 591); also from 
oxalic ester and chlor-acetic ester by the action of zinc (Ketific Acid, Berichte, 
20, 202). It consists of leafy crystals, melting at 77°. Ferric chloride imparts 
an intense red color to its alcoholic solution. Concentrated hydrochloric acid 
sets free the oxaldiacetic acid. This is a white insoluble powder. When heated 
it yields, 2 CO,, and diacetyl (p. 326). Chlorine and bromine convert the ester 
into ¢etrachlor- and tetrabrom-oxaldiacetic ester. The first is called setrachlordi- 
keto-adipic ester, and is also produced when chlorine acts upon dioxyquinone 
dicarboxylic ester (Berichte, 20, 3183). CH,.CO.CH,.CH.CO,H 

2. Oxal-levulinic Acid, C,H,O, = (?). The 

0.CO,H 

ethyl ester results from the action of sodium or sodium ethylate upon oxalic and 
levulinic esters. It is a thick oil. Ferric chloride colors its alcoholic solution 
an intense red. Cupric acetate precipitates the copper salt from an alcoholic 
solution (Berichte, 21, 2583). 

3- Diaceto-succinic Acid, C,H,,O,. Iodine converts sod-aceto-acetic 
ester (2 molecules) into its ethyl ester (Ammalen, 201, 144) :— 


CH,.CO.CHNa.CO,R CH,.CO.CH.CO,R 
= 2=— + 2Nal. 
CH,.CO.CHNa.CO,R CH,.CO.CH.CO,R 


It crystallizes in thin plates and melts at 78°, It is very unstable. It undergoes 
various re-arrangements, in accord with its y-diketonic nature (with the atomic 
group—CO.CH.CH.CO—), Thus, when heated or when acted upon by acids, 


438 ORGANIC CHEMISTRY. 


it yields carbopyrotritartaric ester (a derivative of furfurol). Pyrrol derivatives 
result when it is acted upon with ammonia and amines. This reaction will serve 
for the detection of diaceto-succinic ester (Berichte, 19,14). Phenylhydrazone 
procs dipyrazolon derivatives (Aumalen, 238, 168). 
Sodium hydroxide causes the ester to prem down into 2CO,, and acetony] 
anetbne (p. 328). 
Iodine, acting upon disod-diaceto-succinic = produces diaceto-fumaric ester, 
CH,.CO.C.CO,R 
| , melting at 96°. 
CH, :CO.C,CO,R 





Analogues of Diacetosuccintce Acid :— 
CH,.CH(CO.CH,).CO,H 
Diaceto-adipic Acid, | . Ethylene bromide acting 
CH,.CH(CO.CH,).CO.H 
upon two molecules of sodacetoacetic ester, forms its diethyl ester (Berichze, 19, 
2045). Phenylhydrazine converts it into a dipyrazolon-derivative (Berichte, 19, 
2045). CH,.CO.CH.CO,H 
Diaceto-glutaric Acid, . Its ester is obtained from 
Fis 5 0 I Bd & eo PR | 
aceto-acetic ester and from levulinic ester (p. 343). Being a y-diketone com- 
pound it unites with ammonia and forms a pyrrol-derivative (Aerichte, 19, 47). 
CO. ig CO,H’ 
Oxal-succinic Acid, C,H,O, = | , is an analogous ketone 
CO, HCH, .CO,H 
tricarboxylic acid. Its ethyl ester forms when sodium ethylate acts upon oxalic 
ester and succinic ester. When its dilute solutions are digested, oxalic and 
leevulinic acids are produced. Being a (§-ketonic acid derivative, its ester yields 
a pyrazolon compound with phenylhydrazine (Berichte, 22, 885). 
When metallic sodium is permitted to act upon a mixture of oxalic ester, with 
two molecules of acetic ester, the product will be— 
CO.CH,.CO,.C.H,. 
Oxalyl-diacetic Ester, d eee has OO,” Tas is’a leafy 
ae 5 Wp © & a Soe © 
crystalline mass, melting at 76-77°. Its alcoholic solution becomes an intense 
red upon the addition of ferric chloride (Berichte, 20,591). This ester is also 
called etipic ester and results in the action of zinc upon a mixture of oxalic ester 
and chloracetic ester (Berichte, 20, 202). 





CARBAMIDES OF THE DICARBOXYLIC ACIDS. 


The urea derivatives or carbamides (ureides) of these acids are 
' perfectly analogous to those of the dihydric acids (p. 399). By the 
replacement of two hydrogen atoms in urea we obtain the true 
ureides. The alkalies convert these then into acids of the uric acid 
group :— 

NH.CO NH.CO.CO.OH 
PA = 00? 
co \NH, 
Oxalyl Urea. . Oxalurio Acid. 








CARBAMIDES OF THE DICARBOXYLIC ACIDS. 439 


The latter decompose further into urea (also CO, and NH;) and 
acid, whereas the ureides of the divalent acids yield amido-acids. 
Most of the carbamides were first obtained as decomposition pro- 
ducts of uric acid. . J NH.CO 

Oxalyl Urea, C,H,N,O; = CO | , Parabanic Acid, 
| ‘“NH.CO 
is produced in the energetic oxidation of uric acid and alloxan (p. 
443), and is obtained by evaporating a solution of uric acid in 
three parts of ordinary nitric acid (Annalen, 172, 74). It is syn- 
thetically prepared by the action of POCI, upon a mixture of urea 
and oxalic acid. It issoluble in water and alcohol, but not in ether, 
and crystallizes in needles or prisms. Under peculiar conditions 
it crystallizes with one molecule of water, which it does not lose 
until heated to 150°. Oxalyl urea reacts acid, possesses an acid 
character, as it contains two imide groups (p. 412) linked to car- 
bonyls, and is ordinarily termed parabanic acid. ' 


Its sa/¢s are unstable; water converts them at once into oxalurates. The primary 
alkali salts, e. g., C;SHKN,Os,, are obtained as crystalline precipitates by the addi- 
tion of potassium or sodium ethylate to an alcoholic solution of parabanic acid. 
Silver nitrate precipitates the crystalline dist/ver salt, C,Ag,N,O,, from solutions ot 
the acid. 

Methyl Parabanic Acid, C,H(CH;)N,O,, is formed by boiling methyl uric 
acid, or methyl alloxan, with nitric acid, or by treating theobromine with a chromic 
acid mixture. It is soluble in ether and crystallizes in prisms, which melt at 149.5°. 
Alkalies convert it into methyl urea and oxalic acid. 

Dimethyl Parabanic Acid, C,(CH,),N,O,, Cholestrophane, is ‘obtained 
from theine by boiling with nitric acid, chlorine water or chromic acid, or by 
heating methyl] iodide with silver parabanate, C,Ag,N,O,. It crystallizes in pearly 
laminze, melts at 145°, and distils at 276°. Alkalies decompose it into oxalic acid 
and dimethyl urea; the latter even yields CO, and two molecules of CH,.NH,. 


Oxaluric Acid, CH,N,O, = CO¢NH: COCO 

2 
are formed by the action of bases on parabanic acid. They are not 
readily soluble in water, and usually separate in crystalline form. 
The ammonium salt, C;H;(NH,)N,O,, and the s¢/ver salt, C;H;AgN, 
O,, crystallize in glistening needles. Free oxaluric acid is liberated 
by mineral acids from its salts as a crystalline powder, dissolving 
with difficulty. When boiled with alkalies or water it decomposes 
into urea and oxalic acid; heated to 200° with POCI, it is again 
changed into parabanic acid. 


Its salts 


The ethyl ester, C,H,(C,H,;)N,O,, is formed by the action of ethyl iodide on 
the silver salt, and has been synthetically prepared by letting ethyl oxalyl chloride 
act upon urea :— 


NH,  COCl /NH.CO.CO,.C,H, 
I == 00 + HCl. 
\NH, CO, C,H, \NH, - 


440 ORGANIC CHEMISTRY. 


It crystallizes from warm water in thin, shining needles, which melt with decom- 
position at 177°. Ammonia and silver nitrate added to the solution of the ether 
precipitate silver parabanate. 


Oxaluramide,C,H;N,0, = CO 
heating ethyl oxalurate with ammonia, and by fusing urea with ethyl oxamate, 


COL Co, *c HH. It is a crystalline precipitate, dissolving with difficulty in water, 
eat 


x *! H.CO.CO.NH, Oxalan, is produced on 


and decomposing when boiled with water into urea, ammonia and oxalic acid. 





NH.CH.OH 
Glyoxyl Urea, C,H,N,0,= CO’ | , Allanturic Acid, is the 
\NH.CO 
ureide of glyoxalic acid, CH(OH),.CO,H, and is obtained from allantoin on warm- 
ing with baryta water or with PbO,, and by the oxidation of glycolyl urea (hydan- 
toin, p. 391). It is a deliquescent, amorphous mass, insoluble in alcohol; it forms 
salts with one equivalent of base. When the potassium salt is boiled with water it 
decomposes into urea and glyoxalic acid, which is further transposed into glycollic 
and oxalic acids (see p. 330). 
Allantoin, C,H,N,O,, is a di-ureide of glyoxalic acid. It is present in the 
‘urine of sucking calves, in the allantoic liquid of cows, and in human urine after 
the ingestion of tannicacid. It is produced artificially on heating glyoxalic acid 
(also mesoxalic acid CO(CO,H),.) with urea to 100° :— 


NH, CHO /NHLCH.NH , 
2CO tl = CO ‘| CcO.+ 2H,0. 
NH,  CO.OH NH.CO.NH, 


Pyruvil (C;H,N,O,) is formed in a similar manner from urea and pyroracemic 
acid. 

Allantoin is formed by oxidizing uric acid with PbO,,MnO,, potassium ferri- 
cyanide, or with alkaline K MnO, (Berichte, 7, 227) :— 


C,H,N,O, + O + H,0 =C,H,N,O, + CO,. 


Allantoin crystallizes in glistening prisms, which are slightly soluble in cold 
water, but readily in hot water and in alcohol. It has a neutral reaction, but dis- 
solves in alkalies, forming salts. Ammeniacal silver nitrate precipitates the com- 
pound, C,H,AgN,O,—a white powder. When boiled with baryta water it decom- 
poses into CO,, NHg, oxalic acid and glycolyl urea (hydantoin). 

Sodium amalgam converts allantoin into glyco-uril, C,H,N,O,, which is 
identical with acetylene urea (erichde, 19, 2479) :— 


NH, CHO / NH.CH.NH 
Ve L — CO | Sco + 2H,0. 
HO \NH.CH.NH% 


It crystallizes in long needles or prisms. It breaks down into hydantoic acid (p. 
392) and urea when boiled with baryta water. 


NITROBARBITURIC ACID. 441 


Malonyl Urea, C,H,N,O; = COCR gy Cis Barbituric 


Acid, the ureide of malonic acid, is obtained from alloxantin (p. 
444) by heating it with/concentrated sulphuric acid, and from di- 
brombarbituric acid by the action of sodium amalgam. It may also 
be synthetically obtained by heating malonic acid and urea to 100° 
with POCI,. It crystallizes with two molecules of water in large 
prisms from a hot solution, and when boiled with alkalies is decom- 
posed into malonic acid and urea. 

The hydrogen of CH, in malonyl urea can be readily replaced 
by bromine, NO, and the isonitroso-group. The metals in its salts 
are joined to carbon and may be replaced by alkyls (Berichie, 14, 


1643; 15, 2846). 


When silver nitrate is added to an ammoniacal solution of barbituric acid, a 
white silver salt, C,H,Ag,N,Os, is precipitated. Methyl iodide converts this 
J 
into Dimethylbarbituric Acid, COC Nit COS C(CH,). This forms shining 
laminze, does not melt at 200°, and sublimes readily. . Boiling alkalies decompose 
it into CO,, NH,, and dimethyl malonic acid. Its isomeride, 8- Dimethyl Bar- 
bituric Acid, COC NicH'y;co DCH» is produced from malonic acid and 

dimethyl urea through tht agency of POCI,. It melts at 123°. 

Bromine converts barbituric acid, nitro-, isonitroso-, and amido-barbituric acids 
into Dibrombarbituric Acid, C,H,Br,N,O, = CO aera Cl This 
dissolves readily in hot water, in alcohol and in ether. It crystallizes in laminz 
or prisms. Boiling water converts it into mesoxalyl-urea (alloxan). Nascent 
hydrogen or hydriodic acid causes it to revert to barbituric acid, and hydrogen 
sulphide transforms it into tartronyl-urea (dialuric acid). 

Nitrobarbituric Acid, C,H,(NO,)N,O,, Dilituric Acid, is obtained by the 
action of fuming nitric acid upon barbituric acid and by the oxidation of violuric 
acid ( Berichte, 16, 1135). It crystallizes with three molecules of water in color- 
less laminz or prisms, which impart a yellow color to water. It can exchange 
3 hydrogen atoms for metals. Its salts are principally those having but one equiva- 
lent of metal. They are very stable and, as a general thing, are not decomposed 
by mineral acids. 

Isonitroso-barbituric Acid, C,H,(N.OH)N,O,, Violuric Acid, is obtained 
by acting with potassium nitrite upon barbituric acid. Barium chloride precipi- 
tates a red colored salt from the solution; this is decomposed by sulphuric acid. 
Furthermore, it is prepared (according to the usual methods of forming isonitroso- 
compounds, p. 214) by the action of hydroxylamine upon alloxan. It crystallizes 
in yellow, rhombic octahedra with 1 molecule of water. It gives blue, violet and 
yellow colored salts with one equivalent of metal. The fotassium salt, C,H,K 
(NO)N,O, + 2H,0, crystallizes in dark blue prisms and dissolves in water with 
a violet color. Ferric acetate imparts a dark blue color to the solution. When 
heated with alkalies violuric acid breaks up into urea and isonitroso malonic acid 

Pp. 409). 
{ Amido-barbituric Acid, C,H,(NH,)N,O, (Uramil, Dialuramide, Murexan), 
is obtained in the reduction of nitro- and isonitroso-barbituric acid with hydriodic 


37 


442 _ ORGANIC CHEMISTRY. 


acid; by boiling thionuric acid with water, and by boiling alloxantin with an 
ammonium chloride solution :— 
Uramil. Alloxan. 


Alloxantin. 


Alloxan remains in solution, while uramil crystallizes out. It is only slightly soluble 
in water, and crystallizes in colorless, shining needles, which redden on exposure. 
Murexide (p. 445) is produced when the solution is boiled with ammonia. Nitrous 
acid converts uramil into alloxan :— 


/NH.COX% 


/NH.CO\ 4 
\NH.CO/ : 


CO \.NH.CO/ 


CH.NH, yields CO 


Thionuric Acid, C,H,N,SO, = COL NiT.CO>C< $0, 2, ,sulphamidobar- 
bituric acid, is obtained by heating isonitrosobarbituric acid or alloxan with ammo- 
nium sulphite. Its ammonium salt, C,H,(NH,)N,50, + H,O,is made by 
boiling alloxan with sulphurous acid and ammonia. It forms bright scales. Free 
thionuric acid is obtained by acting on the lead salt with hydrogen sulphide. It is 
a readily soluble crystalline mass. It reduces ammoniacal silver solutions, and 
when boiled with water breaks up into sulphuric acid and uramil. 





* 


‘Uracyl, C,H,N,0, = CoC nH co DCH, the ureide of B-oxyacrylic acid, 
CH(OH):CH CO,H, is only known in its derivatives. 
NH.C(CH,)\ ge 
Methyl Uracyl, C,H, (CH,)N,0, = OO NCO *) NcH. This is pro- 
duced when urea acts upon aceto-acetic ester, which reacts in the tautomeric form 
of B-oxycrotonic ester (Anmalen, 229, 1) :— 


NH CH(CH,) NH.C(CH3)\ 
Ce ey seeded ‘ 
\NH,  C(OH).CO.OR \NH.CO. 
Concentrated nitric acid converts it into Nitrouracyl-carboxylic Acid, 


ae SC.NO,. This passes, by elimination of CO,H, and reduc- 

tion of its nitro-group, into amdouracy/, cog Rice > SSC.INH,, and oxyura- 
‘ penne 

cyl, COC NHLCO. CON, tsobarbituric acid. Bromine water converts the 


NH.CO__Y 
latter into zsodialuric acid, CaCnaco NC.OH. This yields uric acid when 





CH + R.OH + H,0. 





heated with urea and sulphuric acid (p. 445) (Berichte, 21, 999; Annalen, 251, 
235). 





Tartrony! Urea, C.H,N,0, = CO Sty Go >CH.OH, dialu. 
ric acid, the ureide of tartronic acid, CH(OH)(CO,H),, is formed 
by the reduction of mesoxalyl urea (alloxan) with zinc and hydro- 
chloric acid, and from dibrombarbituric acid by the action of hydro- 
gen sulphide. On adding hydrocyanic acid and potassium car- 


ae * 


TS aa eae 


MESOXALYL UREA. | 443 


bonate to an aqueous solution of alloxan, potassium dialurate separates 
but potassium oxalurate remains dissolved :— 
2C,H,N,O, + 2KOH = C,H,KN,O, + C,H,KN,0O, + CO,. 
Potassium Dialurate. Potassium Oxalurate. 

Dialuric acid crystallizes in needles or prisms, has a very acid 
reaction and forms salts with 1 and 2 equivalents of the metals. It 
becomes red in color in the air, absorbs oxygen and passes over into 
alloxantin, 2C,H,N,O, + O = C,H,N,0, + 2H,0O. 





Mesoxalyl Urea,C,H. NO.= COC Ney eas Alloxan, 


the ureide of mesoxalic acid, is produced by the careful oxidation. 
of uric acid, or alloxantin with nitric acid or chlorine and bromine. 


Preparation.—Add uric acid gradually to cold nitric acid of specific gravity 
1.4, as long as areaction occurs. Then let the whole stand for some time. The 
separated, crystalline mass of alloxan is drained upon an asbestos filter, warmed 
upon a water bath to expel all nitric acid, and then recrystallized from water; 
alloxantin remains in the mother-liquor. 

Moisten alloxantin with concentrated nitric acid (sp. gr. 1.46), let stand until it 
has been completely changed to alloxan (a small portion should dissolve readily 
in cold water), and then purify the latter as already described. 


Alloxan crystallizes from warm water in long, shining, rhombic 
prisms, with 4 molecules of H,O. » When exposed to the air they 
effloresce with separation of 3H,O. ‘The last molecule of water is 
intimately combined (p. 434), as in mesoxalic acid, and does not 
escape until heated to 150°. Small stable crystals, with 1 H,O 
separate out from hot solutions. Alloxan is easily soluble in water, 
has avery acid reaction and possesses a disagreeable taste. The 
solution placed on the skin slowly stains it a purple red. Ferrous 
salts impart a deep indigo blue color to thesolution. When hydro- 
cyanic acid and ammonia are added to the aqueous solution the 
alloxan decomposes into CO,, dialuric acid and oxaluramide (p. 440), 
which separates asa white precipitate (reaction for detection of 
alloxan). 


The primary alkali sulphites unite with alloxan just as they do with mesoxalic 
acid, and we can obtain crystalline compounds, e. ¢., C,H,N,O,.SO,KH + H,0. 
Pure alloxan can be preserved without undergoing decomposition, but in the 
presence of even minute quantities of nitric acid it is converted into alloxantin. 
Alkalies, lime or baryta water, change it to alloxanic acid, even when acting in the 
cold. Its aqueous solution undergoes a gradual decomposition Eee rapid on 
heating) into alloxantin, parabanic acid and CO, :— 


3CHAN,O, = CH.N,O, + C)H,N,O, + CO, 
Alloxantin, Oxal yl Urea 


444 ORGANIC CHEMISTRY. 


Boiling dilute nitric acid oxidizes alloxan to parabanic acid (oxalyl urea) and 


OS: 


NH.CO NH.CO 
co’ NCO GS Oe ore = CO. 

~ \NH.CO” \NH.CO 

Mesoxalyl Urea. Oxalyl Urea. 


The mesoxalic acid residue, like the free acid (p. 434), splits off a CO-group, 
readily forming oxalyl. 

Reducing agents, like hydriodic acid, change alloxan, in the cold, to alloxantin, 
on warming, however, into tartronyl urea (dialuric acid). 

Methyl Alloxan, C,H(CH,)N,O,, is produced by the oxidation of methyl uric 
acid. Alkalies convert it at once into methyl alloxanic acid. Nitric acid changes 
it to methyl parabanic acid (p. 439). 

Dimethyl Alloxan, CO(N.CH,),C,0,, is produced when aqueous chlorine 
(hydrochloric acid and KCIO,) acts on theine, and by the careful oxidation of 
tetramethyl] alloxantin with nitric acid. When the solution is concentrated, dime- 
thy] alloxan remains as a non-crystallizable syrup. It gives all the reactions of 
alloxan. H,S reduces it to tetramethyl alloxantin (see below). By energetic 
oxidation, it yields dimethyl oxalyl urea (p. 405). 


Alloxanic Acid. C,H,N,0, — Co’ NH-CO.CO.CO.OH | Wren the alkalies 
S24 Oe" 2G NN, 


act on alloxan the latter absorbs water and passes into the acid. If baryta water 
be added to a warm solution of alloxan, as long as the precipitate which forms con- 
tinues to dissolve, barium alloxanate, C,H,BaN,O, + 4H,O, will separate out in 
needles when the solution cools. To obtain the free acid, decompose the barium 
salt with sulphuric acid and evaporate at a temperature of 30-40°. A mass of 
crystals is obtained by this means. Water dissolves them easily. Alloxanic acid 
shows a very acid reaction, dissolves zinc, and is indeed a dibasic acid, inasmuch 
as both the hydrogen of carboxyl and of the imide group can be exchanged for 
metals. When the salts are boiled with water, they decompose into urea and 
mesoxalates. 





By the union of two molecules of the ureides of the dicarboxylic acids we get 
the compounds oxalantin, alloxantin, and hydurilic and purpuric acids. These are 
termed di-ureides. 

Oxalantin, C,H,N,O,, Leucoturic Acid, is obtained by the action of zinc 
and hydrochloric acid upon oxalyl urea:—2C,H,N,O, + H, = C,H,N,0O,. 
HS separates it from the zinc salt. It forms crystalline crusts which dissolve with 
difficulty in water, and it also reduces ammoniacal solutions of both silver and 
mercury. : ; 

Alloxantin, C,H,N,O,, is obtained by reducing alloxan with SnCl,, zinc and 

hydrochloric acid, or H,S in the cold: 2C,H,N,O, + H, =C,H,N,0, + 
H,O; or by mixing solutions of alloxan and dialuric acid: C,H,N,O, + C,H,N,O, 
= C,H,N,0O, + H,O. Most readily prepared by warming uric acid with dilute 
nitric acid (Ammalen, 147, 367). It crystallizes from hot H,O in. small, hard 
prisms with 3H,O and turns redin air containing ammonia. Its solution has an 
acid reaction; ferric chloride and ammonia give it a deep blue color, and baryta 
water produces a violet precipitate, which on boiling is converted into a mixture © 
of barium alloxanate and dialurate. 

Tetramethyl Alloxantin, C,(CH,),N,O, = C,,H,,N,0,, Amalic Acid, 
is formed by the action of nitric acid or chlorine water upon theine, or better, by 





URIC ACID. 445 


the reduction of dimethyl] alloxan (see above) with hydrogen sulphide (Anna/en, 
215, 258) :-— 
2C,(CH;),.N,0, + H, = C,(CH;),N,O, + H,0. 


It consists of colorless, sparisigly soluble crystals, which impart a red color to the 
skin; alkalies and baryta water give it a violet-blue color. When carefully 
oxidized by nitric acid, or by the action of chlorine (Anna/en, 221, 339) it is again 
altered to dimethyl] alloxan; more energetic reaction produces dimethyl parabanic 
acid. 

Hydurilic Acid, C,H,N,0,. The ammonium salt is formed on boiling 
alloxantin with dilute sulphuric acid; by heating dialuric acid with glycerol to 
150°; and also on heating aqueous alloxan or alloxantin to 170°. The free acid 
is obtained by decomposing the copper salt with hydrochloric acid. It crystallizes 
from hot water in little prisms having 2H,O, and is a dibasic acid. Ferric chlor- 
ide imparts a dark green color to the solution of the acid or its salts. Ordinary 
nitric acid decomposes hydurilic acid into nitro- and nitroso-barbituric acid ; fuming 
nitric acid forms alloxan. 

Purpuric Acid, C,H,N,O,, is not known in the free state, because as soon 
as it is liberated from its salts by mineral acids it immediately decomposes into 
alloxan and uramil. The ammonium salt, C,H,(NH,)N,O, + H,O, is the 
dye-stuff murexide. ‘This is formed by heating alloxantin to 100° in ammonia 
gas; by mixing ammoniacal solutions of alloxan and uramil :— 


C,H,N,0, + C,H,;N,0O, + NH, = C,H,(NH,)N,O, + H,0O; 


and by evaporating uric acid with dilute nitric acid and pouring ammonia over 
the residue (murexide reaction). It is most readily obtained from uramil (p. 441). 
Dissolve 4 parts of the latter in dilute ammonium hydroxide, add 3 parts of mer- 
curic oxide and heat to boiling, when mercury will separate and the solution 
assume a dark-red color :— 


2C,H,N,O, + O = C,H,(NH,)N,0, + H,0. 


Murexide separates from the solution on cooling. It forms four-sided plates or 
prisms with one molecule of H,O, and has a gold-green color. It dissolves in 
water with a purple-red color, but isinsoluble in alcohol and ether. It dissolves 
with a dark blue color in potash; on boiling NH, is disengaged and the solution 
decolorized. 





Uric Acid, C;H,N,O,, occurs in the juice of the muscles, in the 
blood and in the urine, especially of the carnivore, the herbivore 
separating hippuric acid; also, in the excrements of birds, reptiles 
and insects. When urine is exposed for awhile to the air, uric acid 
separates ; this also occurs in the organism (formation of gravel and 
joint concretions) in certain abnormal conditions. 

Uric acid is prepared artificially by heating glycocoll with urea 
(10 parts) to 200-230° (Berichte, 17, 443,), or trichlorlactamide 
with urea (Berichte, 20, Ref. 472). It may be directly synthesized 
by heating isodialuric acid (p. 442) and urea with sulphuric acid (p. 
446) (Behrend, Berichte, 22, Ref. 397). 


446 ORGANIC CHEMISTRY. 


Uric acid is best prepared from guano and the excrements of reptiles. Guano is 
boiled with a hot borax solution (1 part borax in 120 parts H,O) and the uric 
acid precipitated from the filtrate by hydrochloric acid. Or, after. removing the 
phosphates from guano by means of dilute hydrochloric acid, it is dissolved in 
concentrated sulphuric acid (in equal weight), and the uric acid precipitated by 
pouring the solution into water (12-15 vols). To obtain the acid pure, it is dis- 
solved in caustic potash and carbon dioxide conducted into the liquid, when potas- 
sium urate will be precipitated; hydrochloric acid sets free the uric acid. 

The excrements of reptiles (ammonium urate) are boiled with dilute potassium 
or sodium hydroxide until the odor of ammonia is no longer perceptible, the hot 
solution filtered and the filtrate poured into dilute hydrochloric acid. 


Uric acid is precipitated as a shining, white powder, from solu- 
’ tions of its salts. It is odorless and tasteless, insoluble in alcohol 
and ether, and dissolves with difficulty in water; 1 part requires 
15,000 parts water of 20° for its solution, and 1800 parts at 100°. 
Its solubility is increased by the presence of salts like sodium phos- 
phate and borate. Water precipitates it from its solution in con- 
centrated sulphuric acid. On evaporating uric acid to dryness with 
nitric acid, we obtain a yellow residue, which assumes a purple-red 
color if moistened with ammonia, or violet with caustic potash or 
soda (murexide reaction, p. 445). Heat decomposes uric acid into 
NH;, CO,, urea and cyanuric acid. 

Uric acid acts like a weak dibasic acid, forming chiefly, how- 
ever, salts containing but one equivalent of ‘metal. The secondary 
alkali salts are obtained by dissolving the primary salts or the free 
acid in the hydroxides of potassium and sodium; they show a very 
alkaline reaction, and are changed to the primary form by CO, and 
water. When CO, is conducted through the alkaline solution, the 
primary salts are precipitated. Uric acid forms primary salts with 
the alkaline carbonates, 


ss 


The dipotassium salt, CSH,K,N,Os, separates in needles when its solution is 
evaporated. It dissolves easily i in potash and in 40 parts of water at ordinary tem- 
peratures. The primary salt, C;H,KN,O,, is precipitated from solutions of the 
dipotassium)salt as a jelly, which soon becomes granular and dissolves in 800 parts 
of water at 20°. The primary sodium salt is more insoluble. The primary am- 
monium salt, CH,(NH,)N,Og, is precipitated as a sparingly soluble powder, by 
ammonium chloride, from the solutions of the other salts. 

_ Methyl Uric Acid, C,H,(CH,)N,O,, is obtained by heating primary lead 
urate with methyl iodide and ether % 160°. It consists of small needles, which 
are rather insoluble in water. When heated with concentrated hydrochloric acid 
to 170° it decomposes into NH,, CO,, methylamine and glycocoll (Berichie, 17, 


330). 

Dimethyl Uric Acid, C,H,(CH,),N,O,, obtained from the secondary lead 
salt, crystallizes with one molecule of water, which is not expelled until heated to 
160°, -It yields the same decomposition products as the preceding (2 molecules 
methylamine). Both acids are capable of forming primary and secondary salts, 
which are perfectly analogous to those of uric acid. 


URIC ACID. | 447 


Careful oxidation converts dimethyl uric acid (analogous to uric acid) into 
methyl alloxan and methyl urea. ine 
Consult Berichte, 17, 1777, for an isomeric $-methyl- and 6-dimethyl uric acid. 


When uric acid is carefully oxidized, either with cold nitric acid 
or with potassium chlorate and hydrochloric acid, it yields mesoxalyl 
urea and urea :— 


apa / NNO H,N\, 
CJH.N,O; + O + H,O = COK Ny 9 YOO + H?n DCO: 


Its structure is probably represented by the formula :— 
ys 
CO C_NH” 


which was first’ proposed by Medicus. This would make it the di- 
ureide of acrylic acid, or more correctly, that of the hypothetical 
compound, CO = C(OH)—CO.,H (Berichte, 17, 1776). This is 
demonstrated by its synthesis from urea and the amide of trichlor- 
lactic acid (p. 445), and more directly by its synthesis from iso- 
dialuric acid and urea :— 


NH—C(OH) H,N, /NH—C—NH, 
/ Coe Tl co 
co C(OH) H,N% ~ C—NH + H,0. 
| x | 
NH—CO NH—CO 
Isodialuric Acid. Uric Acid. 


The presence of four imide groups explains how it and also di- 
methyl uric acid are capable of forming salt-like compounds with 
1 and 2 equivalents of the metals. 3 

Guanine, xanthine, hypoxanthine, and carnine stand in close 
relation to uric acid. Like it they occur as products of the meta- 
bolism of the animal organism. Xanthine and hypoxanthine occur 
in the extract of tea. Theobromine and caffeine found in the 
vegetable kingdom are very similar to them; these are also in- 
cluded among the alkaloids because of their basic character. An — 
approximate representation of the constitution of xanthine, theo- 
bromine and caffeine is given in the following formulas :— 


oe CHEN-= te CHAN-uCN 
| * bee | roe 
° C_nH /©O | ae Se geO COs Con eee s 
I | | % 3 
H—N-—CH H-N_¢ CH, cH (CH, 








Xanthine. Theobromine. Caffeine. 


448 ORGANIC CHEMISTRY. 


They would accordingly be the di-ureides of an acid with three 
carbon atoms (as mesoxalic acid). Theobromine is dimethyl- and 
caffeine trimethyl-xanthine. They may be artificially prepared by 
introducing methyl into xanthine. The decomposition of caffeine 
(by action of chlorine) into dimethyl] oxalyl-urea (dimethy] alloxan, 
p- 444) and methyl urea (also Annalen, 221, 313) is especially sug- 
gestive in explaining the constitution :— 


SA OE econ. H,N\ 
C,H, .N,0, + H,0 + 0, =CO¢ Nic} _co DOO + (cH, rin DOO: 
Caffeine, Dimethyl Alloxan, Methyl Urea. 


Nitrous acid converts guanine into xanthine, and in its decomposition yields 
guanidine, = i o= NH; hence we can consider it as xanthine, in which a 
guanidine residue occurs instead of that of urea, z. ¢., the oxygen of a CO-group 
has been replaced by imide, NH. 

Sodium amalgam converts uric acid into xanthine and sarcine, hence all these 
compounds are intimately related to uric acid, which fact is manifest in their 
analogous formulas, 


Guanine, C;H;N,0, occurs in the pancreas of some animals and 
very abundantly in guano.. 


To obtain it, guano is boiled several times with milk of lime until the liquid no 
longer shows a brown color; in this manner coloring substances and certain acids 
are removed; uric acid and guanine constitute the chief portion of the residue. The 
latter is boiled with soda, filtered, sodium ‘acetate added, and the whole strongly 
acidulated with hydrochloric acid, which causes the precipitation of guanine, 
accompanied by some uric acid. The precipitate is dissolved in boiling hydro- 
chloric acid and the guanine thrown down by ammonium hydroxide. 


Guanine is an amorphous powder, insoluble in water, alcohol and 
ether. It yields crystalline salts with 1 and 2 equivalents of acid, 
é. g., C;H;N,O.2HCl. It also forms crystalline compounds with 
bases. Silver nitrate gives a crystalline precipitate, C;H;N;O. 
NO, Ag. 

Nitrous acid converts guanine into xanthine. Potassium chlorate 
and hydrochloric acid decompose it into parabanic acid, guanidine 
and CO, (see above). 


Xanthine, C,H,N,O,, occurs in slight amounts in many animal secretions, in 
the blood, in urine, in the liver, in some forms of calculi and in tea extract. It 
results from the action of nitrous acid upon guanine (Anumnaden, 215, 309). Itis a 
white, amorphous mass, somewhat soluble in boiling water, and combines with 
both acids and bases. It is readily soluble in boiling ammonia; silver nitrate pre- 
cipitates C; H,Ag,N,O, + H,0O from its solution. The corresponding lead con.- 
pound yields theobromine (dimethyl xanthine) when heated to 100° with methy] 
iodide. When xanthine (analogous to caffeine, page 449) is warmed with potas- 
sium chlorate and hydrochloric acid it splits into alloxan and urea. 


THEOBROMINE—CAFFEINE. 449 


Sarcine, C;H,N,O, Hypoxanthine, is a constant attendant of xanthine in the 
animal organism, and is distinguished principally by the difficult solubility of its 
hydrochloride, It consists of needles not very soluble in water, but dissolved by 
alkalies and acids. Silver nitrate precipitates the compound C,H,Ag,N,O + 
H,O from ammoniacal solutions, 

Adenine, C,H.N,, has been isolated from beef pancreas. It also occurs in 
tea extract. It crystallizes in leaflets with pearly lustre. It has three molecules 
of water of crystallization. At 54° the salt becomes white in color, owing to loss 
of water. Nitrous acid converts it into hypoxanthine. It is, therefore, an amide, 
C,H3(NH,)N,, or imide, C,H ,(NH)N,, (Berichte, 23, 225). 

Carnine, C,H,N,O + H,0O, has been found in the extract of beef. It isa 
powder, rather easily soluble in water, and forms a crystalline compound with 
hydrochloric acid. Bromine water or nitric acid converts carnine into sarcine. 


Theobromine, C,;H;N,O, = C;H,(CH;),.N,O., dimethyl xan- 
thine, occurs in cocoa-beans (from Zheobroma Cacao) and is pre- 
pared by introducing methyl into xanthine (see above). 


Divided cocoa-beans are boiled with water, tannic acid and other substances 
precipitated by basic lead acetate, and hydrogen sulphide conducted into the fil- 
trate to remove excess of lead. The solution is then evaporated to dryness and 
the theobromine extracted from the residue with alcohol. 


Theobromine is a crystalline powder with a bitter taste and dis- 
solves with difficulty in hot water and alcohol, but rather easily in 
ammonium hydroxide. It sublimes (about 290°) without decompo- 
sition, when it is carefully heated. It has a neutral reaction, but 
yields crystalline salts on dissolving in acids; much water will de-— 
compose these. Silver nitrate precipitates the compound, C,H,Ag 
N,O,, in crystalline form from the ammoniacal solution after pro- 
tracted heating. When this salt is heated with methyl iodide it 
yields methyl theobromine, C,;H,(CH,)N,O.,, z. ¢., caffeine. 


Theophylline, C,H,N,O, = C,H,(CH,),N,O,, is isomeric with theobro- 
mine. It is present in tea extract. It contains one molecule of water of crystal- 
lization, which it loses at 110°, The introduction of methyl converts it into 
theine, (erichte, 21, 2164). 


Caffeine, Theine, C;H,,.N,O,, methyl theobromine, trimethyl 
xanthine (p. 447), occurs in the leaves and beans of the coffee tree 
(3% per cent.), in tea (2-4 per cent.), in Paraguay tea (from //ex 
paraguayensis), and in guarana (about 5 per cent.) the roasted pulp 
of the fruit of Paudllinia sorbilis. The caffeine is procured from 
these sources, just as theobromine is obtained. It is also found in 
minute quantities in cocoa. 

Caffeine consists of long, silky needles with 1 molecule of water ; 
they are only slightly soluble in cold water, and alcohol. At 1oo° 
it loses its water, melts at 225° and sublimes at higher temperatures. 

It has a feeble bitter taste and forms salts with the strong min- 
eral acids; water readily decomposes them. On evaporating a 

38 


° 


45° . ORGANIC CHEMISTRY. 


solution of chlorine water containing traces of caffeine we get a 
reddish-brown spot, which acquires a beautiful violet-red color 
when dissolved in ammonia water. 


Sodium hydroxide converts theine into caffeidine carboxylic acid, C,H,,N,0. 
CO,H, which readily decomposes into CO, and caffeidine, C,H,,N,O (Berichte, 
16, 2309). The latter is also obtained when caffeine is boiled with baryta water ; 
it is a readily soluble, strong base and decomposes on protracted boiling into NH,, 
methylamine, formic acid and methyl glycocoll. For other caffeine derivatives a 
caffeine, caffuric acid, caffolin) see Annalen, 215, 261, and 228, 141. 

Chlorine water breaks caffeine up into dimethyl alloxan and methylurea (p. 448). 
By energetic action of chlorine, dimethyl parabanic acid is produced. This is 
also formed in the oxidation of theine with chromic acid, while theobromine 
yields methyl parabanic acid. 





TRIVALENT (TRIHYDRIC) COMPOUNDS. 


_ The trivalent compounds are derived from the hydrocarbons in 
the same manner as the mono- and divalent ; three hydrogen atoms 
are replaced by three monovalent groups. Their methods of for- 
mation and transposition are also perfectly analogous to those of 
the mono- and di-derivatives. 

When three hydroxyl groups are introduced trivalent (trihy- 
dric) alcohols are formed :— 

C,H,(OH), ==.CH,(OH),CH(OH). CH,. OH. 
Glycerol. 

By the conversion of one primary alcoholic group, CH,.OH, into 
carboxyl, we obtain the “valent monobasic acids, in which two 
alcoholic hydroxyls remain, hence they can be termed dioxy-mono- 
carboxylic acids :— 


CO.OH 

. 
CH.OH = CH,(OH).CH(OH).CO.OH. 
| 

CH,.OH. 


Trivalent Monobasic Acid, 
Glyceric Acid or Dioxypropionic Acid. 


The ¢rivalent dibasic acids contain two carboxyl groups and one 
alcohol group; hence may be called oxy-dicarboxylic acids :— 


CO.0H 
ct OF ss: CH(OH)2 gon ot 
CO.0H 


Trivalent Dibasic Acid, 
Tartronic or Oxymalonic Acid. 


TRIHYDRIC ALCOHOLS. 451 


The “ibasic acids, finally, contain three carboxyl groups :— 
C,H,(CO,H);. 


Tribasic or Tricarboxylic Acid. 


Many derivatives attach themselves to the trivalent alcohols and 
acids. 


TRIVALENT (TRIHYDRIC) ALCOHOLS, 


In these, three hydrogen atoms can be replaced by alcohol or 
acid residues, forming ethers and esters :— 


OH OH 0.C,H, 

C,H she C,H. OC He Coe w, 
0.C,H, 0.C,H, 

Ethyl Glycerol. Diethyl Glycerol. Triethyl Glycerol. 

OH OH 0.C,H,O 

cH. | oH C4HT, | O.C.HE0 CH, | O.CH 
0.C,H,0 0.C,H,O 0.C,H,0. 

Monacetin. Diacetin. Triacetin., 


The polybasic acids yield similar esters :— 


OH OH OH 
CHy| ON, H,0, C,H, | OF C,H, ) OH- 
O/~4 0.SO,H O.PO(OH),. 
Succinin. Glycerol Sulphuric Glycerol Phosphoric 
Acid. Acid. 


The esters of the haloid acids, like 


C,H,(OH),Cl C,H,(OH)Cl, C,H,Cl, 
Monochlorhydrin. Dichlorhydrin, Trichlorhydrin. 


may be viewed as substitution products of the di- and trivalent 


alcohols. 





Glycerol, C;H,(OH),, is the first member of the trihydric alco- 
hols. Lower homologues cannot exist, because in general one car- 
bon atom is capable of linking only one hydroxyl group in sucha 
manner that the hydrogen in it will be exchangeable in any further 
replacement. Ethers and esters of trihydroxyl compounds, with 
one and two carbon atoms, exist (p. 298). 


The trihydroxyl derivatives are formed artificially in the same manner as the 
mono- and di-hydroxyl compounds (p. 297). They can be obtained by oxidizing 
the unsaturated alcohols with potassium permanganate (pp. 82, 297). Thus allyl 
alcohol yields glycerol :— 


CH,:CH.CH,.OH + 0 + H,O = CH,(OH).CH(OH).CH,(OH). 


Amyl glycerol, C,H;.CH(OH).CH(OH).CH,(OH), is obtained from ethyl viny 
carbinol, C,H, CH(OH). CH:CH,, etc. (Berichte, 21, Ref. 183 ; 22, Ref. 798). 


- 


452 ORGANIC CHEMISTRY. 


Certain hydrates of the fatty acids, having constant boiling points at times (see 
formic acid), may be considered as trihydroxyl derivatives ; hence, they have been 
called ortho-acids :— 


CH,O, + H,O = CH(OH), CH,.CO,H + H,O = CH,.C(OH),, 
Orthoformic Acid. Orthoacetic Acid. 
just as the hydrate of nitric acid, NO,H + H,O = NO(OH),, is termed ortho- 
nitric acid. 
We get the esters of orthoformic acid by heating chloroform with an alcoholic 
solution of sodium alcoholates :— 


CHCl, + 3CH,.ONa = CH(O.CH,), + 3NaCl; 


or by the union of form-imido-ethers (p. 292) with alcohols, resulting in mixed 
esters (Berichte, 16, 1645) :— 


O.CH 
£NH.HC1 ye 3 
CH Ci OF} ae Chie OC NH,Cl. 
~U.C HH. i aah \oc,H. 4 


When sodium mercaptides act on chloroform, we obtain esters of orthothio- 
formic acid, ¢e. ¢., CH(S.CH,),. . 

Methyl Orthoformic Ester, CH(O.CH,),, boils at 102°, and has a specific 
gravity 0.974 at 23°. The Triethyl Ester CH(O.C,H 5)» 1S an aromatic smell- 
ing liquid, insoluble in water, and boiling at 146°; sp. gr. 0.896. It decomposes 
into ethyl formic, and ethyl acetic esters, when heated with glacial acetic acid. 

The Triallyl Ester, CH(O.C,H;),, formed by the action of metallic sodium 
upon chloroform and allyl alcohol, boils about 200°. 

_ Ethyl Orthoformic Ester, CH(S.C,H,),, from sodium chloroform and sodium 
mercaptide, is an oil with an odor like that of garlic. When oxidized it becomes 
a disulphone, CH,(SO,.C,H;), (p. 307). 

Methine Trisulphonic Acid, CH(SO,H),, is obtained by heating chloro- 
picrin, CCl,(NO),, with a concentrated aqueous solution of sodium sulphite, or 
by heating calcium methy] sulphonate (p. 153) with fuming sulphuric acid. This 
acid, like all sulphonic acids, is very stable and is not affected by boiling alkalies. 





Ethyl Ortho-acetic Ester, CH,.C(O.C,H,),, triethyl acetyl ester, is ob- 
tained by heating a-trichlorethane, CH,.CCl,, with an ethereal solution of sodium 
ethylate. It boils at 142°, and when heated with water to 120° breaks up into 
acetic acid and alcohol. 

Isomeric with the preceding is 

Pe som 
Triethyl Ethenyl Ester, | » which is obtained from chloracetal, 
CH(0.C,H;), 
CH,Cl.CH(O.C,H,), (p. 305). It boils at 186°. 





Glycerol, C;H,O; = C,H,(OH), glycerine, is produced in 
small quantities in the alcoholic fefmentation of sugar. It is pre- 
pared exclusively from the fats and oils, which are glycerol esters of 


GLYCEROL. 453 


the fatty acids (p. 458). When the fats are saponified by bases or 
sulphuric acid, they decompose, like all esters, into fatty acids and 
the alcohol—glycerol. It is obtained synthetically from allyl tri- 
bromide (p. 104) by converting the latter, with silver acetate, into 
glycerol acetate and saponifying this ester with boiling alkalies :—- 


CH, Br CH,.0.C,H,O CH,.OH 
| | | 
CHBr yields CH.O.C,H,O and CH.OH 
| 
CH,Br CH,.0.C,H,O CH,.OH. 


Glycerol is similarly formed from glycerol trichloride (from pro- 

pylene chloride) by heating it with water to 170°. 
. 

In preparing glycerol from fats (chiefly olive oil) the latter were formerly 
saponified by boiling them with lead oxide and water. The aqueous solution of 
glycerol was separated from the insoluble lead salt of the fatty acids (lead plaster, 
p. 216), the dissolved lead precipitated by hydrogen sulphide and the filtrate con- 
centrated by eVaporation. 

‘At present glycerol is produced in large quantities in the manufacture of 
stearic acid; the fats are saponified by means of superheated steam, converting 
them directly into glycerol and fatty acids. In most stearic acid factories sul- 
phuric acid is employed for the saponification. The glycerol then exists as gly- 
cerol-sulphuric acid (p. 454) in the aqueous solution. To liberate the glycerol the 
solution is boiled with lime, the gypsum filtered off, the liquid concentrated and 
distilled with superheated steam. In order to obtain a pure product the glycerol 
is again distilled under diminished pressure. 


Anhydrous glycerol is a thick, colorless syrup, of specific gravity 
1.265 at 15°. Under certain conditions it solidifies to a white, 
crystalline mass, which melts at -+17°. Under ordinary atmospheric 
pressure it boils at 290° (cor.) without decomposition ; under 
diminished pressure, or with superheated steam, it distils entirely 
unaltered. See Berichte, 17, Ref. 522, for the specific gravities 
and boiling points of jts aqueous solutions. It has a pure, sweet 
taste, hence the name glycerol. It absorbs water very ener- 
getically when exposed and mixes in every proportion with water 
and alcohol, but is insoluble in ether. It dissolves the alkalies, 
alkaline earths and many metallic oxides, forming with them, in all 
probability, metallic compounds similar to the alcoholates (p. 126). 

When glycerol is distilled with dehydrating substances, like sul- 
phuric acid and phosphorus pentoxide, it decomposes into water and 
acrolein (p. 199). It sustains a similar and partial decomposition 
when it is distilled alone. When fused with caustic potash, it evolves . 
hydrogen, and yields acetic and formic acids. Platinum black, or 
dilute nitric acid, oxidizes it to glyceric and tartronic acids, but 
under energetic oxidation the products are oxalic acid, glycollic 
acid, glyoxylic and other acids. Moderated oxidation (with nitric 


454 ORGANIC CHEMISTRY, 


acid, or bromine) produces g/ycerose, which consists chiefly of dioxy- 
acetone, CO(CH,.OH),. ‘This unites with CNH and forms trioxy- 
butyric acid (Berichte, 22, 106; 23, 387). Phosphorus iodide or 
hydriodic acid converts it into allyl iodide, isopropyl iodide and 
propylene (p. 98). In the presence of yeast at 20-30° it ferments, 
forming propionic acid. 


Nitroglycerine, Trinitrin, glycerol nitric ester, C,H;(O.NO,), (p. 302), is pro- 
duced by the action of a mixture of sulphuric and ‘nitric acids upon glycerol. The 
latter is added, drop by drop, toa well-cooled mixture of equal volumes of concen- 
trated nitric and sulphuric acids, as long as it dissolves ; the solution is then poured 
into water, and the'separated, heavy oil (nitroglycerine) is washed with water and 
dried by means of calcium chloride. 

Nitroglycerine is a colorless oil, of sp. gr. 1.6, and becomes crystalline at —20°. 
It has a sweet taste and is poisonous when taken inwardly. It is insoluble in water, 
dissolves with difficulty in cold alcohol, but is easily soluble in wood spirit and 
ether. Heated quickly, or upon percussion, it explodes very violently (/Vodel’s 
explosive ott); mixed with kieselguhr it forms dynamite. 

Alkalies convert nitroglycerine into glycerol and nitric acid; ammonium sul- 
phide also regenerates glycerol. Both reactions prove that nitroglycerine i is not a 
nitro-compound, but a nitric-acid ester. 

Glycerol-Nitrite, C,H.(O.NO),, is formed by the action of N,O, upon gly- 
cerol. It boils at 150° with partial decomposition. Water breaks it up with evo- 
lution of oxides of nitrogen. Its isomeride, Trinitropropane, C,H,(NO,),, is 
obtained from glyceryl bromide by the action of silver nitrite. It is an oil, boil- 
ing at 200°. (OH), 

Glycerol-Sulphuric Acid, C,H, 0.SO; ap is formed by mixing 1 part gly- 


cerol with I part of sulphuric acid. The free acid decomposes when its aqueous 
solution is heated. Its salts are readily soluble; the calcium salt is crystalline. 

Glycerol-Phosphoric Acid, C,H Om: H,’ occurs combined with the 
fatty acids and choline as lecithin (see this) in the yolk of eggs, in the brain, in 
the bile, and in the nervous tissue. It is produced on mixing glycerol with meta- 
phosphoric acid. ‘The free acid is a stiff syrup, which decomposes into glycerol 
and phosphoric acid when it is héated with water. It yields easily soluble salts 
with two equivalents of metal. The calcium salt is more insoluble in hot than in 
cold water; on boiling its solution, it is deposited in glistening leaflets. 





HALOID ESTERS OF GLYCEROL. 
Monochlorhydrins, C,H,(OH),Cl. There are two possible isomerides :— 


CH,(OH).CH(OH).CH,Cl and CH,(OH).CHCI.CH,.OH. 
a-Chlorhydrin. B-Chlorhydrin. 


a-Chlorhydrin is produced, together with a little of the $-variety, on heating 
‘glycerol and hydrochloric acid to 100°. It is best prepared by heating epichlor- 
- hydrin (p. 456) with water (1 molecule) to 120° (Berichte, 13, 457). It isa thick 
liquid, soluble in water, alcohol and ether; it boils with partial decomposition at 
215°. Sodium amalgam converts it into propylene glycol; and when oxidized, it 
becomes {-chlorlactic acid. 


HALOID ESTERS OF GLYCEROL. 455 


8-Chlorhydrin is obtained from allyl alcohol by the addition of hypochlorous 
acid. It boils at 230°. 
Dichlorhydrins, C,H;(OH)Cl, (Dichlorpropyl Alcohols) :— 


CH,Cl.CH(OH).CH,Cl and CH,Cl.CHCI1.CH,.OH. 
a-Dichlorhydrin. ; B-Dichlorhydrin. 


a-Dichlorhydrin is produced by the action of hydrochloric 
acid or chloride of sulphur upon glycerol. It is obtained perfectly 
pure by shaking epichlorhydrin (p. 456) with concentrated hydro- 
chloric acid. 


Preparation.—Saturate a mixture of glycerol (3 parts) and glacial acetic acid 
(2 parts) with hydrochloric acid gas, accelerating the absorption toward the end 
by applying heat. The strongly fuming product is washed with a soda solution 
and the separated oil distilled. The portion going over from 160—200° contains 
a-dichlorhydrin and acetochlorhydrin. These are difficult to separate (Annalen, 
208, 361). Therefore, epichlorhydrin is first prepared from the crude dichlor- 
hydrin by adding pulverized caustic soda gradually to the portion which distils at 
170-180°, so that the temperature does not exceed 130°. The resulting epichlor- 
hydrin is distilled off (Berichte, 10, 557) and changed to a-dichlorhydrin by shaking 
with coneentrated hydrochloric acid. 


a-Dichlorhydrin is a liquid, with ethereal odor, of sp. gr. 1.367 
at 19°, and boils at 174°. It is not very soluble in water (in 9 
parts at 19°), but dissolves readily in alcohol and ether. When 
heated with hydriodic acid it becomes isopropyl iodide; sodium 
amalgam produces isopropyl alcohol. Chromic acid oxidizes it to 
&-dichloracetone (p. 205) and chloracetic acid. 


When sodium acts on an ethereal solution of a-dichlorhydrin, we do not get 


H 
"CH.OH, but allyl alcohol as a result of molecular 
H 


2 
transposition (Berichte, 21, 1289). 


&-Dichlorhydrin, CH,Cl.CHCI.CH,.OH, obtained by adding 
chlorine to allyl alcohol, or hypochlorous acid to allyl chloride, boils 
at 182-183°; its sp. gr. = 1.379 at o°. Sodium converts it into 
allyl alcohol. Fuming nitric acid oxidizes it to af-dichlorpro- 
pionic acid. 

Both dichlorhydrins are changed to epichlorhydrin by the 
alkalies. 

Trichlorhydrin, C,H;Cl,, is made by the action of PCI; upon 
both dichlorhydrins, and has already been described, p. 104, as 
glyceryl trichloride. 


trimethylene alcohol, | 
C 





a-Monobromhydrin, C,H,(OH),Br, is formed when HBr acts on glycerol. It 
is an oily liquid, which boils at 180° under diminished pressure ( Berichie, 21, 2890). 

a-Dibromhydrin, CH,Br.CH(OH).CH,Br, is an ethereal-smelling liquid, 
which boils at 219°; its sp. gr. at 18° is 2.11. 


456 ORGANIC CHEMISTRY. 


B-Dibromhydrin, CH, Br.CHBr.CH,.OH, boils at 212~214°. 

Tribromhydrin, C,H -Bra, i is described on p. 104. a- Monoiodhydrin, C, tt, 
(OH), I, ae obtained by heating glycerol and HI to 100°; it is a thick liquid of 
Sp. gt. 1.753. 

a-Di-iodhydrin, CH,I.CH(OH).CH,I, is prepared by heating a-dichlorhy- 
drin with aqueous potassium | iodide. A ‘thick oil of specific gravity 2.4 and 
solidifying at —15°. 





GLYCIDE COMPOUNDS. 


By this designation we understand certain compounds formed 
from glycerol derivatives by the exit of H,O or HCl. These are 
again readily converted into glycerol derivatives. 

Epichlorhydrin, C,;H;OCI, is isomeric with monochloracetone, 
and obtained from both dichlorhydrins (p. 455) by the action of 
caustic potash or soda (analogous to the formation of nengaene oxide 
from glycolchlorhydrin, (p. 302) :— 


CH,Cl CH,\ ; 
| O 

CH.OH + KHO = CH Y +KC1+H,0. 

| 

CH,Cl CH,Cl 


It is a very mobile liquid, insoluble in water and boils at 117°. 
Its sp. gravity at o°.is 1.203. Its odor resembles that of chloro- 
form, and its taste is sweetish and burning. It forms a-dichlorhy- 
drin with concentrated hydrochloric acid. PCl, converts it into 
trichlorhydrin. Continued heating with water to 180° changes it 
to a-monochlorhydrin. Concentrated nitric acid oxidizes it to 
8-chlorlactic acid. 


Like ethylene oxide, epichlorhydrin combines with sodium bisulphite, and with 
CNH to the oxycyanide, C,H CK CN: Hydrochloric acid changes the latter to 
an acid. Epicyanhydrin, C,H;.0.CN, is formed when CNK acts on epichlorhy- 
drin. Brilliant crystals which fuse at 162, 3°, and become Epihydrin-carboxylic 
Acid, C,H,O.CO,H, under the influence of HCl (Berichte, 15, 2586). 

The ethers of ‘chlorhydrin, like C,H,Cl(OH)O.C,H,, are produced on warm- 
ing epichlorhydrin with alcohols. When they are ‘distilled with caustic potash 
glyctde ethers appear: 


CH,.Cl Hay 


| 

CH.OH + KOH = CH a 4+ KCl + H,0. 
| 

CH,,.0.C,H, -CH,.0.C,H, 


Ethyl Glycide Ether, C,H;0.0.C,H, (Epiethylin), boils at 126-130° ; amyl 
glycide ether, C,H,0.0. C Nc oe at 188°, 

Acetic Glycide Ester, Cc H,0.0.C,H,0, is produced by heating epichlorhy- 
drin with anhydrous potassium acetate. “It boils at 168-169°. 


ALCOHOL ETHERS OF GLYCEROL. 457 


Glycide Alcohol, C,H,O.OH, is formed by the decomposition of its acetate 
by caustic soda or baryta. Tt boils near 162° and is miscible with water, alcohol 
and ether; its specific gravity is 1.165 ato°. Jt reduces ammoniacal silver solu- 
tions at ordinary temperatures. © This is also true of its acetic ester: 

When epichlorhydrin is héated with sodium acetate and absolute alcohol, the 
reaction proceeds as follows :— 


C,H,OCl-+ C,H,0,Na+ C,H,.0H=C,H,0.0H + C,H,0,.C,H, -+ NaCl 


The glycide formed at first condenses to polyglycides, chiefly diglycide (C,H,O. 
OH),, which boils at 250° (p. 459). 

Glycidic Acid, C,H,O,, an oxide or anhydridic acid, is formed (similar to 
epichlorhydrin) from °B- chiorlactic acid and a- chlorhydracrylie acid, when treated 
with alcoholic potash or soda :— 


CH,Cl CH,.0H 


| | L.’do. 

CH.OH and CHCl yields CH 

| | | 

CO.OH CO.OH CO.OH. 
B-Chlorlactic Acid. a-Chlorhydracrylic Acid. Glycidic Acid. 


When séparated from its salts by sulphuric acid, it is a mobile liquid, miscible 
with water, alcohol and ether. It volatilizes when heated and possesses a pun- 
gent odor. Its potassium salt, C,H,KO, + %H,O, forms warty, crystalline 
aggregates. Ferrous sulphate does not color the acid or its salts red (distinction 
from the isomeric pyroracemic acid). It combines with haloid acids to form 
B-halogen lactic acids, and on warming yields glyceric acid. 

Its ethyl ester, obtained by the action of ethyl iodide upon its silver salt, is a 
liquid, with an odor resembling that of malonic ester. It boils at 162°. 

See p. 461 for the homologous glycidic acids. 

Epibromhydrin, C,H,OBr, from the dibromhydrins, is analogous to epichlor- 
hydrin and boils at 130-140°. 

Epi-iodhydrin, C,H,OI, results from the treatment of epichlorhydrin with a 
solution of potassium iodide, and boils at 160°. 





ALCOHOL ETHERS OF GLYCEROL. 


Mixed ethers of glycerol with alcohol radicals (p. 299) are obtained by heating 
the mono- and dichlorhydrins with sodium alcoholates :— 


OH 
GH,{q, + 


Monoethylin, C,H, Svan 2 _ 7 is soluble in water, and boils at 230°. Dit 


4+ 2C,H,.ONa = CH, { Oc.H,),+ 2NaCl. 


ethylin, C,H {tox Cc wH,)2 . Aeebivin with difficulty in water, has an odor re- 


sembling that of peppermint, and boils at 191°; its specific gravity is 0.92. When 
its sodium compound is treated with ethyl iodide we obtain 77riethylin, C,H, 
(O.C,H,),, insoluble in water and boiling at 185°. 


Allylin, C,H 51 O.c. Mi , monoallyl ether, is produced by heating shpceeal 
ea 


with oxalic acid, and is present in the residue from the preparation of allyl alcohol 
(p. 134). It is a thick liquid, boiling at 225—240°. 


458 ORGANIC CHEMISTRY. 


A compound of the formula, C,H,,O,, and designated glycerin ether, 
(C,H,),03, occurs with allylin, and boils at 169-172° (see Berichte, 14, 1496 and 
2270). 


* 


ACID ESTERS OF GLYCEROL. 


By replacing 1, 2 and 3 hydrogen atoms in glycerol with acid 
radicals we obtain the so-called mono-, di-, and triglycerides. They 
are formed when glycerol and fatty acids are heated to 100-300° ; 
whereas in the action of acid chlorides upon glycerol, esters of the 
chlorhydrins (p. 455) are produced :— 


C,H,(OH), + C,H,0.Cl = C,H,Cl(OH)(0.C,H,0) + H,0. 


When the acid glycerides are acted upon with alkalies, lime water, 
or lead oxide, they all revert to glycerol and salts of the fatty acids 
(soap) (p. 216). Concentrated sulphuric acid decomposes them 
into free acids and glycerol sulphuric acid (p. 454). 


Monoformic Ester, C,H, {CRO Monoformin, is produced by heating 
glycerol with oxalic acid (p. 217). It distils near 200°, and decomposes partly 
into allyl alcohol, carbon dioxide and water; it distils without decomposition in 
a vacuum. OH) 

Monacetin, C,H, i CH.o is formed on heating glycerol with glacial 

Rare ame 


acetic acid to 100°. It is a liquid which dissolves readily in water and ether. 
Diacetin, C,H, { (OCH, O),’ is obtained from glycerol and glacial acetic acid 


when they are heated to 200°. “It boils at 280°. 

Triacetin, C,H,(O.C,H,0),, is prepared by prolonged heating of diacetin 
with an excess of glacial acetic acid to 250°; it boils at 268°. It is found in 
slight quantities in the oil of Zuonymus europeus. 

Tributyrin, C,H;(O.C,H,O),, occurs along with other higher triglycerides 
in cow’s butter. . 

The glycerides of the higher fatty acids, C, H),O,, and those of the oleic acid 
series, C, Hy,—. O,, occur in the natural fatty oils, fats, and tallows; they can be 
obtained artificially by heating glycerol with the acids. 

Monopalmitin, C,H; es Jae Gr melts at 58°. Dipalmitin, C,H, 
sey ? Tripalmitin C,H,(0.C,,H.,O)., is found in most 

(0.C, .H;,0),’ at 59°. Tripalmitin, C,H;(0.C,,H;,0)s;,1 : 


fats, especially in palm oil, from which it can be obtained by strong pressing and 
recrystallization from ether. It separates from olive oil when the latter is strongly 
cooled. It crystallizes from ether in pearly, glistening laminze, which melt at 63°. 
By repeated fusion and solidification the melting point falls quite considerably. 
Like all higher triglycerides, it is not very soluble in alcohol. 

Trimyristin, or Myristin, C,H,(0.C,,H.,O),, glycerol myristic ester, oc- 
curs in spermaceti, in muscat butter, and chiefly in oil nuts (from Myristica surina- 
mensis), from which it is most readily obtained (Berichte, 18, 2011). It crystal- 
lizes from ether in glistening needles, melting at 55°. It yields myristic acid (p. 
215) when saponified. : 

Tristearin, C,H,(O.C,,H,,O0),, occurs mainly in solid fats (tallows). It can 
be obtained by heating glycerol and stearic acid to 280-300°. It crystallizes from 


, POLYGLYCEROLS. 459 


ether in shining leaflets, and melts at 66.5°. Its melting point is also lowered by 
repeated fusion. 

Triolein, C,H,(O.C,,H,,0),, is found in oils, like olive oil. It solidifies at 
—6°. It is oxidized on exposure to the air. Nitrous acid converts it into the 
isomeric elaidin, which melts at 36° (p. 243). 


Nearly all the natural fatty oils and fats (tallows) of animal and 
vegetable origin are mixtures of the triglycerides of the fatty acids. 
The former are chiefly triolein, the latter (beef tallow, sheep tallow, 
cocoa butter, etc.), tristearin and tripalmitin. They are insoluble 
in water, dissolve with difficulty in alcohol, readily in ether, carbon 
disulphide, benzene ether, etc. They are lighter than water and 
swim upon it. They form spots on paper which do not disappear 
when heated—distinction from the volatile oils. ‘They are not 
volatile, and decompose when strongly heated. 

The fatty oils are distinguished as drying and non-drying otis. 
The former oxidize readily in the air, are coated with a film and 
become solid; they comprise the glycerides of the unsaturated 
acids—linoleic and ricinoleic acids (p. 243). The non-drying oils 
are glycerides of oleic acid; the production of free acid in them 
is the cause of their becoming rancid. Among the drying oils are 
‘linseed otl, hemp otl, walnut oil, castor oil, etc. Non-drying oils 
are Olive oil, rape-seed oil (from Arassica campestris), also from 
the oil of Brassica rapa, almond oil, train oil and cod oil. 

Boiling alkalies saponify all the fats. 





SULPHUR DERIVATIVES OF GLYCEROL. 


Glycerol mercaptans are formed on heating the chlorhydrins with an alcoholic 
solution of potassium sulphydrate ;— 


C,H,Cl, + 3KSH = C,H,(SH), + 3KCL. 


The hydrogen atoms in the SH groups can be replaced by heavy metals. 
Hydrochloric acid precipitates them in the form of thick oils. When oxidized 
they yield sulpho-acids, which may be prepared from the chlorhydrins by means of 
alkaline sulphites, 


POLYGLYCEROLS. 


They are obtained like the polyglycols (p. 304), viz., by the union of several 
molecules of glycerol and withdrawal of water. To obtain them, glycerol 
(diluted 14 with water), is saturated with HCl and heated to 130° for some hours ; 
or glycerol and monochlorhydrin are heated together. They are thick liquids, 
which can be separated from each other by distillation under diminished pressure. 
When heated with solid caustic potash they sustain further loss of water and 


become polyglycides (p. 457) :— 


Gao C,H, a 
C,H, (OH), Cy. OH 


Diglycerol. Diglycide. 


460 ORGANIC CHEMISTRY. | : 


Of the higher trihydric alcohols which have been prepared, we have: Butyl 
glycerol, C,H,,0, = CH,.CH(OH).CH(OH).CH,.OH, from the bromide of 
crotyl alcohol, by boiling it with water. It is a thick, sweet liquid, boiling at 
172-175° under 27 mm. pressure. 

Hexyl Glycerol,C,H,,0,. There are three isomeric derivatives of this class, 
obtained from the corresponding unsaturated, monohydric alcohols, C,H, .O, by the 
addition of bromine, and then boiling with water. They are thick liquids, readily 
soluble in water (Berichte, 22, Ref. 788). 

Other glycerols have been obtained by oxidizing unsaturated monohydric alco- 
hols with potassium permanganate (p. 451). 





a ) 


MONOBASIC ACIDS, C,H.,O,. 


The acids of this series bear the same relation to the glycerols. 
that the lactic acids bear to the glycols. They, too, can be re- 
garded as dioxy-fatty acids (p. 345). 

_ They may be synthetically prepared by the common methods 
used in the production of oxyacids (p. 346), also by oxidizing un- 
saturated acids with potassium permanganate (p. 236) (Berichte, 31, 
Ref. 660). 


The first and lowest dioxyacid (p. 330) has been described as glyoxylic acid, 
(dioxyacetic acid). Both free and in its salts it has one molecule of water firmly 
combined: CHO.COOH + H,O = CH(OH),.CO,H. However, the two 
hydroxyl groups do not manifest the usual reactions, but split off water with for- 
mation of the aldehyde group. 


Glyceric Acid, C;H,O, (dioxypropionic acid), s formed: (1) 
by the careful oxidation of glycerol with nitric acid :— 


CH,(OH).CH(OH).CH,(OH) + 0, = CH,(OH).CH(OH).CO.OH + H,0; 


(2) by the action of silver oxide upon #-chlorlactic acid, CH,Cl. 
CH(OH).CO,H, and a-chlorhydracrylic acid, CH,(OH).CHCI. 
CO.H (p. 457); (3) by heating glycidic acid with water (p. 457). 


Preparation.—A mixture of I volume of glycerol and 1 volume of water is 
placed in a tall glass cylinder and then 1 part HNO, (sp. gr. 1.5) is introduced 
by means of a funnel whose end reaches to the bottom of the vessel. Two layers 
of liquid form and the mixture is permitted to stand for several days at 20°, until 
the layers have completely united. The liquid is then evaporated to syrup con- 
sistence, diluted with water, saturated while boiling with calcium carbonate and 
some lime water added, to precipitate any impurities. When the filtrate is con- 
centrated calcium glycerate separates in warty crusts. It is decomposed with 
oxalic acid, filtered from the separated oxalate and the filtrate boiled with lead 
oxide to remove all excess of oxalic acid. Hydrogen sulphide precipitates the 
lead in this filtrate and the liquid is then concentrated upon a water bath (Berichie, 
Q, 1902, 10, 267, 14, 2071). 

The acid may be obtained in small quantities by oxidizing glycerol with mer- 
curic oxide and baryta water (Berichte, 18, 3357). 


GLYCERIC ACID. 461 


Glyceric acid forms a syrup which cannot\be crystallized. It is 
easily soluble in water and alcohol. It is optically inactive, but 
as it contains an asymmetrical carbon atom (p. 63), it may be 
changed to active levo-rotatory glyceric acid by the fermentation 
of its ammonium salt, through the agency of Penicillium glaucum 


(p- 357)- 


Its calcium salt (C,H,O,),Ca + 2H,0, crystallizes in warty masses, consisting 
of concentrically grouped needles. It dissolves readily in water but not in 
alcohol. The /ead salt, (C,H,O,),Pb, is not very soluble in water. The ethy/ 
ester, C,H.O,.C,H,, is formed on heating glyceric acid with absolute alcohol. It 
is a thick liquid of sp. gr. 1.193 at 0°, and boils at 230—240°. 

a 


When the acid is heated to 140° it decomposes into water, pyro- 
racemic and pyrotartaric acids. When fused with potash it forms 
acetic and formic acids, and when boiled with it yields oxalic and 
lactic acids. Phosphorus iodide converts it into f-iodpropionic 
acid. Heated with hydrochloric: acid it yields a-chlorhydracrylic 
acid and af-dichlorpropionic acid. 


When glyceric acid is preserved awhile it forms an ester-like modification or 
anhydride, (C,H,O,), (?). This is sparingly soluble and crystallizes in fine needles. 
When boiled with water it again reverts to the original acid. - 

Amido-glycerol, or Serin, CH,(OH).CH(NH,).CO,H, a-amidohydracrylic 
acid, is obtained by boiling serecin with dilute sulphuric acid. It forms hard 
crystals, soluble in 24 parts of water at 20°,.but insoluble in alcohol and ether. 
Being an amido-acid it has a neutral reaction, but combines with both acids and 
bases. Nitrous acid converts it into glyceric acid. 

Isomeric B-amido-lactic acid, CH,(NH,).CH(OH).CO,H, is obtained from 
B-chlorlactic acid and glycidic acid by the action of ammonia (Berichte, 13, 1077). 
It dissolves with more difficulty in water than serin. 

The Hydrate of trichlorpyroracemic acid, CCl,.CO.CO,H + H,O, may be 
considered as isotrichlorglyceric acid, CCl,.C(OH),.CO,H. It is formed from 
trichloracetyl cyanide, CCl,.CO.CN, by the action of hydrochloric acid (p. 332). 
It crystallizes in long needles, melts at 102° and distils undecomposed. It 
reduces ammoniacal silver solutions and alkaline copper solutions. An interest- 
ing method of forming it (along with tricarballylic acid) consists in the action 
of KCIO, and hydrochloric acid upon gallic acid, salicylic acid and phenol 
(Berichte, 13, 1938). 


Mention may be made of the following higher dioxyacids :— 


The dioxybutyric acids, C,H,O,, are known in three isomeric forms: 

(1) a8-Dioxybutyric Acid, CH,.CH(OH),.CH(OH).CO,H, £-Methylgly- 
ceric Acid, is prepared from a{-dibrombutyric acid on boiling it with water, or 
upon digesting 6-methyl glycidic acid (see below) with water. A thick liquid, 
gradually becoming solid and crystalline. It melts at 80° C. Its corresponding 
B-Methyl glycidic acid, CH;.CH.CH.CO,H (p. 457), has been obtained from 

ye 


chloroxybutyric acid (m. p. 62-63°, from normal crotonic acid and CIOH) by 
the action of alcoholic potash. It crystallizes in rhombic prisms, melting at 84° 


462 ORGANIC CHEMISTRY. 


(Annalen, 234, 204). The same acid is also formed from the chloroxybutyric 
acid melting at 82-85° (from isocrotonic acid by addition of CIOH and from 
$-methyl glycidic acid with HCl) (Axznalen, 234,221). It yields af-dioxybutyric 
acid when heated with water. 

(2) By-Dioxybutyric Acid, CH,(OH).CH(OH).CH,.CO,H, butyl glyceric 
acid, from a-chlorhydrin (p. 454), HCN and HCl, is a thick liquid, which passes 
into an anhydride ar ieabiepar se at-ro0°-C.. 


Dioxyisobutyric Acid, AC St OH).CO,H, a-methyl glyceric acid, 
3 H, / y's 


results upon warming a-methyl sipeidic acid with water to 100°. It crystallizes 
after long standing and melts at 100°, The a-methyl glycidic acid corresponding 
to it, has been obtained from chloroxyisobutyric acid (melting at 106-107°, from 
methacrylic acid p. 457, by addition of CIOH) when acted upon by alcoholic 
potash. Itis athick liquid. It combines with HCI to form chloroxyisobutyric 
acid. 





The following acids have been obtained by oxidizing unsaturated fatty acids 
with potassium permanganate :— 

Dioxyundecylic Acid, C,,H,,(OH),O,, from undecylenic acid, C,,H,,0,, 

melts at 84-86°. 

Dioxybehenic Acid, C,,H,,(OH),O,, from erucic acid, C,,H,,O,, melts at 133°. 

Dioxystearic Acid, ‘CisHs,(OH),O,, from oleic acid, ‘CO: melts at 136° 
(Berichte, 22, 743). 





DIBASIC OXY-ACIDS, C,H,,_.0;. 


We can regard these as derivatives of the dibasic acids, 
C,H,,(CO,H),, from which they are obtained by the introduction 
of one OH-group for one atom of hydrogen (p. 345). Those 
oxydicarboxylic acids, in which the hydroxyl group occupies the 
y-position with reference to one of the two carboxyls, a-oxyglu- 
taric acid (p. 467) excepted, immediately decompose when set free 
into water,—and: lactonic acids or lactone carboxylic acids (see 
itamalic acid, p. 468). Such lactonic acids can be directly pre- 
pared synthetically by digesting the aldehydes with sodium succin- 
ate in the presence of acetic anhydride (Berichte, 18, 2523; 23, 
Ref. 85) :—: 


cO,H 
CH,.CO,H = CH,.CH.CH. 
CH,.CHO + \ 
Acetaldehyde. CH,.CO,H CH, + H,0. 
Succinic 
Acid. O co 








Methyl Paraconic Acid. 


Ethyl paraconic acid is formed, in a similar manner, from suc- 
cinic acid.and propionic aldehyde, and Bropisaperconic acid 
from succinic acid and butyraldehyde. 


ST BSN SS a Se ee er ee 


TARTRONIC ACID. 463 


The reaction probably proceeds in a manner analogous to that of aldehyde 
upon aceto-acetic ester and malonic ester. First, unsaturated acids are produced. 
These undergo a rearrangement of atoms and become lactonic acids. This is 
analogous to the conversion of allylacetic acid into valerolactone. Or, they can 
also be obtained from the corresponding unsaturated dicarboxylic acids by mole- 
cular transposition (when acted upon by hydrobromic acid) (see allyl malonic 
acid, p. 430, and allyl succinic’acid, p. 430). The aldehydes also react with pyro- 
racemic acid. ‘Two isomeric lactonic acids result (Berichte, 23, Ref. 90). When 
neutralized in the cold with caustic alkali, or with alkaline carbonates, the Jactonic 
acids from the oxydicarbonic acids usually form monobasic salts with the free car- 
boxyl group, whereas when boiled with alkalies dibasic salts of the oxydicarboxylic 
acids result. Heated alone, or when boiled with dilute sulphuric acid, the lactonic 
acids split up into CO, and lactones, which are in part converted into the isomeric 
Py-unsaturated acids (p. 352); unsaturated dibasic acids are formed at the same 
time. The lactonic acids derived from pyroracemic acid yield carbon dioxide 
and unsaturated hydrocarbons when they are distilled: Lactones and unsatu- 
rated acids are also formed (Berichte, 23, Ref. 91). 


. Tartronic Acid, C;H,O;, = cH(oH)¢ C2: 4 oxymalonic 
ae is produced from chlor- and brom-malonic acid, CHCI(CO,H)., 
by the action of silver oxide or by saponifying their esters with 
alkalies ; from mesoxalic acid, CO(CO,H),, by the action of sodium 
amalgam ; from dibrompyroracemic acid, CHBr,.CO.CO,H, when 
digested with baryta water; from glycerol by oxidation with potas- 
sium permanganate. Also from glyoxylic acid, CHO.CO,H, by 
the action of CNH and hydrochloric acid, and from nitro-tartaric 
acid, and dioxytartaric acid, as well as from trichlorlactic acid 
when the latter is digested with alkalies. 


Preparation.—Nitrotartaric acid is gradually introduced into warm aqueous 
alcohol (Berichte, 10, 1789). A better method consists in adding trichlorlactic 
ester (p. 360) to a warm sodium hydroxide (4 molecules) solution. After acidu- 
lation with acetic acid barium chloride is added to precipitate barium tartronate, 
and this is then decomposed with sulphuric acid. To obtain the ethyl ester mix 
the barium tartronate with alcohol and saturate with hydrochloric acid gas (Be- 
richte, 18, 754, 2852). 


Tartronic acid is easily soluble in water, alcohol and ether, and 
crystallizes in large prisms. When pure it melts at 184°, decom- 
pee into carbon dioxide and glycolide, (C,H,O,), (Berichte, 18, 
756 

The calcium salt, C,H,O;Ca, and darium salt, C,H,O;,Ba + 2H,0, 
dissolve with difficulty in water and are obtained as crystalline 
precipitates. The ethyl ester, C,H,0O;(C,Hs), (see aboven is a liquid 
boiling at 219°. 


sao 
a 


4 


rycen Acid, CH(NH,).(CO,H),, was described on p. 409 as amidomalonic 
aci 


404 | ORGANIC CHEMISTRY. 


CH,.CO,H 
2. Malic Acid, C,H,O; = | - Oxysuccinic Acid, 
CH(OH).CO,H, 
(Acidum malicum), occurs free or in the form of salts in many plant 
juices, in unripe apples, in grapes and in mountain-ash berries 
(from Sorbus aucuparia). It is artificially prepared by the action 
of nitrous acid upon asparagine or aspartic acid (p. 466); by boil- 
ing bromsuccinic acid with silver oxide :— 


CO,H /CO,H 
CoH + AgOH = GH(OH)< Coy + AgBrs 


C,H,Br 
by the reduction of tartaric and racemic acids with hydriodic acid 
(p. 411); by heating fumaric acid with caustic soda to 100° or with 
water to 200°; and by saponifying the esters of chlorethenyltri- 
carboxylic acid (p. 471). 


The best source of malic acid is the juice of unripe mountain-ash berries. 
This is concentrated, filtered, and while boiling saturated with milk of lime. The 
pulverulent lime salt which separates is dissolved in hot dilute nitric acid (1 part 
HNO, in 10 parts water); on cooling acid calcium malate crystallizes from the 
liquid. To obtain the pure acid, the lead salt is prepared and decomposed with 
hydrogen sulphide (Azza/len, 38, 259). 


Malic acid forms deliquescent crystals, which dissolve readily in 
alcohol, slightly in ether, melt at 100°, and at 140° lose water and 
pass into fumaric and maleic acids (p. 425). 

It exists in three different modifications; these are identical in 
structure (Berichte, 18, 2170, 2713). They are chiefly distinguished 
by their optical deportment. As malic acid contains an asymmetric 
carbon atom, it is possible for it, according to van’t Hoff’s theory, 
to appear in three forms—a levo-rotatory, a dextro-rotatory, and an 
inactive (para) form. ‘The latter can be resolved into the active 
varieties. 

The natural malic acid (from mountain-ash berries) rotates the 
plane of polarization to the left, that obtained from dextrotartaric 
acid and. aspartic acid turns it to the tient (fal a= 2.2"), The 
variety obtained from fumaric and chlorethenyltricarboxylic acids is 
inactive and melts at 130-135° (Aznalen, 214, 50). ‘The inactive 
acid, formed in the reduction of racemic acid, fumaric acid and 
maleic acid, can be resolved, by means of the cinchonine salt, into 
a dextro- and laevo-rotatory malic acid (Berichte, 18, Ref. 537). 

Succinic acid is formed by the reduction of malic acid, This is 
accomplished by the fermentation of the lime salt with yeast, or by 
heating the acid with hydriodic acid to 130° (p. 411). When it is 
warmed with hydrobromic acid, it forms monobrom-succinic acid. 
Bromine converts malic acid into bromoform and carbon dioxide. 


: 


- 





MALIC ACID. 465 


When the acid is heated to 180° it decomposes into water, fumaric 
acid, maleic acid and maleic anhydride (p. 427). The coumarines are 
produced when the acid is heated with phenols and sulphuric acid. 
This result is probably to be explained by assuming that the malic 
acid first changes to the first aldehyde of malonic acid, CHO.CH:. 
CO,H, and this then condenses with the phenols (Berich/e,17, 1647). 
When malic acid is heated alone, or with sulphuric pie | or zinc 
chloride, the product is cumalic acid (see this). 


‘ 


The neutral a/kali malates do not crystallize well and soon deliquesce; the 
primary salts, however, do crystallize. The primary ammonium salt, C§H;(NH,)O,, 
forms large crystals, and when exposed to a temperature of 160—200°, becomes 
fumarimide, C,H,O,.NH. 

Neutral Calcium Malate, CjH,O;Ca + H,O, separates as a crystalline powder 
on boiling. The acid salt, (C,H;O;),Ca + 6H,O, forms large crystals which are 
not very soluble (Berichte, 19, Ref. 679). Sugar of lead precipitates an amorphous 
lead salt from the aqueous solution. This melts in boiling water. 


Sodium Brommatate (from the acid, C,H;BrO,), is formed when the aqueous 
solution of sodium dibromsuccinate is boiled; milk of lime transforms it into 
tartaric acid. : 

The diethyl ester, C§H,(C,H;),O0,, suffers partial decomposition when boiled. 
Acetyl chloride converts it into ethyl aceto-malate, CAs {ieee » which 

(CO,.C,H5)2 
boils at 258°. 

Consult Berichte, 18, 1952, for the boiling temperatures of the malic acid esters. 

As an isomeride of malic acid, may be mentioned :— 

a-Oxyisosuccinic Acid, CH,.C(OH).(CO,H),, Methyl ‘Tartronic Acid, 
which is formed from pyroracemic acid, CH,.CO.CO,H, by means of CNH, etc. 
Isomalic acid, obtained from bromisosuccinic acid by the action of silver oxide, is 
probably identical with the preceding. Both decompose at 178° into carbon di- 
oxide and a-lactic acid. 

Its ethyl ester, CH,.C(O.C,H;)(CO,H),, and not methylene-malonic acid (p. 
428), is formed when bromisosuccinic acid is acted upon with alcoholic potash. 

B-Oxytsosuccinic Acid, CH,.OH.CH.(CO,H),. Its ethyl ester is produced 
when methylene-malonic ester (p. 428) is saponified with alcoholic potash (e- 
richte, 23, Ref. 194). 





Amides of Malic Acid :— 


/CO,H /CO.NH 
©2H3(OH)< coNu, ©2H(OH)< Co.NH,: 
Malamic Acid. Malamide. ; 


/CO,H CO,H CO.NH 
CoH, (NH2)< Co? CH, (NH) CoH, C.H4(NH2)¢ Co NH? 


Aspartic Acid. Asparagine, Triamide (unknown). 


Aspartic acid bears the same relation to malic and succinic acids, as glycocoll 


bears to glycollic acid and acetic acid (p. 366); hence, it may be called amido- — 


succinic acid. 


‘ 


466 ORGANIC CHEMISTRY. 


Malamide, C,H,O,N,, is formed by the action of ammonia upon dry ethyl 
malate. It forms large crystals. When heated with water,it breaks up into malic 
acid and ammonia, thus plainly distinguishing itself from isomeric asparagine. 

Ethyl Malamate, C5H,(OH)< Co.-c, H,? is obtained by leading ammonia 


into the alcoholic solution of malic ester; it forms a crystalline mass. 


CH(NH,).CO,H 
Aspartic Acid, C,H,NO,= | , amidosuccinic 
CH,.CO,H 
acid, occurs in the vinasse obtained from the beet root, and is 
procured from albuminous bodies in various reactions. It is pre- 
pared by boiling asparagine with alkalies and acids (Bertchie, 17, 
2924). 


It may be synthetically formed as follows: By the reduction of isonitroso- 
succinic acid (the oxime of oxalacetic acid, p. 435) with sodium amalgam; by 
heating fumaric and maleic esters to 110° with alcoholic ammonia (Serichée, 21, 
86, 644); and by heating fumarimide and maleimide with water : C,H,O,:NH + 
2H,O — C,H,NO,. As it contains an asymmetric carbon atom, it can (like 
malic acid) exist in a levo-rotatory, dextro-rotatory and inactive variety. Naturally 
occurring aspartic acid is levo-rotatory ; it crystallizes in rhombic prisms, or leaflets, 
and dissolves with difficulty in water (in 256 parts at 10° and in 18 parts at 100°). 
The synthetic acid is zzactive. It is more soluble in water, and consists of mono- 
clinic crystals. Active aspartic acid is changed to the inactive form by heating it 
with hydrochloric acid to 180°, Like glycocoll it combines with alkalies and 
acids yielding salts; with the former it yields acid and neutral salts, ¢. ¢., C,H, 
NO,Na + H,0 and (C,H,NO,),Ba + 3H,O. 

Nitrous acid changes it to malic acid :—— 

/CO,H /CO,H 


C2H,(NH:)< co-H yields C2H3(OH)< co: 


from the active variety there results the active malic acid, and from the inactive, 
the inactive malic modification. 


CH(NH,).CO,H 
Asparagine, C,H,N,O,; = | , the monamide of 
CH,.CO.NH, 
aspartic acid, is found in many plants, chiefly in their seeds; in 
asparagus, In beet-root, in peas and beans, etc. It often crystal- 
lizes from the pressed juices of these plants after evaporation. It 
is artificially produced when bromsuccinic ester is heated to 100° 
with ammonia (Berichte, 20, Ref. 152), or by the action of alco- 
holic ammonia upon aspartic ester (Berichte, 20, Ref. 510; Berichte, 
22, Ref. 243). Natural asparagine forms shining, four-sided, rhom- 
bic prisms, containing one molecule of water, and is readily solu- 
ble in hot water, but not in alcohol or ether. Its aqueous solution 
is levo-rotatory. Dextro-asparagine, from the sprouts of vetches, 
has been produced on heating inactive aspartic ester with alcoholic 
ammonia. It differs from ordinary asparagine in having a sweet 


OXY-PYROTARTARIC ACIDS. 467 


taste, and in forming right-hemihedral crystals (Berichte, 19, 1691). 
It forms salts with bases and acids (requivalent). It changes to 
aspartic acid, giving off ammonia, when it is boiled with water ; 
the conversion is more speedy when alkalies or acids are employed. 
Nitrous acid converts it into malic acid :— 
CH(NH,).CO,H | CH(OH).CO,H 
yields | : 
CH,.CO.NH, CH,.CO,H - 
It forms ammonium succinate when it ferments in the presence 
of albuminoids. 
a-Amido-isosuccinic Acid, CH,.C(NH).€ Go"¢p is the only amid-de- 


rivative prepared from oxysuccinic or isomalic acid. It has been obtained by the 
action of hydrocyanic acid and alcoholic ammonia upon pyroracemic acid, CH,. 
CO.CO,H (Berichte, 20, Ref. 507). 





3. OXY-PYROTARTARIC ACIDS, C,H,0; = GHAOH)< Cony 
‘ 2 


(1) a-Oxyglutaric Acid, CH CH CoH | (Annalen, 208, 66, and 
Berichte, 15, 1157), is obtained by the action of nitrous acid upon glutaminic 
acid; it occurs in molasses. It crystallizes with difficulty, and melts at 72°. 
Heated with hydriodic acid it yields glutaric acid (p. 417). 

Glutaminic Acid, CHC CH CO = C,H,(NH,)O,, occurs with 
aspartic acid in the molasses from beet root, and is formed along with other com- 
pounds (p. 366) when albuminoid substances are boiled with dilute sulphuric 
acid. It consists of brilliant rhombohedra, soluble in hot water but insoluble in 
alcohol and ether. It melts at 140° and suffers partial decomposition. Like all 
other amido-acids, it forms salts with acids and bases. Mercuric nitrate throws it 
out of aqueous solution as a white precipitate. 

Ordinary glutaminic acid is dextro-rotatory. Upon decomposing the albuminoid 
conglutin with hydrochloric acid, the ordinary active variety of glutaminic acid is 
produced, but if the rupture be brought about by baryta water, an zzactive gluta- 
minic acid is obtained. The latter is converted into levorotatory glutaminic acid 
by Penicillium glaucum (p. 65) (Berichte, 17, 388). 

As glutaminic acid is a y-amido-acid it has power to form an amido-anhydride 
(a lactam); the resulting (by heating to 190°) Pyroglutaminic Acid, C,H, 
NOs, yields pyrrol, C,H,N (Berichte, 15, 1222), when heated further :— 

CO,H CH:CH 
CH,.CHY 
| SNH 
CH,.CO” 


Glutamin, CH.(NH,) Con the amide of amido-glutaric acid, corres- 
2 


ponding to asparagine, occurs together with this in beet sprouts. It crystallizes in 


468 ORGANIC CHEMISTRY. 


needles. When digested with baryta water, glutamin changes to amido-glutaric 


acid. 

(2) 6-Oxyglutaric Acid, CH(OH)< Gyy" Cott i8 obtained from a-dichlor- 
hydrin (p. 455) by means of potassium cyanide. It forms crystals which dissolve 
easily in water, alcohol and ether, and melt at 135°. 

: . #GH,.COLF.. 

(3) a-Oxypyrotartaric Acid, CH,.C(OH) {CO SM ae produced by the 
action of hydrocyanic and hydrochloric acids upon ethyl aceto-acetate, or by oxid- 
izing isovaleric acid with nitric acid (p. 347). It forms a thick syrup, which 
solidifies ina vacuum and then melts at 108°. Near 200° it decomposes into water 
and citraconic anhydride. 

(4) Itamalic Acid is only stable in its salts. When free, it decomposes into 
water and Paraconic Acid, C;H,O, (Aunalen, 218, 77) :— 








CO,H /CO,H 

CH, (OH).CH ! yields») Ste-CRS cH. - 
CH,.CO,H & he 
Itamalic Acid. Paraconic Acid. 


Calcium itamalate is obtained by boiling itachlorpyrotartaric acid (p. 418) with 
calcium carbonate. Paraconic acid is best prepared by boiling itabrom-pyrotartaric 
acid with water. Itis very deliquescent and melts at 57-58°. When boiled with 
bases, it forms salts of itamalic acid; it yields citraconic anhydride when it is 
distilled, ‘ 

(5) y-Oxy-ethyl Malonic Acid, CH,(OH).CH,.CH(CO,H),. Butyro- 
lactone carboxylic acid is its lactone acid. This is obtained from brom-ethy]- 
malonic acid (melting at 117°—from vinyl malonic acid = trimethylene dicarboxy- 
lic acid) when heated with water :— 

et CH ,.CH,.CHCO,H 


CO,H 
Ce cid + HBr; 
ea ee 


and when isomeric vinaconic acid (a-trimethylene dicarboxylic acid) is digested 
with dilute sulphuric acid (p. 352) (Ama/en, 227, 13). 
Heated to 120° it breaks up into carbon dioxide and butyrolactone (p. 362). 
(6) Citramalic Acid, C,H (OH) Gop is obtained by the action of zinc 
and hydrochloric acid upon chlorcitramalic acid, C,H,ClO, (by addition of CIOH 
to citraconic acid).. Large crystals, melting at 119° and decomposing at 130° into 
water and citraconic acid. 


CH, Br.CH,.C 


(7) Ethyl Tartronic Acid, ChH CO) Got: is obtained by chlorinating 
2 


ethyl malonate, C,H,.CH(CO,H),, and subsequently saponifying it with baryta 
water (p. 409). It melts at 98° and at 180° decomposes into carbon dioxide and 
a-oxybutyric acid. 


4. Acids, C,H,,O;. 


(1) Methyl Itamalic Acid, C,H,,O,, and Methyl Paraconic Acid, 
C,H,O,, 


/OOatd 
CH,.CH(OH).CH 


‘CH, :CO,H 





4) 0? ai othe Eh) ot 


DIATEREBIC ACID. 469 


Methyl paraconic acid is produced when acetaldehyde and sodium succinate 
are heated with acetic anhydride (p. 463). It crystallizes from benzene in needles 
or leaflets. It melts at 79°, and resolidifies at 84°. It unites with bases, in the 
cold, to form salts of the formula, C,H,O,Mé. When it is boiled with bases salts 
of methyl itamalic acid are produced : C,H,O,Mé,. When distilled methyl para- 
conic acid yields valerolactone, ethylidene propionic acid (p. 241), methylitaconic 
acid and methyl citraconic acid (p. 463 and Berichte, 24, Ref. 91). 

(2) Oxypropyl Malonic Acid, C,H,,0,;, and a-Carbovalerolactonic 
Acid, C,H,O, :— 

CO,H CH,.CH.CH,.CH.CO,H 
CH,.CH(OH).CH,.CHZ yields 
\co,H O O. 


The second acid has been prepared from allyl malonic acid (p. 430). At 200° 
it decomposes into valerolactone and carbon dioxide (p. 363). 
(3) Methyl Oxyglutaric Acid, C,H,,O,, and y-Carbovalerolactonic Acid, 


6*43V4°— 





CO,H Oot 
CH,.C(OH)Z yields CH,.C¢ 
\CH,.CH,.CO,H CH,.CH, 
O CO. 





The latter is produced when isocaprolactone (p. 364) is oxidized with nitric 
acid (Annalen 208, 62), and by the action of CNK and hydrochloric acid upon 
leevulinic acid (p. 343). It yields deliquescent needles, melting at 68—70°. Salts 
of methyl] glutaric acid are formed when it is boiled with bases. 

5. Acids, C,H,,0,. 

(1) Ethyl Itamalic Acid, C,H,,0,, and Ethyl Paraconic Acid, 


7H 904 -— 


cO,H CO,H 
C,H..CH(OH).CHZ ields - C,H.CH-CH~ 
2t45 a y gtts Me 
CH,.CO,H CH, 
| 
O CO 





8-Caprolactonic acid is obtained from propionic aldehyde and sodium succinate 
(p. 463), and-crystallizes in needles or leaflets, melting at 85° C. If boiled with 
bases it forms salts of ethylparaconic acid with the formula C,H,,O,Mé,. When 
distilled it breaks up chiefly into carbon dioxide and caprolactone (p. 364). Iso- 
meric hydrosorbic acid is formed at the same time (p. 245) (Berichte, 23, Ref. 93). 
(2) Diaterebic Acid, C,H,,O,, and Terebic Acid, C,H, ,0,:— 


\co,H 


2 


OH ——CO. 


CO 
(CA) CCH CH yields  (CH,),C.CH,.CH.CO,H 


Terebic acid is formed when turpentine oil is oxidized with nitric acid (also 
some dimethyl fumaric acid, p. 430) and when teraconic acid (p. 431) is heated 
with hydrobromic or sulphuric acid (p. 352). It is sparingly soluble in cold 
water, crystallizes in shining prisms, melts at 175° and sublimes even below this 
temperature. It is a monobasic acid, and with carbonates yields the salts 
C,H,MeO,, which are generally easily soluble; stronger bases will change these 
compounds into salts of dibasic-diaterebic acid, C,H,,Me,0,. When terebic 


470 ORGANIC CHEMISTRY. 


acid is distilled it forms carbon dioxide and pyroterebic acid (isocaprolactone is 
produced at the same time, p. 364). When sodium acts on the ethyl salt it forms 
ethyl teraconate (431) (Annalen, 226, 363). 

(3) Carbocaprolactonic Acid, CH,.CH.CH,.CH.CH,.CO,H, from allyl 


O CO 
succinic acid (p. 430), melts at 69°, and distils with scarcely any decomposition 
at 260°. 
6. Acids, C,H, ,O,. 
(1) Propylitamalic Acid, C,H,,0,;, and Propylparaconic Acid, 
H,,0,:— 
ertis“"4 





CO _CO,H 
C,H,.CH(OH).CH yields C,H,.CH.CHY ~ . 
\CH,.COH, CH, 
O co 





Propylparaconic acid is obtained from butyraldehyde and succinic acid. It melts 
at 73.5°. On boiling with bases it forms salts of propylitamalic acid, C,H, ,0; Mé,. 
Heptolactone, heptylenic acid, C,H,.,O,, and propylitaconic acid,C,H,,O, (Be- 
richte, 20, 3180), are produced by the distillation of propylparaconic acid. 

(2) Isopropylitamalic and Isopropylparaconic Acids are similarly obtained 
from isobutyraldehyde and succinic acid. The second melts at 69°, and when dis- 
tilled decomposes into isoheptolactone and isoheptylenic acid (Berichte, 23, Ref. 
94). 
(3) Diaterpenylic Acid,C,H,,0;. Its lactone, Terpenylic Acid,C,H,.O,, 
is obtained by oxidizing turpentine oil and various terpenes with potassium chlo- 
rate and sulphuric acid ( Berzchze, 18, 3207). It crystallizes in large leaflets with one 
molecule of water, and melts when anhydrous at 90°. It unites with carbonates 
and forms salts of terpenylic acid, C,H,,MeO,. Caustic alkalies convert these 
into salts of dibasic diaterpenylic acid, C,H,,Me,0,. When distilled, terpenylic 
acid decomposes into carbon dioxide and teracrylic acid, C,H, .O, (p. 241). 


UNSATURATED OXYDICARBOXYLIC ACIDS, C,H,,—,O; 


The supposed Oxymaleic Acid,C,H,O, — CHOW) Cop from _brom- 
maleic acid, appears not to exist (Annalen, 227, 233). 

Oxyitaconic Acid, C,H,0O,, is only stable in its salts. Its lactone acid—mono- 
basic Aconic Acid, C,H,O,—+results from boiling monobromitaconic acid (from 
itabrompyrotartaric acid, p. 418), with water. Soluble rhombic crystals, melting 
at 164°. It is not capable of combining with bromine (Axzalen, 216, 91). 

Oxycitraconic Acid, C,H,O,, is obtained from chlorcitramalic acid (p. 468) 
by means of baryta water. It forms readily soluble prisms. It does not unite with 
bromine or nascent hydrogen, but when heated to 110° with hydriodic acid, it is 
converted into citramalic acid, C;H,O;. When boiled with water, it decomposes 
into 2CO, and propionic aldehyde (Annalen, 227, 237). 

Oxyhydromuconic Acid, C,H,O,. Its lactone-anhydride, monobasic Mu- 
colactonic Acid, or Muconic Acid, C,H,O,, is obtained by heating dibrom- 
adipic acid, C,H,Br,O, (from hydromuconic acid, p. 430), with silver oxide. 
Large, readily soluble crystals, which melt near 100°. It decomposes into carbon 
dioxide and acetic and succinic acids when boiled with baryta water. 


TRIBASIC ACIDS. 471 


TRIBASIC ACIDS, C,H, ,05. 


Formyl Tricarboxylic Acid, Methenyl Tricarboxylic Acid, CH(CO,H), 
= C,H,0,, is decomposed into carbon dioxide and malonic acid, CH,(CO,H),, 
when it is freed from its esters by alkalies or acids (p. 401). The ¢riethy/ ester, 
CH(CO,.C,H;);, is obtained from sodium malonic ester, CHNa(CO,.C,H,),, 
and ethyl chlorcarbonate (Berichte, 21, Ref. 531); it is crystalline, melts at 29°, 
and boils at 253°. Sodium alcoholate decomposes it. 

CH,.CO,H 
Ethenyl Tricarboxylic Acid, | = C,;H,0O,, is obtained by the 
CH(CO,H), 
saponification of ethyl acetylene tetracarboxylate, C,H,(CO,.C,H;),, and from 
esters of cyansuccinic acid, C,H,(CN)(CO,R),. . It melts at 159° and is decom- 
posed into carbon dioxide and succinic acid. The ethyl ester, C;H,(C,H;)30g, 
is obtained from sodium ethyl malonate and the ester of chloracetic acid. It boils 
at 278°. Chlorine converts it into Chlorethenyl Tricarboxylic Ester, C,H,Cl 
(CO,.C,H;);. This boils at 290°, and when heated with hydrochloric acid, 
yields carbon dioxide, hydrochloric acid, alcohol and fumaric acid ; when saponi- 
fied with alkalies, carbon dioxide and malic acid are the products (Azna/en, 214, 


44). 
diigher tricarboxylic acids have been variously produced by analogous methods : 
1) By the action of the esters of haloid fatty acids upon the sod-malonic esters, 
CHNa.(CO,R),, and the sod-alkyl-malonic esters, R.CNa(CO,R),. 

(2) By the action of alkyl haloids upon esters of ethenyl tricarboxylic esters. 

Of the resulting isomeric acids, those obtained by the second method are desig- 
nated #-derivatives of ethane- or ethenyl-tricarboxylic acid (see above). 

Many tri- and poly-carboxylic acids have been prepared. They lose carbon 
dioxide, and yield the corresponding mono- and dialkylic succinic acids (p. 400) 
(Annalen, 214, 58; Berichte, 16, 333; 23, 633). ’ 

CH,.CH.CO,H 
a-Methyl Ethenyl Tricarboxylic Acid, C,H,O, = 
H(CO,H), 
a—propenyl tricarboxylic acid (isomeric with tricarballylic acid), Its e¢hy/ eséer, 
C,H;O,(C,H;);,is prepared from ethyl malonate and the ester of a-brompropio- 
nic acid. It boils at 270°. 
The free acid melts at 140°, and,breaks down into carbon dioxide and methyl 


succinic acid. 
CH,.CO,H Rae 
£-Methyl Ethenyl Tricarboxylic Acid, | ,6 propeny] tricar 
CH,.C(CO,H), 
boxylic acid. Its methyl ester is formed when chloracetic ester acts upon methyl 
malonic ester, or methyl iodide upon ethenyl tricarboxylic ester. It boils at 273°. 
It yields methyl succinic acid when saponified with sulphuric acid. 
C,H,.CH.CO,H 
a-Ethyl Ethenyl Tricarboxylic Acid, | , a-butane tricar- 
CH(CO,H), 
boxylic acid. The ethyl ester is obtained from malonic ester and a-brombutyric 
ester. It boils at 278°. It passes, by saponification, into ethyl succinic acid. 
: H,.CO,H 
$8-Ethyl Ethenyl Tricarboxylic Acid, | ah he , B-butane tricar- 
C,H,.C(CO,H), 
boxylic acid. The ethyl ester is formed in the action of chloracetic ester upon 
ethyl malonate, as well as that of ethlyl iodide upon ethenyl tricarboxylic ester. It 
boils at 281°, It forms ethyl succinic acid when saponified. 


472 ORGANIC CHEMISTRY. 


(CH,),.C.CO,H 
a-Dimethyl Ethenyl Tricarboxylic Acid, , isobutylene 
CH(CO,H 
tricarboxylic acid. Its ethyl ester is obtained from a-bromisobutyric ester, (CH,),. 
CBr.CO,.C,H,, and malonic ester. It boils at 277°C. It yields unsymmetrical 
dimethyl succinic acid (p. 420) when saponified. 
CH, .CH:.CO,H 


cH,.c(co,h), 
boxylic acid. Its ethyl ester is made from a-brompropionic ester and methy] 
malonic ester, as well as by the action of methyl iodide upon a-propeny] tricarboxy- 
lic ester. It boils at 279°, and yields both dimethyl succinic acids (p. 420) when 
saponified. 

aB-Methyl-ethyl-, a6-diethyl-, etc., ethenyl tricarboxylic esters, (RR’)C,H, 
(CO,R),, have been produced in an analogous manner. They have also yielded 
the corresponding alkylic succinic acids when saponified (p. 400 and Berichte, 23, 


647). 


Tricarballylic Acid, C,H,0, = C;H;(CO,H);, is obtained: 
(1) by heating tribromallyl with potassium cyanide and decompos- 
ing the tricyanide with potash :— 


CH,Br CH,.CO,H 


af Dimethyl Ethenyl Tricarboxylic Acid, , butane tricar- 


CHBr yields. ..0H.CO,H; 
bu, Br CH,.CO,H 


(2) by oxidizing diallyl acetic acid (p. 245); (3) by acting upon 
ethyl aceto-succinate with sodium and the ester of chloracetic acid, 
then saponifying the aceto-tricarballylic ester (p. 342); (4) by the 
decomposition of a-propylene-tetracarboxylic acid ; (s) by the ac- 
tion of nascent hydrogen upon aconitic acid, C,H,O, (Berichie, 22, 
2921), and by the reduction of citric acid with hydriodic acid ; also 
from dichlorglycide, C,H,Cl,, and chlorcrotonic ester, C,H,C1O,,. 
C.H;, by the action of potassium cyanide. The acid occurs in un- 
ripe ‘beets, and also in the deposit in the vacuum pans used in beet- 
sugar works. Itcrystallizes in rhombic prisms, which dissolve easily 
in water, alcohol and ether, and melt at 158° (166°). 


The sever salt, C,H,0,Ag,, is insoluble in water. Calcium tricarballylate 
(G,11,0,)5Ca, ~ 4H, O; is a powder. that dissolves with difficulty. The ¢rzme- 
thyl ester, is H,O .(CH, ),, boils at 150°, under a pressureof 13 mm. The ch/or- 
ide of tricarballylic acid, C,H,(CO.Cl),, results from the action of phosphorus 
pentachloride. The ¢riamide, C,H,(CO.NH,),, melts at 206°. 


Aconitic Acid, C,H,O, — C,;H;(CO,H),* belongs to the class 
‘ of unsaturated tricarboxylic acids. 





* It is isomeric with trimethylene tricarboxylic acid (see this). 


TETRAHYDRIC ALCOHOLS. 473 


It occurs in different plants, for example, in Aconitum Napellus, 
in Eguisetum fluviatile, in sugar cane and in beet roots. It is ob- 
tained by heating citric acid alone or with concentrated hydrochloric 
acid :— 


CH,.CO,H CH.CO,H 
I 
C(OH).CO,H = CCO,H 4+ H,O. 
CH,.CO,H CH,.CO,H 
Citric Acid. Aconitic Acid. 


Its formation, when acetylene dicarboxylic acid is treated with 
alcoholic potash, is rather peculiar (Berichte, 22, 3055). 


Preparation.—Citric acid is rapidly heated ina flask until the formation of white 
vapors ceases and oily streaks line the neck. The residue is taken up in a little 
water, evaporated to crystallization, and the crystalline deposit extracted with ether, 
which will dissolve only aconitic acid. ‘To obtain the latter pure, decompose the 
lead salt with hydrogen sulphide (Berichte, 9, 1751). 

A better method consists in boiling citric acid (100 grs.) with water (50 grs.) 
and sulphuric acid (100 grs.) for a period of 4-6 hours ( Berichte, 20, Ref. 254). 


Aconitic acid crystallizes in small plates, which dissolve readily in 
alcohol, ether and water. It melts at 186-187° and decomposes into 
carbon dioxide and itaconic acid. Nascent hydrogen converts it 
into tricarballylic acid, C,H,O, + H, = C,H,O,. 


It gives rise to three series of salts. The tertiary ad salt is insoluble in hot 


water. The calcium salt (C,H,O,),Ca, + 6H,O, dissolves with difficulty. The 


esters of aconitic acid are obtained by conducting hydrochloric acid gas into alco- 
holic solutions of the acid (Berichte, 21, 670); as well as by heating aceto-citric 
esters to 250-280°. The trimethyl ester, CsH,0,(CH,),, is a yellow oil. It boils 
at 200°, 

Concentrated ammonia oo the esters into aconitictriamide, C,H,(CO.NH,)s. 
A yellow, crystalline powder, soluble in water. Acids change it to citrazic acid 
(= dioxypyridine carboxylic acid) (Berichte, 22, 1078, 3054; 23, 831). 

Isomeric Pseudo-aconitic Acid, C,H,Og, results upon heating a-propylene tetra- 
carboxylic acid (p. 482) to 200°, when it splits off carbon dioxide. It melts at 
145-150° C, 





TETRAVALENT COMPOUNDS, 


TETRAHYDRIC ALCOHOLS. 


Ortho-carbonic Ester, C(O.C,H,;),(of Basset), may be regarded as the ether ot 
the tetrahydric alcohol or normal carbonic acid, C(OH),. It is produced when 
sodium ethylate acts on chloropicrin :— 


CCl,(NO,) + 4C,H,.ONa. = C(O.C,H,), + 3NaCl + NO,Na. 


It is a liquid with an ethereal odor, and boils at 158-159°. When heated with 
ammonia it yields guanidine, 


40 


474 ORGANIC CHEMISTRY. 


The propyl ester, C(O.C,H,,),4, boils at 224, the zsodutyl ester at 250°, and it 
seems the methyl ester cannot be prepared (Aznalen, 205, 254). 


Erythrol, Erythrite, C,H,O, = CH,(OH).CH(OH).CH 
(OH).CH,.OH, Erythroglucin or Phycite, occurs free in the 
alga Protococcus vulgaris. It exists as erythrin (orsellinate of 
-erythrite) in many lichens and some alge, especially in Roccella 
Montagnei, and is obtained from these by saponification with caus- 
tic soda or milk of lime :— 


C,H {foe C41,0,), + 220 = CxH,(OH), + 2C,H,0,. 
Exythrin. Erythrol. Orsellinic Acid. 


Erythrol forms large quadratic crystals, which dissolve readily in 
water, with difficulty in alcohol, and are insoluble in ether. Like 
all polyhydric alcohols erythrol possesses a sweet taste. It melts at 
126° and boils at 330° (Berichte, 17, 873). When heated with 
hydriodic acid it is reduced to secondary butyl iodide :— 


C,H,(OH), + 7HI = C,H,I + 4H,0 + 3I,. 


By carefully oxidizing erythrol with dilute nitric acid an aldehyde body is ob- 
tained, which combines with two molecules of phenylhydrazine to form phenyl 
erythrosazone, C,H,O,(N,H.C,H,),, melting at 167° (Berichte, 20, 1090). 
More intense oxidation with nitric acid produces inactive tartaric acid. 

Erythrol yields esters with acids. The nitric acid ester, the so-called sztroery- 
_ thrite, C,H,(O.NO,),4, is obtained by dissolving erythrol in fuming nitric acid; 
it separates in brilliant plates, melting at 61°. It burns with a bright flame and 
explodes violently when struck, 

Concentrated hydrochloric acid converts Zrythro/ into the dichlorhydrin, C,H, 
(OH),Cl, (melting at 125°). Caustic potash converts this into the dioxide, the 
so-called Erythrol ether, CH,.CH.CH.CH,. This is a pungent-smelling liquid 

Nia wetonse! 
of sp. gr. 1.113 at 18°; boils at 138° and volatilizes with ether vapors. In its 
_ reactions it is perfectly similar to the alkylen oxides (p. 300). It combines gradu- 
ally with water, forming erythrol, with 2HCI yielding dichlorhydrin, with 2CNH 
to form the nitrile of dioxyadipic acid, etc. (Berichte, 17, 1091). 


MONOBASIC ACIDS. 


Erythritic Acid,C,H,O, = C,H {SO Hi» erythroglucic acid, trioxybutyric 


acid, is produced in the oxidation of an aqueous erythrol solution with platinum 
sponge. It forms a deliquescent crystalline mass. The same acid is probably 
formed on oxidizing leevulose with mercuric oxide or bromine water (Berichée, 19, 
390). It also results from the oxidation of mannitol with potassium permanga- 
nate (Berichte, 19, 468). 


TARTARIC ACID. 475 


DIBASIC ACIDS. 


Dioxymalonic Acid, C,H,O, = C(OH),< Go2tp obtained from dibrom- 
malonic acid, is identical with mesoxalic acid (p. 434). 
CH(OH)—CO,H 
Tartaric Acid, C,H,O, = , or Dioxysuccinic Acid. 
H(OH)—CO,H 
Several modifications of this acid are known ; all possess the 
same structure (Berichte, 21, 519) and can be converted into each 
other. They are the ordinary or dextro-tartaric acid, levo-tartaric 
acid, racemic acid and inactive mesotartaric acid. They are chiefly 
distinguished by their different optical rotatory power, but all, how- 
ever, yield the same products of transposition, hence they are 
viewed as physical isomerides (p. 49). 


The differences in these acids, according to the Le Bel-van’t Hoff theory, are 
attributable to the presence of two asymmetric carbon atoms in dioxysuccinic 
acid (p. 63) :— 





Hocmae 
| | 
HO+0— C—OH. 
CO,H --CO,H 


The two intermediate carbon tetrahedra, having a common axis and joined by 
one summit, have the three different groups arranged right or left. This would 
result in a dextro- and levo-rotatory tartaric acid. If, however, the three side 
groups are arranged in opposite directions, their influence will cease, and the pro- 
duct will be an zzactive tartaric acid. This cannot be resolved; it is known as 
the meso- or anti-form. Again, the dextro- and levo-modifications can unite, 
producing an optically zzactive modification, that can be resolved into its two 
active components. This is the fara-form. It is represented by racemic acid 
(p. 478). Consequently, dioxysuccinic acid can exist according to theory in three 
or four different modifications. This is confirmed, too, by many facts (Berichte, 
21, 2106; 22, 1813). 


Dioxysuccinic acid is synthetically prepared by boiling dibrom- 
succinic acid with moist silver oxide :— 


CHBr.CO,H CH(OH).CO,H | 
| 4+. 2AgOH = I +. 2AgBr. 
CHBr.CO,H H(OH).CO,H 
The product in this reaction consists of inactive tartaric acid and 
racemicacid, Only the latter is formed when hydrocyanic acid and 
hydrochloric acid (p. 324) act upon glyoxal :— 


CHO CH(OH).CO,H 


L 4+ 2GNH + 4H,O = L NH,. 
HO H(OH).CO,H 


476 ORGANIC CHEMISTRY. 


Racemic acid is also produced when fumaric acid is oxidized with 
potassium permanganate, while maleic acid, by the same treatment, 
yields inactive tartaric acid. Mannitol, when oxidized with nitric 
acid, yields racemic acid, and sorbine yields inactive tartaric acid. 

Racemic acid can yield dextro- and levo-tartaric acid (p. 478). 
Heat converts ordinary dextro-tartaric acid and also racemic acid 
into inactive tartaric acid; conversely, the latter can change to 
racemic acid by heat (p. 478). 

All the tartaric acids, when heated with badtedic acid, sustain a 
reduction of the OH-groups and change first to malic and then into 
succinic acid (p. 410); in this case active tartaric acid yields malic 
acid, the inactive tartaric, however, inactive malic acid—whereas 
succinic acid is always inactive (p. 64). 

1. Dextro-rotatory or Ordinary Tartaric Acid (4cidum 
tartaricum) is widely distributed in the vegetable world, and occurs 
principally in the juice of the grape, from which it deposits after 
fermentation in the form of acid potassium tartrate (argol). It 
results on oxidizing saccharic acid and milk sugar with nitric acid. 


Preparation.—Crude argol is purified by crystallization and boiled with pul- 
verized chalk and water; this causes it to separate into easily soluble, neutral potas- 
sium tartrate and neutral calcium tartrate, which separates as- an insoluble powder. 
Calcium chloride precipitates all the tartaric acid as neutral calcium salt from the 
filtered solution containing neutral potassium tartrate. The calcium salt is decom- 
posed by dilute sulphuric acid, the gypsum filtered off, and the solution concentrated 
by evaporation. 


Common tartaric acid crystallizes in large monoclinic prisms, 
which dissolve readily in water and alcohol, but not in ether. Its 
solution turns the ray of polarized light to the right. It melts at 
167-170° (Berichte, 22, 1814), when rapidly heated, and in so 
doing is converted into an amorphous modification, called mezazar- 
taric acid, which crystallizes again from water as tartaric acid. 
Heated for some time at 150° water escapes, and we get the anhy- 
drides (p. 351): Ditartaric acid (or tartralic acid), CsH,Oy, ¢a7- 
trelic acid and tartaric anhydride, CLH,O;. The latter is a white 
powder which reverts to tartaric acid when boiled with water. Py- 
roracemic and pyrotartaric acids are products of its dry distillation. 

When gradually oxidized tartaric acid becomes oxymalonic acid 
(p. 463); stronger oxidizing agents decompose it into carbon 
dioxide and formic acid. 


Tartrates.—The acid forms salts which contain usually one and two equivalents 
of metal; there are, however, some with four equivalents of metal; here four hy- 
drogen atoms (two of the CO,H groups and two of the OH groups) are replaced. 
The polyvalent acids form such salts with less basic metals, like lead and tin. 

The neutral potassium salt, C,H ,K,0, + %H,0, is readily soluble in water ; 
from it acids precipitate the salt c. H sKO.; which i is not very soluble in water, and 
constitutes natural tartar (Cremor tartari). 


er he 


LAVO-TARTARIC ACID. 477 


Potassium- Sodium Tartrate,C,H,KNaO, + 4H,O (Seignette’s salt), is made 
by saturating cream of tartar with a sodium-carbonate solution. It crystallizes in 
large prisms with hemihedral faces. The calcium salt, C,H,CaOg + 4H,O, is 
precipitated from solutions of neutral tartrates, by calcium chloride, as an insoluble, 
crystalline powder. It disSolves in acids and alkalies, and is reprecipitated on 
boiling—a reaction serving to distinguish tartaric from other acids. Consult Anma- 


_ len, 226, 161, upon the calcium salts of the different tartaric acids. 


The neutral lead salt, C,H,PbOg, is a curdy precipitate. On boiling its ammo- 
nia solution a basic salt, C,H, Pb,O,, is deposited; in this the hydrogen atoms of 
the four OH groups of tartaric acid are replaced by lead. 

Potassto-antimonious Tartrate, CgH,(SbO)KO, + %H,O, tartar emetic. 
In this an atom of hydrogen is replaced by antimonyl (SbO) (Berichte, 13, 1787). 
It is prepared by boiling cream of tartar with antimony oxide and water. It crys- 
tallizes in rhombic octahedrons, which slowly lose their water of crystallization on 
exposure and fall to a powder. It is soluble in 14 parts water at 10°. Its solu- 
tion possesses an unpleasant, metallic taste, and acts as a sudorific and emetic. 
When the salt is heated to 200°, 1 molecule of water escapes and we get the basic © 


“dd 
salt, C,H,SbKO,, corresponding to basic lead tartrate. Consult Berichte, 16, 
2379. 

To obtain the esters of tartaric acid, C,H,O,(CO,R),, dissolve the acid in me- 
thyl or ethyl alcohol, conduct hydrochloric-acid gas through the solution, and distil 
the liquid under diminished pressure, repeating the process (Berichte, 13, 1175). 
The esters of the other tartaric acids are similarly obtained (Berichée, 18, 1397). 
The dimethyl ester, C,H,Og(CHs),, is crystalline, melts at 48°, and boils at 280°. 
The diethyl ester, CH,O,¢(C,H;),, is a liquid, also boiling at 280°. It is dextro- 
rotatory. The dipropyl ester, boils at 300° C. 

When acetyl chloride acts upon the diethyl ester, the hydrogen of the alcoholic 


-hydroxyl groups is replaced and we obtain acetyl and diethyl diacetyl tartaric esters, 


C,H,(0.C,H,O),(CO,.C,H,),; the first is a liquid; the second melts at 67°, 
and boils without decomposition at 290°. 

The nitro-group, NO,, can effect the same kind of substitution as noted above 
(p- 302). By dissolving pulverized tartaric acid in concentrated nitric acid and 
adding sulphuric acid, so-called Vitro-tartaric Acid, C,H,(0.NO,).¢ Coty’ 
results. This is a gummy mass, which on drying becomes white and shining. : It 
is soluble in water. When its solution is heated tartronic acid is produced. It 
slowly decomposes into tetra-oxysuccinic acid. 

Tartramic Acid, C,H (0H).¢ CoH Its ammonium salt is obtained by 
acting on tartaric anhydride, C,H,O,, with ammonia. From a solution of this 
salt calcium chloride precipitates calcium tartramate. The acid can be obtained 
in large crystals from the latter. . 


Tartramide, CsH,(0H),< Conus produced by the action of ammonia 
* 2 


upon diethy] tartrate. 


2. Levo-Tartaric Acid is very similar to the dextro-variety, also 
melts at 167—170°; and only differs from it in deviating the ray of 
polarized light tothe left. Their salts are very similar, and usually 
isomorphous, but those of the levo-acid exhibit opposite hemihedral 
faces. On mixing the two acids, we get the optically inactive ra- 
cemic acid, which in turn may be separated into the two original 
acids (see below). 





478 ORGANIC CHEMISTRY. 


The esters of levo-tartaric acid are obtained in the same manner as those of 
the dextro-acid (see above). The dimethyl ester, C,H,O,(CH,),, is similar to 
that of the latter. It melts at 48°, and boils at the same temperature as the 
dextro-ester. It is, however, lzevo- -rotatory. 


3. Racemic Acid is sometimes found in conjunction with tartaric 
acid in the juice of the grape, and is obtained from the mother 
liquor in crystallizing cream of tartar. 


The mother liquor is boiled and saturated with chalk; the calcium salt which 
separates is decomposed with sulphuric acid and the filtrate evaporated to crystal- 
lization. As the crystals of racemic acid effloresce on exposure to the air, they can 
be readily separated mechanically from ordinary tartaric acid. 


_ Racemic acid appears in the oxidation of mannitol, dulcitol and 
mucic acid with nitric acid. It is synthetically obtained from 
glyoxal by means of prussic and hydrochloric acids, and (together 
with meso-tartaric acid) from dibromsuccinic acid, by the action of 
silver oxide (p. 475); in addition by heating desoxalic acid or its 
ester (p. 485) with water or dilute acids to 100° :—C;H,O; = C,H,O, 
CO,. An interesting method of preparing it is that of oxidizing 
fumaric acid with potassium permanganate (p. 426). 

Racemic acid is most readily | made by heating ordinary tartaric 
acid with water (;'5 part) to 175°. The product consists of inac- 
tive tartaric acid and racemic acid. These can be separated very 
easily by crystallization. 
_ Racemic acid crystallizes in prisms having a molecule of water. 

These slowly effloresce in dry air, and at 100° lose water. It is 
less soluble (1 part in 5.8 parts at 15°) in water than the tartaric 
-acid, and has no effect on polarized light. It loses its crystal water 
when heated to 110°. In the anhydrous condition it melts at 205- 
206°. It foams at the same time. Its salts closely resemble those 
of tartaric acid, but do not show hemihedral faces. The acid 
‘potassium salt is appreciably more soluble than cream of tartar. 
The calcium salt dissolves with more difficulty, and is even precipi- 
tated by the acid from solutions of calcium chloride and gypsum. 
Acetic acid and ammonium chloride do not dissolve it. 

The acid is composed of dextro- and lzvo-tartaric acids. It is 
most readily converted into these through the sodium ammonium 
salt, C,H,Na(NH,)O, + 4H,O. On saturating acid sodium race- 
mate with ammonia and allowing it to crystallize, large rhombic 
crystals form. Some of these show right, others left hemihedral 
faces. Removing the similar forms, we discover that the former 
possess right-rotatory power and yield common tartaric acid, whereas 
the latter yield the leevo-acid. The separation is easier if we project 
crystal fragments into a supersaturated mixture of the acids. In 
_ this case only crystals of the forms introduced will separate. By 


DIBASIC ACIDS. 479 


mixing dextro- and levo-acid, we again obtain racemic acid. Peni- 
cillium glaucum destroys the dextro-tartaric acid, and thus decom 
poses the racemic acid. 


The methods employed for the preparation of the esters of ordinary tartaric 
acid (p. 477) will serve for the production of those of racemic acid. The dime- 
thyl ester, ChH,O,(CH,),., consisting of monoclinic prisms, melts at 85° and 
boils at 282°. Itis inactive. It can be made with exactly the same properties by 
fusing together the dimethyl ester of dextro- and lvo-tartaric acids. In vapor 
form the ester of racemic acid has the simple formula given above; hence, in this 
condition it consists of the dimethyl ester of the dextro- and lzevo-tartaric acids, 
and upon cooling these reunite to the dimethyl ester of racemic acid (Berichée, 
18, 1397). The dimethyl-diethyl racemic ester deports itself similarly (Berichée, 
2t, Ref. 643.) 


4. Inactive Tartaric Acid, Mesotartaric Acid, Antitartaric Acid, 
is obtained when sorbine and erythrol are oxidized with nitric acid, 
or when dibromsuccinic acid is treated with silver oxide (p. 475) 
and maleic acid with potassium permanganate (p. 426). It is most 
readily prepared by heating common tartaric acid with water to 65° 
for two days. The acid potassium salt affords a means of separating 
it from unaltered acid and the little racemic acid produced at the 
same time. At 175° more racemic acid is obtained. The latter 
acid, when heated alone or with water to 170-180°, may be changed 
to the inactive acid. Conversely, when the inactive acid is raised 
to the same temperature with water, it is transformed into racemic 
acid ; a state of equilibrium occurs between the two acids in solu- 
tion; this can be overcome by removing one of the acids and by 
repeated heatings (Jungfleisch). 

Mesotartaric acid resembles racemic acid very much. It is more 
soluble in water (1 part in 0.8 parts at 15°). It crystallizes in long 
prisms containing one molecule of water. These effloresce in the 
dessicator, lose all their water at 110°, and then melt at 143°. The 
acid is optically inactive and cannot be directly transformed into 
the active tartaric acids. Its salts and esters also distinguish it from 
racemic acid (Berichte, 17, 14123 21, 519). 


CH,.C(OH).CO,H 
Dimethyl Racemic Acid, C,H,,0, = , is a homologue of 
CH,.C(OH).CO,H 
racemic acid. It is produced when hydrocyanic and hydrochloric acids act upon 
diacetyl, CH,.CO.CO.CH, (p. 326). This procedure is analogous to that by which 
glyoxal yields racemic acid. The acid contains one molecule of crystal water and 
when anhydrous, melts at 179° (Berichte, 22, Ref. 137). 


480 ORGANIC CHEMISTRY. 


TRIBASIC ACIDS. 


The supposed Carboxytartronic Acid,C,H,O, = C(OH)(CO,H),, has been 
proved to be a dibasic acid — Tetraczxysuccinic Acid, C,(OH),. ART) a 
C,H,O, (p. 491). 


Citric Acid, C,H,O, = C,;H,OH)(CO,H);, oxytricarballylic 
acid (Aczdum citricum), occurs free in lemons, in black currants, in 
bilberry, in beets and in other acid fruits. It is obtained from 
lemon juice for commercial purposes. 


Lemon juice is boiled (to coagulate albuminoid substances), filtered and satu- 
rated with calcium carbonate and slacked lime, The calcium salt which separates 
is decomposed with sulphuric acid and the filtrate concentrated. 


The acid can be prepared synthetically from #-dichloracetone ; this 
is accomplished by first acting on the latter compound with prussic 
acid and hydrochloric acid, when we get dichloroxyisobutyric acid 
(p. 363), which is then treated with KCN and a cyanide obtained. 
The latter is saponified with hydrochloric acid :— 


CH,Cl CH,Cl CH,.CN CH,.CO,H 
| | | 
CO C(OH).CO,H C(OH).CO,H C(OH).CO,H. 
CH,Cl bax ea CH,.CN CH, CO, Ft 
B-Dichloracetone. Dichloroxyisobutyric Dicyanoxyisobutyric Citric Acid. 
ci 


Citric acid is also obtained by the action of prussic and hydro- 
chloric acids upon acetone dicarboxylic acid, and from cyanacetic 
ester, CN.CH,.CO.CH,.CO,.R, by the same reagents (Berichie, 22, 
Ref. 256). 

Citric acid crystallizes with one molecule of water in large rhom- 
bic prisms, which melt at 100°, lose their crystal water at 130° and 
then melt at 153°. It dissolves in 4 parts of water of ordinary 
temperatures, readily in alcohol and with difficulty in ether. The 
aqueous solution is not precipitated by milk of lime when cold, but 
on boiling the tertiary calcium salt separates. This is insoluble, 
even in potash (see Tartaric Acid). When heated to 175° citric 
acid decomposes into water and aconitic acid (p. 472). It breaks 
up into acetic and oxalic acids when fused with caustic potash, and 
by oxidation with nitric acid. Acetone dicarboxylic acid (p. 435) 
is produced when citric acid is — with concentrated sulphuric 
acid. 


tL: a hapiee acid it forms three series of salts. Tertiary potassium citrate, 
C,H,K,0, + H,0, is made by saturating the acid; it consists of deliquescent 
needles. +The secondary salt, C,H,K,0O,, is amorphous; the primary salt, C,H, 
KO, + 2H,0, forms large prisms. "All three dissolve readily in water. Ter. 


TETRABASIC ACIDS. eee. 


tiary calcium citrate, (C,H,O,),Ca, + 4H,O (p. 480), is a crystalline powder. 
The silver salt, C,H,Ag,O,, is a white precipitate which turns black on ex- 
sure. 

PeThe neutral esters are produced by conducting hydrochloric acid into hot alco- 
holic solutions of the acid. ; The ¢vimethyl ester, C,H,(OH).(CO,.CH,),, is 
crystalline, melts at 79° and distils near 285°, decomposing partially at the same 
time into aconitic ester and water (Berichte, 17, 2683). The ¢riethyl ester, 
C,H,(OH).(CO,.C,H,),, boils near 280° (Berichte, 13, 1953)- 

The action of acetyl chloride on the esters replaces the alcoholic hydrogen. 
The aceto-compound, C,H,(O.C,H,0)(CO,.C,H,),, boils at 280°. It breaks 
down into acetic acid and aconitic ester, when it is distilled. Nitric acid, too, 
substitutes the nitro-group for the hydrogen of hydroxy] in the esters. 

Citramide, C,H ,(OH)(CO.NH,),, is formed by the action of NH, upon ethyl 
citrate. The mono- and diamine acids are formed at the same time (Berich/e, 17, 
2682). Citramide is crystalline, dissolves readily in hot water and blackens when 
heated above 200° C. When digested with hydrochloric or sulphuric acid it is 
condensed to citrazinic acid (dioxypyridine carboxylic acid) (Berich/e, 23, 831). 


TETRABASIC ACIDS. 


CH(CO,.H), 
Acetylene Tetracarboxylic Acid, | .. its ester, C,H, 
; CH(CO,.H), 
(C,H,),O,, is obtained from sodium malonic ester, CHNa(CO,.C,H;),, by 
the action of chlormalonic ester, CHCI(CO,.C,H,),, or from sodium malonic 
ester and iodine (Berichte, 17, 2781). It consists of long, shining needles, which 
melt at 76° and boil at 305°. Aqueous potash converts it into ethenyl tricarboxylic 
acid and CO, (p. 471). 

Acetylene tetracarboxylic ester and sodium ethylate yield a disodium com- 
pound which unites with o-xylylene bromide, C,H,(CH,Br),, to form tetrahydro- 
naphthalene tetracarboxylic ester (Berichte, 17, 449). 

See Berichte, 21, 2085, upon diethyl-etheny] tetracarboxylic acid. 

Acids, C,H,O, = C,H,(CO,H),. 

Sodium and ethyl chloracetate change ethenyl tricarboxylic ester into the ester 

: : CH,.CO,H ‘ ; 
of a-Propane-Tetracarboxylic Acid, C(CO.H).€ CH” CO? which boils 
with slight decomposition at 295°. The free acid is obtained by saponifying the 
ester. It melts at 151° and decomposes into carbon dioxide and tricarballylic 
acid. : 

B-Propane Tetracarboxylic Acid, CH GHtCotHy- Its tetraethyl ester 
is obtained by the condensation of formic aldehyde, CH,O, or methylene iodide 
( Berichte, 22, 3294) with two molecules of malonic ester, and by the action of 
zinc dust and acetic acid upon #-propylene tetracarboxylic acid (Berichte, 23, 
Ref. 240). It is a thick oil, boiling at 240° under 100mm. pressure. The free acid 
decomposes into 2CQ, and glutaric acid, CH,.(CH,.CO,H), (p. 417). Its 
disodium compound and alkyl iodides yield dialkyl derivatives. Bromine converts 
it into £.trimethylene tetracarboxylic ester. 

Acids, C,H,,O, = C,H,(CO,H),. 

(1) Ethidene Dimalonic Acid, CH,.CHY Gitco’H}"- Its ethyl ester is 
produced by the union of ethidene malonic ester (p. 428) and .malonic ester. It 


482 -’ ORGANIC CHEMISTRY. 


is a thick oil, boiling at 210° under 20 mm, pressure. The free acid separates 
into 2CO, and ethidene diacetic acid (p. 420) when distilled. 

CH,.C(CO,H), 

(2) Dimethyl-Acetylene Tetracarboxylic Acid, . The 

CH ,.C(CO,H), 
tetraethyl ester is produced by the introduction of 2 CH,-groups into acetylene 
tetracarboxylic ester; also from sodium-methyl malonic ester, CH,.CNa(CO,R),, 
by the action of iodine (Berichte, 18, 1202). The free acid splits off CO, and 
yields symmetrical dimethyl succinic acid (p. 420). 

C.H,.C(CO,H), 


(3) Ethyl-Acetylene Tetracarboxylic Ester, | . Itsethyl 
CH(CO,H), 
ester is obtained from ethyl malonic ester and chlormalonic ester. It is a thick 
oil (Berichte, 17, 2785). 
CH,.CH(CO,H), 
(4) Butane Tetracarboxylic Acid, | . The methyl ester 
CH,.CH(CO,H), 
is formed together with a-trimethylene dicarboxylic ester when ethylene bromide 
acts upon sodium malonic ester (Berichte, 19, 2038) : 


CH, Br CH,.CH(CO,R), 
+ 2CHNa(CO,R), = | + 2NaBr. 
CH, Br CH,.CH(CO,R), 


Tetramethylene tetracarboxylic ester is produced when bromine acts upon its 
disodium compound. 


Acids, C,H,,0,. 

Pentane-Tetracarboxylic Acid, CH. GH CHICOH} The ethyl ester 
is formed, together with tetramethylene dicarboxylic ester (see this) in the action of 
trimethylene bromide upon two molecules of sodium malonic ester (Berichte, 18, 
3249). Its disodium compound, when acted upon by bromine, yields penta- 
methylene-tetracarboxylic ester. 


UNSATURATED TETRACARBOXYLIC ACIDS. 


C(CO,H), 
Dicarbon-Tetracarboxylic Acid, || . Its tetra-ethyl ester is ob- 
C(CO,H), 
tained by letting sodium ethylate act upon chlormalonic ester, and by the action of 
iodine upon disodium malonic ester (Berichte, 17, 2781). Its ester crystallizes in 
large plates, melting at 58°, and boiling near 325°. The free acid is unstable. 
CH.CO,H 


| 
a-Propylene Tetracarboxylic Acid, C,H,O, = C7 CO,8 _ Its ethyl 
3 : \CH(CO,H),. 
ester is formed from brommaleic ester and sodium malonic ester. The acid con- 
tains two molecules of water of crystallization. These escape at 100°. The anhy- 
drous acid melts at 191°, with decomposition into CO, and pseudo-aconitic acid 


(p. 473) (Annalen, 229, 89). : 
B-Propylene-Tetracarboxylic Acid, CH(CO,H),.CH:C(CO,H),, dicar- 
boxyl-glataconic acid. Its ethyl ester results from the interaction of sodium 


\ 


PENTAVALENT COMPOUNDS. 483 


malonic ester and chloroform. When saponified with hydrochloric acid it yields 
glutaconic acid. Sodium amalgam converts it into dicarboxyl-glutaric ester. It 
splits off alcohol and then condenses to a pyrone derivative (Berich/e, 22, 1419). 





PENTAVALENT (PENTAHYDRIC) COMPOUNDS.. 


Arabite, C;H,,O, = CH,OH.(CH.OH),;.CH,OH, normal penta- 
oxypentane, is formed from its aldehyde arabinose, C;H,O;, by 
the action of sodium amalgam. It crystallizes from hot alcohol in 
shining needles, melting at 102°. It has a sweet taste but does not 
reduce Fehling’s solution. 

Arabinose, C;H,,.O; = CH,(OH).(CH.OH),;.CHO, is its alde- 
hyde. This was formerly thought to be a glucose, C,H,,O,, although 
it contains but five C-atoms, and belongs to the group of pentaglu- 
coses or pentoses (p. 497). It is made from gum arabic (also from 
other gums which yield no, or at least but traces of, mucic acid, 
when oxidized by nitric acid) -on boiling with dilute sulphuric acid 
(Berichte, 19, 3030). 


It crystallizes in shining prisms that melt at 100°. It is dextro-rotatory, is 
slightly soluble in cold water, has a sweet taste (less than that of cane sugar) and 
reduces Fehling’s solution, but is not fermented by yeast. Oxidation converts it 
into arabonic acid, C,H,,O, (p. 484) and trioxyglutaric acid. Boiling mineral 
acids convert it into furfurol, and not into lzvulinic acid (as in the case of the car- 
bohydrates). 

Two molecules of phenylhydrazine and arabinose (like the glucoses) anite and 
form a phenylosazone, C;H,O,(N,H.C,H,),, melting at 158° (Berichie, 20, 
345). Hydrocyanic acid, etc., converts it into /:mannonic and /gluconic acids 
(p. 490). The constitution of arabinose is thus established (Berichie, 20, 341, 
1234). Sodium amalgam converts it into arabite. 

Xylose, C,H,,O,, is alloisomeric with arabinose. It is obtained by boiling 
wood-gum (beech-wood, jute, etc.) with dilute acids (Berichte, 22, 1046; 23, Ref. 
15). It is perfectly similar to arabinose, and has also been included in the group 
of pentaglucoses. It assumes a cherry-red coloration when digested with phloro- 
glucin and hydrochloric acid. Its phenylosazone, like that of arabinose, melts at 
160°. Nitric acid oxidizes it to trioxyglutaric and trioxybutyric acids. 

Pentaoxyhexane, C,H,,0, = CH,(CH.OH),.CH,.OH, is an homologous 
pentahydric alcohol. It is rhamnite. (Berichte, 23, 3103). Its aldehyde is 

Rhamnose, C,H,,0, = CH,(CH.OH),CHO, or Isodulcite. It results 
upon decomposing different glucosides (quercitrine, xanthoramnine, hesperidine) 
with dilute sulphuric acid. It forms large vitreous crystals containing one mole- 
cule of water. It melts at 93°. The crystals lose water at 100°, and form 
C,H,,0,. By the absorption of water they revert to C,H,,0,. Isodulcite 
yields a-methylfurfurol when distilled with sulphuric acid (Berichte, 22, Ref. 751). 

In its properties rhamnose resembles the glucoses, and (with arabinose and 
xylose) is included under the Penzéoses (p. 497). It reduces alkaline copper solu- 
tions, but is not fermented by yeast. Being an aldehyde-alcohol it combines with 
two molecules of phenylhydrazine to form an osazone, C,H, ,O,(N,H.C,H;),, 


484 : : ORGANIC CHEMISTRY. 


melting at 180°. Its phenyl/hydrazone, C,H,,0,(N,H.C,H,), melts at 159° 
(Berichte, 20, 2575). Hydrocyanic acid and hydrochloric acid convert it into 
rhamnose carboxylic acid, CH,.(CH.OH),.CH(OH).CO,H (p. 491). Nitric 
acid oxidizes it to trioxyglutaric acid (p. 485) (Berichte, 22, 1702). 

Quercite, C,H,,0,, and Pinite, C,H,,O,, are two pentahydric derivatives 
similar to arabite and the various sugars. ‘The latest researches show that they 
belong to the benzene series; they will, therefore, be discussed under the poly- 
hydric phenols. 





MONOBASIC ACIDS. 


Arabonic Acid, C;H,,O, = CH,(OH).(CH.OH);.CO,H, tetra- 
oxyvaleric acid, is obtained by the action of bromine water or nitric 
acid upon arabinose (Berichte, 21, 3007). When liberated from 
its salts by mineral acids, it splits off water and becomes the lactone 
C;H,O; (Berichte, 20, 345). Further oxidation changes it to tri- 
oxyglutaric acid. Its phenylhydrazide melts at 215°. 


Saccharic Acid, C,H,,0O,, tetraoxycaproic acid, readily changes, when free, 
into Saccharin, its lactone :— 

CH,(OH).CH(OH).CH(OH).C(OH 

Saccharic Acid. 


CH,(OH).CH.CH(QH).C(OH).CH, 


/CH, 
\co, H 


O CO 








Saccharin, 

Calcium saccharate is obtained by boiling dextrose and levulose (or from invert 
sugar) with milk of lime. As soon as the acid is liberated from its salts it decom- 
poses into water and saccharin (Berichte, 15, 2954). The latter dissolves with 
difficulty in water (in 18 parts), forms large crystals, tastes bitter, melts at 160° and 
sublimes without decomposition. It is reduced to a-methylvalerolactone (365) when 
heated with hydriodic acid and phosphorus. 

' Aqueous saccharin possesses right-rotatory power; the salts are levo-rotatory. 

Nitric acid oxidizes it to saccharonic acid (p. 485). Oxidized with silver oxide 
it yields glycollic, oxalic and also acetic acids. Boiling potash produces lactic 
acid. Lzevulinic acid is not formed by the action of hydrochloric acid (Berichée, 
18, 1334). It yields a phenylhydrazide with phenylhydrazine. It melts at 165°. 

Isomerides of saccharin :— 

Isosaccharin, C,H,,O,, results from the action of lime upon milk sugar 
and maltose (Berichte, 18, 631). It is very similar to saccharin, and when 
heated with HI and phosphorus it also yields a-methylvalerolactone. However, 
it does not yield acetic acid with silver oxide, and when acted upon by nitric acid 
it forms dioxypropeny] tricarboxylic acid (p. 486). See Berichte, 18, 2514, upon 
the constitution of isosaccharic acid. ‘ 

Metasaccharin, C,H, ,O,, is found in small quantities together with the pre- 
eeding (Berichte, 18, 642). It crystallizes in plates and melts at 142°. Hydri- 
odic acid and phosphorus reduce it to normal caprolactone (p. 364). Nitric acid 
oxidizes it to trioxyadipic acid, C,H,,O,. 


TRIBASIC ACIDS. *- 485 


DIBASIC ACIDS. 


Aposorbic Acid, C,H,0, = C,H,(OH),€ G0?4, is produced on oxidizing 
gtts 


sorbine with nitric acid. It crystallizes in small leaflets which melt with decompo- 
sition at 110°. It is easily soluble in water. 

Trioxyglutaric Acid, C,H,O, = (CH.OH),¢ Gow appears to be different 
from the preceding. It is found when arabinose, sorbinose and rhamnose are 
oxidized with nitric acid (Berichte, 22, 1698). The free acid crystallizes in small 
plates, that melt at 118—120°. 


Saccharon, C,H,O,, is the lactone of Saccharonic Acid, 
CABO; ———— 








CO,H.CH.CH(OH).C(OH).CH, CO,H.CH.CH(OH).C(OH).CH, 
| 
OH CO,H O Co 
Saccharonic Acid. Saccharon. 


Both are formed when saccharin is oxidized by nitric acid (Az- 
nalen, 218, 363). 


The acid is quite soluble in water. It forms large crystals. In the dessicator 
or when heated to go° it breaks up into water and saccharon, which yields salts, 
C,H,MeO,, with carbonates. On boiling, with HI and phosphorus, it is reduced 
to a-methyl glutaric acid (p. 420). /CO,H 

Trioxyadipic Acid, C,H,,O, = C.H5(OH)3< coon? results from the 


oxidation of metasaccharin (see above) with dilute HNO, (Berichte, 18, 1555). 
It crystallizes in small laminz, and melts at 146° with decomposition. It is not 
capable of forming a lactonic acid. Heated with HI and phosphorus it is reduced 
to adipic acid, C,H,(CO,H),. 





TRIBASIC ACIDS. 


Desoxalic Acid, C,H,O, — C,H(OH),(CO,H),, dioxyethenyl tricarboxylic 
acid. Its tri-ethyl ester, C;H,(C,H,),O,, results from the action of sodium 
amalgam upon diethyl oxalate. Large, shining prisms, which melt at 85°. Soluble 
in I0 parts water and readily in ether. The free acid is obtained by saponifying 
the ester with baryta water, decomposing the salt with sulphuric acid and slowly 
evaporating the solution at 40°. The product is a crystalline, deliquescent mass. 
When its aqueous solution is evaporated or when its ester is heated with water or 
dilute acids to 100°, the acid yields carbon dioxide and racemic acid : C,HgO, = 
C,H,O, + CO,. Acid radicals can be substituted for the two hydroxyl groups of 
the desoxalic ester. Heated with hydriodic acid desoxalic acid gives off carbon 
dioxide, and is reduced to succinic acid. Its structure and transformation into 
racemic acid are expressed by the following formulas :— 


/CO,H 
CcoH __ HO.cCH—CO,H 


HO.CH—CO,H HO.CH—CO,H 
Desoxalic Arid Racemic Aeid 


HO.C 
CO,. 


486 ORGANIC CHEMISTRY. 


Oxycitric Acid, C,H,O, = C,H,(OH),.(CO,H),, dioxytricarballylic acid, 
accompanies aconitic, tricarballylic and citric acids in beet juice, and is produced 
by boiling chlorcitric acid (from aconitic acid and ClIOH) with alkalies or water 
(Berichte, 16, 1078). 

Dioxypropenyl Tricarboxylic Acid, C,H,O, = C,H,(OH),(CO,H),, re- 
sults from the oxidation of isosaccharin with nitric acid. "It is a thick syrup. At 
100° it loses carbon dioxide, and forms dioxyglutaric acid, C,H,(OH),.(CO,H),, 
which is different from the dioxyglutaric acid obtained from glutaconic acid (Be- 
vichte, 18, 2514). Hydriodic acid and phosphorus convert it into glutaric acid, 
Cy, (CO,H),. 

"Propenyl Pentacarboxylic Acid, C,H,O,, =C,H,(CO,H,;), is a penta- 
basic acid. Its ethyl ester is formed by the action of sodium malonic ester upon 
chlorethenyl tricarboxylic ester (p. 471). 


HEXAVALENT (HEXAHYDRIC) COMPOUNDS. 


(OH), (OH), 
C,H,(OH), CoH } to, CAH. ¢ (co, Hh, 
Mannitol, Dulcitol, Mannonic Acid, lee Be Kei: 
Sorbite. Gluconic Acid. Mucic Acid. 


Since in all alcohols each carbon atom bears but one hydroxyl 
group, we conclude that in the hexahydric alcohols, mannitol and 
dulcitol, the six hydroxyl groups are attached to 6 different carbon 
atoms. Mannitol, dulcitol and sorbite are reduced to secondary 
hexyl iodide when heated with hydriodic acid (p. 95) :— 


C,H,(OH), + 1rHI = C,H,,I + 6H,O + 51. 


The three are, therefore, derivatives of normal hexane, C,H,,, and 
normal hexoxy- ‘hexane, C,H,(OH), = CH,(OH)(CH. OH),. CH. 
OH. They are examples of alloisomerism. To explain them, it 
will be necessary to introduce stereochemical considerations. 


According to LeBel and vant’ Hoff’s theory upon asymmetric carbon atoms, 
the presence of one asymmetric C-atom determines the existence of two modifi- 
cations, differing chiefly in their opposite optical rotatory power. In the sexivalent 
hexaoxyhexane there are four such asymmetrical carbon atoms; hence, a number 
of modifications are possible. In fact, recent research has shown that we have not 
only ordinary, right-rotatory or d-mannitol, but also a leevo-variety, and further that 
these may combine to inactive, z-mannitol. The latter is zwentical with so-called 
a-acrite, derived from synthetic a-acrose. In this manner, it has been possible to 
effect the syzthesis of the compounds of the mannitol series (Berichte, 23, 373). 


The hexahydric alcohols approach the sugars very, closely in their 
properties. They have a very sweet taste. They differ from them 
in that they do not reduce an alkaline copper solution and are not 
fermented by yeast. Their optical activity can only be observed 
after the addition of borates. Moderate oxidation converts them 


~ 


HEXAVALENT COMPOUNDS. 487 


into glucoses, C,H,,O,. They are obtained from the latter by the 
action of sodium amalgam. 

1. Mannitolor Mannite, C,H,,O,, exists in three modifications: 
dextro-, levo-, and inactive mannitol (see above). The ordinary, 
or d-mannitol, occurs rather frequently in plants and in the manna- 
ash (Fraxinus ornus), whose dried sap is manna. It is produced in 
the mucous fermentation of the different varieties of sugar, and may 
be artificially prepared by the action of sodium amalgam upon ¢@- 
mannose and fruit-sugar, and with more difficulty from grape sugar 
(Berichte, 17, 227): CsH,.O, + H,= C,H,,0O,. Mannitol is also 
obtained by extracting manna with alcohol and allowing the solution 
to crystallize. 

Mannitol forms delicate needles or rhombic prisms; it dissolves 
in 6.5 parts of water at 16°, and readily in boiling alcohol. It pos- 
sesses a very sweet taste and melts at 166°. Its solution is dextro- 
rotatory in the presence of ‘borax. When oxidized with care, it 
yields fruit-sugar (called mannitose, Berichte, 20, 831), and man- 
nose (Berichte, 21, 1805). Nitric acid oxidizes mannitol to sac- 
charic acid and oxalic acid. Hydriodic acid converts it into hexyl 
iodide (p. 486). 


When mannitol is heated to 200° it loses water and forms the anhydrides, MWan- 
nitan, C,H,,0,, and Mannide, C,H, 0,4. The latter is also obtained by dis- 
tilling mannitol in a vacuum, It melts at 87° and boils at 274° (Berich/e, 17, 
Ref. 108). 

Mannitol resembles the sugars in combining with bases to yield compounds like 
C,H,,0,.CaO. When heated with organic acids mannitan esters are usually 
produced :— 


C,H,,0, + 4C,,H,,0, = C,H,(C,,H;,0),0, + 5H,0. 


annitol. Stearic Acid. Mannitan Stearate. 


The hexacetate of mannitol, C,H,(O.C,H,O),, is produced by heating man- 
nitol with acetic anhydride; it is crystalline and melts near 100°. 

Mannitol dichlorhydrin, CHG, is formed when mannitol is heated 
with concentrated hydrochloric acid. It consists of laminze, melting at 174°. Hydro- 
bromic acid yields the dibromhydrin, C,H, { bet melting at 178°. _ 


Nitro-mannite, C,H,(O.NO,),, isobtained by dissolving mannitol in a mixture 
of concentrated nitric and sulphuric acids. It crystallizes from alcohol and ether 
in bright needles; it melts when carefully heated and deflagrates strongly. When 
struck it explodes very violently. Alkalies and ammonium sulphide regenerate 
mannitol. 

Lzvo-mannitol, C,H,,O,, /Mannite, is obtained by the reduction of /man- 
nose (from arabinose carboxylic acid, p. 488) in weak alkaline solution with sodium 
amalgam (Berichte, 20, 375). It is quite similar to ordinary mannite, but melts a 
little lower (163-164°), and in the presence of borax is lzevorotatory. 

Inactive Mannitol, C,H, ,0,, z-Mannite, is produced in a similar manner, 
from inactive mannose (from z-mannonic acid), It is identical with the syntheti- 
cally prepared a-acrite (from a-acrose, p. 499) (Berichte, 23, 383). It resembles 


488 ORGANIC CHEMISTRY. 


ordinary mannitol, melts 3° higher (at 168°), and in aqueous solution is inactive 
even in the presence of borax. Nitric acid oxidizes it to inactive mannose and 
inactive mannonic acid. The latter can be resolved into d- and /-mannonic acids 
(Berichte, 23, 391). 


2. Dulcitol, Dulcite, C,H,,O,, occurs in various plants and is 
obtained from dulcitol manna (originating from Madagascar 
manna). It is made artificially by the action of sodium amalgam 
upon milk sugar and galactose. It crystallizes in large monoclinic 
prisms, having a sweet taste. It dissolves in water with more dif- 
ficulty than mannite, and is almost insoluble in boiling alcohol. It 
melts at 188°. The hexacetate, C,H,(O.C,H;O),, melts at 171°. 
Hydriodic acid converts it into the same hexyl iodide that mannitol 
yields. Nitric acid oxidizes dulcitol to mucic acid. There is also 
an intermediate aldehyde compound that combines with two mole- 
cules of phenylhydrazine and forms the osazone, C,H, O,(N,H. 
C.H;). (Berichte, 20, 1091). : 


(3) Sorbite, C,H,,0, + HO, occurs in mountain-ash berries, forming small 
crystals which dissolve readily in water. When heated they lose water and melt 
near 110°. It is reduced to secondary hexyl iodide (Berichte, 22, 1048) when 
heated with hydriodic acid and phosphorus. It corresponds, in all probability, to 
grape sugar (Berichte, 23, 2623). 





HEXAVALENT (HEXAHYDRIC) ALDEHYDES AND 
KETONES. 


When the hexahydric alcohols, C,H,,O,, are carefully oxidized, 
they lose two atoms of hydrogen, and are converted into their alde- 
hydes and ketones. These products are identical with the glucoses 
that occur naturally as such and are treated with these under the 
carbohydrates. Polyhydric mono- and poly-carboxylic acids result 
if the alcohols or glucoses are further oxidized :— 


C,H, ,O,, or C,H, .O0,, or C,H,.,0,,0r 
C,H;(OH),.CH,.OH.  C,H,(OH),.CHO. C,H,(OH),.CO,H. 
Hexahydric Alcohols. Glucoses.* Monocarboxylic Acid. 
Mannitol. Fruit Sugar, Mannose. Mannonic Acid, Gluconic Acid. 





MONOBASIC ACIDS. 


The penta-oxy-monocarboxylic acids are produced by the further 
oxidation of the alcoholsand glucoses corresponding tothem. They 
may also be obtained synthetically from the pentoses (arabinose, 
rhamnose, p. 483) by the aid of HCN, etc. (p. 494) :— 

C,H,,0,._ yields C,H,(OH),.CO,H. 


Arabinose. Arabinose Carboxylic Acid. 





HEXAVALENT ALDEHYDES AND KETONES. 489 


Being y-oxy-derivatives, nearly all of these acids are very unstable 
when ina free condition. They lose water readily and pass into 
lactones (p. 352): C,H,.O, = CsHy»O, + H,O. When acted upon 
in acid solution by sodium amalgam, these lactones (not the acids) 
reabsorb two atoms of hydrogen, and are converted into the cor- 
responding glucoses (E. Fischer, Berichte, 22, 22043; 23, 370, 799, 
930) (p. 494): C,H,O, + H, = C,H,.0,. 

Thus, the three mannonic acids yield three mannoses, the three 
gluconic acids three glucoses, and galactonic acid galactose. 


These acids (like other carboxylic acids), when acted upon with one mole- 
cule of phenylhydrazine, lose the hydroxyl of the carboxyl group, and form char- 
acteristic phenylhydrazides, C,H,,0,.N,H,.C,H, (p. 495). The latter generally 
result on heating the acids (1 part) with phenylhydrazine (1 part), water (10 parts), 
and 50 per cent. acetic acid (1 part). They usually separate from the solution in 
a crystalline form (Berichte, 22, 2728).. They are resolved into their components 
when boiled with alkalies. They are distinguished from the hydrazones of the 
aldehydes and ketones by the reddish-violet coloration produced upon mixing them 
with concentrated sulphuric acid and a drop of ferric chloride. 


These acids are reduced to normal caprolactone, if they are heated 
with hydriodic acid and phosphorus (p. 364). They must, there- 
fore, be considered as pentaoxycaproic acids, having the same struc- 
tural formula,C;H,(OH;).CO,H, and are physical or geometrical iso- 
merides (p. 486). Gluconic and mannonic acids also occur in 
dextro- and levo-rotatory modifications. These unite and produce 
inactive forms (Berichte, 23, 371, 2623). 


I. Mannitic Acid, C,H,,0,, is obtained by the action of platinum black 
upon aqueous mannitol. It is a very soluble gummy mass which reduces Fehling’s 
solution (Berichte, 23, 3223). 


2. Gluconic Acid, C,H,,0,, exists in a dextro-, a levo- and 
an inactive form, @-Gluconic Acid is formed by the oxidation 
of dextrose, cane sugar, dextrine, starch and maltose with chlorine 
or bromine water, and is most readily obtained from glucose (Be- 
richte, 17, 1298). , Gluconie acid, separated from its lead salt by 
hydrogen sulphide, forms a syrup which i is almost insoluble in alco- 
hol. When evaporated, or upon standing, it changes in part to its 
crystalline lactone, C,H,O,, melting at 130-135°. Its barium salt 
crystallizes with three molecules of water, the calcium salt with one. 
The acid is dextro-rotatory, but does not reduce Fehling’s solution. © 

Its phenylhydrazide, C.H,,O,(N.H,.C,H;), ‘crystallizes in bril- 
liant leaflets and prisms. When rapidly heated it melts about 200°. 
(Berichte, 23, 802, 2625). 


When @-gluconic acid is heated to 140° with quinoline it is converted into 
d-mannonic acid. And, the latter, when similarly treated, becomes d@-glu- 


‘41 


490 ORGANIC CHEMISTRY. 


conic acid. A state of equilibrium occurs in this case similar to that observed in 
the transposition of racemic acid and mesotartaric acid when heated with water 
(p- 479). If sodium amalgam be allowed to act upon the lactone of gluconic 
acid, when in a cold, acid solution, it is changed to grape sugar (Berichte, 23, 
804). 

/-Gluconic Acid is obtained by heating /mannonic acid. This is similar to 
the formation of d-gluconic acid from d-mannonic acid (see above). A more con- 
venient course consists in exposing arabinose to the action of CNH, etc. This 
acid is more soluble than 7/-mannonic acid, and is, therefore, found in the mother 
liquor from the latter. It is separated by means of its phenylhydrazide, 5 «I 6 
N,H,.C,H;. This melts at 200° (Berichte, 23, 2613). Heated to "140° to- 
gether with quinoline, it is partially converted into /-mannonic acid, 

z-Gluconic Acid (and its lactone) is formed upon evaporating the aqueous solu- 
tion of a mixture of d- and /gluconic acids. Its calcium salt dissolves with diff- 
culty. The acid is inactive. Its phenylhydrazide is also inactive. It melts at 
190° (Berichte, 23, 2618). 

The three gluconic acids yield the three corresponding saccharic acids, when 
.. they are oxidized with nitric acid (p. 492). The three glucoses result upon their 
reduction (p. 503). 


3: Mannonic Acid, C,H,,0,, occurs as dextro-, leevo- and in- 
active mannonic acid. 


Ordinary or d-mannonic acid is produced when ordinary ¢-mannose is oxidized 
with bromine water. It is obtained pure by boiling its phenylhydrazide with 
baryta water (Berichte, 22, 3220). When the solution is evaporated it solidifies 
to a crystalline mass. This is the /actone, Celt ,oOg, which crystallizes from alcohol 
in long shining needles, melting at 149-153°. ‘The aqueous solution of the lac- 
tone is neutral and dextro- -rotatory [a], = + 53.8°. Its phenylhydrazide, 
C,H,,0,(N,H,.C,H,) crystallizes from hot water in brilliant prisms, melting 
at *214~216°, When the acid is heated to 140° together with quinoline, it changes 
to gluconic acid (see above). 

Lzvo-mannonic Acid, C,H,.,0O,, is identical with arabinose-carboxylic 
acid, obtained from arabinose by the action of hydrocyanic acid, etc. (Berichte, 
IQ, 3033). It is further produced, together with ¢d-mannonic acid, by the decom- 
position of z-mannonic acid. When its solution is concentrated it passes into the 
lactone, C,H,,O,. The latter crystallizes from alcohol in needles that dissolve 
with difficulty. They become soft at 140-150°. Its solution is lvo-rotatory 
[a], 54.8°. The phenylhydrazide of /-mannonic acid is very similar to that 
of d-mannonic acid. It also melts at 214~—216°. /-Mannose and /-mannitol result 
from the reduction of /-mannonic lactone (p. 487). 

Inactive Mannonic Acid, C,H,,0,, z-mannonic acid, is obtained by the 
union of equal parts of d- and /-mannose. Its lactone, C tO. separates in 
colorless radiating crystals, when the solution is evaporated. When the latter is 
concentrated the crystals assume a prism form. The lactone melts somewhat 
higher than its components, softens at 149° and fuses at 155°. The phenylhydra- 
side of the acid crystallizes from hot water in forms similar to those of sodium 
’ chloride. When rapidly heated it melts at 230°. The acid can be resolved into 
-its components if it be fermented by penicillium glaucum, or by the crystallization 
of the strychnine salt. Sodium amalgam converts it into z-mannose and 7-man- 
nite, which is identical with a-acrite—prepared synthetically from a-acrose. If 

z-mannite be oxidized with nitric acid it yields 7-mannose, which bromine water 
can further change to z-mannonic acid. Thus, the symthests of all the members 
of the mannite sertes has been realized ( Berichte, 23, 391). 


DIBASIC ACIDS. 491 


When the mannonic acids are oxidized with nitric acid they yield the correspond- 
ing mannosaccharic acids (p. 494). 

4. Lactonic Acid, C,H,,0,, galactonic acid, is produced from milk sugar, 
galactose and gum arabic by the action of bromine water ( Berich/e, 18, 1552). 
It crystallizes, on standing oyer sulphuric acid, in small needles. Prolonged heat- 
ing to 100° converts it into the corresponding lactone, C,H,,O,. Its phenylhy- 
drazide crystallizes in brilliant laminze, melting at 200-205°. Sodium amalgam 
causes the lactone to revert to galactose (Berichte, 23, 935.) It yields mucic acid 
on oxidation with nitric acid. /OH 

Rhamnose-carboxylic Acid, C,H,,O, = Fe Ch-OH). CR com ; 


from rhamnose, is homologous with the preceding acids. When its solution is 
evaporated it leaves the /actone, C,H,,0,, a crystalline mass, melting at 162— 
168° (Berichte, 21, 2173). Its phenylhydrazide, C,H,,0,.N,H,.C,H,, forms 
six-sided leaflets, melting about 210° (Berichte 22, 2733). 

When the acid is heated with hydriodic acid and phosphorus it is reduced to 
normal heptylic acid. Sodium amalgam converts the lactone into methylhexose, 
C,H, 40, = C,H, ;(CH;)O, (Berichte 23, 936). 

Glycuronic Acid, C,H,,O, = CHO. (CH.OH),.CO,H, a tetraoxyaldehydic 
acid, is obtained by decomposing euxanthic acid (see this) on boiling with dilute 
sulphuric acid. Various glucoside-like compounds of glycuronic acid with camphor, 
borneol, chloral,'phenol and different other bodies (Berichie, 19, 2919; Ref. 762) 
occur in urine after the introduction of these compounds into the system. Boiling 
acids decompose them into their components. Glycuronic acid is a syrup, which 
rapidly passes into the lactone C,H,O,g on warming. ‘The latter consists of large 
plates, of sweet taste, melting at 169° C. Bromine water oxidizes it to saccharic 
acid. It also appears that when saccharic acid is reduced glycuronic acid results 
(Berichte, 23, 937): 





DIBASIC ACIDS. 


C(OH),.CO,H 
1. Tetra-oxysuccinic Acid, C,H,O, = | , Dioxytartaric Acid. 
C(OH),.CO,H 
This was formerly regarded as carboxytartronic acid, C(OH).(CO,H),. It is 
obtained when protocatechuic acid, pyrocatechin and guaiacol, in ethereal solu- 
tion, are acted upon with N,O,, or from nitro-tartaric acid through the action of 
an alcoholic solution of nitrous acid (Aznalen, 221, 246). The addition of sodium 
carbonate to the aqueous solution separates the sodium salt, C,H,Na,O, + 
2H,O, as a sparingly soluble crystalline powder. When heated with water it 
decomposes into CO, and sodium tartronate,C,H,Na,O,. The free acid, obtained 
from the sodium salt by means of hydrochloric acid and ether, is crystalline. It 
melts with decomposition at 98° (Berich/e, 22, 2015). On reducing the acid with 
zinc and hydrochloric acid, it passes into inactive tartaric acid and racemic acid. 
This deportment is explained by the fact that tetraoxysuccinic acid represents a 
CO.CO,H 
diketonic acid, | » which, like glyoxylic acid and mesoxalic acid, con- 
CO.CO,H : 
tains two molecules of water that may be readily split off. 
Being a diketonic acid dioxytartaric acid combines with 1 and 2 molecules of 
phenylhydrazine, forming, 
CO,H.C(OH), F CO,H.C:N,H.C,H, 
an > 
CO,H.C:N,H.C,H, CO,H.C:N,H.C,H, 


Phenylizine dioxytartaric acid. Diphenylizine dioxytartaric acid, 


492 ORGANIC CHEMISTRY. 


The first melts with decomposition at 218°. The second is an orange yellow 
powder, yielding yellow salts with bases: Concentrated (fuming) sulphuric acid 
converts it into a disulpho-acid, which is also formed by the union of dioxytartaric 
acid with phenylhydrazine-sulphonic acid. . The disodium salt of this acid, 
CO,H.C:N,H.C,H,.SO,Na 

, is an orange yellow powder. As Zartrazine, it is 
CO,H.C:N,H.C,H,.SO,Na 
applied as a yellow dye for wool (Berichte, 20, 834). 


2. Acids, C,H,,O, = C,H,(OH),(CO,H),. 

There are four known isomeric acids of this formula: saccharic, 
mucic, isosaccharic and manno-saccharic acids. All are obtained 
by the oxidation of various carbohydrates with nitric acid, and are 
readily prepared from the corresponding monocarboxylic acids, 
C;H,(OH),.CO,H (p. 488), upon oxidation with chlorine or bromine 
water. Gluconic acid yields saccharic acid, galactonic mucic acid, 
arabinose carboxylic acid, manno-saccharic acid, while the mono- 
carboxylic acid, corresponding to isosaccharic acid, is not known. 
When reduced by HI and phosphorus all four acids are converted 
into normal adipic acid, C,H,(CO,H),; hence all of them must be 
considered as normal tetraoxyadipic acids. ‘They are physical or 
stereochemical isomerides. 

1. Saccharic Acid, C,H,,O,, Acidum saccharicum, like glu- 
conic and mannonic acids, exists in three modifications: dextro-, 
lzvo- and inactive saccharic acid. Ordinary, or @d-saccharic acid, 
results in the oxidation of cane sugar, d-glucose (grape sugar), 
a-gluconic acid, and many other carbohydrates with nitric acid. 


Cane sugar (I part) is heated with common nitric acid (3 parts) until a stormy 
reaction sets in, then cooled and heated anew to 50°, until brown vapors cease 
coming off. The liquid is then diluted with 1% volume of water, saturated with 
potassium carbonate, and an excess of acetic acid added. In the course of a few 
days the primary potassium salt will separate in hard crystals, which may be puri- 
fied by recrystallization from hot water. The free acid is obtained by decomposing 
_the cadmium salt with hydrogen sulphide, or the silver salt with hydrochloric acid 
(Berichte, 21, Ref. 472). 


Ordinary, @-saccharic acid forms a deliquescent, gummy mass, 
readily soluble in alcohol. If the pure, syrupy acid be allowed to 
stand for some time, it changes to its crystalline lactonic acid, 
C,H,O,, that melts at 130-132° (Berichte, 21, Ref. 472). When 
prepared from cane sugar, its solution is levo-rotatory and reduces 
ammoniacal silver solutions. It turns brown at 100° and decom- 
poses. When oxidized with nitric acid, dextro-tartaric acid and 
oxalic acid are formed. Hydriodic acid reduces it to adipic acid. 


It forms acid and neutral salts. The primary potassium salt, C,H,KO,, and 
the ammontym salt, C,H,(NW,)O,, crystallize well and dissolve with difficulty in 
cold water. The neutral alkali salts are deliquescent; thesalts of the heavy metals 


MUCIC ACID. 493 


are insoluble. The die‘hy/ ester, C,H,(OH),(CO,.C,H,),, is crystalline and is 
readily soluble in water. With ammonia it forms the amide, C,H,(OH),(CO.NH,),, 
a white powder. When acetyl chloride acts on the ester we obtain the Zefra-ace- 
tate, C§H,(O.C,H,O),.(CO,-C,H;),, which forms prisms, melting at 61°; insoluble 
in water. Acetyl chloride, acting upon free saccharic acid, converts it into the 
lactone of diacetyl-sacchari¢ acid, C§H,(O.C,H,0),O,, melting at 188°. 

Two molecules of phenylhydrazine and d@-saccharic acid form a diphenylhydra- 
side, C,H,O,(N,H,.C,H,)., that melts at 210° with decomposition (p. 489 and 
Berichte, 21, Ref. 186). 

/-Saccharic acid is obtained upon oxidizing 7. gluconic acid with nitric acid. It 
is quite similar to d-saccharic acid, but is levorotatory. It also forms a dihydra- 
zide, melting at 214°. 

i-Saccharic acid is formed when 7-gluconic acid is oxidized, or by mixing d@-sac- 
charic with /-saccharic acid. It is inactive and forms a dihydrazide, melting at 
210°. 

The monopotassium salts, C,H,O,K (Berichte, 23, 2621), are characteristic _ 
derivatives of the three saccharic acids. 


2. Mucic Acid, C,H,,O,, Acidum mucicum, is obtained in the 
oxidation of dulcitol, milk-sugar, galactose, galactonic acid and 
nearly all the gum varieties. 


Preparation.—Heat 100 grams of lactic acid with 1200 c.c. of nitric acid (sp. 
gr. 1.15), until the volume is reduced to 200 c.c. Cool, and wash the mucic acid 
that is formed with water (Berichie, 227, 224). 


It is a white crystalline powder, soluble in 60 parts of boiling 
water. It is almost insoluble in cold water and alcohol. It melts 
at 210° with decomposition. When boiled for some time with water 
it passes into an isomeric paramucic acid. Boiling nitric acid de- 
composes it into racemic acid and oxalicacid. Hydriodic acid reduces 
it to adipic acid. 


The neutral potassium salt and ammonium salt, C,H,(NH,),Og, crystallize 
well and dissolve with difficulty in cold water; the primary salts dissolve readily. 
The szlver salt, CgH,Ag,O,, is an insoluble precipitate. When heated the neutral 
ammonium salt decomposes into NHg, water and pyrrol, C,H,N 

The diethyl ester, CH,(OH),(CO,.C,H,),, is obtained by heating mucic acid 
and alcohol with sulphuric acid. It is crystalline, is soluble in hot water and melts 
at 158°. Acetyl chloride converts it into the tetra-acetate, which melts at 177°. 
The free acid also forms a tetra-acetyl compound (Berich/e, 21, Ref. 186). 


The ready conversion of mucic acid into furfurane derivatives 
is rather remarkable. Digestion with fuming hydrochloric or 
hydrobromic acid changes it to furfurane dicarboxylic acid 
(dehydromucic acid) :— 

CO,H 
CH(OH).CH(OH).CO,H CH = C”% 
= > 0 + 3H,0. 
CH(OH).CH(OH).CO,H CH=C 

\co,H 


494 ORGANIC CHEMISTRY. 


- When mucic acid is heated alone it splits off carbon dioxide and 
becomes furfane monocarboxylic acid (pyromucic acid) :— 


C,H,(OH),(CO,H), = C,H,0.CO,H + 3H,O + CO,. 


Heated with barium sulphide it passes in like manner into a-thio- 
phene carboxylic acid (Berichte, 18, 456). 


3. Isosaccharic Acid, C,H,,O, (see above), results from HCl-glucosamine 
(p. 505) upon oxidizing it with nitric acid (Berichte, 19, 1258). It is very soluble 
in water and alcohol, forms rhombic crystals and melts at 185°. Its solution is 
dextrorotatory; (a), == 46.1°. Its diethyl ester, CSH,O,(C,H,)., melts at 73°. 
Acetyl chloride converts the ester into the tetra-acetyl compound, C,H,(O.C,H,0O),. 
(CO,.C,H;)., melting at 47°. Hydriodic acid reduces isosaccharic acid to norma! 
adipic acid (see above). 

Like mucic acid it yields furfane derivatives. It breaks up into water, carbon 
dioxide and pyromucic acid when distilled. Dehydromucic acid is formed on 
heating isosaccharic acid in a current of hydrogen chloride. Pyromucic acid and 
a-thiophene carboxylic acid are produced when the iso-acid is heated with barium 
sulphide. When its die/hy/ ester is heated with alcoholic ammonia axhydro- 
diamide, C,11,0.(OH),.(CO.NH,),, is produced; this by distillation yields pyro- 
mucamide, C,H,0.CO.NH, (Berichte, 19, 1277). 

4. Metasaccharic Acid, C,H,,O,, /-mannosaccharic acid, is produced by 
oxidizing arabinose carboxylic acid with nitric acid (Berichte 20, 2710; 23, 2131). 
On evaporating the solution, its double lactone, CEO, + 2H,O, crystallizes. It 
has a neutral reaction, and on standing over sulphuric acid loses two molecules of 
water. When air-dried it melts at 68°,and when anhydrous, at 180°, Hydri- 
odic acid reduces it to adipic acid. Sodium amalgam converts it into mannite, 
CgH,,0g (Berichte, 22, 2204). 

The diphenylhydrazide of metasaccharic acid, C,H,(OH),.(CO.N,H,.C,H;,),, is 
produced on heating the double lactone with phenylhydrazide and sodium acetate. 
It melts at 213°. Concentrated sulphuric acid and ferric chloride color it red 
(p. 489). Acetic anhydride converts the double lactone into the diacetyl deriva- 
tive, CsH,O,(C,H,O),, melting at 155° ( Berichze, 21, 1422; 22, 524). 

Butane Hexacarboxylic Acid, C,,H,,O,,. = C,H,(CO,H)g, is a hexabasic 
acid. Its hexa-ethyl ester is formed by the action of iodine upon the sodium com- 
pound of ethenyl tricarboxylic ester (p. 471). It forms hexagonal plates, which 
melt at 56° (Berichte, 17, 2786). 


HEPTAVALENT (HEPTAHYDRIC) COMPOUNDS. 


Perseite, C,H,,O, = C,H,(OH),, is an heptahydric alcohol. It is found in 
the leaves and seeds of Laurus persea. It is artificially prepared by reducing its 
aldehyde mannoheptose, C,H,,O, (p. 507), with sodium amalgam ( Berich/e, 23, 
935). It crystallizes in needles, melting at 184°. At 250° it parts with water, 
and forms a compound resembling mannitan. It does not reduce Fehling’s solu- 
tion, and is not fermented by yeast. Nitric acid reoxidizes it to mannoheptose, 


The heptahydric aldehydes, C,H,,O,, resemble the sugars in 
their behavior. They will be discussed with them under the desig- 
nation of hepioses (p. 507). 


GLUCOSE-CARBOXYLIC ACID. 495 


The heptahydric monocarboxylic acids, C,H,O,, are obtained 
synthetically from the hexaglucoses or hexoses, C,H,,0,, by the 
action of hydrocyanic acid, and the subsequent transformation 
of the oxycyanides first formed (Kiliani, Berichte, 19, 767 ; 21, 915. 
E. Fischer, Berichte, 22,'370) :— 


: ; OH 
CH,(OH)(CH.OH),.CHO yield CH,(OH)(CH.OH),.CHE GG, yy 
Glucoses, Galactoses, Mannoses. Glucose-, Galactose-, and Mannose- 
Carboxylic Acid. 
: /CH,OH 
CH,(OH)(CH.OH),.CO.CH, OH yields CH,(OH)(CH.OH),.C(OH)< € "4 
Fructose. Fructose-Carboxylic Acid. . 


Glucose-, galactose-, and mannose-carboxylic acids have the. 
same constitutional formulas, They also yield normal heptylic 
acid, C,H,;.CO,H, when reduced with hydriodic acid and phos- 
phorus. Therefore, they are either to be considered as physical 
or stereochemical isomerides. 


Like other carboxylic acids, all of these acids combine with phenylhydrazine to 
form phenylhydrazides, C,H, ,0,.N,H,.C,H,, which are distinguished from the 
phenylhydrazones by the violet coloration they give when acted upon with sul- 
phuric acid and ferric chloride (Berichte, 22, 2728). 


Sodium amalgam reduces these acids (their lactones) to the corres- 
ponding aldehydes or aldoses, C,;H,,O, (this is similar to the reduc- 
tion of the pentaoxy-monocarboxylic acids to the hexoses, C,H,,0,, 


p- 489) :— 
CH,(OH).(CH.OH),.CO,H yields CH,(OH)(CH.OH),.CHO. 


These are the higher synthetic varieties of sugar—the hef/oses. 
From the latter, it is possible, by similar reactions, to obtain the 
heptocarboxylic acids and the ocfoses, corresponding to them (E. 
Fischer, Berichte, 22, 22043; 23, 930). 


Glucose-carboxylic Acid, C,H,,O,, hexaoxyheptylic acid, is obtained from 

dextrose (grape sugar) by means of CNH, etc. The lactone, C,H,,O,, crystallizes 
from the concentrated solution. This is a neutral substance, that dissolves readily 
in water. It softens about 145°. Hydriodic acid and phosphorus reduce it to 
heptolactone, C,H, ,O,, and normal heptylic acid. Sodium amalgam reduces the 
lactone to dextroheptose (glucoheptose) (p. 507) (Berichte, 23, 936). The phenyl- 
_ hydrazide of dextrose-carboxylic acid melts at 171°. Pentaoxypimelic acid (p. 496) 
_ is formed when dextrose-carboxylic acid is oxidized with nitric acid. 
_ d@-Mannose-carboxylic Acid, C,H,,O,, from ordinary ¢-mannose (p. 503), 
_ separates from concentrated solutions as a /actone, C,H,,O,, in warty crystals. It 
_ is very soluble in water, has a neutral reaction, and melts at 148-150°. Hydriodic 
_ acid and phosphorus reduce the acid to heptolactone and heptylic acid (see above 
and Berichte, 22, 370). Its phenylhydrazide (see above) melts about 220° with 
decomposition. Sodium amalgam reduces the lactone to mannoheptose, C,H,,O,, 
and then to the heptahydric alcohol perseite, C,H,gO, ( Berichte, 23, 936, 2226). 


496. ORGANIC CHEMISTRY. 


Galactose-carboxylic Acid, C,H,,O,, from galactose, crystallizes in minute 
hydrous needles. It has an acid reaction. After the acid has been dried over 
sulphuric acid it melts at 145°, and passes into its /acfone ; this is also producec! 
on heating the solution. It consists of needles, melting at 150°. Sodium amal. 
gam changes it into galaheptose, C,H,,O,. 

Fructose-carboxylic Acid, C,H,,O,, is obtained from lzevulose by the action 
of hydrocyanic and hydrochloric acids (Berichte, 19, 222). When oxalic acid 
acts upon its calcium salt, it liberates a mixture of the acid and its lactone, C,H,,0,. 
Reduction with hydriodic acid forms heptolactone and heptylic acid, C,H,,0,. 
The latter is identical with methyl-normal butyl acetic acid (p. 230). Hence it is 
evident that /evulose is a ketone-alcohol 





: ; CO,H 
Pentaoxy-dicarboxylic Acids, C,H, (OH), CoH 

Pentaoxy-pimelic Acid, C,H, .Og, is produced in the oxidation or dextrose- 
carboxylic acid with nitric acid, The /acéone is crystalline, and melts at 143° 
( Berichte, 19, 1917). 

Carboxy-galactonic Acid, C,H,.,Og, is formed in the oxidation of galactose- 
carboxylic acid with nitric acid. It dissolves with difficulty in water, crystallizes 
in plates, and melts at 171° with decomposition (Berichte, 22, 523). Aldehyde- 


galactonic Acid, C,H,,0, = C,H (OH) : nga is a transition product in 
2 


the formation of the preceding acid. Itis an analogue of glycuronic acid (p. 491) 
(Berichte, 22, 1385). 

Butane-heptacarboxylic Acid, C,H,(CO,H),, is a heptacarboxylic acid, 
formed by the action of chlormalonic ester, CHC] (CO, R),, upon sodium propeny!- 
pentacarboxylic ester (p. 486). It boils at 280-285° under a pressure of 130 mm. 

Higher polycarboxylic esters have been prepared in an analogous manner (Se- 
richte, 21, 2113) :— 

Hexane decacarboxylic Ester, C,H,(CO,R), , is produced by the action 
of chlor-propenyl-pentacarboxylic ester (p. 486) upon sodium-propenyl-pentacar- 
boxylic ester. It is a yellow oil. 

Octan-tesserakaideca-carboxylic Acid, C,H,(CO,R),,, is the highest 
_ polycarboxylic acid that has been prepared. It is obtained from sodium butane- 
heptacarboxylic ester and chlorbutane-heptacarboxylic ester. It is a thick oil 
(Berichte, 21, 2113). 


OCTO- AND NONO-HYDRIC COMPOUNDS. 


@-Manno octite, C,H,,O,, is an octohydric alcohol. It is produced when 
@-mannoctose is reduced with’sodium amalgam. It dissolves with difficulty in water, 
crystallizes in small plates, melts at 258°, and sublimes without decomposition. 
Its aldehyde is described on p. 507 as manno-octose. 

d-Manno-octonic Acid, C,H, ,0,, has been obtained as a syrup by the action 
of CNH, etc, upon d-mannoheptose, C,H,,0,. Its hydrazide, C,H,,O,.N,H,,. 
C,H,, is crystalline, and melts at 243°. The /actone, C,H,,0O,, has a neutral 
reaction, a sweet taste, and melts about 168°. By reduction it forms ¢-mannoctose 
(Berichte, 23, 2234). 

a@-Mannononite, C,H, ,QO4, is a nono-hydric alcohol. It may be prepared by 
reducing its aldehyde, mzannononose, C,H, ,O, (p. 507) with sodium amalgam. 

d-Manno-nononic Acid, C,H,,0, , has been obtained from manno-octose, 


GLUCOSES. 497 


C,H,,O,, by means of CNH, etc. Its hydrazide, C,H,,O,.N,H,.C,H,, dis- 
solves with difficulty, and melts about 254°. Its /actone, CgH,,Og, forms minute | 
needles, melting at 176°. When reduced it forms ¢ manno-nonose, C,H,,O, 
(p. 507) (Berichte, 23, 2236). 


‘CARBOHYDRATES. 


This term is applied to a large class of compounds, widely dis- 
tributed in nature. They contain six, or a multiple of six carbon 
atoms. The ratio of their hydrogen and oxygen atoms is the same 
as that of these elements in water. ‘The carbohydrates may be ar- 
ranged into three groups: the glucoses, C,H,,.O,, grape sugar and 
fruit sugar; the sugars, C,,H,.,O,, or disaccharides, as cane sugar, 
and the polysaccharides (Cg,H,Q;),, as starch and dextrine. The 
glucoses were discovered to be the aldehyde- or ketone-detivatives 
of the hexahydric alcohols (chiefly through the investigations of 
Kiliani (1885) upon the hydrogen cyanide addition- products), into. 
which they might be converted by the absorption of two hydrogen 
atoms. Consequently, they could be produced by the oxidation of 
the alcohols. ‘The di- and polysaccharides proved to be ethereal 
anhydrides of the glucoses (similar to polyglycols, p. 304); inasmuch 
as all of them could be converted into the glucoses by hydrolytic 
decomposition.. ‘The more recent and widely extended researches 
. of E. Fischer have amplified these views quite considerably, and in 
many cases modified them very materially (Berichte, 23, 2114). 
The glucose character of a compound is very much affected by its 
constitution, as aldehyde alcohol—CH(OH).CHO, or ketone 
alcohol—CO.CH,.OH, and we thus have glucoses containing not 
only szx, but even a less or greater number of carbon and oxygen 
atoms. According to the number of the oxygen atoms, they are 
known as fentoses, hexoses, heptoses, octoses, etc. It is also obvious 
that only those compounds contain twice as many hydrogen atoms 
as oxygen atoms in which the number of oxygen and carbon atoms 
is equal, z. ¢., those in which the valence corresponds to the number 
of carbon atoms—as the pentoses, C;H,O;, and hexoses, C,H,,O,, 
whereas rhamnose (methyl pentose) has the formula C,H,,O,;, and 
methyl hexose, the formula C,;H,,O,. 


1. GLUCOSES (MONOSES). 


The glycoses, or glucoses, are mostly crystalline substances, very 
soluble in water, but dissolving with difficulty in alcohol. They 
possessa sweet taste. Their reducing power distinguishes them from 
other sweet-tasting, polyhydric alcohols, e g., glycerol, erythrol and 
mannitol, This is in accord with their aldehyde or ketone charac- 
ter. The aldehyde alcohols, containing the atomic group—CH(OH). 


42 


498 ~ ORGANIC CHEMISTRY. 


CHO, are also known as aldoses, while the ketone alcohols—CO. 
CH,.OH, have been called efoses. The reducing properties of the 
latter correspond to those of acetyl carbinol, and the analogous 
a-ketols (p. 321). 


(1) Glycerose, C,H,O,, Triose, derived from glycerol, may be considered the 
lowest glucose. It consists of a mixture of glycerol aldehyde and dioxy-acetone, 
CH,(OH) CO.CH,(OH) (p. 454). 

(2) Erythrose, C,H,O,, Tetrose, from erythrol, probably represents a mixture 
of an aldose and a ketose. 

(3) Pentoses; Arabinose and Xylose, C,H,,O;, and. Rhamnose, 
C,H,,0,, methyl arabinose, belong to this class. They are aldoses or aldehyde 
derivatives of pentahycric alcohols, with which they are more fully discussed 
(p. 483). They manifest the general character of hexoses, in that they reduce 
Fehling’s solution, yield osazones with phenylhydrazine, but cannot be fermented. 
They readily pass into furfurol when distilled with sulphuric and hydrochloric 
acids (Berichie, 23, 1751). 


(4) Hexoses. These are the aldehyde or ketone derivatives of 
the hexahydric alcohols. Mannose, glucose and galactose are alde- 
hyde derivatives. Fructose and probably sorbinose are ketoses. 
These compounds correspond to the formulas :— 


CH,(OH)(CH.OH),CHO and CH,(OH).(CH.OH),.CO.CH, (OH). 


Glucose, Mannose, Galactose. ructose, Sorbinose. 


This is evident from the conversion of the glucoses, by means 
of CNH, etc., into the corresponding hexa-oxy-carboxylic acids, 
and also by the reduction to heptylie acids. The first three yield 
normal heptylic acids, while fructose is converted into methyl- 
butyl acetic acid (pp. 495, 496). Bromine water, even in the cold, 
oxidizes the aldoses to their corresponding monocarboxylic acids 
(p. 489), whereas the ketoses (fructose and sorbinose) are not 
attacked (Berichte, 23, 2116). 

Mannose, glucose, and galactose have the same structural formula, 
and are therefore (like the hexahydric alcohols, p. 486) alloisomeric 
or stereo-isomeric compounds. Mannose and fructose are derived 
from mannitol; galactose is the aldose of dulcitol, while glucose 
(grape sugar) probably corresponds to sorbite (p. 488). Further, 
mannose, glucose, and fructose, in accordance with the hypothesis 
of asymmetric carbon atoms (like mannitol, p. 487) exist in three 
optically different modifications—the dextro-, the levo- and inactive 
forms. 


In some reactions the glucoses behave differently from the aldelrydes. Thus, 
they do not oxidize on exposure to the air, and do not react with fuchsine-sulphu- 
rous acid (p. 189). The penta-acetyl- and penta-benzoyl derivatives of dextrose 
and galactose do not manifest an aldehyde character (Berichte, 21, 2842; 22, 
Ref. 669). It has therefore been assumed that the hexoses possess a constitution 
similar to ethylene oxide or the lactones (Berichte, 22, 2211). However, it is 


HEXOSES. : 499 


hardly probable that this assumption is correct (Berich/e, 21, 2841; 22, 2212; 
23, 2117). 


The hexoses occur frequently in plants, especially in ripe fruits. 
‘They are formed by the hydrolytic decomposition of all di- and 
poly-saccharides when they are boiled with dilute acids, or by 
ferments (p. 507). Mannose and fructose have been made artifi- 
cially by oxidizing mannite. A more common method pursued in 
the formation of the glucoses is to reduce the monocarboxylic 
acids (their lactones) with sodium amalgam in acid solution (Be- 
richte, 23, 930). Different hexoses have been directly synthesized 
by the condensation of formic aldehyde, CH,O, acrolein, C;H,O, 
and glyceric aldehyde, C,H,O; :— 


6CH,O = C,H,,0, 2C,H,O, = CgH,.0,. 
Formic Formose, Glyceric Acrose. 
Aldehyde. Aldehyde. 


E. Fischer (1890) effected the complete synthesis of grape sugar 
and fruit sugar by these methods. | 


Methylenitan was the first compound, resembling the sugars, that was pre- 
pared. Butlerow (1861) obtained it by condensing trioxymethylene (p. 192) with 
lime water. O. Loew (1885) obtained formose ( Jour. pr. Chemie, 33, 321) in an 


analogous manner from oxymethylene, and somewhat later the fermentable — 


methose, by the use of magnesia (Berichte, 22, 470, 478). E. WKischer considers 
these three compounds mixtures of different glucoses, among which a-acrose 
occurs (Berichte, 22, 360). The latter (together with §-acrose) is obtained by. 
the action of barium hydroxide upon acrolein bromide, C,H,OBr,. This is © 
probably because the glyceric aldehyde in it condenses (Berich/e, 23, 389, 2131). | 
By reduction with sodium amalgam a-acrose (identical with inactive fructose) 
passes into a-acrite, identical with inactive mannitol (p. 487). When the latter is 
oxidized it yields z-mannonic acid, which can be resolved into ¢d- and / mannonic 
acid (p. 490). By reduction these acids are converted into d- and /-mannose. 
d-Mannose is changed through its osazone into d-fructose, 7. ¢., fruit sugar (p. 505) 
(E. Fischer, Berichte, 23, 373). ¢-Mannonic acid is converted into ¢-gluconic acid 
when heated, and by reduction with sodium amalgam the latter becomes @-glucose, 
t.é., grape sugar (Berichte, 23, 799). 


The hexoses show the ordinary aldehyde reactions :— 

(1) By reduction they become hexahydric alcohols. Mannose 
and fructose yield mannitol, galactose yields dulcitol, and sorbite 
seems to result from the reduction of glucose (grape sugar). 

(2) The oxidation of the hexoses does not occur directly upon 
exposure to the air. Oxidizing agents are necessary. Hence they 
show feeble reducing power. They precipitate the noble metals 
from solutions of their salts, and even reduce ammoniacal silver 
solutions in the cold. A very marked characteristic is their 
ability to precipitate cuprous oxide from warm alkaline cupric 
solutions (this is accelerated by tartaric acid). One molecule of — 
hexose precipitates about five atoms of copper, as Cu,O. This is 


500 ORGANIC CHEMISTRY. 


the basis of the volumetric method for the estimation of the glu- 
coses by means of Fehling’s solution. Maltose and milk sugar, of 
the di- and polysaccharides, only act directly upon the application 
of heat. The others must be first converted into glucoses (p. 508). 


To prepare Fehling’s solution, dissolve 34.65 grams of crystallized copper 
sulphate in water, then add 200 grams Rochelle salt and 600 ccm of NaOH 
(sp. gr. 1.1200), and dilute the solution to 1 litre. 0.05 gram hexose is required 
to completely reduce 10 c.c. of this liquid. The end reaction is rather difficult to 
recognize, hence it is frequently recommended to estimate the separated cuprous 
oxide gravimetrically (Berichte, 13, 826; Jour. pr. Chem., 21, 524). Consult 
Berichte, 23, 1035 for Soldaini’s suggestion of using a copper carbonate solution 
for the estimation of the hexoses. 


The hexoses are converted into their corresponding mono- 
carboxylic acids (p. 488) by moderated oxidation with chlorine 
and bromine water, or silver oxide. More energetic oxidation 
changes them to saccharic and mucic acids. Milk sugar yields 
both acids at the same time. When boiled with dilute hydrochloric 
or sulphuric acid the hexoses, and apparently all the carbohydrates, 
sustain a gradual oxidation, the product being levulinic acid, 
C;H;O; (p.-343) (Berichte, 21, 230). 


When the glucoses are heated with dilute alkalies they turn brown, and pass 
into humus-like compounds. Saccharinic acids are produced when they are 
boiled with lime. The hexoses form tartaric acid chiefly when they reduce an 
alkaline copper solution. 

In many reactions, for example, when heated alone or with sulphuric acid, we 
find that nearly all the carbohydrates yield traces of furfurol. This may be 
detected by the red coloration it yields with aniline (Berichte, 20, 541). The 
reaction of Molisch, for the detection of carbohydrates by means of a naphthol 
and sulphuric acid (production of deep violet colors), is due to this compound 
(Berichte, 19, Ref. 746; 20, Ref. 517; 21, 2744). 


(3) Being aldehydes or ketones the glucoses unite with hydro- 
cyanic acid to form cyanhydrins. These yield the monocarboxylic 
acids. ‘They combine with H,N.OH to form oximes. Only those 
of galactose and mannose have been isolated (Berichte, 20, 2673). 

(4) The phenylhydrazine derivatives are especially interesting 
(pp. 191, 326). If one molecule of the phenylhydrazine (acetate) 
is allowed to act the first product will be a hydrazone, C,H1,0;. 
(N.NH.C,H;). This class of compounds dissolves readily in water 
(with the exception of those derived from the mannoses and the 
higher glucoses, Berichte, 23, 2118). They generally crystallize 
from hot alcohol in colorless needles. Cold concentrated hydro- 
chloric acid resolves them into their components. ; 

Diphenylhydrazine, H,N.N(C,H;)., often produces dipheny- 
hydrazones, C,H,,.0;:N.(C,H;). (Berichte, 23, 2619), that dissolve 
with difficulty. 


HEXOSES. 501 


In the presence of an excess of phenylhydrazine the hexoses, 
like all glucoses, combine with two molecules of it upon applica- 
tion of heat and form the osazones (E. Fischer) :— 


C,H,.,0, -+- 2H,N.NH.C{H, = C,H,,0,(N.NH.C,H,), + 2H,O + H,. 


Glucosazone.. 


The reaction is carried out by adding two parts of phenylhydrazine, two parts of 
50% acetic acid, and about twenty parts of water to one part of glucose. This 
mixture is digested for about one hour upon the water bath. ‘The osazone then 
separates in a crystalline form (Berichte, 17, 579; 20, 822; 23, 2117). In_ this 
reaction a hydrazone is first produced, and one of its alcohol groups, adjacent to 
either an aldehyde or ketone group, is oxidized to CO (inasmuch as two hydrogen 
atoms in the presence of phenylhydrazine produce aniline and ammonia), which 
then acts further upon a second molecule of phenylhydrazine. The same g/ucosa- 
, zone, CH,(OH).(CH.OH),.C(N,H.C,H;).CH(N,H.C,H,) (see Berichie, 23, 
2118), is thus obtained from mannose, glucose and fructose. 

The osazones are yellow colored compounds (see tartrazine, p. 492). They are 
usually insoluble in water, dissolve with difficulty in alcohol, and crystallize quite 
readily. When glucosazone is reduced with zinc dust and acetic acid it becomes 
isoglucosamine (p. 505). Nitrous acid converts the latter into fructose (Berichte, 
23, 2110). The reformation of the hexoses from their osazones is readily effected 
by digestion with concentrated hydrochloric acid; they are then resolved into 
phenylhydrazine and the osones (Berichte, 22, 88; 23, 2120) :— 


C,H, ,0,(N,H.C,H,), + 2H,0 = 
Glucosazone. 


CH,(OH).(CH.OH),.CO.COH + 2N,H,.C,H;. 


Glucosone. 


The osones dissolve readily in water, and have not been obtained free. They — 
combine, like ketone-aldehydes, with two molecules of phenylhydrazine and form 
an osazone (p. 326). They are converted into glucoses by reduction (when 
digested with zinc dust and acetic acid), In this way fruit-sugar is prepared from 
glucosazone (Berichte, 23, 2121). 

The osones yield quinoxalines with the orthodiamines. The glucoses also com- 
bine directly with the ortho-phenylenediamines (Berichte, 20, 281), 


The alcoholic character of the hexoses is made manifest in the 
following reactions :— 

1. The hydrogen of the hydroxyls can be readily replaced by 
acid radicals. ‘The mixture of nitric and sulphuric acids (p. 454) 
converts them into esters of nitric acid—the nitro compounds 
(p. 514). The acetyl esters are best obtained by heating them 
with acetic anhydride and sodium acetate (or ZnCl,). Five acetyl 
groups are thus introduced (Berichte, 22, 2207). The benzoyl 
esters are prepared with even less difficulty, it being only necessary 
to shake the hexoses with benzoyl chloride and caustic soda (p. 299). 
Pentabenzoyl derivatives are then formed (Berichte, 22, Ref. 
668). 


An elementary analysis will not yield a positive conclusion as to the number of 
acidyls that have entered compounds like those just mentioned. This is ascer- 


502 ORGANIC CHEMISTRY. 


tained by first saponifying them with titrated alkali solutions, or better, with mag- 
nesia (Berich/e, 12, 1531). Or, the acetic esters are decomposed by boiling them 
with dilute sulphuric acid. The acetic acid that distils over is then titrated (47- 
nalen, 220, 217; Berichte, 23,1442). The presence of hydroxy] in the glucoses 
may also be proved by means of phenylisocyanate, with which they form carbani- 
lic esters (Berichte, 18, 2606). 


Alkyl-sulphuric acids result upon treating the glucoses with 
chlorosulphonic acid, CIHSO;. ‘This is similar to the bebavior of 
alcohols when exposed to like treatment (Berichte, 17, 2457). 
Anilides of the glucoses are formed when the latter are digested 
with the anilines. This is due to the replacement of a hydroxyl 
group (Berichte, 21, Ref. 399). 

The esters of .sugars with organic acids do occur abundantly in 
plants and are termed g/ucosides. ‘Thus, the tannins are glucosides 
of aromatic acids. All glucosides yield their components, when 
heated with acids or alkalies, or through the action of ferments. 

The alcoholic hydrogen of the glucoses can also be replaced by 
bases, like CaO, BaO, and PbO, forming saccharazes, which corres- 
pond to the alcoholates, and which are again decomposed by car- 
bon dioxide. 

The hexoses can be made to undergo fermentation quite readily 
when exposed to schizomycetes. They sustain various decompo- 
sitions. ‘The alcoholic fermentation is especially important. It is 
induced by yeast cells. 


Alcoholic Fermentation.—This is induced by yeast, which is composed of micro- 
scopic (0.01 mm.) cells of Saccharomyces cerevisig and vint, which multiply during 
fermentation by budding. Alcoholic fermentation occurs at temperatures varying 
from 3—35° and is most rapid from 20-30°. Oxygen is requisite at the commence- 
ment, but it afterwards proceeds without air access. The thexoses mainly decom- 
_ pose, during fermentation, into alcohol and carbon dioxide: CgH,,.O, = 2C,H,O 
+ 2CO,. Glycerol (as much as 2.5 per cent.), succinic acid (0.6 per cent.), and 
fusel oils are formed simultaneously. The hexoses ferment directly; grape sugar 
somewhat more rapidly than fruit sugar. The disaccharates, C,,H,.O,,, are first 
decomposed by the soluble ferment of the yeast into hexoses; hence their fermen- 
tation proceeds very slowly and demands more yeast. 

Other budding fungi, like AfZucor mucedo, cause alcoholic fermentation. The 
fermentation phenomena occasioned by schizomycetes are exceedingly interesting. 
It is evident that the production of fusel oils in ordinary yeast fermentation (butyl 
and amyl alcohol) is due to these. 

Alcoholic fermentation can occur unaccompanied by organisms in unimpaired, 
ripe fruits (grapes, cherries), providing the latter are exposed to an atmosphere of 
carbon dioxide. : 

In the Zactic actd fermentation, the hexoses, milk sugar and gums decompose 
directly into lactic acid :— 
CgH,,0¢ — 2C,H,0. 


_ The active agents are little, wand-like organisms (bacteria and micrococci). 
Decaying albuminous matter (decaying cheese) is requisite for their development, 
and it only proceeds in liquids which are not too acid (p. 357). The temperature 


GLUCOSE. 503 


most favorable varies from 30-50°. By prolonged fermentation the lactates suffer 
butyric fermentation ; this is owing to the appearance of other bacilli (p. 226): 
2C,H,O, = C,H,O, + 2CO, + 2H,. - 

In mucous fermentation chain-like cells (of 0.001 mm. diameter) appear. These 
convert grape sugar, with evelution of carbon dioxide, into a mucous, gummy sub- 
stance; mannitol and lactic acid are formed at the same time. 


Almost all the naturally occurring carbohydrates are optically 
active, as their solutions deviate the plane of polarization. Their 
specific rotatory power (p. 62) is not only governed by tem- 
perature and the concentration of their solutions, but is also very 
frequently influenced by the presence of inactive substances 
(Berichte, 21, 2586 and 2599). Further, some substances show the 
phenomena of bi-rotation and semi-rotation. Brief heating of their 
solutions will usually bring about a recurrence of constant rotation. 
The determination of the rotatory power of the carbohydrates by 
means of the saccharimeter serves to ascertain their purity and is 
frequently applied in estimating their percentage content—ofiical 
sugar test. 

1. Mannose, C,H,.0,, is the aldehyde of mannitol. Like the 
latter, it exists in three forms (p. 487): dextro-, levo- and inactive 
mannose. 


d-Mannose was first prepared by oxidizing ordinary ¢d-mannitol (together with 
a fructose) with platinum black or nitric acid (Berichte, 22, 365). It is also ob- 
tained from salep mucus (Annalen, 249, 251; Berichte, 21, 2150), and most easily 
from seminine (reserve-cellulose), occurring in different plant seeds, when this is 
boiled with dilute sulphuric acid (hence called semznose) (Berichte, 22, 609, 3218). 
a@-Mannonic acid yields it upon reduction. It is an amorphous mass, very soluble 
in water, and dextro-rotatory. It reduces Fehling’s solution, and is fermented by 
yeast ( Berichte, 22, 3224). Its hydrazone dissolves with difficulty in water, and 
forms brilliant leaflets, that melt at 195°. Its osazone, C,H,,0,(N,H.C,H,),, 
is identical with d-glucosazone. Nascent hydrogen converts it into. d-mannitol. 
Bromine oxidizes it to d-mannonic acid. Hydrocyanic acid. causes it to pass into 
d-mannoheptonic acid (p. 495). 

/-Mannose results when /-mannonic acid is reduced (p. 490, Berichte, 23, 
373). Itis very similar to the preceding compound, but is levo-rotatory, and is 
fermented with more difficulty. Its Aydrazone also dissolves with difficulty, and 
melts at 195°. It unites with two molecules of phenylhydrazine to form / gluco- 
sazone (see below). It becomes /-mannitol by reduction. 

?-Mannose is formed by the reduction of inactive mannonic acid. It is quite 
similar to the two preceding compounds, but is inactive. Its Aydrazone dissolves 
with difficulty, melts at 195°, and is inactive. Its osazone is z-gluccsazone. Yeast 
decomposes it, the d-mannose is fermented, and /-mannose remains (Berichte, 23, 


382). 


2. Glucose, C,H,,0,, is probably the aldehyde of sorbite, and 
occurs as dextro- levo- and inactive glucose (p. 498). 

d-Glucose, or Grape Sugar, formerly called dextrose, occurs 
(always with fruit sugar) in many sweet fruits and in honey ; also 


Rod ORGANIC CHEMISTRY. 

in the urine in Diabetes mellitus. It is formed -by the hydrolytic 
decomposition of poly-saccharides (cane sugar, starch, cellulose) 
and glucosides. - It is prepared on a large scale by boiling starch 
with dilute sulphuric acid (see Berichte, 13, 1761). The synthests 
of grape sugar has been made possible by the production of glucose 
im the reduction of d-gluconic actd (p. 499). 


Commercial grape sugar is an amorphous, compact mass, containing only about 
60 per cent. glucose, along with a dextrine-like substance (gallesine, C,,H,,O,,), 
which is not fermentable (Berich/e, 17, 2456). Pure grape sugar, with one mole- 
cule of water, can be prepared from this, by crystallization from alcohol. 

The best method for preparing pure crystallized grape sugar consists in adding 
to 80 per cent. alcohol, mixed with ;. volume fuming hydrochloric acid, finely 
pulverized cane sugar, as long as the latter dissolves on shaking (/vurn. prakt. 
Cheit,, 20, 244). 


Grape sugar crystallizes from water at the ordinary temperature, 
or dilute alcohol, with one molecule of water, in nodular masses, 
melting at 86°; at 110° it loses its water of crystallization. At 
30-35° it crystallizes from its concentrated aqueous solution, and 
from its solution in ethyl or methyl alcohol, in anhydrous, hard 
crusts, melting at 146° (Berichte, 15,1105). 

Grape sugar is not quite so sweet to the taste as cane sugar, and 
serves to doctor wines. 


Aqueous grape sugar is dextro-rotatory [a], = 52.6°, and exhibits 42-ro/atory 
_ power, z. ¢., the freshly prepared solution deviates the polarized ray almost twice 
as strongly as it does after standing some time. At ordinary temperatures the 
deviation does not become constant unul the expiration of twenty-four hours, 
whereas when boiled it does so in the course of a few minutes. Furthermore, the 
specific rotation of dextrose is appreciably augmented by concentration (Berichie, 
17, 2234). This is dependent upon the decomposition of more complex crystal- 
molecules into normal molecules. This has been proved by determining the mole- 
cular weight by the method of Raoult ( Berich/e, 21, Ref 505). 

With baryta and lime grape sugar forms saccharates, like C,H,,0,.CaO, and 
C,H,,0,.BaO. These are precipitated by alcohol. With NaCl it forms larze 
crystals, 2C,H,,0,.NaCl + H,O, which sometimes separate in the evaporation 
of diabetic urine. 

When grape sugar and acetyl chloride are heated, so-called aceto-chlorhydrose, 


GH;O { (Oc, H,0)/ results, This has been used in the synthesis of the disac- 


charates. 


Grape sugar exhibits all the properties of the aldoses (p. 498). 
Its phenylhydrazone is very soluble and melts at 145°.* 

a-Glucosazone, its osazone, consists of yellow needles, melting 
at 204-205° to a red liquid. Its aqueous solution is levo-rotatory. 





* Skraup (Berichte, 22, Ref. 669) maintains that grape sugar forms two hydra- 
zones with phenylhydrazine, the one melting at 143°, and the other at 116°. 


FRUIT SUGAR. 505 
It may also be prepared from ¢@-mannose and @-fructose, as well as from 
glucosamine and isoglucosamine. Invert sugar is best adapted for 
the preparation of d-glucosazone (see below, Berichte, 19, 1921). 
Concentrated hydrochloric acid converts @-glucosazone into phenyl- 
hydrazine and glucosone, CsHyO., (p. 501); which regenerates 
a-glucosazone with two molecules of phenylhydrazine. It is a non- 
fermentable liquid, and if it be reduced with zinc and acetic anhy- 
dride, is converted into fruit sugar (= d@-fructose) (Berichte, 22, 88). 


The following are derivatives of grape sugar :— 

Isoglucosamine, C,H,,NO, = CH,(OH)(CH.OH),.CO.CH,.NH,, is 
formed by reducing glucosazone with zinc dust and acetic acid. It reduces alka- 
line copper solutions, combines with phenylhydrazine to reform @ glucosazone and 
is converted by nitrous acid into fruit sugar (Berichte, 23, 2120). 

Glucosamine, C,H,,NO,, is produced on warming chitine (found in lobster 
shells) with concentrated HCl ( Berichte,17, 243). Free glucosamine separates from 
alcohol in needles. Nitric acid oxidizes it to isosaccharic acid. It forms glucosa- 
zone with phenylhydrazine. 

/-Glucose,C,H,.O,, is formed when the lactone of /-gluconic acid (p. 490) is 
reduced with sodium amalgam. It is perfectly similar to grape sugar. It melts at 
143°, but is levo-rotatory, [e], == —51.4°. Its glucosazone is, however, dextro- 
rotatory. Its diphenylhydrazone, C,H, .O;:N.N(C,H;)., dissolves with difficulty, 
and melts at 163° (Berichte, 23, 2618). 

i-Glucose, C,H,,0,, results from the union of @- and /-glucose, and by the 
reduction of 7- gluconic lactone. Phenylhydrazine converts it into 7-g/ucosazone, 
C,H,,0;(N,H.C,H,),. This may also be obtained from 7-mannose. It crys- 
tallizes in yellow needles, melting at 217-218°. The same 7-glucosazone is pro- 
duced from synthetic a-acrose (fructose), d-mannose, d glucose and d-fructose 
(fruit-sugar) ( Berichte, 23, 383, 2620). Inactive fructose is formed when 7-gluco- 
sazone is decomposed with hydrochloric acid, and by the reduction of the z-gluco- 
sone, first formed, with zinc dust and acetic acid. Diphenylhydrazine and z-glu- 
cose yield a diphenylhydrazone, crystallizing in leaflets, melting at 133°. z-Glucose 
is fermented by yeast. /-Glucose remains behind. 


3. Fruit Sugar, C,H,,0,, is the ketone derivative (the ketose) 
of mannitol. It occurs as dextro-, lzvo- and inactive fruit sugar 
(p. 498). 

d-Fructose, or Fruit Sugar, formerly called /evu/ose, is found 
in almost all sweet fruits, together with an equal amount of grape 
sugar. It is likely that cane sugar first forms in the plants and that 
a ferment at once breaks it up into grape sugar and fruit sugar. It 
is formed, together with grape sugar, in the so-called zaverston, or. 
decomposition of cane sugar, by boiling with acids or by the action 
of ferments.. The mixture of the two is called znvertsugar. The de- 
composition of inosite yields fruit sugar. It is artificially prepared 
(together with d-mannose) by oxidizing d-mannitol, as well as 
from @-glucosazone and isoglucosamine. Jn this way the complete 
synthests of fruit sugar has been effected (p. 499). 


Preparation.—Mix 10 parts invert sugar with 6 parts calcium hydroxide and 50 
parts of water. On pressing the moist mass, the liquid lime compound of dextrose 





506 ORGANIC CHEMISTRY. 


is removed and the residual solid is the lime compound of lzvulose. This is decom- 
posed by oxalic acid, the lime oxalate filtered off, and the solution evaporated 
(Berichte, 14, 2418). 

A much simpler method is to heat inuline, with water, to 100° for twenty-four 
hours, when it is completely changed to levulose (Aunalen, 205, 162; Berichie, 


23, 2107). 


Fruit sugar forms a thick syrup which at 1oo° dries to a gummy, 
deliquescent mass. When the syrup is repeatedly extracted with 
cold absolute alcohol, the lzevulose gradually crystallizes out in fine, 
silky needles, which fuse at 95° and lose water at 100°. It is more 
readily soluble in water and alcohol than grape sugar, and rotates 
the plane to the left more powerfully than the latter. Its specific 
rotatory power in 20 per cent. solution is [a], = — 71.4° at 20° 
(Berichte, 19, 393). Consequently invert sugar (grape sugar and 
fruit sugar) is levo-rotatory. Fruit sugar is more slowly fermented 
by yeast than grape sugar; therefore in the fermentation of invert 
sugar the solution finally contains only fruit sugar. 

In all reactions fruit sugar closely resembles grape sugar, and 
reduces an alkaline copper solution in the same proportion as the 
latter. It is converted into.¢-mannitol by sodium amalgam. It 
yields the same d@-glucosazone with phenylhydrazine. However, in 
oxidations it sustains, owing to its ketone character, more complete 
decompositions, resulting in the production of gluconic and tartaric 
acids. Hydrochloric and hydrocyanic acids convert it into fruc- 
tose-carboxylic acid, which may be reduced to methylbutyl acetic 


acid (p. 496). 


/-Fructose, C,H,,O,, is produced by fermenting inactive fructose (a-acrose) 
with yeast; the ¢-fructose being destroyed. It has not been isolated, but yet forms 
?-glucosazone (p. 505) with phenylhydrazine (Berichze, 23, 389). 

7-Fructose, inactive lzevulose, is probably identical with synthetic a-acrose. 
Sodium amalgam converts it into a-acrite, identical with z mannitol (p. 487). 
Yeast breaks it up, leaving /-fructose. Its osazone is identical with z-glucosazone, 
from which z-fructose can again be regenerated. a-Acrite can also yield z-manno- 
nic acid, and the latter fruit sugar and grape sugar. 

4. Galactose, C,H,,0,, Lactose, is the aldose of dulcitol (p. 488). It is 
formed on boiling milk sugar with dilute acids, and is obtained from such gums 
(called galactans) ( Berichze, 20, 1003), as yield much mucic acid when oxidized. 
To prepare # boil milk sugar with dilute sulphuric acid (Anma/en, 227, 224). It 
crystallizes in nodules of grouped needles or leaflets, which melt at 166°; it dis- 
solves with much more difficulty in water than @-glucose, Its solution is dextro-' 
rotatory. It readily reduces alkaline copper solutions and is fermentable with 
yeast (Berichte, 21, 1573). .Nitric acid oxidizes it to mucic acid, bromine to 
galactonic acid (p. 491) and sodium amalgam converts it into dulcitol. Hydro- 
cyanic and hydrochloric acids convert it into galactose-carboxylic acid. Pheny]- 
hydrazine converts galactose into a Aydrazone, C,H,,0,;:N,H.C,H,, melting at 
158°, and galactosazone, C,11;,0,.(N,H.C,H;)., melting at 193°. 

5. Sorbinose, Sorbine, C,H,,O,, a ketone alcohol (ketose), is found in 
mountain-ash berries, and consists of large crystals, which possess a very sweet 
taste. It reduces alkaline copper solutions, but is incapable of fermentation under 


DISACCHARIDES. . 507 


the influence of yeast. Oxidized with nitric acid it yields trioxyglutaric acid 
(Berichte, 21, 3276). Its osazone, sorbinosazone, melts at 164°. 

6. Methyl Hexose, C,H,,0, = C,H,,(CH,)O,, rhamno-hexose, is pro- 
duced in the reduction of rhamnose-carboxylic acid (p. 491). It crystallizes quite 
readily from alcohol and melts at 181°. Its osazone melts near 200° (Berichte, 
23, 936). Hydrocyanic acid and hydrochloric acid convert it into methylheptonic 
acid. This yields methylheptone by reduction. 

(5) Heptoses, C,H,,0,. 

These compounds are synthetically prepared by reducing the corresponding 
heptonic acids, C,H,,O, (their lactones), with sodium amalgam. In their 
properties they are very similar to the hexoses. They are not fermented by yeast 
(Berichte, 23, 935). 

d-Manno-heptose, C,H, ,O,,.is obtained from mannoheptonic acid (Berichte, 
23, 2228). Perseite yields it when oxidized (p. 494). It crystallizes in needles 
melting at 135°. Its Aydrazone, C,H, ,0,(N,H.C,H,), dissolves with difficulty 
and melts about 198°. Its osazone, C,H,,0,(N,H.C,H,)., melts near 200°. 
Sodium amalgam converts it into perseite (p. 494). Manno-octonic acid, 
C,H,,O,, is obtained upon treating it with hydrocyanic and hydrochloric acids 
(Berichie, 23, 2233). 

d-Gluco-heptose, C,H, ,0,, from gluco-heptonic acid, crystallizes in beautiful 
plates, melting at 190°. Its hydrazone is very soluble. Its osazone melts at 197°. 
Hydrocyanic acid and hydrochloric acid convert it into gluco-octonic acid. 

Gala-heptose, C,H,,0,, from galaheptonic acid, forms a hydrazone that 
dissolves with difficulty. Its osazone melts about 220°. 

Methyl Heptosée, C,H,,O0, = C,H,(CH,)O,, rhamno-heptose, is derived 
from methyl heptonic acid. Its hydrazone dissolves with difficulty. 

(6) Octoses, C,H,,O, and Nonoses, C,H,,0,. The octoses are derived 
from the heptose-carboxylic acids, 

d-Manno-octose, C,H, ,O,, from manno-octonic acid (p. 496), is syrup-like, 
but yields a beautiful hydrazone and osazone. Sodium amalgam converts it into 
d-manno-octite, C,H, ,O, (Berichte, 23, 2234). Prussic and hydrochloric acids 
convert it into d-manno-nononic acid, C,H,,0,, (p. 496). By reduction the 
latter yields 

d-Manno-nonose, C,H,,0,. This is very similar to grape sugar. It fer- 
ments under the influence of yeast. The heptoses and octoses do not ferment. 
The hydrazone melts at 223°, the osazone about 217° (Berichte, 23, 2237). 


2, DISACCHARIDES. 


Only the disaccharides of the hexoses, C,H,,O,;, are known. 
They consist of two molecules of the glucoses or monoses (p. 497), 
and therefore are called dzoses. Their formula would therefore 
be C,.H,.O,,. By the absorption of water—by hydrolysis—they 
are resolved into two molecules of the hexoses :— 


C,,H,,0,, + H,O = 2C,H,,0,. 


Thus cane sugar decomposes into grape-sugar (d-glucose) and 
fruit-sugar (d-fructose), milk sugar into d-glucose and galactose, 
maltose into two molecules of d-glucose, etc., etc., etc. 


505. ORGANIC CHEMISTRY. 


When the di- and poly-saccharides are heated with water and a little acid they 
undergo hydrolysis. Its rapidity, according to Ostwald, bears a close relation to 
the affinity of the acids ( Jour. pr. Chem. (2), 31, 307). The action of various 
unorganized ferments, such as diastase and synaptase or emu/sin (contained in 
sweet and bitter almonds), upon the saccharides produces a similar decomposition. 
Invertin (the ferment of yeast), ptyalin (the ferment of saliva), trypsin, pepsin, 
and other animal secretions exert a like action. Thus, yeast resolves cane sugar 
into grape sugar and fruit sugar, and starch into dextrine and maltose. 

Formerly the decomposition of cane sugar was termed inversion, because the 
optical rotation was reversed (owing to the stronger lzvo-deviation of the plane 
by the fruit sugar). The product (a mixture of dextrose and levulose) is caver 
sugar (p. 505). 

Prolonged heating with acids causes reversion ,; the glucoses (especially fructose) 
undergo a retrogressive condensation to dextrine-like substances (Berich/e, 23, 


2094). 


The constitution of the disaccharides indicates that they are 
ether-like anhydrides of the hexoses. The union is effected through 
the alcohol or aldehyde groups. Milk sugar and maltose also 
contain the -aldose group, CH(OH).CHO, because they reduce 
Fehling’s solution upon boiling, form osazones with phenylhydra- 
zine, and when oxidized with bromine water yield monobasic acids, 
C,,H..0;,, lacto- and malto-bionic acid (p. 510) (Berichte, 21, 
2633; 22, 361). 

Cane sugar does not show reducing power and does not yield an 
osazone. ‘The reducing groups (of grape sugar and fruit sugar) 
appear to be combined in this compound. It is consequently not 
capable of direct fermentation with yeast. Inversion must first 
take place. Maltose is fermented quite readily, while milk sugar 
ferments with difficulty. After inversion cane sugar forms the same 
glucosazone as grape sugar and fruit sugar. 

Cane Sugar, C,,H,.O,, = C,.H,,0;(OH),, Saccharose, occurs 
in the juice of many plants, chiefly in sugar cane, in some varieties 
of maple and in beet-roots (10-20 per cent.) from which it is pre- 
pared on a commercial scale. While the hexoses occur mainly in 
fruits, cane sugar is usually contained in the stalks of plants. 


Its commercial manufacture from cane or beet sugar is, from a chemical point 
of view, very simple. The sap obtained by pressing or diffusion*is boiled with 
milk of lime, to saturate the acids, and precipitate the albuminoid substances. 
The juice is next saturated with carbon dioxide, filtered through animal charcoal, 
concentrated in.a Roberts’ Machine, and further evaporated in vacuum pans to 
a thick syrup, out of which the solid sugar separates on cooling. The raw sugar 
obtained in this manner is further purified with a pure sugar solution, in the 
centrifugal machine, etc.—vefined sugar. 

The syrupy mother liquor from the sugar is called molasses; it contains 
upwards of 50 per cent. of cane sugar which is prevented from crystallizing by 
the presence of salts and other substances. It is either converted into alcohol or 
the cane-sugar is extracted from it by the fermenting process. The sparingly 
soluble saccharates of lime and strontium are obtained from the molasses (see 


DISACCHARIDES. 509 


below) and these are freed from impurities by washing with water or dilute alcohol. 
The purified saccharates are afterwards decomposed by carbon dioxide, and the 
juice which is then obtained, after the above plan, is further worked up. 


When its solutions are evaporated slowly cane sugar separates in 
large monoclinic prisms and dissolves in % part water of medium 
temperature; it dissolves with difficulty in alcohol. Its sp. gr. 
equals 1.606. Its aqueous solution is levo-rotatory ; the influence 
of concentration upon the specific rotation is slight; it, however, 
diminishes (opposite of grape sugar) with increased concentration. 
Its real rotatory power, A,, at 20° is + 64.1 (p. 62). Cane sugar 
melts at 160° and on cooling solidifies to an amorphous glassy 
mass ; in time this again becomes crystalline and non-transparent. 
At 190-200° it changes to a brown non-crystallizable mass, called 
Caramel, which finds application in coloring liquors. 

Cane sugar decomposes into dextrose and lavulose (invert sugar) 
when boiled with dilute acids. Mixed with concentrated sulphuric 
acid it is converted into a black, humus-like body. Sacccharic 
acid, inactive tartaric acid and oxalic acid are formed when it is 
boiled with nitric acid. ele 


Cane sugar yields saccharates (p. 502) with the bases. An aqueous sugar solu- 
_ tion readily dissolves lime. If finely divided burnt lime (CaO) (1 molecule to I 
molecule sugar) be dissolved in a dilute sugar solution (6-12 per cent.) alcohol 
will precipitate the monobasic saccharate, C,,H,,0,,-Ca0 + 2H,0O, which, 
when deprived of its water at 100°, is a white amorphous mass, that is quite 
soluble in cold water. Two molecules of CaO afford C,,H,,0,,. 2CaO, which 
separates, in the cold, in beautiful crystals. If CaO be added to its solution at 
temperatures below 35°, all the sugar will be precipitated as tribasic saccharate, 
C,,H,,0,,.3CaO; this is not readily soluble in water. Upon the above deport- 
ment is based C. Steffen’s substitution process, by which sugar is separated from 
molasses ( Berichte, 16, 2764). Strontium and barium give perfectly similar sac- 
charates ( Berichte, 16, 984). On boiling the sugar solution with lead oxide we 
get C,,H),Pb,0)). 

Cane sugar heated to 160° with an excess of acetic anhydride gives octacetlyi 
ester, C,,H,,0,(0.C,H,0),; this is a white mass, insoluble in water and acetic 
acid. ‘The action of concentrated nitric acid and sulphuric acid yields the tetra- 
nitrate, C,,H,,(NO,),0,,, a white mass; it explodes violently. 


Milk Sugar, C,,H,.0,,-+ H,O, Lactose, has thus far been 
found in the animal kingdom only, and occurs in the milk of 
mammals, in the amniotic liquor of cows, and in certain patholog- 
ical secretions. 


Milk sugar is prepared from whey. This is evaporated to the point of crystal- 
lization and the sugar which separates purified by repeated crystallization. 


_ Milk sugar crystallizes in white, hard, rhombic prisms, contain- 
ing one molecule of water. It is soluble in 6 parts cold or 2% 
_ parts hot water, has a faint sweet taste, and is insoluble in alcohol, 


x. 


pe 


Ps 


510 ORGANIC CHEMISTRY. 


Its aqueous solution is dextro-rotatory and exhibits 47-rofation 
(p. 504). When the constant rotatory point is obtained by heating, 
the specific rotatory power will vary considerably with the concen- 
tration. Milk sugar loses its water of crystallization at 140°, chars, 
melts at 205°, and suffers further decomposition. It resembles the 
hexoses in reducing ammonical silver solutions; this it effects even 
in the cold, but in case of alkaline copper solutions boiling is 
necessary to reach the desired end. Milk sugar yields galactose 
and d-glucose when it is heated with dilute acids; it ferments with 
difficulty with yeast, but undergoes the /ac/ze fermentation with 
great readiness. Nitric acid oxidizes it to saccharic acid, mucic 
acid and additional oxidation products. 


Bromine water converts it into lactobionic acid, C,,H,,0,,, which is changed 
to gluconic acid and galactose upon digesting it with acids (Berichte, 22, 361). 

An octacetyl ester is obtained by treating the acid with acetic anhydride. A 
so-called nitro-lactose, C,,H,,(NO,);O,,, crystallizes from alcohol in leaflets. 
This melts at 139° and explodes at 155°. 

It unites with phenylhydrazine and forms phemyl-lactosazone, C,,H,,)0,.(N.H. 
C,H,),, that melts at 200° (Berichle, 20, 829). 


Maltose, C,,H,.0,, + H,O, is a variety of sugar formed, 
together with dextrine, by the action of malt diastase (p. 508) upon 
starch (in the mash of whiskey and beer). It is capable of direct 
fermentation. It was formerly supposed to be grape sugar. It is 
also an intermediate product in the action of dilute sulphuric acid 
upon starch, and of ferments (diastase, saliva, pancreas) upon gly- 


cogen (p. 513). 


In the normal sugaring of pasty starch’ by diastase, at a temperature of 50-63°, 

nearly 24 maltose and 1% dextrine are produced :— 
3C,H,,0; + H,O = C,,H,,0,; + C,H, 03. 
Starch. Maltose. Dextrine. 

The quantity of maltose. produced at more elevated temperatures (above 63°) 
_ steadily diminishes up to 75° when the action of diastase ceases ( Berichie, 12, 
949). These conditions are important in the manufacture of rum and the brewing 
of beer. In the first case the mash obtained by the production of sugar at 60° is 
cooled, then the maltose at once ferments and dextrine in consequence of the after- 
action of the diastase, is first converted into grape sugar and then fermented ; 
therefore, the fermentation of starch is almost a perfect one. In beer-brewing the 
mash is boiled, to destroy the diastase, so that by the action of ferments only the 
maltose suffers fermentation; dextrine remains unaltered. 

In preparing maltose, starch paste made by boiling with water is converted, at 
60°, into sugar, by diastase, the solution then boiled, the filtrate concentrated to 
a syrup and the maltose extracted by strong alcohol (Azza/en, 220, 209). 


Maltose is usually obtained in the form of crystalline crusts, com- 
posed of hard, white needles, that lose their water of crystallization at 
100°. _ In properties it closely approaches grape sugar. It is directly 
fermented by yeast and reduces an alkaline copper solution, but to 


MELITOSE, RAFFINOSE. 511 


only about 24 the amount effected by grape sugar; 100 parts malt- 
ose, judging from its reducing power, are equivalent to 61 parts grape 
sugar, but in the case of Fehling’s solution diluted four times, they 
correspond to about 66.8 parts of the second (Aznalen, 220, 220). 
Its rotatory power is but’slightly influenced by the temperature and 
concentration of the solution, [a], = -++140.6° (Azna/en, 220, 200). 


Diastase does not exert any further change upon maltose; when boiled with 
dilute acids, it passes completely into grape sugar. Nitric acid oxidizes it to 
saccharic acid, while chlorine changes it to malto-bionic acid, C,,H,,0,,. This 
yields grape sugar and gluconic acid when it is heated with acids. Maltose and 
milk sugar very probably possess the same structural formula (Berichée, 22, 1941). 

When heated with sodium acetate and acetic anhydride, it yields octoacet-maltose, 
C,,H,,(C,H,0),0,,, which melts at 150-155°. : 

When boiled with lime water, it forms isosaccharin (p. 484). Phenylhydra- 
zine converts it into phenylmaltosazone, C,,H,,O,(N,H.C,H,)., melting at 
82°. 

Mycose, C,,H,,0,, + 2H,0, Trehalose, occurs in several species of fungi, 
in ergot of rye, and in the oriental 7reha/a. It is distinguished from cane sugar 
by its ready solubility in alcohol, greater stability and stronger rotatory power. - 

Melebiose, C,,H,,O,,, is produced, together with d-fructose, in the bydroly- 
sis of meletriose. Its osazone, C,,H,,O,.(N,H.C,H,),., is soluble. Further 
hydrolysis converts it into d-glucose and galactose (Berichte, 22, 3119; 23, 1438). 


Raffinose and melezitose are 77risaccharides. 


Melitose, Raffinose, C,,H,,0,,-+ 5H.O, Melitriose. It occurs 
in rather large quantity in Australian manna (varieties of Eucalyp- 
tus), in the flour of cotton seeds, in small amounts in sugar beets, and 
being more soluble than cane sugar, it accumulates in the molasses 
in the sugar manufacture. From this it crystallizes out with the 
sugar. Its crystals have peculiar terminal points, and show strong 
rotatory power (Plus sugar). 


Raffinose is obtained from molasses, or by treating plus sugar with alcohol, in 
which the raffinose dissolves with more difficulty than the sugar (4mma/en, 232; 
173). To determine the raffinose in the molasses and tailings, extract it with 
methyl alcohol (Berichte, 19, 2872), then polarize and invert, or determine the 
amount of mucic acid obtained by oxidizing the raffinose with HNO, (Berichie, 
19, 3116). 


It crystallizes in needles, more soluble in water and lessin alcohol 
than cane sugar. It dissolves quite readily in methyl alcohol.- It 
loses its water of crystallization in a vacuum and when warmed. It 
is more strongly dextro-rotatory than cane sugar: (a), 104°. It 
does not reduce Fehling’s solution, but is easily fermented by yeast. 


By hydrolysis it yields fructose and melibiose (Berichte, 23, Ref. 103). The 
determination of its molecular weight by the method of Raoult showed it to be a 
triose ( Berichte, 21, 1569). 

Melezitose, C,,H,,0,, + 2H,0, occurs in the juice of: Pinus Larix, and 
resembles cane sugar very much. It is distinguished from the latter by its greater 
rotatory power and in not being so sweet to the taste. It melts at 148° when anhy- 
drous. It is alsoa triose (Berichte, 22, Ref. 759). 


512 ORGANIC CHEMISTRY. 


3. POLYSACCHARIDES. 


It is very probable that the polysaccharides having the empirical 
formula C,H,,O;, really possess a much higher molecular weight, 
(C,HyO;),. ‘They differ much more from the hexoses than the di- 
and tri-saccharides. ‘They are, as a general thing, amorphous, dis- 
solve with difficulty in water, and lack most of the chemical char- 
acteristics of the: hexoses. By hydrolysis, that is when boiling them 
with dilute acids, or under the influence of ferments (p. 508), nearly 
all are finally broken up into their component hexoses (see dextrine). 
Their alcoholic nature is shown in their ability to form acetyl and 
nitric esters. 

Starch, Amylum, (C,H,.O;), or C3,Hg.Os (p. 497), is found in 
the cells of many plants, in the form of circular or elongated micro- 
scopic granules, having an organized structure. ‘The size of the 
granules varies, in different plants, from 0.002-0.185 mm. Air 
dried starch contains 10-20 per cent. of water; dried over sulphuric 
acid it retains some water which is only removed at 100°. Starch 
granules are insoluble in cold awaler and alcohol. When heated 
with water they swell up at 50°, burst, partially dissolve and form 
starch paste, which turns the plane of polarization to the right. 
The soluble portion is called granudose, the insoluble, starch cellulose. 
Alcohol precipitates a white powder—so/uble starch—from the 
aqueous solution. The blue coloration produced by iodine is char- 
acteristic of starch, both the soluble.variety and that contained in 
the granules (Berichte, 20, 694). Heat discharges the coloration, 
but it reappears on cooling. 

Boiling dilute acids convert starch into dextrine and d-glucose. 
When heated from 160—200° it changes to dextrine. Malt diastase 
changes it to dextrine and maltose. 


Concentrated sulphuric acid combines with starch, yielding a compound which 
forms salts with bases. Heated with acetic acid we get the ¢riacety/ derivative, 
C,H,O,(0 C,H,0O),, an amorphous mass, which regenerates starch when treated 
with alkalies. _Concentrated nitric acid produces nitrates. 

Other starch-like compounds are :— 

Paranylum, C,H, O,;, which occurs in form of white grains in the infusoria 
Euglena viridis. \t resembles common starch, but is not colored by iodine, and 
is soluble in po'assium hydroxide. 

Lichenine, C,H, ,O;, moss-starch, occurs in many lichens, and in Iceland moss 
( Cetraria islandica), from which it may be extracted by water. The solution 
becomes gelatinous, dries to a hard mass, and on treatment with boiling water 
again forms a jelly. lodine imparts a dirty blue color to it. It yields dextrose 
when boiled with dilute acids. 

Jnulin is found in the roots of dahlia, in chicory, and in many Composite (like 
Lnula Hel-nium); itis a white powder which dissolves in boiling water, forming 
a clear solution. Jodine gives it a yellow color. When boiled with water it is 
completely changed to fruit sugar. 


POLYSACCHARIDES. > 513 


Glycogen, C,H,,O;, animal starch, occurs in the liver of mammals and isa 
mealy powder, which is precipitated from solution by alcohol; it forms a paste 
with cold water, and on heating is dissolved in it. Iodine imparts a reddish-brown 
color to it. Boiling with dilute acids causes it to revert to dextrose, and ferments 
change it to maltose. 





The Gums, (C,H,,.O;),. These are amorphous, transparent sub- 
stances widely disseminated in plants; they form sticky masses with 
water and are precipitated by alcohol. They are odorless and 
tasteless. Some of them yield clear solutions with water, while 
others swell up in that menstruum and will not filter through paper. 
The first are called the rea/ gums and the second vegetable mucilages. 
Nitric acid oxidizes them to mucic and oxalic acids. 

Dextrine. By this name are understood substances, readily 
soluble in water and precipitated by alcohol; they appear as by- 
products in the conversion of starch into dextrine, ¢. g., heating 
starch alone from 170—-200°, or by heating it with dilute sulphuric 
acid. Different modifications arise in this treatment; amylo- 
dextrine, erythrodextrine, achrodextrine; they have received little 
study. They are gummy, amorphous masses, whose aqueous solu- 
tions are dextro-rotatory, hence the name dextrine. They do not 
reduce Fehling’s solution, even on boiling, and are incapable of 
direct fermentation ; in the presence of diastase, however, they can © 
be fermented by yeast (p. 510). They are then converted into 
ad-glucose. They yield the same product when boiled with dilute 
acids, 


Dextrine is prepared commercially by moistening starch with two per cent. 
nitric acid, allowing it to dry in the air, and then heating it to 110°. It is em- 
ployed as a substitute for gum ( Berichte, 23, 2104). 

Arabin exudes from many plants, and solidifies to a transparent, glassy, 
amorphous mass, which dissolves in water toa clear solution. Gum arabic or 
gum Senegal consists of the potassium and calcium salts of arabic acid. The 
latter can be obtained pure by adding hydrochloric acid and alcohol to the solu- 
tion. It is then precipitated as a white, amorphous mass, which becomes glassy 
at 100°, and possesses the composition (C,H,,0O;), + H,O. It forms com- 
pounds with nearly all the bases; these dissolve readily in water. 

Some gum varieties, ¢. g., gum-arabic, yield galactose in considerable quantity 
when boiled with dilute sulphuric acid; and with nitric acid they are converted 
into mucic acid; others (like cherry gum) are transformed on boiling with sul- 
phuric acid into arabinose, C;H,,O; tp. 483), and into oxalic acid, not mucic acid, 
by nitiic acid. The gum, extracted from beechwood by alkalies and precipitation 
with acids, is converted into xylose (p. 483) by hydrolytic decomposition. 

Bassorin, vegetable gum, constitutes the chief ingredient of gum tragacanth, 
Bassora gum, and of cherry and plum gums (which last also contain arabin). It 
swells up in water, forming a mucilaginous liquid, which cannct be filtered; it 
dissolves very readily in alkalies, 


43 


514 ORGANIC CHEMISTRY, 


Cellulose, C,,H..O,, wood fibre, lignose, forms the principal 
ingredient of the cell membranes of all plants, and exhibits an 
organized structure. To obtain it pure, plant fibre, or better, 
wadding, is treated successively with dilute potash, dilute hydro- 
chloric acid, water, alcohol and ether, to remove all admixtures 
(incrusting substances). Cellulose remains then as a white, amor- 
phous mass. Fine, so-called Swedish, filter paper consists almost 
entirely of pure cellulose. 

Cellulose is insoluble in most of the usual solvents, but dissolves 
without change in an ammoniacal copper solution. Acids, various 
salts of the alkalies and sugar precipitate it-as a gelatinous mass 
from such a solution. After washing with alcohol it is a white, 
amorphous powdér. Cellulose swells up in concentrated sulphuric 
acid and dissolves, yielding a paste from which water precipitates 
a starch-like compound (amyloid), which is colored blue by iodine. 
After the acid has acted for some time the cellulose dissolves to 
form dextrine, which passes into grape sugar, when the solution is 
diluted with water and then boiled. 

So-called parchment paper (vegetable parchment) is prepared by 
immersing unsized filter paper in sulphuric acid (diluted % with 
water) and then washing it with water. It is very similar to ordi- 
nary parchment, and is largely employed. 


Hexacet-cellulose, C,,H,,0,(0.C,H,0),, is obtained by heating cellulose 
(cotton) with acetic anhydride to 180°. It is an amorphous mass, soluble in con- 
centrated acetic acid. 


Cold, concentrated nitric acid, or what is better, a mixture of 
nitric and sulphuric acids, converts cellulose or cotton into esters 
or so-called zitro-celluloses. ‘That these compounds are not nitro- 
derivatives, but true esters, is manifest, when we consider that upon 
treatment with alkalies they yield cellulose and nitric acid (p. 454). 
Alkaline sulphides and ferrous chloride also regenerate cellulose, 
the nitrogen escaping as ammonia or nitric oxide. The latter 
only is evolved by iron sulphate in a concentrated hydrochloric 
acid solution (Berichte, 13, 172). 


The resulting products exhibit varying properties, depending upon their method 
of formation. Pure cotton dipped for a period of 3-10 minutes into a mixture of 
IHNO, and 2-3H,SO,, then carefully washed with water, gives gun cotton 
(pyroxylin). This is insoluble in alcohol and ether or even in a mixture of the two. 
It explodes violently if fired in an enclosed space, either by a blow or percussion. 
It burns energetically when ignited in the air, but does not explode. Cotton 
exposed for some time to the action of a warm mixture of 20 parts pulverized 
nitre and 30 parts concentrated sulphuric acid becomes soluble pyroxylin, which 
dissolves in ether containing’ a little alcohol. The solution, termed co//odion, 
leaves the pyroxylin, on evaporation, in the form of a thin, transparent film, not 
soluble in water. It is employed in covering wounds and in photography. 


DERIVATIVES OF CLOSED CHAINS. 515 


In composition gun cotton is cellulose hexa-nitrate, C,,H,,(O,.NO,),O,, 
whereas the edt soluble in ether and alcohol, is essentially a tetra nitrate, 
C,.H,,(O.NO,),O,, and a penta-nitrate, C,H, ,(0. NO,),0,; (Berichte, 13, 
186). 


Collodion dissolved in nitroglycerol (equal parts), yields explosive gelatine or 
smokeless powder. 





DERIVATIVES OF CLOSED CHAINS. 


. Polymethylene Compounds. 

All the compounds considered in the preceding pages, in other 
words, the so-called fatty derivatives, contain open, not closed carbon 
chains, in which terminal and intermediate carbon atoms can be 
distinguished very readily (p. 42). The numerous derivatives of 
the benzene class, on the other hand, possess throughout a similar 
and hence supposed c/osed carbon chain, made up of six carbon 
atoms. Preceding the very stable benzene nucleus is a class of 
compounds discovered in recent years, in which we have closed 
chains. As examples we may mention trimethylene, tetra- 
methylene and pentamethylene :— 


CH, CH,—CH, CH,—CH, 


of 2 2 2 4 
cH | pe CHS 
CH, CH,—CH, CH,—CH, 
Trimethylene. Tetramethylene. Pentamethylene. 
C,H,. C,H,. CH: 


In these closed rings or chains of symmetrically combined 
C-atoms, the latter are all alike, so that isomerides are only possible 
by the introduction of two or several substituting groups. These 
parent substances and their derivatives have the same general form- 
ula, C,X,,, as the olefines and the other unsaturated compounds of 
the same series; the latter, however, are chiefly distinguished by 
their great additive power (p. 81). Indeed, the trimethylene 
derivatives can, by energetic action, absorb bromine and HBr (but 
not H, or I,): the tetra- and pentamethylene compounds, on the 
other hand, attach themselves fully to the hexahydro-benzene de- 
rivatives. 


The absence of “ double linkage” in the polymethylene derivatives is very 
evident from the fact that they cannot be oxidized by potassium permanganate. 
An alkaline solution of the latter is not decolorized even upon standing for long 
periods (p. 82) (Baeyer, Annalen, 245, 146). Consult A. Baeyer, Berichte, 18, 
2278; Sachse, Berichte, 23, 1363, for stereochemical views relating to the poly- 
methylene rings. 


516 - ORGANIC CHEMISTRY. 


1. TRIMETHYLENE GROUP. 


Trimethylene, C,H, (see above), was first obtained by heat- 
ing trimethylene bromide (p. 102) with metallic sodium (Freund, 
1882) :— 

CH, Br CH 
HY ° (“4 oNa=CH,¢ | ‘°+ 2NaBr. 
NCH, Br CH, 


It is more easily produced by the action of alcohol and zinc dust (Berichie, 
20, Ref. 706; 21, 1282). 


It is a gas, like its isomeride, propylene. It differs from 
this, in that it unites with difficulty with bromine and _ hydriodic 
acid—forming trimethylene bromide and normal propyl iodide. 
To account for this we assume that the closed ring has been 
broken. Unlike the olefines it is not oxidized by potassium per- 
manganate. 


Experiments have been made to prepare ¢rimethylene alcohol by acting upon 
a-dichlorhydrin with metallic sodium. The product, however, was allyl alcohol. 


Carboxyl-derivatives of trimethylene are produced 

(1) From malonic ester, acetic ester and analogous compounds by 
the action of alkylen bromides and sodium alcoholate (2 molecules) 
(Perkin, 1884) (Annalen, 236, 193; Berichte, 21, 2693) :— 


CH, Br CO,R rei rand 
Bats cH,< _ Se 4. 2HBr. 
CH,Br CO,R big CED are 


Melgpis Rates a-Trimethylene-dicarboxylic Ester. 


(2) By heating the addition products of diazo-acetic esters and 
acrylic esters, when two nitrogen atoms split off (p. 375) (Cur- 
tius) :-— 


" “*\y,:CH.CO,R = zs r MN cH, CO,R + N,. 
RO,C.—CH R.O,C.CH ~ 
Acryl-diazo-acetic Ester. Trimethylene- dicarboxylic Ester, 


Fumaric ester, C,H,(CO,R),, yields trimethylene-tricarboxylic ester, and cin- 
namic ester yields phenyltrimethylene-tricarboxylic ester, etc., when exposed to 
like treatment (Berichte, 23, 701). ‘ 

Trimethylene-carboxylic Acid, CH,~< | , isomeric with vinylacetic 

\CH.CO,H 
acid (isocrotonic acid, p. 238), is formed from a-dicarboxylic acid by heating it 
to 160°. Carbon dioxide is eliminated. It is an oil with faint odor and boils at 
190°. It does.not unite with bromine, like the isomeric crotonic acids (p. 238). 
Its ethyl ester, C,H,O,.C,H,, from ‘the silver salt and ethyl iodide, boils at 
133°. It cannot take up bromine. 


TRICARBOXYLIC ACIDS. 517 


DICARBOXYLIC ACIDS. 


CH, 
ed , is isomeric with hypo- 
N¢(CO,H), 
thetical vinyl malonic acid, C,H,.CH(CO,H),, or Vinaconic Acid (Annalen, 227, 
25). Its diethyl ester (see above) is formed from ethylene bromide and malonic 
ester. Butan-tetracarboxylic ester is formed at the same time by the action of 
ethylene bromide upon two molecules of malonic ester. The diethyl ester is an 
oil that boils at 207°. The free acid melts at 140° and above 160° decomposes 
into CO, and trimethylene carboxylic acid (with butyro-lactone). Digestion with 
dilute sulphuric acid converts it into isomeric butyrolactone carboxylic acid 
(p. 468). It, however, combines with HBr, disrupting the trimethylene ring and 
forming bromethyl malonic acid (p. 418). It unites in an analogous manner with 
bromine and forms dibrom-ethyl-malonic acid, which decomposes and melts at 
100-110° ( Berichte, 18, 3414). These reactions indicate that the acid is vinyl- 
malonic acid. However, it cannot be further alkylized, and, unlike the mono- 
alkylic-malonic acids, it is not attacked by nitric acid, potassium permanganate—or 
even sodium amalgam (Zerichte, 23, 704). This behavior argues in favor of its 
trimethylene character. CH.CO,H 

B- or (1, 2)-Trimethylene-dicarboxylic Acid, CH, l , is obtained 

‘ CH.CO,H 


a-Trimethylene-dicarboxylic Acid, CH 


(together with its anhydride) from a-trimethylene tricarboxylic acid, by heating the 
latter to 190°, when CO, splits off, and also from /-trimethylene tetracarboxylic acid 
by a similar loss of 2CO,. It crystallizes in vitreous prisms and melts at 139°. It 
is not affected by either potassium permanganate or sodium amalgam. Its anhy- 
dride, C,H,(CO),O, forms needles, melting at 59° and unites with water at 140°, 
regenerating the acid ( Berichte, 23, Ref. 241). 

y-Trimethylene-dicarboxylic Acid, C,H,(CO,H),. Its dimethyl ester is 
formed (together with the ester of glutaconic acid, p. 428) upon distilling acryl- 
diazo-acetic ester. It boils at 210° under a pressure of 720° mm. ‘The free acid © 
melts at 175°, distils unaltered, and does not form an anhydride. Potassium per- 
manganate and sodium amalgam do not affect it. 

The y-acid appears to have the same structural formula as the {-acid. It is, 
therefore, assumed that they are stereochemical isomerides. As the (-acid readily 
yields an anhydride, it is called the ma/einotd-, and the y-acid fumaroid (1, 2)-tri- 
methylene dicarboxylic acid (p. 424) (Berichte, 23, 702). 


TRICARBOXYLIC ACIDS. 


J C(CO,H), 
. The trimethyl ester 
\ CH.CO,.H 
is obtained in a manner analogous to that employed in the case of the dicarboxylic 
ester. It is an agreeably smelling liquid, which boils at 276° ( Berichée, 17, 1187). 
The same ester results from the union of malonic ester and a-bromacrylic ester. It 
is, therefore, probably CH,:C(CO,H).CH(CO,H), (Berichie, 20, Ref. 140, 258). 
The free acid crystallizes in shining needles and melts at 184°, decomposing into 
CO, and 8-trimethylene-dicarboxylic acid. CH.CO,H 
Sym. (1, 2, 3)-Trimethylene-tricarboxylic Acid, (CO,H),CHS ; 
e : N\CH.CO,H 
is formed from a-tetracarboxylic acid by splitting off carbon dioxide. It melts 
about 150° (Berichte, 17, 1652). When fumaric-diazoacetic ester is- heated, 


a-Trimethylene-tricarboxylic Acid, CH, 


es - ORGANIC CHEMISTRY. 


.it yields the trimethyl ester of a trimethylene-tricarboxylic acid that is identical 
with the preceding.. It is not changed by potassium permanganate or sodium 
amalgam. It melis at 220°. If it is heated to 240°, it loses water and 


becomes the ‘anhydride, CyHy(CO,H) EQ>O, melting at 187°. It boils at 265° 
(75 mm.) (Berichte, 21, 2641). : 


TETRACARBOXYLIC ACIDS. 


> CH.CO,H 
a-Trimethylene-tetracarboxylic Acid, (CO,H),C< | . Its tetra- 
‘\ CH.CO,H 
ethyl ester is obtained from malonic and dibromsuccinic esters. It boils at 246°. 
The free acid melts at 95-100° C., decomposing into CO, and symmetrical (1, 2, 3)- 
tricarboxylic acid. sv C(CO,H), 
8-Trimethylene-tetracarboxylic Acid, CH,< | ‘ 
‘ C(CO,H), 
ester is produced by the action of bromine upon disodium propan-tetracarboxylic 
ester (p. 482) :— 


CNa(CO,R), C(CO,R), 
4 2Br— CH,¢ l 4 2NaBr- 


Its tetra-ethy] 


ar 
*\CNa(CO,R), 


It melts at 43°, and under a pressure of 12 mm. boils at 187°. 
The free acid decomposes into 2CO, and (-trimethylene dicarboxylic acid ( Be- 
richte, 23, Ref. 241) when heated above 200° C. 


KETONIC ACIDS. 


Aceto-trimethylene Carboxylic Acid, CH,CO.C,H,.CO,H. Its ester is 
formed when ethylene bromide and sodium ethylate (2 molecules) act upon aceto- 
acetic ester :— 


CH,Br OLH, CH,.2,CO.CH 


| 1H 
CH, Br “\CO,R 


Diaceto-adipic ester (p. 438) results simultaneously through the action of C,H , Br, 
upon two molecules of sodium aceto-acetic ester. 

The ethyl ester is a faintly-smelling liquid, boiling about 195°. As a ketone, it 
combines with phenylhydrazine. HBr induces the rupture of the trimethylene ring 
and brom-ethyl aceto-acetic ester results (p. 340) (Berichte, 16, 2565). The free 
acid is a thick oil, which decomposes at 200° into CO, and aceto-trimethylene, 
CH,.CO,.C,H,, which boils at 113° (Berichte, 22, Ref. 502, 572; 22, 1210). 

Benzoyl-trimethylene Carboxylic Acid, C,H,.CO.C,H,.CO,H, is pro- 
duced, like the preceding, from benzoyl-acetic ester. It forms large prisms, melts 
at 149°, and decomposes into CO, and benzoyl-trimethylene, C,H,.CO.C,H,;. 
An oil,-boiling at 239°. It forms an oxime with hydroxylamine (erichZe, 19, 
2565). 

Boiling alkalies do not decompose benzoyl- and aceto-trimethylene carboxylic 
acids. Herein they differ from allyl aceto-acetic and allyl-benzoyl acetic’acids. 
In a similar manner paranitro-benzoyl acetic ester yields paranitrobenzoy] tri- 
methylene tricarboxylic ester (Berichte, 18,958). - 


TETRAMETHYLENE DERIVATIVES. 519 


2. TETRAMETHYLENE DERIVATIVES. 


Tetramethylene derivatives (p. 515) are obtained by acting upon malonic ester 
with trimethylene bromide and sodium alcoholate (2 molecules) (Perkin) :— 


cH, 7CH2Br CHiN 


2 cH Bet ACOs et ale C(CO,R), + 2HBr. 


2\ CH, 


Tetramethylene-carboxylic Acid, C,H,.CO,H, isomeric with allyl-acetic 
acid, is formed from the dicarboxylic acid by withdrawal of CO,. It is an oil, 
which boils at 194°, and has an odor like that of a fatty acid. 

Not tetramethylene, C,H,, but Ditetramethylene Ketone, C,H,.CO.C,H,, 
is formed by distilling its lime salt. This is a liquid, with an odor like that of pep- 
permint. It boils at 205° (Berichte, 19, 3113). 

a-Tetramethylene-dicarboxylic Acid, C,H,(CO,H),. Its diethyl ester 
(isomeric with allyl malonic ester, p. 430) is formed (together with pentan-tetra- 
carboxylic ester, p. 482) from trimethylene bromide and malonic ester ( Berichie, 
21, 2693). Itis an oil with camphor-like odor, and boils at 224° (Berichéz, 16, 
1787). The free acid dissolves easily in ether and benzene, but not in chloroform 
and benzine; it crystallizesin shining prisms, and melts at 155°, decomposing into 
the monocarboxylic acid and CO,. CH,—CH.CO,H 

$B-Tetramethylene Dicarboxylic Acid, | b 
CH,—CH.CO,H 
heating tetracarboxylic acid (see below) to 180° C. with water. It splits off 2CO, 
groups, It is crystalline and melts at 130° C. At 300° it loses water and becomes 
the anhydride C,H,(CO),O, melting at 77° (Berichte, 19, 2042). 

The third Tetramethylene Dicarboxylic Acid, (CO,H)CHE G}j? >CH. 
CO,H, appears to be tetrylene dicarboxylic acid, whose ester results from the 
action of a-chlorpropionic ester and sodium ethylate. It boils above 230° (Anna/en, 
208, 333). Its free acid is crystalline, melts at 171° and sublimes in needles. 
The acid and the ester do not combine with nascent hydrogen, HBr or bromine. 
Consult Berichte, 23, Ref. 432 for its anhydride derivatives. 

CH,.C(CO,H), 
a-Tetramethylene Tetracarboxylic ae | . Its ethyl ester 
H,.C(CO,H), 


, results upon 


is produced by the action of bromine (as with f trimethylene tetracarboxylic ester) 
upon butan-tetracarboxylic ester (its disodium compound) :— = 


CH,.CNa(CO,R), CH,—C(CO,R), 
Be ec | * ++ 2NaBr. 
CH,.CNa(CO,R), CH,—C(CO,R), 
The free acid is crystalline, melts at 145-150° C., and decomposes into 2CO, 
and £ tetramethylene dicarboxylic acid (Berichte, 19, 2041). 
; ; CH 
6-Tetramethylene Tetracarboxylic Acid, (CO,H) CQ Gyq? >C(CO,H),. 
Its tetraethyl ester has been obtained from the disodium dicarboxy]-glutaric ester 
by means of methylene iodide (Berichte, 23, Ref. 240). 


520 ORGANIC CHEMISTRY. 


KETONIC ACIDS. 
* When trimethylene bromide acts upon acetoacetic ester the product is not the 


analogous— 

Aceto-tetra-methylene Carboxylic Ester, CH, Soa ton” 
but the ester of an zsomeric acid, which probably represents the carboxylic acid of 
the anhydride of acetobutyl alcohol, as it breaks up, when distilled, into CO, and 
that anhydride (p. 322). C,H,Br, also acts analogously upon benzoyl-aceto-acetic 
ester and acetone dicarboxylic ester (Berichte, 19, 2557; 21, 736). 

Diaceto-tetramethylene Dicarboxylic Acid, (CH,CO),C,H,(CO,H),, 
is a true diketonic acid. Its diethyl ester is produced in the action of bromine 
upon the disodium compound of diaceto-adipic ester (see above) :— 


/CO.CH ie YCOICH 
CH,.CN 3 CH,—C 3 
; ie + Br, = | a Sos Ce! -+ 2NaBr. 
CH,.CNat Co 'cH | C€-CO,R 
CH,” \CO.CH, 


It is a liquid, which is colored a violet red by ferric chloride. The free acid 
from it crystallizes with 2H,O, which it loses at 80°. When anhydrous the acid 
melts, with decomposition, at 210° ( Berichie, 19, 2048). ; 





3. PENTAMETHYLENE DERIVATIVES. 
/CH.—C(CO,H), 


Pentamethylene-tetra-carboxylic Acid, CH, . Bro- 
NcH,—C(CO,H), 
mine converts disodium pentan-tetra-carboxylic ester into its tetraethyl ester 
(Berichte, 18, 3246) :— 


CH,.CNa(CO,R) e 
cH, 7 CH: 2R)e 4 Bre — CH 
*\CH,.CNa(CO,R), 7°"? *\CH,.C(CO,R), 


The free acid, from the oily ester, decomposes when heated to 200—-220° into 
2CO, and Pentamethylene-dicarboxylic Acid, C;H,(CO,H),, crystallizing 
in warty masses, melting at 160°. At 300° it yields water and the anhydride, 
C,H,(CO),O, melting about 65° (Berichte, 18, 3251). 


CH,.C(CO,R),. 
+ 2NaBr. 


Ketopentamethylene, | ? eo, may be obtained by distilling calcium 
CH,.CH 

adipate. If two of its O-atoms be replaced by two chlorine atoms, and further 

acted upon with nascent hydrogen the product will be Pentamethylene, C,H, 9. 

This is a liquid boiling at 30-31° (J. Wislicenus). 

Derivatives of (1, 2)- and (1, 3)-diketo pentamethylene have been prepared 
by oxidizing orthoamidophenol and pyrocatechol with chlorine. The ‘six-mem- 
bered’ benzene ring is changed to the ‘five-membered’ pentamethylene ring 
(Zincke, Berichte, 21, 2718; 23, 813, 2200). The naphthalene ring by similar 
treatment yields the indene ring. : 

Diketo-pentamethylene derivatives have been prepared by the action of chlorine 
upon alkaline solutions of phenol and chloranilic acid (Hantzsch, Berichte 22, 1238 


FURFURANE, THIOPHENE AND PYRROL DERIVATIVES, 521 


and 2841). Consult Berichte, 22, 2827; 23, 1478 for the transformations of 
pentamethylene compounds into derivatives of benzene, pyridine and thiophene 
(Berichte 22, 2827; 23, 1478). 

Leuconic Acid, C,O, + 5H,O, and Croconic Acid, C,O0,H,, keto-deriva- 
tives of pentamethylene, will be discussed- together with the triquinoline deriva- 
tives. ; 

Methronic acid, carbopyrotritartaric acid and their compounds are considered 

Cai =e CH 
derivatives of hypothetical ketopentene, | C0, tetrylone. 
CH 


2 





CH,—CH . * 
Hexamethylene, C,H,, = CH, Gy? cH? >CHa» is described under 
the benzene derivatives as hexahydrobenzene (benzene hydride). 
A Heptamethylene derivative, C,H,,, seems to have been obtained from 
diaceto-adipic ester (Berichte, 19, 2052). 





FURFURANE, THIOPHENE AND PYRROL DERIVATIVES. 


The polymethylene closed chains consist of carbon atoms only ; 
but there are those which in addition to the C-atoms also contain 
atoms of other polyvalent elements (oxygen, sulphur and nitrogen). 
Closed chains of this class are numerous among the fatty bodies, 
é. g., the anhydrides of the dicarboxylic acids (succinic anhydride, 

CH,CO 
p- 412) succinimide, | NH (p. 412), parabanic acid,. the 
. CH,CO ; 
derivatives of cyanuric acid and melamine (p. 290), etc., etc. In 
all of them 2CO are usually united by O, S or N, and the com- 
pounds are very unstable and change rapidly to the normal open 
chains. The chain of the 7-lactone. contains but one CO-group, 
2 ee 
C,H,O, Thiophene, C,H,S, and Pyrrol, C,H,(NH), consist of 
closed chains in which the linking is even firmer than in the deriva- 
tives mentioned. These bodies attach themselves to the benzene 
series ; their constitution is very probably represented by the fol- 
lowing structural formulas :— 


CO (p. 351), and is more stable. .Furfurane, 


No Ns \NH 
CH — CH” CH — CH” CH — CH” 
Furfurane. Thiophene, Pyrrol. 


In accordance with these formulas the three parent substances 
and their derivatives exhibit many striking analogies in their entire 
deportment. Thus furfurane, thiophene and pyrrol yield bluish 

44 


522 ORGANIC CHEMISTRY. 


violet dyestuffs with isatin and sulphuric acid, and compounds hav- 
ing a violet red color, when acted upon with phenanthraquinone 
and sulphuric acid. Again, these compounds, and all those 
obtained from them, exhibit a striking and astonishing similarity 
to benzene. This is especially true of thiophene. All the peculiar 
reactions of benzene derivatives, those which distinguish the latter 
from the fat-bodies, are shown by furfurane, pyrrol and thiophene. 
Thus, the halogens produce substitution derivatives and not 
additive compounds (as with the olefines). This would scarcely 
be expected from the fact that double unions occur in furfurane, 
etc. ete... 

The synthetic methods, applied in the formation of furfurane, pyrrol and thio- 
phene, correspond in every particular to the accepted structural formulas. All 
three compounds are obtained from y-diketone derivatives, in which the atomic 
group—CO.CH,.CH ,CO—is present, by the separation of water and the linking of 
the two carbonyl carbon atoms by O, S or N (p. 329). It may be assumed that 
here the diketone form sustains a transposition into the unstable, unsaturated 
dihydroxy] form (syntheses of Paal, Berichte, 17, 2757; 18, 367), etc. :— 


CH,—CO—R CH = C(OH)—R CH = 1 
yields* | Pos or NH). 
CH = C7 


| or | 
CH,—CO—R CH = C(OH)—R 
i NR 


Analogous hydroxyl derivatives react in harmony with this view; thus, by with- 
drawing water from mucic and isosaccharic.acids furfurane dicarboxylic acid is 
formed, and by distillation with BaS thiophene carboxylic acid is ‘ca product 


(p. 534) : — 
CO,H 


CH(OH)—CH(OH)—CO,H CHa? 
yields | YO (or S) + 3H,0. 
H(OH)—CH(OH)—CO,H CH cr 
a \co,H 
Diaceto-succinic acid (p. 437) yields dimethyl furfurane dicarboxylic acid and 
dimethylpyrrol dicarboxylic acid (syntheses of Knorr, Berichte, 17, 2863; 18, 


299, etc.) :— 


CH 
CH,.CO.CH.CO,R NG eO.CO LR 
l yields (or NH)OC | + H,0. 
CH,.CO.CH.CO,R SG =C.CO,R 
CH,” 
CH,.CO.CH, 
In a similar manner acetonyl-acetoacetic ester, (p. 340), 


CH,.CO,CH:CO,R 
yields the dimethyl monocarboxylic acids, etc. Consult Berichte, 21, 2932, 3451 
for other furfurane derivatives. 
To distinguish the possible isomerides the replaceable hydrogen atoms, or the 


THE FURFURANE GROUP. 523 


C-atoms in furfurane, thiophene and pyrrol are designated by numbers as with 
benzene :— 


2 1 
CH = CH CH = CH 
l yO me yo. 
CH = CH CH = CH 
3 4 p/ a’ 


The positions 1 and 4 are equal in value, also 2 and 3. The first are also 
termed a-, the latter 8-positions. It is obvious that the mono-derivatives of fur- 
furane, etc., can exist in two isomeric forms (a-derivatives and (- derivatives). 





1. THE FURFURANE GROUP.* 


Furfurane, C,H,O (see above), was formerly held to be tetrol- 
phenol, C,H;.OH. It was first obtained by distilling barium pyro- 
mucate (p. 526) with soda-lime: (C,H,0.CO,H = C,H,0 + CO,), 
It is present in the distillation products of pine wood. It is a 
liquid, insoluble in water, has a peculiar odor, and boils at 32°. 
Metallic sodium has no effect upon it, nor does it combine with 
phenyldrazine. It yields dye substances with isatin and phenanthra- 
quinone (see above). It reacts very violently with hydrochloric 
acid, and forms a brown amorphous substance (like pyrrol red, 
p. 539). A pine shaving moistened with hydrochloric acid, assumes 
a green color when brought in contact with the vapors of furfurane. 


Brominated derivatives can be obtained from brom-pyromucic acids, or by the 
direct action of bromine upon furfurane. Other addition products result from 
an excess of bromine. 


ALKYLIZED FURFURANES. 


Methyl Furfurane, C,H,(CH,)O, is in all probability sy/van, which occurs 
in pine tar oil. It boils at 63° (Berichte, 13, 881). : 
a-Dimethyl Furfurane, C,H,(CH,),O(1, 4), is formed by the distillation of 
carbopyrotritartaric acid (p. 528), and has been directly synthesized from aceto- 
nyl acetone upon heating it with ZnCl, or P,O, (p. 328). A mobile liquid with a 
peculiar odor. It boils at 94°. It is resinified when heated with concentrated 
mineral acids (Berichte, 20, 1085). 
It regenerates acetonyl acetone when it is heated with dilute hydrochloric acid 
to 170°. 
a-Methyl-phenyl Furfurane,C,H, { ca ‘ O(1,4), is produced from aceto- 
CH,.CO.CH, . 
phenone-acetone, | , upon digesting it with acetic anhydride, or 
CH,.CO.C,H, 
hydrochloric acid, (Berichte, 17, 915 and 2759). It crystallizes from alcohol in 
shining needles, melting at 42°. The compound boils at 235-240° C. Sodium, 
in alcoholic solution, converts it into the tetrahydro-compound, C,,H,,0. 
Nitroethylene Furfurane, C,H,0.CH:CH(NO,). This results from the 
condensation of furfurol, C,H,O.CHO, with nitroethane. It consists of yellow 





* Compare “‘ Das Furfuran, etc,’ von A. Bender, 1889. 


tag ORGANIC CHEMISTRY. 


needles, melting at 75° ( Berichte, 18, 1362). By nitration it passes into nitro- 
furfurane-nitroethylene. 

Butylene Furfurane, C,H;0.C,H,, has been obtained by the condensation 
of furfurol with isobutyric acid (see below). A liquid, boiling at 153° (Berichée, 


17, 850). 

Diphenyl Furfurane, C,H,(C,H,;),0, see Berichte, 21, 3057. Triphenyl 
Furfurane, C,H(C,H,),O, see Berichie, 21, 2933. Tetraphenyl Furfurane, 
C,(C,H,;),0, Lepidene, Berichte, 22, 2880. 


ALCOHOLS. 


Furfuryl Alcohol, C;H,O, = C,H,0.CH,OH (the monovalent group 
C,H,0 is called furfur-), results from the action of sodium amalgam and acetic 
acid upon the aldehyde furfurol, but more easily by treatment with aqueous caustic 
potash (Berichte, 19, 2154). Furfurane carboxylic acid is produced at the same 
time (2C,H,0.CHO + H,O = C,H,0.CH,OH + C,H,0.CO,H). Ether 
extracts it as a colorless syrup, which in drying becomes gummy. It is colored 
green by hydrochloric acid. 

Ethylfurfur-Carbinol, &444°° >CH.OH, results from the action of furfurol 


and zinc ethide. It boils at 180° (Berichte, 17, 1968). 


ALDEHYDES AND KETONES. 


a-Furfurol, C;H,0, = C,H;0.CHO, (1-4), the aldehyde of 
furfuryl alcohol, or of pyromucic acid, is produced in the distilla- 
tion of bran with dilute sulphuric acid, or of sugar, as well as most 
carbohydrates and glucosides. When present in even the merest 
traces it can be detected by the red coloration given by aniline 
or xylidine (Berichté, 20, 541). It yields a violet coloration with 
a-naphthol and sulphuric acid (Berichte, 21, 2744). 

Preparation.—Distil 1 part of bran with 1 part sulphuric acid; dilute with 3 
parts of water. Throw out the furfurol from the distillate by the addition of com- 
mon salt, and repeat the distillation (Anmalen, 116, 257; 156, 198). The pro- 


duct obtained on distilling algze with sulphuric acid consists chiefly of furfurol and 
methyl furfurol (Berichte, 23, Ref. 154). 


Furfurol is a colorless liquid with an aromatic odor. Its specific 
gravity at 13° is 1.163. It boils at 162°. It is soluble in 12 parts 
of water at 13°, and very soluble in alcohol. It becomes brown 
on exposure to the air, and shows all the properties of an aldehyde. 
It combines with bisulphites, passes into furfuryl alcohol under the 
influence of sodium amalgam, and is changed to pyromucic acid 
by argentic oxide, and to the alcohol and acid through the action 
of caustic potash (this is similar to the behavior of the benzalde- 
hydes). It yields furfuraldoxime, C,H;0.CH:N(OH) with hy- 
droxylamine; it melts at 89° and boils at 205° (Berichte, 23, 2336). 
It unites similarly with phenylhydrazine, forming a hydrazone, 
C,H;0.CH:(N,H)C,H,, melting at96°, Furthermore, furfurol mani- 
fests all the condensation reactions of benzaldehyde (see below). 
It combines with dimethylaniline to form a green dye-stuff, cor- 
responding to malachite green. 


AMIDE DERIVATIVES. 525 


In furfurol the aldehyde group occupies the a-position. This is 
evident from the fact that the furonic acid, obtained from it, can be 
reduced to normal a-pimelic acid (p. 528). 


a-Methyl Furfurol, C,H,(CH,)O.CHO, occurs together with furfurol in wood 
oil. It can be isolated from this by fractional crystallization (Berichte, 22, 608). 
It is also present in the product obtained by distilling varec with sulphuric acid 
(Berichte, 22, Ref. 751). When rhamnose is distilled with sulphuric acid, it re- 
sults, and may, therefore, be considered as the anhydride of rhamnose (Berichte, 
22, Ref. 752) :— 


CH, 
CH(OH).CH(OH).CH, CH=C~ 


>. .-+ 2H,0. 


\CHO 


It is an oil, boiling at 184-186°. It may be oxidized to methyl pyromucic acid. 
Alcohol and sulphuric acid color it green. 

Furfurol condenses with fatty aldehydes and ketones, forming furfuryl-aldehydes 
and ketones having unsaturated side-chains. As in the case of benzaldehyde this 
reaction here proceeds with ease on digesting with sodium hydroxide (Berichte, 
12, 2342). Thus acetaldehyde or paraldehyde reacts according to the equation: — 


C,H,0.CHO ++ CH,.CHO = C,H,0.CH:CH.CHO, Furfur-acrolein. 


CH(OH).CH(OH).CHO CH=C 


Furfur-acrolein, C,H,O,, melts at 51° and boils above 200°. Propionic alde- 
hyde yields Furfur-crotonaldehyde, C,H,O.CH:C(CH,)CHO, which is an oil 
with ethereal odor. With acetone, furfurol forms Furfur-acetone, C,H,O.CH: 
CH.CO.CH,, ete. 

When furfurane is exposed to the action of KCN in alcoholic solution, it suffers 
a peculiar transposition into Furoin (like that of benzaldehyde to benzoin) :— 


C,H,0.CO 
2C,H,0.CHO = , Furoin. 
C,H,0.CH.OH 


Furoin, C,,H,O,, is crystalline and melts at 135°. The oxygen of the air oxi- 
dizes it, when in alkaline solution, to Furil, C,,H,O, = C,H,0.CO.CO.C,H,0,a 
compound analogous to benzil. KCN decomposes furil into furfurol and the ester 
of pyromucic ester (Berichte, 16, 658). When furil is digested with caustic potash 
it becomes furilic acid (analogous to benzilic acid (see this). 

Mixed furoins, ¢.g., Benzfuroin, C,H,.CO.CH(OH).C,H,, are produced, 
like furoin from furfurol, by letting KCN act upon a mixture of furfurol and benz- 
aldehyde. 





AMIDE DERIVATIVES. 


Furfurylamine, C,H,0.CH,.NH,, is obtained by reducing furfuro-nitrile, 
C,H,0.CN (p. 526), and furfurol hydrazone (p. 524) with sodium amalgam. It. 
is a liquid, boiling at 146° (Berichte, 20, 399). 

Furfuramide, (C,;H,O),N,, results from the action of aqueous ammonia upon 
furfurol (same as hydrobenzamide from benzaldehyde, see this) :— 


C,H,O.CH:N\, 


3C,H,0.CHO + 2NH,= CHO. CHN> 


CH.C,H,O + 3H,0. 


520 ORGANIC CHEMISTRY. 


It is very soluble in alcohol and ether. It crystallizes in yellowish-colored 
needles, melting at 117°. It has a neutral reaction, and does not combine with 
acids. Acids and boiling water decompose it into furfurol and ammonia. If 
heated to 120°, or if boiled with KOH, it undergoes a transposition (like that of 
hydrobenzamide into amarine) into the isomeric base, Furfurin, C,,H,,N,O3;, 
melting at 116°, and forming salts with one equivalent of the acids. It is perfectly 
analogous to amarine of the benzene series. 

Benzene amido-compounds of varying composition are produced by the union 
of furfurol with anilines and aromatic diamines (1 and 2 molecules of the same) 
(Annalen, 201, 355). In this way, dye-stuffs, resembling rosaniline, have been 
produced. Their salts show an intensely red color, e, g., furoxylidine, C,H,0. 
CH(C,H,.NH,)., and answer for the detection of furfurol (Berichte, 20, 541). 





ACIDS. 


a-Furfurane-carboxylic Acid, C,H,O,; = C,H,O.CO,H, syvo- 
mucic acid, is obtained by the oxidation of furfurol with silver oxide 
or caustic potash, and in the distillation of mucic and isosaccharic 
acids (p. 522); it, therefore, contains the carboxyl group in the 
a-position. 


To prepare pyromucic acid, distil about 30 grams of mucic acid from a retort 
(Annalen, 165, 256). A better course is to let alcoholic caustic potash act upon 
furfurol (Annalen, 165, 279). 


Pyromucic acid is very soluble in hot water and alcohol. It crys- 
tallizes in needles or leaflets, melting at 134°, and subliming at 
100° C. : 


Its ethyl ester, C,H,0.CO,.C,H,, melts at 34° and boils at 210° C. Its chlor- 
ide, C,H,0.COCI, obtained by distilling the acid with PCl,, boils at 170°. Am- 
monia converts this into an amide, C,H,O.CO.NH,, which is changed into 
Jurfuryl-nitrile, Cy¥,0.CN, by PCI. 

Bromine vapor converts pyromucic acid into a tetrabromide, C,H,OBr,.CO,H, 
which is oxidized to dibromsuccinic acid by chromic acid. Fumaric acid results 
on evaporating pyromucic acid with bromine water (2 molecules). An excess of 
bromine or chlorine water produces mucobromic acid, C,H,Br,O,, and muco- 
chloric acid, C,H,C1,0, (p. 427). 

a-Brom-pyromucic Acid, C,H,BrO.CO,H (4 or a’) is formed by heating the 
tetrabromide, and by brominating pyromucic acid in glacial acetic acid solution. 
It consists of pearly leaflets, melting at 184° (Berichte, 19, Ref. 241). $-Brom- 
pyromucic Acid, C,H,BrO.CO,H, from the two dibrompyromucic acids and 
zinc, melts at 129°. 

Two Dibrompyromucic Acids, C,HBr,.CO,H, have been obtained from 
pyromucic tetrabromide by means of alcoholic soda. The £(’-acid melts at 192°, 
the Ba’-acid at 168° (Berichte, 17, 1759). 

Nitropyromucic Acid, C,H,(NO,)O.CO,H, is formed by nitrating furfurane 
dicarboxylic acid with a mixture of nitric and sulphuric acids, and by oxidizing 
nitroethylene-nitrofurfurane (p. 523). It crystallizes from water in bright yellow 
plates, melting at 183° (Berichte, 18, 1362). 

Isopyromucic Acid, C;H,O,, apparently does not exist (Berichte, 23, Ref. 
154). 


FURFUR-ACRYLIC ACID. 527 


Methyl Pyromucic Acid, C;H,(CH,)O,, has been obtained by the oxidation 
of methyl furfurol. It melts at 109° tertoe, 22, 608). Bromine water converts 
it into aceto-acrylic acid (Berichte, 23, 452). 

CH, 


Methyl Furfurane Acetic Acid, CHOC CH,.CO,H, Sylvan-acetic acid, has 


been obtained by the condensation of glyoxal with aceto-acetic ester, etc. It melts 
at 137° (Berichte, 21, Ref. 636). 

aa-Dimethyl Furfurane-§-carboxylic Acid, Pyrotritartaric Acid, C,H,O, 
= C,H(CH,),0.CO,H (Berichte, 20, 1074), Uvinic Acid, was first obtained 
from tartaric acid (with pyroracemic) by distillation. It can also be produced 
from pyroracemic acid by protracted boiling with baryta water or sodium acetate, 
etc. It has been synthetically prepared (its ethyl ester) by the action of fuming 
hydrochloric acid upon acetonyl aceto-acetic ester (Berichte, 17, 2765). It also 
results from carbopyrotritartaric acid and from methronic acid (p. 528) by the 
splitting-off of carbon dioxide. This occurs when the acid is heated beyond its 
melting point. This is the best method for the obtainment of uvinic acid. 

Pyrotritartaric acid dissolves with difficulty even in hot water (in 400 parts), 
from which it crystallizes in needles, melting at 135° C. It sublimes readily and 
is quite volatile with steam. When heated to 150-160° with steam it breaks up 
into carbon dioxide and acetonyl acetone (p. 328). Rapidly distilled, it decom- 
poses into carbon dioxide and a-dimethyl furfurane. See Berichte, 20, 1077, for 
brompyrotritartaric acid. CH 

aa-Methylphenylfurfurane-carboxylic Acid, C,H Cc H )o.co,H. Its 

61*5 


ethyl ester is produced by the action of hydrochloric acid upon acetophenon-aceto- 
C,H,;.CO.CH, 


cH, co.CH.co,R 
tion, melts at 181°, and upon boiling with dilute sulphuric acid yields methyl- 
phenylfurfurane (p. 524) (Berichte, 17, 2764). 


acetic ester, (p. 522). The free acid, obtained by saponifica- 





Furfurane acids, with unsaturated side chains, are produced in the condensation 
of furfurol and fatty acids, on heating it with the anhydrides and sodium salts of the 
fatty acids. This is analogous to the formation of cinnamic acid (see this) from 
benzaldehyde. Furfur-acrylic acid results on heating furfurane with acetic anhydride 
and sodium acetate :— 


C,H,O.CHO + CH;,.CO,Na = C,H,0.CH:CH.CO,Na + H,0. 
Furfurane. Furfur-acrylic Acid. 


Furfur-acrylic Acid, C,H,O,. This acid is also formed on oxidizing furfur- 
acrolein with silver oxide ; furfur-malonic acid also yields it (Berichte, 21, 1081). 
It dissolves with difficulty in water, crystallizes in long needles, has an odor like 
that of cinnamon, and melts at 135°. When it is heated with hydrochloric acid it 
becomes acetone-diacetic acid. Sodium amalgam converts it into i 

Furfur-propionic Acid, C,H,0O.CH,.CH,.CO,H, melting at 51°. Bromine 
disrupts the furfurane ring in this compound, and the product is the aldehyde of 
furonic acid (Berichte, 10, 695) :-— ; 


CH = a CH—CHO. 
CH = CL : CH—CO.CH,.CH,.CO,H, 
CH,.CH,.CO,H 


me ORGANIC CHEMISTRY. 


CH.CO,H 
which silver oxide converts into furonic acid, C,H,O, = || 

CH.CO.CH,.CH,CO,H. 
Needles, melting at 180°. Sodium amalgam changes furonic acid to hydrofuronic 
acid, C,H,,O;, which passes into normal pimelic acid, C;H,,(CO,H), (p. 421), on 
heating it with hydriodic acid and phosphorus (Berichte, 11, 1358). 

Furfur-angelic Acid, C,H,,O, = CH,O.C:C£ 66, - Hs) from furfurol and 

butyric acid (see above), melts at 88°, and passes into the corresponding Furfur- 
valeric Acid under the influence of sodium amalgam. 





DICARBOXYLIC ACIDS. 


a-Furfurane Dicarboxylic Acid, C,H,0, =C,H,O(CO,H),, dehydromucic 
acid, is produced by heating mucic acid to 100° with hydrochloric and hydro- 
bromic acid (p. 522). It dissolves with difficulty in water, crystallizes in needles, 
and when heated does not melt but breaks up into carbon dioxide and pyromucic 
acid. 

a-Dimethylfurfurane-8-dicarboxylic Acid, C,H,O, = C,(CH,),0(CO,H),, 
carbopyrotritartaric acid, results upon boiling diacetsuccinic ester (p. 437) with 
dilute sulphuric acid. When the ester is heated alone, or is acted upon by con- 
centrated hydrochloric acid, the primary ester, C,H,O,.C,H,, is produced, but if 
allowed to stand with sulphuric acid, the diethyl ester, C, HgO,(C,H;), (Berichde, 
17, 2864), is the product. Carbopyrotritartaric acid crystallizes from hot water 
in minute needles, melting at 231°, and at higher temperatures breaks up into 
carbon dioxide and pyrotritartaric acid. 

Methronic Acid, C,H,O, = C,(CH,),0(CO,H),, is isomeric with carbopyro- 
tritartaric acid. It is produced by digesting aceto-acetic ester with sodium succin- 
ate and acetic anhydride (Fittig, Berichte, 18, 3410). By similar action, aceto- 
acetic ester and pyrotartaric acid yield methyl methronic acid, and benzoyl-acetic 
ester and succinic acid form phenylmethronic acid (Berichte, 21, 2134). Methronic 
acid is more soluble in water and melts at 204°. At higher temperatures it also 
decomposes into carbon dioxide and pyrotritartaric acid. It is, therefore, very 
probable that methronic acid and carbopyrotritartaric acid, with their compounds, 
are derived from furfurane (Knorr). R. Fittig thinks that they are derivatives of 
hypothetical ze¢rylone (p. 521) (Berichte, 22, 146). 

Isocarbopyrotritartaric Acid, C,H,O,, of unknown constitution, is isomeric 
with methronic and carbopyrotritartaric acids. It is formed when diaceto-succinic 
ester is distilled (Berichte, 22, 158). 





j THIOPHENE GROUP.* 


Thiophene, C,H,S, an analogue of furfurane, C,H,O (p. 521), 
exhibits, in a more marked degree than the latter, a complete anal- 
ogy with benzene, C,H,; its derivatives are perfectly analogous to 
those of benzene. It may be viewed asa benzene, in which one 
of the three acetylene groups, CH:CH, has been replaced by S, 





* V. Meyer, Die Thiophengruppe, 1888. 


- THIOPHENE GROUP. 529 


the original properties not being essentially altered. By the replace- 
ment of the 4-H atoms in thiophene, by other elements or groups, 
we obtain innumerable derivatives, in all respects analogous to those 
derived from benzene. » All thiophene compounds give an intense 
blue coloration—the indophenin reaction, Berichte, 16, 1473— 
when mixed with a little isatin and concentrated sulphuric acid. 
The methods of forming the thiophenes synthetically from (1, 4)- 
or y-dicarboxyl compounds, have been given on pp. 329, 522). It 
may be well to again direct attention to the ready transposition of 
the 7-ketonic acids, which yield oxythiophenes when heated with 
P,S;, or thiophene hydrocarbons if P,S, be employed (Berichte, 19, 


5513; 23, 1495) :— 


CH CH 
CH,.CO.CH, CHCA Hac 4" 
l yields i >s and | SS 
CH,.CO,H H=C CH—CH 
‘NOH 
Levulinic Acid. (x, 4)-Oxythiotolene. a-Thiotolene. 


(1, 3)-Thioxene, C,H,S(CH;), (Berichte, 20, 2017), and (1, 2)- 
thioxene (Berichte, 20, 2577) are similarly produced from a-methyl- 
levulinic acid, CH;.CO.CH,.CH(CH;).CO,H, and #-methyl-levu- 
linic acid, CH;.CO.CH.CH;.CH,.CO,H (Berichte, 21, 3451). The 
isomerisms of thiophene derivatives correspond to those of furfurane 
and are similarly named (p. 523). The a-derivatives (those in 
which the H-atom is adjacent to the sulphur-atom) were formerly 
termed f-derivatives, and the real £-derivatives considered as and 
designated y-derivatives. In the following pages the correct desig- 
nations, corresponding to the thiophene formula (p. 521), have 
been introduced (Berichie, 19, 2890). 

The thiophene bodies were discovered by V. Meyer, in 1883. 

Thiophene, C,H,S, and its homologues, occur in ordinary, im- 
pure coal tar. The individual thiophenes are contained in the 
corresponding commercial benzene hydrocarbons (about 6%). 
They have the same boiling points as the latter. Thiophene is pres- 
ent in benzene, methyl thiophene (thiotolene), C,H,S.CH,, in tolu- 
ene, C,H;.CH,, dimethyl thiophene (thioxene), C,H,S(CH;),, in 
xylene, C,H,(CH;),, etc. Benzenes containing thiophene show the 
indophenin reaction (see above). The latter is not observed until 
the benzenes have been fully purified by shaking them with sul- 
phuric acid. The latter withdraws the thiophenes. 

Thiophene is synthesized by various reactions: By conducting 
ethyl sulphide through tubes heated to redness or passing ethylene 
or illuminating gas over heated pyrite, FeS,; and by heating cro- | 
tonic acid, butyric acid, etc., with P,S,;. It is produced quite abun- 


530 ORGANIC CHEMISTRY. 


dantly upon heating a mixture of succinic anhydride, or sodium 
succinate with P,S,; (Volhard) :— 


CH,.CO,Na CH=CH 
and P,S, yield | 6. 
CH,.CO,Na CH ce 


Preparation.—Shake ordinary benzene for some hours with sulphuric acid 
(10-4 per cent.), then separate the black acid-layer (containing the thiophene as a 
sulpho-acid) from the benzene, and dilute the former immediately with water. 
Some benzene sulphonate is usually present with the thiophene sulphonate, but its 
quantity diminishes as the quantity of sulphuric acid is decreased. When but 4 
per cent. of the latter is present the thiophene-sulphonate is almost pure. To lib- 
erate the thiophene from its sulphonate, convert the latter into its lead salt, and 
decompose this by distilling it with ammonium chloride (Berichte, 17, 792). Or 
the thiophene sulphonic acid is mixed with water and distilled in a current of 
steam (Berichte, 18, 497). 

All the thiophene present in crude benzene can be removed from it as dibrom- 
thiophene, C,H,Br,S, by the addition of a little bromine (Berichte, 18, 1490). 

To obtain thiophene from: succinic acid heat a mixture of sodium succinate 
(100 gr.) and P,S, (100 gr.) in a retort over the direct flame until the reaction 
sets in. The thiophene is expelled from the distillate when the latter is heated 
upon a water bath (Berichte, 18, 454). 


Thiophene is a colorless liquid, with an odor resembling that of 
benzene. It boils at 84°. Its sp. gr. is 1.062 at 23°. It becomes 
crystalline when exposed to a mixture of solid carbon dioxide and 
‘ether. Sodium has no effect upon it even when it is heated. 
Mixed with a little sulphuric acid and isatin it becomes dark blue 
in color. ‘The same occurs when its solution in sulphuric acid is 
added to phenanthraquinone in glacial acetic acid (Reaction of 
Laubenheimer, Berichte, 19, 673). All the dicarbonyl compounds, 
CO.CO, like benzil, alloxan, etc., behave the same as phenanthra- 
quinone (Berichte, 16, 2962). 


THIOPHENE HOMOLOGUES. 


In these compounds the hydrogen of thiophene has been re- 
placed by alkyls. They may be obtained by the action of alkyl 
iodides and metallic sodium upon iodothiophene (analogous to 
Fittig’s synthesis of the benzenes) (Berichte, 17, 1559) :— 


C,H,IS + C,H,I + 2Na = C,H,(C,H,)S + 2Nal. 


Only the methylated thiophenes occur already formed in coal tar 
oil. They correspond fully to the homologous benzenes, and with 
isatin and phenanthraquinone yield colors similar to those obtained 
with thiophene. 


THIOPHENE HOMOLOGUES. 531 


1. Methyl Thiophenes, Thiotolenes, C,H,S.CH,. 

a-Thiotolene, C,H,S.CH,, containing the methyl group in the a-position 
(p. 523), is produced from iodothiophene by the aid of methyl iodide and sodium, 
and from lzvulinic acid by the action of P,S, (p. 529). It boils at 126°, and is 
converted into a-thiophenic acid by oxidation. b 

B-Thiotolene, C,H,S.CH,, is formed when sodium pyrotartrate is heated with 
PS, (Berichte 18, 454) :— 


CH,.CH.CO,Na CH, .C = CH ©: 
and P,S, yield | p> It boils at 113°. 
CH,.CO,Na CHiax€ 


It becomes {-thiophenic acid when oxidized. 

Both thiotolenes occur in coal tar (in toluene), and may be isolated from it in 
the same manner that thiophene is extracted. Formerly their mixture was con- 
sidered a distinct thiotolene, as the tribromthiophene and the thiophenic acid, ob- 
tained from it appeared to differ from the corresponding a-.and (-thiophene deriv- 
atives. Later research has shown it to be a mixture (Berichte, 18, 3005). 

2. Dimethyl Thiophene, Thioxene, C,H,S(CH,),. 

(1, 2)-Dimethyl Thiophene is obtained from #-methyl-lzvulinic acid, CH,. 
CO.CH(CH,).CH,.CO, H, by the action of P,S, (p. 529). It boils at 136°, and 
is oxidized to (1, 2)-thiophene-dicarboxylic acid by potassium permanganate. _ 

(1, 3)-Dimethyl Thiophene is formed when P,S, acts upon a-methyl-lzevulinic 
acid (p. 529). It is an oil, boiling at 137-138°. It gives an emerald green col- 
oration with isatin. Alkaline permanganate oxidizes it to (1, 3)-thiophene-dicar- 
boxylic acid. 

(1, 4)-Dimethyl Thiophene is 7iioxene, obtained from xylene. It may be syn- 
thesized by acting upon a-iodothiotolene with methyl iodide and sodium. It is also 
formed when P,S, acts upon acetonyl acetone (p. 329). It boils at 135°, yields 
a cherry-red color with isatin, and with phenanthraquinone, etc., a violet colora- 
tion. Potassium permanganate oxidizes it to (1, 4)-thiophene-dicarboxylic acid. 

(2, 3)-Dimethyl Thiophene has been obtained from symmetrical dimethyl- 
succinic acid by the action of P,S,. It boils at 145° (Berich/e, 21, 1836). 

a-Ethyl Thiophene, C,H,S.C,H,, from a-iodo- or brom-thiophene by means 
of ethyl bromide and sodium, is very similar to ethyl benzene. It boils at 132- 
134°. Permanganate oxidizes it first to thiénylglyoxylic acid, and then to a-thio- 
phenic acid. 

B-Ethyl Thiophene, C,H,S.C,H,, is produced upon heating ethyl succinic acid 
with P,S,. It is perfectly similar to the a-compound, but yields 6-thiophenic acid 
when oxidized (Berichte, 19, 3284). 

Trimethyl Thiophene, C,H(CH,),S, has been obtained from dimethyl-levu- 
linic acid by the action of P,S,; (Berichte, 20, 2085). 

a-Normal Propyl Thiophene, C,H,S.C,H,, boils at 158°, and yields a-thio- 
phenic acid when oxidized (Berichte, 20, 1740). Isopropyl Thiophene, C,H,S. 
C,H,, is prepared by the action of aluminium chloride upon thiophene and iso- 
propylbromide. Sodium will not answer in this reaction. It boils at 154°. Un- 
like all other homologous thiophenes it yields an intense violet color directly with 
phenanthraquinone (Berichte, 19, 673). , 

Tetramethyl Thiophene, C,S(CH,),, is obtained from iodo-trimethyl thio- 
phene by the action of methyl iodide and sodium. It boils about 183° (Berichte, 
21, 1838). 


E H 
a-Methyloctyl Thiophene, CH,8(¢ H ) (1, 4), from a-methylthiophene, 
ae 1 


is identical with that obtained from a-octylthiophene. This is proof of the s7mz- 
larity of the two a-positions (1) and (4) in thiophene (Berichze, 19, 649). 


532 ORGANIC CHEMISTRY. 


a-Phenylthiophene, C,H,S.C,H,, is prepared by heating (-benzoy] propionic 
acid or 6-benzoylisosuccinic acid with P,S, or P,S, :— 


CH,.CO.C,H, CH,.CO.C,H, Ch 07 “els 
ands | yield | »>$ 
CH,.CO,H CH(CO,H), CH=CH 
B-Benzoyl-propionic Acid. B-Benzoyl-isosuccinic Acid. a-Phenylthiophene. 


The product crystallizes from alcohol in small plates, melting at 40-41° 
(Berichte, 19, 3140). /CH 
Methylphenyl Thiophene, CAS C H.: The (1, 4)-compound results from 
6 


the action of P,S, upon acetophenon-acetone, C,H,.CO.CH, CH,.CO.CH,. It 
melts at 51° and boils at 270°. (1, 3)-Methylphenyl thiophene, from a-pheny]l- 
levulinic acid and P,S, (p. 529), melts at 73° (Berichte, 20, 2558). 


HALOGEN DERIVATIVES. 


Chlorine and bromine attack thiophene in the cold. The action is even more 
energetic than with the benzenes. Iodine, in the presence of mercuric oxide 
(p. 91), also attacks it at the ordinary temperature. The three halogens first 
enter the a-position. In properties the haloid thiophenes are very similar to the 
benzene haloids. 

a-Chlorthiophene, C,H,CIS, boils at 130°, and Dichlorthiophene, C,H,C1,S, 
at 170°. Tetrachlorthiophene, C,Cl,S, melts at 36°, and boils from 220-240°. 
When thiophene is brominated, even in the cold, the chief product is the dibromide. 
A little of the monobromide is formed at the same time. 

a-Bromthiophene, C,H,BrS, boils at 150°. It yields a-ethylthiophene, when 
acted upon by ethyl iodide and sodium. (1, 4)-Dibromthiophene, C,H,Br,S, 
boils at 211°. Its formation serves for the complete isolation of all the thiophene 
that may be present in a thiophene-benzene (Berichie, 18, 1490). Tribromthio- 
_phene, C,HBr,S, melts at 29°, and boils at 260°, Tetrabromthiophene, C,Br,S, 
is the final product in the bromination of thiophene. It crystallizes in brilliant 
needles, that melt at 112°, and boil at 326°. 

a-Iodo-thiophene, C,H,IS, is obtained from thiophene by the action of iodine 
and mercuric oxide, even in the cold. It is a liquid and boils at 182°. Chlorcar- 
bonic ester and sodium convert it into a-thiophene carboxylic acid. Diiodothio- 
phene, C,H,I,S, melts at 40°. 


NITRO-DERIVATIVES. 


The action of nitric acid upon thiophene is so very energetic that in order to 
moderate the reaction air charged with thiophene vapor is conducted into the 
fuming nitric acid. Mono- and dinitrothiophene are then produced (erichée, 17, 
2648). 

Nitrothiophene, C,H,(NO,)S, is quite similar to paranitrotoluene. From cold 
solutions it separates in bright yellow prisms, melting at 44° and boiling at 225°. 
Its odor resembles that of nitrobenzene. 

Dinitrothiophene, C,H,(NO,),S, resembles dinitrobenzene. It melts at 52° 
and boils at 290°. It is volatile with steam. Caustic potash colors its alcoholic 
solution dark red. The same coloration of dinitrobenzene, caused in the same 
way, is due to admixed dinitrothiophene (Berichte, 17, 2778). When repeatedly 
distilled with water dinitrothiophene is converted into a modification, melting at 78°. 


THIOPHENE PHENOLS, 533 


AMIDO-DERIVATIVES. 


Nitrothiophene is reduced with much more difficulty than the nitrobenzenes. 
The reduction succeeds when zinc and hydrochloric acid are allowed to act upon 
the dilute alcoholic solution (Berichte, 18, 1490). 

Amidothiophene, Thiophenin, C,H,S.NH,, analogous to aniline, is a bright 
yellow oil. It rapidly resinifies on exposure tothe air. Its HCl-salt consists of 
deliquescent needles. It does not yield a diazo-derivative when ‘acted upon with 
nitrous acid. It combines immediately with salts of diazobenzene, forming stable, 
mixed azo-dyestuffs, ¢. g., CgH;.N:N—C,H,S.NH,.HClI (Berichée, 18, 2316). 


SULPHO-ACIDS, 


Like the benzene sulphonic acids, the thiophene sulpho-derivatives are produced 
by dissolving thiophene in sulphuric acid, generally at the ordinary temperature. 
They can also be prepared from the thionyl-ketones (p. 534) (Berichte, 19, 674, 
2623) :— 

C,H,S.CO.CH, + SO,H, = C,H,S.SO,H + CH,.CO,H. 


a- Thiophene Sulphonic Acid, C,H,S.SO,H, is formed upon shaking thiophene 
with ordinary sulphuric acid (Berichte, 19, 1615). The acid, liberated by hydro. 
gen sulphide from its lead salt, consists of very deliquescent crystals. If it be 
distilled it yields thiophene. Its derivatives are perfectly analogous to those of 
benzene-sulphonic acid. 

8-Thiophene Sulphonic Acid, C,H,S.SO,H, is obtained when sodium amal- 
gam acts upon a-dibrom-thiophene sulphonic acid. It is very similar to the 
a-acid. 

(1, 4)-Thiophene Disulphonic Acid, C,H,S(SO,H),, is produced by the 
action of fuming sulphuric acid upon the a-mono-sulphonic acid, while (2, 3)- 
Thiophene Disulphonic Acid, C,H,S(SO,H),, is obtained by reducing a-dibrom- 
oe acid, C,Br,S(SO,H),, with sodium amalgam (erich/e, 19, 
184). 

The sulphonic acids of the homologous thiophenes cannot be prepared by 
sulphonating the latter, but are derived from their ketone compounds. Thus, 
methylthiényl-methyl-ketone yields Methylthiophen-sulphonic Acid, C,H, 
(CH,)S.SO,H (Berichte, 19, 1620) :— 


C,H,(CH,)S.CO.CH, + SO,H, = C,H,(CH,)S,SO,H + CH,.CO,H. 


PHENOLS. 


a Oxythiophene, C,H,S.OH, is not known. Thiénylsulphydrate, C,H,S. 
SH, corresponding to it, is prepared by reducing a-thiophene-sulphonic chloride, 
C,H,S.SO,Cl, with zine and hydrochloric acid. It is present in the crude thio- 
phene product obtained by distilling succinic acid with P,S;. It is a yellow oil, 
with a very unpleasant odor. It boils about 166°. It unites with benzene diazo- 
aera to form azo-dyestuffs. Phenol does not show this reaction (Berichée, 
19, 1617). 

a-Oxymethylthiophene, Oxythiotolene, C,H,(CH,)S.OH(1, 4), is synthet- 
ically prepared by heating levulinic acid with P,S,. If P,S, be employed the 
oxythiotolene will be further reduced to a-thiotolene (p. 531). It is a colorless oil, 
with a disagreeable odor. It boils about 200°. It is soluble in alkalies. Carbonic 
acid again separates it (Berichte, 19, 555). 


534 ORGANIC CHEMISTRY,’ 


ALDEHYDES AND KETONES. 


a-Thiophen-Aldehyde, C,H,S.CHO, results from the distillation of thiényl- 
glyoxylic acid, C,H,S.CO.CO,H (Berichie, 19, 1885). It is a yellow oil, with an 
odor resembling that of benzaldehyde, C,H,.CHO. It boils at 198°. It has all 
the properties of an aldehyde. It reacts with fuchsine-sulphurous acid and diazo- 
benzenesulphonic acid (p. 189) ; combines with hydroxylamine to ¢hiophenaldoxime 
and with phenylhydrazine to ¢hiophenalhydrazone, C,H,S.CH(N,H.C,H,), melt- 
ing at 119° (Berichte, 19, 637; 1854). Thiophenaldehyde, like benzaldehyde, 
condenses with dimethyl aniline, forming a green dye, corresponding to malachite 
green. 

If oxidized, even in the air, it forms a-thiophenic acid. Aqueouscaustic potash 
converts it into thiophenic acid and thiophene alcohol: 2C,H,S.CHO + KOH = 
C,H,S.CO,K + C,H,S.CH,.OH. 

a-Thiophene Alcohol, C,H,S.CH,.OH, thiényl carbinol, is an aromatic liquid, 
boiling at 207°. It is perfectly analogous to benzyl alcohol, C,H;.CH,.OH. 

The ketone derivatives of thiophene are obtained in the same manner as those of 
the benzene series, viz., by the action of acid chlorides upon thiophene in the pres- 
ence of aluminium chloride (reaction of Friedel) (Berichte, 17, 2643) :— 


C,H,S + C,H,OCl = C,H,S.CO.CH, + HCl. 


a-Thiényl-methyl Ketone, C,H,S.CO.CH,, Acetothiénone, the analogue of 
acetophenone, C,H;.CO.CH,, is obtained from thiophene and acetyl chloride by 
means of aluminium chloride. It is an oil, boiling at 213°. Its odor resembles 
that of acetophenone. Being a ketone, it unites with both hydroxylamine and 
phenylhydrazine. If it be oxidized with permanganate, it first forms thiophene gly- 
oxylic acid, C,H,S.CO.CO,H, and then a-thiophenic acid (Berichte, 19, 2115). 

Methyl thiényl-methyl ketone, C,H,(CH,)S.CO.CHs, acetyl thiotolene, from 
a-methyl thiophene and acety! chloride, boils at 216°. 

Acetyl thioxene, C,H(CH,),S.CO.CH,, from thioxene and. acetyl chloride, 
boils at 224°. It yields thiophene tricarboxylic acid when oxidized with perman- 
ganate. 

When these ketones are heated with concentrated sulphuric acid, the acid radical 
breaks off, and thiophene sulphonic acids are produced (p. 533). If, however, SO, 
or pyrosulphuric acid be allowed to act in the cold upon the ketones, then the pro- 
ducts will be ketone-sulphonic acids (Berichte, 19, 2624). 

Thiényl Cyanide, C,H,S.CN, Thiophene nitrile, is obtained by distilling po- 
tassium thiophen-sulphonate with potassium cyanide or yellow prussiate of potash. 
It is perfectly similar to benzonitrile (phenylcyanide), and is an oil, having an odor 
very similar to that of oil of bitter almonds. It boils at 190°. 





THIOPHENE CARBOXYLIC ACIDS. 


Thiophene carboxylic acids are formed by methods which are per- 
fectly analogous to those employed in the preparation of the aro- 
matic acids :— 

(1) By the oxidation of the homologous thiophenes with a solu- 
tion of alkaline potassium permanganate (Berichte, 18, 546). The 
side chains are thus converted into carboxyl groups. Ethyl-thio- 
phene first yields thiophene-glyoxylic acid, C,H,S.CO.CO,H, but 


OT 


eo Le Seeger ee oT oe aes 


METHYL-THIOPHENIC ACID. 535 


this changes to thiophenic acid. The thiophene ketones, under 
similar treatment, yield first ketonic acids and then carboxylic acids 
(Berichte 18, 537). 

(2) By the action of chlor-carbonic ester and sodium amalgam 
upon iodo- or brom- thiophene:— 


C,H,IS + CICO,.C,;H, + 2Na = C,H,S.CO,.C,H, + NaCl + Nal. 


The thiophene carboxylic acids are perfectly similar to the ben- 
zene carboxylic acids in external properties and reactions. They 
split off carbon dioxide and revert to thiophene, C,H,5.CO,H = 
C,H,S + CO,, when distilled with lime. 

a-Thiophene Carboxylic Acid, C,H,S.CO,H, is formed when 
a-ethyl thiophene is oxidized with potassium permanganate ; when 
chlorcarbonic ester and sodium act upon mono- or di-iodo-thiophene 
(Berichte, 18, 2304); and upon heating mucic acid with barium 
sulphide (p. 522), when carbon dioxide is expelled. The acid is 
very similar to benzoic acid; it crystallizes from hot water in flat 
needles, melts at 126.5°, and boils at 260°. It is very volatile ina 
current of steam. Its vapors, like those of benzoic acid, produce 
coughing. Its ethyl ester, C,H,S.CO,.C,H;, boils at 218°. 

8-Thiophene Carboxylic Acid, C,H,S.CO,H (2 = 3), is pro- 
duced when f-methyl thiophene is oxidized with potassium perman- 
ganate (Berichte, 18, 3003; 19, 3284). It crystallizes from water 
in thick needles. It volatilizes very readily in a current of steam. 
It sublimes in leaflets, and melts at 136°. 


If two parts of.the a-acid and 1 part of the f-acid be crystallized seethes, homo- 
geneous needles separate. These melt constantly at 116-117°, and cannot be re- 
solved into their components again by fractional crystallization (Berichte, 19, 2891). 
The same compound, melting at 118°, is produced when crude thiotolene (from a- 
and (-thiotolene, p. 531) is oxidized (Berichte, 18, 548), and when thiophen nitrile, 
C,H,S.CN (from thiophene sulphonic acid, p. 533), is saponified with alcoholic 
potash. It was formerly thought to be a peculiar isomeric thiophene carboxylic 
acid and bore the name of a-thiophene carboxylic acid (Amma/en, 236, 200). 


METHYL-THIOPHENIC ACIDS. 


a-Methyl Thiophenic Acid, C,H SCO! H (1, 4), a-Thiotolenic Acid, is | 


prepared by the action of chlorcarbonic ester and sodium amalgam upon mono- 
and di-iodo-thiotolene (Berichte, 18,2304; 19, 656), as well as by the oxidation of 
synthetic thioxene with a permanganate solution. A little of the dicarboxylic acid 
is formed simultaneously (Berichte, 18, 2254). It melts at 137° (142°), and passes 
into the corresponding dicarboxylic acid when further oxidized. 


8-Methyl Thiophenic Acid, C,H SCC? Hp B. Thiotolenic Acid, results 


from the interaction of 8-iodothiophene and chlorcarbonic ester (Berichte, 19, 657), 
and ay the oxidation of acetyl-{-thiotolene, C,H,S(CH,).CO.CH,. It melts at 


nat 44°. It does not yield a dicarboxylic acid when further oxidized (Berichte, 19, 
80). 


536 ORGANIC CHEMISTRY. 


a-Thiényl-acetic Acid, C,H,S.CH,.CO,H, results upon reducing a-thiényl- 
glycollic acid by digesting it with hydriodic acid and phosphorus. It dissolves 
with difficulty in water, and melts at 76°. 

a-Ethyl Thiophenic Acid, C,H,(C,H,;)S.CO,H (1, 4), is obtained from 
iodoethyl thiophene and chlorcarbonic ester. It melts at 71°. 


Keton-Acids and Oxy-Acids. 


a-Thiénylglyoxylic Acid, C,H,S.CO.CO,H, is obtained by carefully oxidiz- 
ing acetyl thiophene, or ethyl thiophene, with permanganate (Berichte, 18, 537 ; 
19, 2115). It is a crystalline mass, readily soluble in water, and when perfectly 
anhydrous it melts at 91.5°. It decomposes into carbon dioxide and thiophen- 
aldehyde when heated. 

See Berichte, 20, 1746, upon three isomeric methylthiénylglyoxylic acids. 

Sodium amalgam converts thiénylglyoxylic acid into 

Thiénylglycollic Acid, C,H,S.CH(OH).CO,H, corresponding to mandelic 
acid, C,H,.CH(OH).CO,H. It is very soluble in water and melts at 115° (Be- 
richte, 19, 3281). 

POLYCARBONIC ACIDS. 


Thiophene Dicarboxylic Acids, C,H.S.(CO,H),. Four acids of this class 
are possible; three of these are known. 

The (z, 2)-acid, obtained by oxidizing (1, 2)-thioxene with permanganate, de- 
composes if it be heated above 260°. Like phthalic acid, it forms a fluorescein 
with resorcinol. 

The (z, 3)-acid, from (1, 3)-thioxene, is. volatile with steam, and crystallizes 
shal hot water in thin needles, melting at 118°, The (z, )-acid is prepared as 
ollows :— 

(1) By oxidizing (1, 4)-thioxene, a-methyl- and a-ethyl-thiophenic acid, and 
acetyl-ethyl thiophene (p. 534) with permanganate (Berichze, 19, 3275); (2) From 
a-thiophene disulphonic acid by means of the dicyanide (Berichze, 19, 191); and 
(3) From dibromthiophene and chlor-carbonic ester. It dissolves with great diffi- 
culty in cold water. It is a crystalline powder, that sublimes without melting, at 
a temperature above 300°. In most of its properties it resembles terephthalic acid, 
C,H,(CO,H), (1, 4). Sodium amalgam reduces it to * 

Tetrahydro-thiophene Dicarboxylic Acid, C,H,S(CO,H),. This compound 
dissolves readily in cold water, and melts at 162°. It reduces ammoniacal solutions, 
especially upon warming. When heated with sulphuric acid it evolves carbon 
monoxide and sulphur ‘dioxide. In this respect it resembles the hydrophthalic 
acids (Berichte, 19, 3274). 

Thiophene Carboxylic Acid, C,HS(CO,H),, is obtained by oxidizing acetyl- 
thioxene with potassium permanganate. Its ¢rimethy/ ester crystallizes from alco- 
hol in leaflets, melting at 118° (Berichte, 18, 2303). * 

Thiényl Acrylic Acid, C,H,S.CH:CH.CO,H, contains an unsaturated side- 
group. It is analogous to cinnamic acid. Like the latter it can be prepared from 
thiophene aldehyde, by means of sodium acetate and acetic anhydride (see furfur- 
acrylic acid). It crystallizes from hot water in needles, melting at 138° (Berich/e, 


19, 1856). 





a 


CONDENSED THIOPHENE DERIVATIVES. 


Dithiényl, C,H,S.C,H,S, corresponding to diphenyl, C,H,.CgH,, is produced 
when thiophene vapors are conducted through a tube heated to redness. It is quite 
similar to diphenyl, crystallizes in bright leaflets, that melt at 83° and boil at 260°. 


PENTHIOPHENE DERIVATIVES. 537 


Thiophene condenses with the aldehydes of the marsh gas series, forming com- 
pounds quite analogous to the diphenyl-methane compounds :— 


CH,O -+ 2C,H,S = CHC Cas + H,0. 


Dithiényl Methane, C,H,S.CH,.C,H,S, from thiophene and methylal (p. 301) | 
by the action of sulphuric acid, is an oil with the odor of oranges. It boils at 267°. 
It solidifies when cooled, and melts at 43°. - 

Dithiényl Trichlor-ethane, (C,H,S),CH.CCI,, from thiophene and chloral, 
HOC.CCl,, forms plate-like crystals, melting at 76°. 

Thiényl-phenyl Methane, C,H,S.CH,.C,H,, is obtained by the action of 
sulphuric acid upon thiophene and benzyl alcohol, C,H;.CH,.OH. It is an oil, 
boiling at 265°. It has a fruity odor. 

Dithiényl Ketone, C,H,S.CO.C,H,S, Thiénone, is perfectly similar to ben- 
zophenone, (C,H,),CO, and is produced by analogous methods: by the action of 
phosgene upon thiophene in’ the presence of aluminium chloride (Berichde, 18, 
3012): COC], + 2C,H,S = CO(C,H,S), + 2HC1; and by the distillation of 
calcium a-thiophenate. It crystallizes from alcohol in needles or leaflets, melting 
at 88° and boiling at 326°. 

Thiényl-phenyl Ketone, C,H,S.CO.C,H,, is obtained from thiophene and 
benzoyl chloride by the aid of aluminium chloride: C,H,S + C,H,.COC] = 
C,H,S.CO.C,H, + HCl. It melts at 55°, and boils about 360°. When heated 
with lime, it decomposes into thiophene and benzoic acid. 

Thiényl-diphenyl Methane, C,H SCH CAs is produced by the con- 

6°" 5 
densation of thiophene and benzhydrol, (C,H,;),CH.OH, by means of P,O,. It 
crystallizes in white leaflets, that melt at 63° and boil about 335° (Berichée, 19, 
1624). 

th higher, condensed thiophene derivatives, as Thionaphtene, C,H,S, and 
Thiophtene, C,H,S,, will be discussed with the corresponding benzene deriva- 
tives. 





PENTHIOPHENE DERIVATIVES. 


A ring of four carbon atoms linked to or closed by sulphur, exists 
(same in the y-lactone ring) in the thiophene nucleus. Penthio- 
phene is an analogous parent nucleus. In it there is a chain of five 
carbon atoms closed by sulphur (similar to the d-lactones) :— 

Cr = Gt 
(y)CH,Z >S, Penthiophene. 
\cCH = CH 


But very few derivatives are known. 


§-Methyl-penthiophene, C;H.S.CH,, is prepared like thiophene from succinic 
acid, by heating sodium a-methyl glutarate with P,S, (Berichte, 19, 3266) :— ~ 


fH, COA ‘HS cH 
CHA. yields CH, >S. 
CH.CO,H Sc CH 
i, ux, 


538 ORGANIC CHEMISTRY. 


It is a strongly refracting oil, boiling at 134°. Its specific gravity is 0.994 at 
19°. Sodium does not affect it. It resembles thiophene very much in all of its 
reactions. It yields a dark green color with isatin and sulphuric acid, and a violet 
coloration with phenanthraquinone. Acetyl chloride and aluminium chloride con- 
vert it into :— 

Methylpenthiophene-methyl Ketone, C;H,(CH,)S.CO.CH,, acetyl-methyl- 
penthiophene. This is a heavy oil, resembling acetophenone, C,H,.CO.CH.,, in 
odor. It boils about 235°. It forms a £efoxime with hydroxylamine ; this com- 
pound melts at 68°. 

The penthiophene ring is less stable than that of thiophene. Methyl penthio- 
phene is completely oxidized by dilute permanganate even in the cold. 





PYRROL GROUP. 


In pyrrol, C,H;N, there is a chain of four carbon atoms closed by 
nitrogen. The latter is combined with an atom of hydrogen, thus 
forming the imide group (p. 521). The pyrrols, consequently mani- 
fest a feeble basic nature ; they gradually dissolve in acids, but do 
not form salts with them, as they are resinified. The constitution of 
pyrrol and its relations to furfurane and thiophene are deduced from 
its analogous syntheses from the y- or (1, 4)-dicarbonyl compounds. 
These will be more fully discussed later under the individual groups 
(PP. 544, 545)- ae 

A rather remarkable occurrence is the reversal of these syntheses, 
z. e., the decomposition of the pyrrol ring with elimination of the 
imide group. ‘Thisis induced by the action of hydroxylamine. Di- 
oximes are thus produced. ‘Thus, pyrrol yields succindialdoxime (p. 
325) (Berichte,22, 1968) ;— 

CH=CH — CH,.CH:N.OH 
| >NH + 2H,N.OH = | + NH,. 
Ch = cy CH,.CH:N.OH 


(1, 4)-Dimethyl pyrrol yields the dioxime of acetonyl acetone (p. 328) in a simi- 
lar manner. 

(1, 3)-Dimethyl pyrrol, (1, 4)-methyl-phenyl pyrrol, and z-ethyl pyrrol react 
similarly, while #-phenyl pyrrol, (1, 4)-diphenyl pyrrol, etc., do not (Berichée, 23, 
1792). 

i possible isomeric derivatives of pyrrol may be deduced from the following 
symbols :— 


B a 
| >NH or | >NH. 
CH’ = CH CH: CH 
3 4 B’ a! 


The positions 1 and 4 are equal in value; they are called the a-positions. 2 and 
3 are also alike, and are termed the f-positions. Consequently, the mono-deriva- 
tives of pyrrol (those in which the CH-groups suffer substitution) occur in two modi- 


PYRROL GROUP. 539 


fications—the a- and 8. There are four di-derivatives, C,H,R,(NH). Those in 
which the two a-positions are replaced, will be termed in the following pages, a or 
(1, 4)-derivatives, and the 83’-compounds will be called {- or (2, 3) derivatives, etc. 
The compounds formed by the replacement of the hydrogen of the NH-groups, 
will be called /V- or 2-derivatives. 


Pyrrol, C,H,:NH, was first found in coal tar and bone oil. It 
received its name from its property of imparting a red color toa 
pine shaving, moistened with hydrochloric acid. It is produced 
when acetylene and ammonia are conducted through tubes heated 
to redness: 2C,H, + NH; = C,H,NH + H,; and by the distilla- 
tion of ammonium saccharate or mucate, or upon heating glycerol 
to 200°. Its formation upon heating succinimide (p. 412) with 
zine dust containing zinc hydroxide, is very interesting :— 


It also results if pyroglutaminic acid be heated (p. 467). Tetra-, 
chlorpyrrol, C,Cl,NH (Berichte, 19, 3027), is produced in an 
analogous manner from dichlormaleimide (p. 428). 


Preparation.—Shake bone oil with dilute sulphuric acid (1:30) to remove 
all basic substances (pyridine bases), The residual oil contains nitriles of the 
fatty acids (from propionic to stearic acid), which are saponified upon boiling them 
with caustic potash, and in addition benzene hydrocarbons, pyrrol and its homo- 
logues (Beriche, 13, 65). The oil obtained in the distillation of bone-glue (free 
from fats) contains large quantities of pyrrols, with a little pyrocoll (Beriche, 14, 
1108). To isolate the pyrrol that portion of the purified oil boiling at 115-130° 
is treated with metallic potassium, whereupon solid potassium-pyrrol, C,H,NK 
(see below), separates. It can also be obtained by boiling the pyrrol with solid 
caustic potash (Berichte, 19, 173). The potassium-pyrrol is washed with ether, 
decomposed by water, and the oil distilled over in a current of steam. It is then 
dried over fused caustic potash and fractionated. 


Pyrrol is a colorless liquid with an odor resembling that of chloro- 
form. It becomes brown upon exposure and boils at 131°. Its 
sp. gr. is 0.9752 at 12.5°. It is but slightly soluble in water, but 
dissolves very readily in alcohol and ether. <A pine shaving, mois- 
tened with hydrochloric acid, is colored a pale red by its vapors. 
This increases to an intense carmine red. It yields an indigo blue 
coloration with isatin and sulphuric acid, or with phenanthra- 
quinone, etc. (p. 521) (Berichte, 17, 142, 1034; 19,106). Pyrrol 
is a very feeble base. It is dissolved very slowly in the cold by 
dilute acids, but does not yield salts (Berichte, 21, 1478). When 
heated it passes into a red powder, pyrrol red, C,,H,N,O, which 
becomes brown on exposure. Nitric acid resinifies pyrrol and oxi- 
dizes it to oxalic acid. 


540° ORGANIC CHEMISTRY. 


The conversion of pyrtol into chlor- and brom-pyridine upon heating potas- 
sium-pyrrol, or pyrrol and sodium alcoholate, with chloroform or bromoform, etc. 
(see pyridine), is rather interesting :— 


el oa CH. CH = CBr, Cl 
| DNE + CHBr, = | | + KBr + HBr. 
CH= CH CH = CH—N 


Brom-pyridine. 





Pyrrol is a secondary amine. The hydrogen of its NH-group 

can be replaced by potassium (not sodium), acid radicals, and 
alkyls. 
_ Potassium dissolves in pyrrol with an energetic evolution of 
hydrogen: It forms Potassium-pyrrol, C,H,NK, a crystalline 
mass. This compound may also be obtained by boiling pyrrol with 
solid caustic potash (Berichte, 19, 173). Water regenerates pyrrol 
and caustic potash. Sodium will only act upon pyrrol when they 
are heated together under pressure. 


nm-Acetyl Pyrrol, C,H,N.CO.CH,, is produced (together with pyrrol-methyl- 
ketone) upon heating pyrrol with acetic anhydride. A simpler procedure consists 
in treating potassium-pyrrol with acetyl chloride. It is an oil with peculiar odor. 
It boils at 178°. It is decomposed into pyrrol and acetic acid when it is digested 
with caustic potash. Hydrochloric acid converts it into a resin. 

Cyan Pyrrol, C,H,N.CN, is produced in the action of cyanogen chloride upon 
potassium-pyrrol. It rapidly polymerizes to a melamine derivative. In this respect 
it resembles cyanamide (p. 288). 

n-Pyrrol Carboxylic Ester, C,H,N.CO,.C,H,, Pyrrol Urethane, correspond- 
ing to ordinary urethane, is formed when chlor-carbonic ester acts upon potas- 
sium-pyrrol (p.' 382). It is an oil boiling at 180°. Boiling alkalies separate it into 
its components. It passes into Pyrrol Carbamide, C,H,N.CO.NH,, if it is 
heated with aqueous ammonia. This is a crystalline compound that melts at 166°, 
and volatilizes without decomposition. 

Phosgene, COCI,, converts potassium-pyrrol into Carbonyl Pyrrol, 


COON CH (together with the isomeric dipyrryl ketone, p. 545). This com- 


pound consists of large crystals, melting at 63°, and distilling at 238°. When 
heated in a tube to 250°, it is converted into isomeric dipyrryl ketone, 


COC Cit NH (Berichte, 18, 1828). 
4°"3° 


n-Alkyl Derivatives. 

The alkylic pyrrols, C,H,:NR, containing the alkyl group in 
union with the nitrogen atom, correspond to the ordinary amines 
(p. 157), and are called JV- or z-alkyl pyrrols. The homologous 
pytrols are isomeric with the preceding. They contain the alkyls 
attached. to carbon (p. 542). The w#-alkyl pyrrols are produced by 
the action of the alkyl iodides upon potassium-pyrrol, C,H,NK ; 


‘ 


SUBSTITUTED PYRROL. 541 


also in the distillation of the amine salts of mucic and saccharic 
/ CON np 
\CO 7 

(p. 413), with zinc dust. The z-alkyl pyrrols are quite similar to 
pyrrol. They yield intense colorations with isatin and phenanthra- 
quinone. ‘They are not so easily resinified by acids as the pyrrols. 


acids, as well as by heating the alkylic succinimides, C,H, 


n-Methyl Pyrrol, C,H,N.CH,, boils at 113°; its sp. gr. is 0.9203 at 10°. 
n-Ethyl Pyrrol, C,H,N.C,H,, boils at 131°; its sp. gr. is 0.9042 at 10°. A 
pine shaving, moistened with hydrochloric acid, is colored an intense red by its 
vapors. Ethylamine is liberated when it is boiled with hydrochloric acid. Potas- 
sium does not attack it. #-Isoamyl Pyrrol, C,H,N.C,H,,, boils at 180-184°. 
n-Allyl Pyrrol, C,H,N.C,H,, from potassium-pyrrol and allyl iodide, can be 
distilled under reduced pressure. 

n-Phenyl Pyrrol, C,H,N.C,H,, from aniline mucate and saccharate, consists 
of brilliant scales, having a camphor-like odor. They assume a red color on 
exposure to the air, and melt at 62°. 





SUBSTITUTED PYRROLS. 


Tetrachlor-pyrrol, C,Cl,NH, is produced by acting upon dichlomaléimide 
with phosphorus pentachloride (p. 428), and when zinc and acetic acid act upon 
the perchloride of perchlorpyrocoll (p. 547). It crystallizes from benzine in color- 
less leaflets. These volatilize very readily and melt at 110° with decomposition. 


Tetra-iodo-pyrrol, C,I.NH, Iodol, is formed when iodine 
acts upon pyrrol in the presence of some indifferent solvent, but 
more readily if substances are present that will absorb the liberated 
hydriodic acid (such as iodic acid, p. 91, or caustic, alkalies, Be- 
richte, 19, 3027). 

Iodol crystallizes in yellowish-brown prisms. These decompose 
about 140°. It is almost insoluble in water ; 100 parts of go per cent. 
alcohol dissolve 5.8 parts at 15°. If small portions of it be carefully 
digested with sulphuric acid they will dissolve, and the solution 
acquire an intense green coloration, which subsequently becomes 
dirty violet. As tetra-iodo-pyrrol is odorless, but possesses the 
same action as iodoform, it has been substituted for-the latter as an 
antiseptic, under the name of zodo/ (Berichte, 20, Ref. 220). 

Few pyrrol compounds can be directly nitrated. Nitric acid 
attacks them too violently. 


Dinitro-pyrrol, C,H,(NO,),NH, is obtained from pyrrol-methyl-ketone, 
C,H,(CO.CH,)NH (together with nitro-derivatives of the latter), by the action of 
cold fuming nitric acid, and by the nitration of a-pyrrol-carboxylic acid, C,H, 
(NH).CO,H (Berichte, 19, 1078). It crystallizes from hot water in large yellow 
leaflets, melting at 152°. It behaves like an acid, dissolves in alkaline carbonates 
and forms yellow colored salts. 


542 ORGANIC CHEMISTRY. 


HOMOLOGOUS PYRROLS. 


The ¢-alkyl pyrrol homologues contain the alkyls attached to 
carbon. When acted upon by potassium, or if boiled with solid 
caustic potash, they form potassium derivatives. This behavior dis- 
tinguishes them from the isomeric #-alkyl pyrrols. In the preced- 
ing reaction the lower alkyl pyrrols react before the higher pyrrols 
(Berichte, 19, 2199). They occur already formed in bone oil. 
They are artificially prepared from the corresponding carbonic 
acids, which were built up synthetically. The latter lose carbon 
dioxide (p. 545). Some of them have been directly synthesized 
from y-diketones, ¢. g., acetonyl acetone, CH,.CO.CH,.CH,.CO. 
CH;, and acetophenone acetone, C,H,.CO.CH,.CH,.CO.CH; (pp. 
328, 522), by heating the latter with alcoholic ammonia :— 


CH,.CO.R CH << OR 
tN, ] ‘NH + 2H,0. 
CH,.CO.R CH os GR 


The c-alkyl pyrrols are also produced together with the #-alkyl pyrrols (p. 540) 
by the action of the alkyl iodides upon potassium-pyrrol (Berichte, 22, 659). The 
m-alkyl pyrrols, when heated with alkyl iodides and potassium carbonate to 120- 
140°, are converted into z-c-alkyl pyrrols (Berichte, 22, 656, 2515). The H of 
CH is then directly replaced. If the heating be prolonged and intensified a simul- 
taneous conversion of the c-alkyl pyrrols into basic pyridines occurs, ‘The ‘five- 
membered’ pyrrol ring is converted into the pyridine ring, consisting of six mem- 
bers. The c-alkyl pyrrols sustain a similar conversion into pyridines when they 
are digested with concentrated hydrochloric acid (Berichte, 19, 2199). The 
change of the pyrrols, by hydrochloric acid, into derivatives of zudo/, depends 
upon analogous reactions (Berichte, 21, 3429; 22, 1924). 


The ¢-alkyl indols resemble pyrrol, but are more stable towards 
acids. ‘Their aqueous solutions yield a white, caseous precipitate 
when treated with a solution of corrosive sublimate. 

The. possible isomerides of the alkyl pyrrols may be deduced from 
the scheme given upon p. 538. The mono-derivatives exist in two 
isomeric forms, the a- and #. 


Methyl Pyrrols, C,H,(NH).CH,, Homopyrrols. The a- and f-isomerides 
both occur in that fraction of Dippel’s oil that boils from 140-150°. They cannot 
be separated. When carbon dioxide acts upon their potassium compound, two 
isomeric methyl-pyrrol-carboxylic acids, C,H,(CH,)(NH).CO,H, are produced. 
The pure methyl pyrrols result when these acids lose carbon dioxide. a-Methyl 
pyrrol boils at 148°, while the 6-variety boils at 143°. They are more readily 
changed on exposure to the airthan pyrrol. Oxidizing agents convert them into 
acetic acid and carbon dioxide, They pass into the corresponding pyrrolcarboxy- 
lic acids (a--and G-) when fused with caustic alkali. If a mixture of the two 
methyl pyrrols be heated with acetic anhydride, z-acetyl-methyl pyrrol,C,H,(CH,)N. 


CO.CH;, and methyl pyrrol-methyl ketone, C,H, Ors oe NH (Berichie, 19, 
1408), are produced. ba 


4 


HOMOLOGOUS PYRROLS. 543 


aa-Dimethyl Pyrrol, C,H,(CH,),NH(1, 4), is present in Dippel’s oil. It is 
obtained from its mono- and di-carboxylic acids, when these lose carbon dioxide 
(Berichte, 23, 1475). It may be synthesized by heating acetonyl acetone with 
alcoholic ammonia (p. 522). It is a colorless oil, boiling at 165°. It rapidly ac- 
quires a red color on exposure to the air. The colorations with isatin and phe- 
nanthraquinone are less intense (erich/e, 18, 1566, 2254). 

a8-Dimethyl Pyrrol (1, 2) occurs in Dippel’s oil. It boils at 165°. Hydro- 
chloric acid converts it into tetramethyl indol (Berichte, 22, 1923). 

a$’-Dimethyl Pyrrol, C,H,(CH,),NH(1, 3), results when its mono- and di- 
carboxylic acids (p. 548) lose carbon dioxide. Itisan oil, with an odor resembling 
that of chloroform. It boils at 160°, and turns brown on exposure to the air 
(Annalen, 236, 326). 

Ethyl Pyrrol, C,H,(C,H;)NH, is produced by the action of zinc chloride 
upon a mixture of pyrrol and aldehyde: C,H,NH + 2C,H,O = C,H,(C,H;)NH 
+C,H,O,. It boils at 165°. When heated with acetic anhydride, it becomes 
n-acetyl-ethyl pyrrol, C,H,(C,H,;)N.CO.CH,, and ethylpyrrol methyl ketone, 
C,H, (NH) En, (Berichte, 19, 2189). cae 

Trimethyl Pyrrol, C,H(CH,),NH. The two possible isomerides appear to 
be contained in that portion of the bone oil that boils at 180-195° (Berichie, 14, 
1342). 

B-Isopropyl Pyrrol, C,H,(C,H,)NH, is formed, analogous to ethyl pyrrol, 
by the action of zinc chloride upon a mixture of pyrrol and acetone. It is an oil, 
boiling at 175°. It forms {-pyrrolcarboxylic acid when fused with caustic alkali 
(Berichte, 20, 855). 

aa-Methyl Phenyl Pyrrol, C,H, (NH) 6 , is formed by heating aceto- 
phenone-acetone, C,H,.CO.CH,.CH,.CO.CH,, with alcoholic ammonia (p. 542). 
It crystallizes in brilliant white leaflets, that turn red on exposure, melt at 101°, 
and sublime with partial decomposition. 

aa-Diphenyl Pyrrol, CsH(NH)¢ 6°47° (1) 4), is produced by the distillation 

6°" 5 
of pyrrol dibenzoic acid (p. 549), and from aa-diphenyl-pyrrol carboxylic acid (p. 
548). It melts at 143.5° (Berichte, 21, 3061). 

Tetraphenyl Pyrrol, C,(NH)(C,H,),, from bidesyl, melts at 211° (Berichie, 

22, 553). : 





a-Dimethyl pyrrols, in which the imide-hydrogen is also replaced by alkyls, 
are formed by the elimination of carbon dioxide from their dicarboxylic acids (ob- 
tained from diacetosuccinic ester and the primary amines, p. 546) (Anua/en, 236, 
303): 
aa-Dimethyl-z-methyl Pyrrol, C,H,(CH,),.N,CH,, Triméthyl Pyrrol, boils 
at 169°. aa-Dimethyl-z-phenyl pyrrol, C,H,(CH,),N.C,H,, is solid, melts at 
52°, and boils at 252° (Corr.). aa-Dimethyl a-naphthyl pyrrol, C,H,(CH,),N. 
C,,H,, melts at 71° and boils at 341° (Corr.). 

a-Methyl-phenyl pyrrols, the imide-hydrogen of which has also been replaced 
by alkyls, are produced from their monocarboxylic acids (obtained from acetophe- 
none-aceto-acetic ester and amines) (p. 546) by the loss of carbon dioxide (Berichte, 


18, 2595). : CH 
aa-Methyl-phenyl-7-allyl-pyrrol, C,H, (e H )n.c 3H;, melts at 52° and 
boils at 278°. ae 


544 ORGANIC CHEMISTRY. 


aa-Methylphenyl-z-phenyl pyrrol, oF» ie )N.c,H 5, melts at 84°. 
tts 


Pyrrol derivatives, whose imide-hydrogen is replaced by divalent radicals, are 
produced in an analogous manner by the action of the diamines (e. ¢., ethylene 
diamines, phenylenediamine, benzidine) upon acetonyl acetone, as well as upon 
acetophenone-aceto-acetic ester. The compound, C,H,(CH,),:N.CH,.CH,.N: 
C,H,(CH,),, is thus formed from ethylene diamine and acetonyl acetone (Berichte, 
19, 3157). Other amide compounds, such as the amido-phenols and the amido- 
acids, react similarly with acetonyl acetone and acetophenone-aceto-acetic ester, 
forming complex pyrrol imides (Berichte, 19, 558 and 3158). 





PYRROL AZO-COMPOUNDS. 


The azo- and disazo-derivatives of pyrrol are analogous to the benzene azo- dye- 
stuffs. They result from the action of the salts of the benzene diazo-compounds 
upon pyrrol, the pyrrol homologues, and the z-alkyl pyrrols, C,H,N.R, by the 
entrance of one and two molecules of the diazo-compounds :— 


PUGN.C, 
C,H,(NH).N:N.C,H, and CHA(NE) NCH. 
Pyrrol-azo-benzene. Pyrrol-disazo-benzene. 


The mono-azo-compounds are formed in acid solutions, and the disazo-deriva- 
tives in neutral or alkaline solution. The former dissolve in concentrated sul- 
phuric acid with a yellow color, the latter with a dark blue coloration (Lerichie, 


19, 2251). : 





PYRROL KETONES. PSEUDO-ACETYL PYRROLS. 


The pyrrol-methyl ketones, or c-acetyl pyrrols (together with the 
isomeric #-acetyl pyrrols, p. 540), are produced by heating the 
pyrrols with acetic anhydride, and are also prepared by a molecular 
rearrangement of the z-acetyl pyrrols on being heated to 250° (Be- 
richte, 18, 1828) :— 


C,H,N.CO.CH,, yields C,H,(NH).CO.CH,. 


The acetyl group is linked to carbon. They are distinguished 
from the #-acetyl pyrrols by the fact that when they are boiled with 
caustic potash they are not decomposed. Being ketones they unite 
with hydroxylamine and phenylhydrazine. They condense with 
benzaldehyde, when acted upon with caustic potash, to cinnamyl- 
pyrrols. The latter serve to characterize the alkyl pyrrols (Berichte, 
22, 1918). 

a-Pyrryl-methyl Ketone, C,H,(CO.CH,)NH, pseudo-acetyl pyrrol, resulting 
from pyrrol and acetic anhydride (erichte, 16, 2348), crystallizes from hot water 


in long needles, that melt at 90°, and boil about 220°. It is volatile in steam. It 


forms an acetoxime, C,H, (°C cis, J NH, with hydroxylamine, which melts 


PYRROL CARBOXYLIC ACIDS. 545 


at 146°. Potassium permanganate oxidizes it to the ketonic acid, C,H,(NH).CO, 
CO,H (p. 548). Sodium amalgam converts it into pyrryl-methyl carbinol, C,H, 
(NH).CH(OH).CH,, and pyrryl methyl pinacone (ZBerichie, 19, 2204). 

When bromine acts upon pyrryl-methyl ketone in glacial acetic acid it converts 
it into bromine substitution products. If added to cold, fuming nitric acid dinitro- 
pyrrol (p. 541), one dinitro and two mono-nitro- products of pyrryl-methyl ketone 
are formed (Berichze, 19, 1078). 

Pyrryl-ethyl Ketone, C,H,(CO.C,H,;)NH, Propionyl Pyrrol, resulting from 
pyrrol and propionic .anhydride (together with #-propionyl pyrrol, C,H,N.CO. 
C,H;), melts at 52°, and distils about 225° (Berichie, 20, 1761). 

Pyrryl Phenyl Ketone, C,H,(CO.C,H;)NH, Benzoyl Pyrrol, is obtained 
from pyrrol upon heating it with benzoic aldehyde. It melts at 78°. 

The diketone is produced upon heating pyrryl-methyl ketone with acetic anhy- 
dride to 250°. 

Pyrrylene-dimethyl-diketone, C,H,(CO.CH,),NH, diacetyl pyrrol, crystal- 
lizes from hot water in minute needles, melting at 162°. Potassium permanganate 
oxidizes it to carbopyrryl glyoxylic acid (p. 548) (Berichze, 19, 1957). 

Dipyrryl Ketone, CO(C,H,.NH),, is produced together with carbonyl pyrrol 
(p. 540) by the action of phosgene upon potassium-pyrrol, and by the molecular 
rearrangement of carbonyl pyrrol when the latter is heated to 250°. It melts at 
100°, but is not decomposed when boiled with caustic potash. Carbonyl pyrrol 
also yields Pyrroyl-pyrrol, C,H,N.CO.C,H,NH, melting at 63° (Berichie, 18, 
1828). 





PYRROL CARBOXYLIC ACIDS. 


The acids derived from pyrrol are perfectly analogous to the aro- 
matic acids. Their manner of formation is very similar to that by 
which the oxybenzoic acids are produced. They result by the oxi- 
dation of the homologous pyrrols when fused with caustic potash :— 


C,H,(NH).CH, yields C,H,(NH).CO,H, 
by the action of carbon dioxide upon the potassium derivatives of 
the pyrrols :— 
C,H,NK + CO, = C,H,(NH).CO,K, 


or by heating the pyrrols with ammonium carbonate, and the action 
of carbon tetrachloride and alcoholic potash upon pyrrol (Berichie, 


17, 1439) :— 
C,H,NH + CCl, + 4KOH = C,H,(NH).CO,H ++ 4KCl + 2H,0. 


Dimethyl pyrrol dicarboxylic acid is prepared in a purely synthetic manner by 
the action of ammonia upon diaceto-succinic ester (p. 437) :— 


CH, 
CH,.CO.CH.CO,R Se 2. O00. R 
J 4+ NH, = NH J 4 2H,0. 
CH,.CO.CH.CO,R SC=€:00,R 
CH,“ 


46 


546 | ORGANIC CHEMISTRY. 


. The primary amines react the same as ammonia, with formation of dicarboxylic 
acids with the alkyl group attached to nitrogen (Knorr, Berichte, 18, 299, 


1558) :-— 


GH. 
CH,.CO.CH.CO,R Ce OCOR 
3 4+NH,R= RNY | + 2H,0 
CH,.CO-CH.CO,R ye 2 GCOR 
eee CH,” 


a-Dimethyl-n-alkyl Pyrrol-di- 
carboxylic Acid. 


Mono.-carboxylic acids of methyl-phenyl pyrrol are also formed from aceto- 
phenone- (phenacyl-) aceto-acetic ester, by the action of ammonia and primary 
amines (Paal, Berichte, 18, 2591) :— 


C,H; 
C,H,.CO.CH, Ha MO oe 
+ NH,R = RNZ l + 2H,0. 
CH,.CO.CH.CO,R et ck Cee 
CH,” 
Acetophenone-aceto- a-Methylphenyl-#-alkyl Pyrrol- 
acetic Ester. | carboxylic Acid. 


_ The action of amido-acids (like glycocoll) upon acetonyl-acetone (p. 328) and 
acetophenone-aceto-acetic esters produces pyrrol acids, in which the acid residues 
are combined with nitrogen (Paal, Berichte, 19, 559, 3157), ¢. £5 


CH, 
CH = C¢ 
| rs -CgsH,.CO,H, Dimethyl-pyrrol-benzoic Acid. 
CH =.C 
eNO 


Analogous compounds are also obtained.from diaceto-succinic ester (Annalen, 
236, 314; Berichte, 22, 3086). 

When the mono- and dicarboxylic acids are heated they part with one and two 
molecules of carbon dioxide, forming at the same time the corresponding c-alky] 
pyrrols. When the primary esters of the dicarboxylic acids split off carbon dioxide 
they pass into the esters of the mono-carboxylic acids. 





a-Pyrrol Carboxylic Acid, C,H;(NH).CO,H, Carbopyr- 
rolic Acid, was first obtained from its amide, which is produced 
- together with pyrrol upon distilling ammonium mucate. It is 
formed (together with £-pyrrol carboxylic acid) when carbon di- 
oxide acts upon potassium-pyrrol heated to 200°, and from pyrrol 
by heating it with CCl, and alcoholic potash, as well as by oxidizing 
methyl-pyrrol by fusing it with caustic potash. The best method 
for its preparation consists in heating pyrrol and aqueous ammonium 
carbonate to 120-130° (Berichte, 17, 1150). It crystallizes from 
water in colorless leaflets or prisms. When these are dry they 
become green in color. They melt at 192° in a closed tube, 
decomposing at the same time into carbon dioxide and pyrrol. 


PYRROL CARBOXYLIC ACID. 547 


Lead acetate does not precipitate its aqueous solution: When 
digested with dilute acids it breaks up into carbon dioxide and 
pyrrol red. : 


The esters of the acid aré obtained by the action of the alkyl iodides. upon its 
silver salt. The methyl ester, C,H,(NH).CO,.CH,, melts at 73°; the ethyl 
ester at 39°. The amide, C,H,(NH).CO.NH,, is formed together with pyrrol 
by the distillation of ammonium pyromucate. It consists of shining leaflets, melt- 
ing at 176.5°. It is decomposed into ammonia and carbopyrrolic acid when boiled 
with baryta water. 

Pyrocoll, C,,H,N,0, = C,H,:N—CO\ , the amide anhydride of carbo- 

CO.N: CHA 
pyrrolic acid, is produced in the distillation of gelatine (p. 539) and is artificially 
prepared by heating carbopyrrolic acid with acetic anhydride. It crystallizes in 
yellow leaflets, melting about 268°. It yields a-carbopyrrolic acid when it is 
boiled with potash. Its formula is established by a molecular weight determina- 
tion by Raoult’s method (Berichte, 22, 2501). Bromine converts it into mono-, 
di- and tetrabrompyrocoll. These yield brominated pyrrol carboxylic acids when 
boiled with alkalies. When it is heated with PCl,, perchlorpyrocoll, C,)ClgN.O,, 
and the octochloride, C,,Clg(Cl,)N,O,, are produced. Zinc and acetic acid con- 
vert the latter into perchlorpyrrol, C,Cl,NH, and on boiling with dilute acetic acid 
we obtain the imide of dichlormaleic acid (p. 428). 

When pyrocoll is dissolved in nitric acid dinitropyrocoll results ; sodium hydrox- 
ide converts this into nitrocarbopyrrolic acid. The latter crystallizes from water in 
needles, melting at 146°. The nitration of a-carbopyrrolic acid produces dinitro- 
pyrrol (Berichte, 19, 1079) ; the methyl ester cannot be directly nitrated (Berichie, 
22, 2503). 


&-Pyrrol Carboxylic Acid, C,H,(NH).CO,H (2-3), is pro- 
duced on fusing -methyl pyrrol with KOH, and by the action of 
CO, upon potassium-pyrrol at 200°. From an aqueous solution of 
the two acids, lead acetate only precipitates the f-acid. It crystal- 
lizes in needles, melting at 161-162° with decomposition into car- 
bon dioxide and pyrrol. The same decomposition occurs when its 
aqueous solution is evaporated, 


Methyl Pyrrol Carboxylic Acids, C,H,(CH,)(NH).CO,H. Two of the six 
isomerides are known. They are produced when carbon dioxide acts upon the 
potassium derivative of the crude methyl pyrrol (aand 8). The lead salt of the - 
acid is very insoluble. The a-acid crystallizes from water in small leaflets. It melts 
at 169°; the 8-acid meltsat 142°. Both acids, when heated beyond their melting 
points, decompose into carbon dioxide and the corresponding methyl] pyrrols. This 
occurs with the §-acid on evaporating its aqueous solution. 

(1, 4)-Dimethyl Pyrrol-6-—Carboxylic Acid, C,H (CH;),(NH).CO,H. Its 
methyl ester is obtained by distilling the monoethyl ester of a-dimethylpyrrol di- 
carboxylic acid, when it loses carbon dioxide. It melts at 118°. The free acid 
consists of needles, melting at 210—213°, and then decomposes into carbon dioxide 
and aa-dimethyl pyrrol. This happens also when it is treated with concentrated 
acids. 

Two isomeric (1, 3)-dimethyl pyrrol-carboxylic acids, C,H(CH,),(NH).CO,H, 
from (1, 3)-dimethyl-pyrrol-dicarboxylic acid (p. 549) and tetramethylpyrocoll, 
melt at 183° and 137° respectively (Berichte, 22, 40). 


548 ORGANIC CHEMISTRY. 


(1, 4)-Methyl-phenyl-pyrrol-8-carboxylic Acid, C,H ees ) (NH).CO,H. 
Its ethyl ester is produced by the action of ammonia upon acetophenone-aceto- 
acetic ester (p. 546). The free acid crystallizes from glacial acetic acid in yellow 
needles, decomposes partially at 175°, and melts about 190°. 

Its derivatives, containing alkyl or phenyl groups attached to the N-atom, are 
similarly produced by the action of primary amines upon acetophenone-acetoacetic 
ester (p. 546). 

(1, 4)-Diphenylpyrrol-§-carboxylic Acid, C,H(C,H,;),(NH).CO,H, from 
acetophenone-benzoyl acetic ester and ammonia (p. 495), melts at 261° (Beriche, 
21, 3060). 





KETONIC ACIDS. 


a-Pyrroyl Carboxylic Acid, C,H,(NH).CO.CO,H, Pyrryl Glyoxylic Acid, 
is produced by the oxidation of a-pyrryl methyl ketone (p. 544) with alkaline po- 
tassium permanganate (Aerichte, 17, 2949). It crystallizes from water in yellow 
needles, melting with decomposition at 74-76°. They become anhydrous when 
placed over sulphuric acid. The anhydrous acid, from benzene, consists of yellow 
needles, decomposing about 114°. Ferric chloride imparts an intense red color to 
the aqueous solution. When fused with caustic potash, it becomes a-pyrrol-car- 
boxylic acid (Berichte, 19, 1957). 

Pyrryl-methyl-ketone Carboxylic Acid, C,H (NH)Z Oa Rceto- 
‘ y A » Ygtle .CG.8.. 


pyrrol carboxylic acid. Its methyl ester is produced on heating a-pyrrol carboxylic 
methyl ester with acetic anhydride to 250°. It melts at 113°. The free acid is 
oxidized to carbopyrryl-glyoxylic acid by potassium permanganate (Berich/e, 19, 


1961). 
Carbopyrryl Glyoxylic Acid, CANE Go at 
2 


izing pyrrylene dimethyl diketone (p. 545) with potassium permanganate. It is 
very unstable. Its dimethyl ester melts at 145°. If oxidized by fusion with 
caustic potash, it yields’ a pyrrol dicarboxylic acid (Berichze, 19, 1959). 


, is obtained by oxid- 





DICARBOXYLIC ACIDS. 


a-Pyrrol Dicarboxylic Acid, C,H,(NH) eon 4), results upon oxidiz- 
ing carbopyrryl glyoxylic acid by fusion with caustic potash. It separates from 
alcohol in warty crystals. It turns black when heated to 200°, and breaks up into 
carbon dioxide and pyrrol. Its st/ver salt, C,H, NO,Agg, is a caseous precipitate. 
Its dimethyl ester,C,H,NO,(CH,),, from the silver salt and ethyl iodide, melts 
at 132°. The dzethyl ester melts at 82° (Berichte, 19, 1960). 
FA Cerys! 


(1, 4)-Dimethy]l pyrrol-(2, 3)-dicarboxylic Acid, C,(CH,),(NH) <€0;H" 
2 


Its ethyl ester is derived from diaceto-succinic ester and ammonia. It crystallizes 
in minute needles, and melts at 99°. If the diethyl ester be saponified with alco- 
holic potash the ester acid, melting at 227°, and the free dicarboxylic acid result. 
The mineral acids precipitate the latter from its salt solutions in minute needles. 
It crystallizes from alcohol in long needles, It melts at 251°, and decomposes 
readily into two molecules of carbon dioxide and (1, 4)-dimethyl pyrrol. It sus- 


PYRROL HYDRIDES. 549 


tains the same decomposition when it is boiled with water, or is acted up with 
concentrated acids (Berichte, 18, 1558). 

For those derivatives of dimethyl pyrrol-dicarboxylic acid, in which the alkyls 
and acid residues are attached to the nitrogen atom, consult Anzalen, 236, 303. 
Hydroxylamine and phenylhydrazine convert diaceto-succinic ester (Amza/en, 
236, 294) into— ' 


C,(CH,),(N.OH)(CO,R), and C,(CH,),(N.NH.C,H,)(CO,R),. 


Unsymmetrical (1, 3)-Dimethylpyrrol Dicarboxylic Acid, C,(CH,), 
(NH) ¢ COlEL Its diethyl ester may be prepared by reducing a mixture of 


acetoacetic ester and nitroso-acetic ester with zinc dust in an acetic acid solution 
(Annalen, 236, 217). It melts at 135°, and also forms a potassium salt, C,,H,, 
KNO,. If the diethyl ester be saponified two isomeric ester acids (melting at - 
202° and 197°) and the free dicarboxylic acid result. The latter dissolves quite 
readily in water, and melts at 197°, decomposing into carbon dioxide and af/- 
dimethylpyrrol (p. 543). It forms an imide anhydride with acetic anhydride 
(Berichte, 21, 2875). 

Pyrrol Dibenzoic Acid, CHINE) 6 Coon results from the action 


of ammonia upon ethylene dibenzoyl-carboxylic acid :— 


fol y.CO,H 
CH,.CO.C,H,.CO,H 1 eye 
+ NH, = | ‘SNH + 2H,0. 
CH,.CO.C,H,.CO,H H= Ce 

\c,H,.CO,H 


It breaks down into two molecules of carbon dioxide and aa-diphenyl pyrrol 
when distilled with lime (p. 543) (Berichte, 20, 1487). 
Pyrrylen-phthalide, C,H K Cy eHaENO, a derivative of phthalide (see 


this) is produced, when phthalic anhydride and pyrrol are heated together (Be- 
richte, 19, 2201). 





PYRROL HYDRIDES. 


Dihydro-Pyrrol or Pyrroline, C,H,NH, and Tetrahydropyrrol or 
Pyrrolidine, C,H,NH :— 


"NNH > and "J *NNH, 
CH=CH “ CH,—CH,” 
Pyrroline. Pyrrolidine. 


are formed when hydrogen is added to pyrrol. These are two 
parent substances from which a series of derivatives can be ob- 
tained by the replacement of their hydrogen atoms. Pyrrolidine 
is perfectly analogous to piperidine. 

The following hypothetical parent-nuclei are 4eto-derivatives 
of pyrroline and pyrrolidine :-— 


550 ORGANIC CHEMISTRY. . 


: SNH and l NH. 
CH = CH CH,—CH,” 
B-Pyrrolon. a-Pyrrolidon. 


Pyrroline, C,H,NH, is formed when pyrrol is digested with zinc dust and 
acetic acid. It is a liquid that dissolves readily in water, and boils at 91°. It has 
an alkaline reaction, smells like ammonia and unites with acids to form salts. It 
is a secondary base. Nitrous acid converts it into uztrosamine, C,H,N(NO), 
melting at 38°. 

Pyrrol and methyl iodide unite to dimethyl-ammionium iodide, C,H,N(CH,),I. 
Silver oxide converts this into the ammonium hydroxide, C,H,N(CH,),.0OH. 

n-Methyl Pyrroline, C,H,N.CH,, is formed by the action of zinc dust and 
acetic acid upon #-methyl pyrrol. It is very similar to pyrroline and boils at 80°. 
It unites with methyl iodide to form a dimethyl iodide. 

Consult Berichte, 22, 2514 upon benzoyl pyrroline, C,H,N.CO.C,H,, and 
benzyl] pyrroline. 

The supposed derivatives of $-pyrrolon have been proved to be cyanethyl com- 
pounds (Berichte, 22, Ref. 325). 


PYRROLIDINE COMPOUNDS. 


Pyrrolidine, C,H,NH, Tetramethylene-imine, was first obtained by heat- 
ing pyrroline with hydriodic acid and phosphorus to 250° (Berichte, 18, 2079). 
It has been synthetically prepared by distilling the hydrochloride of tetramethylene- 
diamine, and by the action of sodium upon an alcoholic solution of succinimide 
(Berichte, 20, 2215) :— 


CH,.CH,.NH, CH,.CO CH,.CH, 

l and | ‘NH yield | NH. 

CH,.CH,.NH, CH,.cO” CH,.CH,” 
Tetramethylene-diamine. Succinimide, » Pyrrolidine. 


Pyrrolidine is an alkaline liquid with an odor resembling that of piperidine. It 
boils at 87°; its sp. gr. at 0° is 0.879. Its nitrosamine, CJH,N(NO), is a yel- 
low oil boiling at 214° (Berichte, 21,290). It combines with methyl iodide to 
form HI-methyl-pyrrolidine, C,H,N.CH,. This can also be prepared by 
reducing -methyl pyrroline with hydriodic acid. Methyl pyrrolidine unites with 
methyl iodide to dimethyl ammonium ‘iodide, C,H,N(CH,),I, which in its entire 
behavior resembles piperidine dimethyl iodide, C,H,,N(CH,),I. When fused 
with potassium hydroxide it forms dimethyl pyrrolidine, C,H,N(CH,).; this yields 
the ammonium iodide, C,H,N(CH,),I, with methyl iodide. If this be fused with 
caustic potash it becomes trimethylamine, N(CH,),, and the hydrocarbon C,H, 
(Pyrrolylen) (Berichte, 18, 2081). 

a-Methyl Pyrrolidine, C,H,(CH,)NH, has been prepared by reducing 
a-methyl pyrrolidon (see below) with metallic sodium and alcohol. It is a strongly 
alkaline liquid, with a stupefying odor. It boils at 97° (Berichte, 22, 1866). ° 

B-Methyl Pyrrolidine, C,H,(CH,)NH, results from heating 6-methy] tetra- 
methylene-diamine (p. 313) hydrochloride. It is a fuming, alkaline liquid, with 
an odor resembling that of piperidine. It boils at 104° and yields a nitrosamine, 
boiling at 224° (Berichte, 20, 1657). : 

aa-Dimethyl Pyrrolidine, C,H,(CH,),NH, is derived from diamido-hexane 
(p. 314), and boils at 107° (Berichte, 22, 1859; 23, 1544). 

Trimethyl Pyrrolidine, C,H,(CH;),NH, is obtained from amido-trimethyl- 
butylactinic acid (from diacetonamine (p. 208, with CNH, etc). See Annalen, 
232, 206 


PYRAZOLE COMPOUNDS. 551 


The following is a keto-derivate of pyrrolidine, C,H,NH :— 

a-Pyrrolidon, C,Hg0(NH) (p. 550), is produced when y-amidobutyric acid is 
heated to 200° (pp. 369, 372). It distils at 245°. It is a colorless oil, which 
solidifies upon cooling, and melts at 25-28° (Berichte, 22, 3338). 

a-Methyl Pyrrolidon, C,H,(CH,)O(NH), is similarly produced upon heating 
y-amidovaleric acid to 250° (p. 372) (Berichte, 22, 1860) :— 


NH 
/CH(CH).NE, = /PB(CH) 
\CH,.CO,H \CH,.CO 


It forms deliquescent needles, melting at 37°. Nitrous acid converts it into a 
nitrosamine. Boiling alkalies regenerate y-amidovaleric acid. 
For additional derivatives of pyrrolidon see Berichte, 22, 2364; 23, 708, 888. 


+ H,O. 


AZOLE COMPOUNDS. 


The azoles (diazoles, triazoles, etc.) are those compounds in 
which there is present a ‘‘ five-membered ’’ ring, containing two, 
three, etc., nitrogen atoms. These nuclei can also be derived from 
pyrrol, by simply replacing the CH-groups by nitrogen. Diazole 
is known in two isomeric forms—the a- or (1, 2)-dzazole, and the 
B- or (1, 3)-diazole. The first is also called Pyrazole, while the 
latter is more familiar under the name of Glyoxaline or Jmid- 
Azole* :—. 


CH = CH CH = CH CH= tH mee CH 
~~ \ ~ ~*~ 
NH | Se SNE. | NH 
CH = CH7 CH = N N = CH cH = 
Pyrrol, a-Diazole, Pyrazole. B-Diazole, Glyoxaline. Triazole. 


1. PYRAZOLE COMPOUNDS. 


Free Pyrazole, C,H,N,, is prepared by saponifying the addition product of. 
diazo-acetic ester with acetylene dicarboxylic ester, C,HN,(CO,.CH,), (p. 375), 
when the three carboxyl groups are split off (Berichte, 22, 2165). It can also be 
obtained from epichlorhydrin by heating it: with hydrazine hydrate, N,H,.H,O, 
and zinc chloride (Berichte, 23, 1105). It crystallizes in colorless needles, melt- 
ing at 70° and boiling at 185°. It is feebly basic, reacts neutral, and yields salts 
that are not very stable. 

Only those pyrazole derivatives, containing benzene residues, are known. Az/i- 
pyrine belongs to this class. They will be considered after the aromatic com- 
pounds. 

The addition of hydrogen to pyrazole produces the basic compounds Pyrazoline, 
C,H,N,, and Pyrazolidine, C,H,N, :-— 


SNH and *NNH. 





* Consult Widmann, /r. pr. Ch., 38, 185; Berichte, 21, Ref. 888; Knorr, 
Berichte, 22, 2083; Hantzsch, Annalen, 249, 4; Berichte, 20, 3118. 


552 ORGANIC CHEMISTRY. 


2. GLYOXALINE COMPOUNDS. 


Glyoxaline, C,H,N,, the parent substance of the glyoxalines (@-diazoles or 
imid-azoles) probably possesses the formula :— 


T CH See NNH. 


This would ally it both to the amidines, and the anhydrobases and lophines of 
the benzene series (Japp, Berichte, 16, 285, 748). 

The glyoxalines, like the amidines, do not yield acidyl derivatives with the acid 
chlorides, or nitrosamines with nitrous acid. It is for these reasons that the sym- 
metrical formula (without the NH-group) is adopted (Radziszewsky, Berichie, 15, 
2709) (see below). ; 

Glyoxaline is produced by the action of ammonia upon glyoxal (Berich/e, 15, 
645). It is easily soluble in water, alcohol and ether. It crystallizes in brilliant 
prisms, melting at 89°, and boiling at 255°. It reacts strongly alkaline, and forms 
salts with 1 equivalent of the acids. Alkyl iodides and caustic potash cause a sub- 
stitution of alkyl for the imide hydrogen, forming 2-a/kyl glyoxalines (Annalen, 
214, 319). 

These oe liquids with a very peculiar odor. They boil without decomposition, 
and combine with the alkyl iodides to form ammonium iodides. They can be 
prepared synthetically by acting upon the dialkyl oxamides with phosphorus 
pentachloride, and then reducing the amide chlorides and chlorinated bases which 
form at first. . Hence they have been designated oxa/ines (oxalmethylin, oxalethy- 
lin) (Wallach, Azma/en, 214, 257) :— 


CO.NH.CH, CH—N, 
| yields | NCH 
CO.NH.CH, | CH-NG 
CH, 
Dimethy1 Oxamide. a-Methyl-glyoxaline. 


In this manner oxal-ethylin, C,H,,N,, is obtained from diethyl-oxamide. It is 
identical with 7-ethyl-c-methyl-glyoxaline. 

n-Methyl-glyoxaline (#-A/ethyl-imid-azole) has also been made from z-methyl- 
imidazolyl mercaptan (from amido-acetal and methyl mustard oil). This is 
expressed by the accepted unsymmetrical formula of glyoxaline (imid-azole) 
(Berichte, 22, 1361). 

n-Methyl Glyoxaline, C,H,N,.CH,, obtained by the three methods, is a 
strongly alkaline liquid, boiling at 195-199°. It solidifies in the cold and melts 
at —5°. m-Propyl Glyoxaline, C,H,N,.C,H,, boils about 221°. . 

c-Alkyl glyoxalines, homologues of glyoxaline, having the alkyl group attached 
to carbon, are synthetically produced by the action of ammonia upon a mixture of 
glyoxal and aldehyde (therefore called glyoxalethylins) (Berichze, 17, 2402) :— 


CHO CH = N 


dio + Nis + CHO.CH = | De 4+ 3H,0. 


The reaction occurs more readily by using glyoxal and aldehyde ammonia 
(Berichte, 16, 487). The orthodiketones behave in the same manner with 


TRIAZOLE COMPOUNDS. 553 


— 
glyoxal. Thus, diacetyl and aldehyde yield ¢-trimethyl glyoxaline (Berichte, 21, 
1415) :— 
CH,.CO sae il ali gen apne 
| + 2NH, + CHO. = ; 3 : 
CH,.CO the : CH, ¢_NH” ’ : 


Benzaldehyde and diacetyl also yield dimethyl-phenyl-glyoxaline (Berichte, 23, 
Ref. 248), while triphenyl-glyoxaline (lophine, see this) is produced from benzil 
(dibenzoyl) and benzaldehyde. 

The c-alkyl glyoxalines or glyoxalkylins are crystalline solids. They resemble 
the alkaloids very closely in all their reactions. They are mon-acid imide bases. 
The imide hydrogen of the latter is replaced by alkyls. 

c-Methyl Glyoxaline, C,H,(CH,)N,H, glyoxalethylin, consists of brilliant 
needles, melting at 137°, and boiling at 267°. It is also obtained by a molecular 
rearrangement of #-methyl glyoxaline when the latter is distilled with lime 
(therefore it is called Paraoxalmethylin), and from c-methyl-vz-ethyl glyoxaline, 
C,H,(CH,).N,.C,H;, when this loses ethylene (Berichte, 14, 424). 

c-Trimethyl Glyoxaline, C,(CH,),N,H, from diacetyl, melts at 183° and boils 
at 271°. CH, NH 

Derivatives of Tetrahydroglyoxaline, C,H,N, pe poo have 

H,.NH 
been prepared by the action of aldehydes upon ethylene-aniline, GHC NH CH 
(Berichte, 20, 732). Hydantoin may be considered a diketo-derivative of tetra- 
hydroglyoxaline (p. 391). 


3. TRIAZOLE COMPOUNDS. 


The triazole nucleus, of five members, three of which are nitrogen atoms, exists 
in two isomeric forms :— 


\NH and a SNH 
des on SS CH = N% 
Triazole. Qsotriazone, 


The Triazole derivatives appear to be those compounds, which result from 
the union of dicyanphenylhydrazine, C,H;.N,H,.C,N,, with acid anhydrides, or 
with benzaldehyde (Bladin, Berichte, 19, 2598; 22, 796); ditriazole derivatives 
(Berichte, 22, 3114) are also formed from the so-called cyanphenylhydrazine, 
(C,H;-N,H;),C,N. ; 

The Osotriazone derivatives are obtained by boiling the osazones—the dihydra- 
zones of the ortho-diketones (p. 326)—with acids (an amide group is elimi- 
nated) :— 


CH,.C =N.NH.C,H, CH,C=N 


‘a NN.C,H, -- NH,.C7H 
CH,.C = N.NH.C,H, cH,¢= yo footy 


or by the transposition of the osotetrazones which first appear (Berichte, 21, 2757). 
Triphenylosotriazone, C,N,(C,H,), (Berichte, 21, 2806) is similarly obtained from 
benzil dihydrazone. 

Urazole is a diketo-derivative of tetrahydrotriazole. Its compounds have been 
obtained by the action of phenylhydrazine upon urea and derivatives of the latter 
(Berichte, 21, 1219; 20, 3372). 


554 _ ORGANIC CHEMISTRY... 


- 


4. THIAZOLE COMPOUNDS, 


The thiazole nucleus contains five members; one of them is an N-atom and 
another an S-atom :— 


It can be regarded as a diazole, in which the imide group has been replaced by 
sulphur, or as thiophene in which one CH-group has been substituted by nitrogen. 
Its entire character is that of pyridine, in which S has replaced ¢wo CH-groups, 
without affecting any of the essential properties of the parent substance (just as 
thiophene is an analogue of benzene) (Hantzsch, Annalen, 249,13; 250, 257; 
Berichte, 20, 3118; 22, Ref. 17 and 256). 

Free Thiazole, C,H,NS, is produced by exchanging hydrogen for the amido 
group in amidothiazole. This is similar to the formation of benzene from amido- 
benzene. It is a colorless liquid, boiling at 117°. It resembles pyridine very 
closely. 

The mono- and dialkylic thiazoles are produced :— 
(1) By the condensation of chloracetones with thioacetamides (p. 260) :— 


CH,C| = HS, CHS, 
| DOCH sed of fea sa OCH, 4-H,0:4- HCL 
CH,.CO HNZ CH,.C——N7 
Chloracetone. Iso-thio- au-Dimethyl-thiazole. 
acetamide. 


Thioacetamide reacts, in a like manner, with chloracetic ester and chlor (brom)- 
aceto-acetic ester; the products formed first are alkyl thiazole-carboxylic acids, 
from which the carboxy] groups can be eliminated (Berichte, 23, 2341). 

2) .By reduction of the oxythiazoles (p. 555) when heating them with zinc dust. 

3} By the transposition of amido-alkylthiazoles, in the same manner as thiazole 
is obtained from amidothiazole. 

The alkylic thiazoles are very similar to their corresponding pyridine bases, and 
boil usually 2~- 3° higher than the latter. The carboxylic acids of the alkyl thio- 
phenes unite with acids to form salts that are not very stable (Annalen, 259, 228, 
253, 266). 

53 tenga Thiazole, C,H,(CH,)NS, from thiacetamide and chloracetate, boils 
at 128°. a-Methyl Thiazole, from amido-methy] thiazole, and from oxy-methyl 
thiazole, boils at 132°. 

au-Dimethyl Thiazole, C,H(CH,),NS, from chloracetone and thioacetamide, 
boils at 145°. It is very similar to lutidine. Trimethyl-thiazole, C,(CH;),NS, 
is obtained from a-chlormethy]l aceto-acetic ester (Berichte, 23, 2341). 

Amidothiazoles result from the condensation of chloraldehyde or chloracetones 
with thiourea (p. 394) :— 


CH,Cl HS. : CH—S, 
4 CNH ay CNH, + HO + HC. 
CHO Hae Cheer : 
Chlor- Isothiourea, : w-Amido-thiazole. 
aldehyde. 


a-Methyl-y-amidothiazole and a-phenyl-u-amidothiazole are produced, in a simi- 
lar manner, from chloracetone and bromacetophenone, C,H,.CO.CH,Br. 


OXAZOLE COMPOUNDS. 555 


CR—-S. 
Alkyl Amido-thiazoles, || 
CRN“ 


chloracetones upon mono-alkyl-thioureas, while the dialkyl thioureas yield the 


C.NHR, are obtained by the action of 


dialkylimido-thiazolines, || >C:NR. 
CR—NR 7 

The amido.thiazoles are very similar to the aromatic amines. ° 

They yield diazo compounds, as well as derivatives of the latter. 

They become thiazoles by replacing the amido-group by hydrogen. 

u-Amido-thiazole, C,H,(NH,)NS, from chloraldehyde (or dichlor-ester) and 
thiourea, crystallizes in yellow plates, that melt at 90°. It has an alkaline reaction 
and forms salts. 

a-Methyl-u-amido-thiazole, C,H(CH,;)(NH,)NS, from chloracetone, melts 
at 42°. 

a Methyl-v-methyl-amidothiazole, C,H(CH,)NS.NH.CH,, from chlorace- 
tone and methyl thiourea, is an alkaline oil. It boils at 42° (Berichte, 22, Ref. 21). 

Oxythiazoles are prepared from the sulphocyan-acetones. The carbamine thio- 
acetones formed at first are transposed on boiling with hydrochloric acid :— 


CH,.CO.NH. CH,.C——-N 
. he yields a Sc.on 2.0; 
CHW. 2s CH 
Acetone-thiocarbamine. a-Methyl-y-oxythiazole. 


The oxythiazoles are slightly acid, unstable compounds. 

They speedily revert to the carbamin-thio-ketones. They are reduced to thia- 
zoles upon distillation with zinc dust ( Berichte, 22, Ref. 18). 

Imide-derivatives, compounds of dihydrothiazole, or thiazoline, C,H;NS, are 
known (Berichte, 22, 1144). 

Ethylene-isothiourea, C,H,NS (NH), or C,H,NS(NH,), may be viewed as a de- 
rivative of thiazoline, C,H;NS, or thiazolidine, C,H,NS (Berichte, 23, 2824). 


5. OXAZOLE COMPOUNDS. 


The parent nucleus of oxazole is perfectly analogous to thiazole. “It contains an 
oxygen atom instead of the sulphur atom. It bears the same relation to thiazole 
that furfurane, C,H,O, bears to thiophene :— 


CH—O o 
\| Je, Oxazole. 
CH-N7 
The alkylic oxazoles, like the alkylic thiazoles, are produced by the condensa- 
tion of chloracetone with acid-amides (Berich/e, 21, 2192) :— 


CH,Cl HN CH—N 





N \ 
| Sc.c,H, = | CC.4 + H.O + HCl 
CH,.CO HO”: 0h 3 JOH, Cae ae : 
Chloracetone. Isobenzamide. B-Methyl-«-phenyl Oxazole. 


The resulting methyl-phenyl oxazole, C, ,H,NO, isa colorless oil, boiling at 
240°. It has a feeble, alkaline reaction and dissolves in acids. 

Ethylene-pseudo-ureas (p. 391, Berichte, 22, 1151), the products of the transpo- 
sition of brom-ethy] urea, are derivatives of dihydro-oxazole, or oxazoline, C,H,NO. 
These are also formed when bromethylamine acts upon acid anhydrides or acid 
amides ( Berichte, 22, 2221; 23, 2493). : 

#t-Methyl-oxazoline, C,H,ON(CH,), is an oil, with an odor like that of quino- 
line. It forms salts with acids. 


j 
\ 


556 “ ° . . ..ORGANIC CHEMISTRY. 


at 73 


CLASS II. & 
AROMATIC COMPOUNDS OR BENZENE DERIVATIVES. 


~\ The aromatic compounds are mostly obtained from aromatic 


oils and resins. They differ in various respects from the members 
of the fatty or marsh gas series, but are principally distinguished 
from the latter by their greater carbon content. ‘The theoretical 
representations upon their constitution are based chiefly on the 
views developed by Kekulé in 1865—Kekulé’s denzene theory. The 
views of this investigator are in brief as follows (compare Kekulé, 
Lehrbuch der org. Chemie; Annalen, 137, 129) :— 


1. All aromatic compounds are derived from a nucleus consisting of six carbon 
atoms; its simplest compound is denzene, C,H,.. All other aromatic derivatives 
may be obtained from the latter by substituting other atoms or atomic groups (side 
chains) for its hydrogen atoms. The new derivatives are distinguished from the 
methane compounds by their specific benzene character, and are, therefore, called 
benzene derivatives. 

2. Benzene has a symmetrical constitution. Each carbon atom is combined 
with one hydrogen atom. Differences between the individual C- and H-atoms 
have not been discovered. Isomerides are, therefore, only possible when two or 
more side-chains are present. 

3. The structure of the benzene nucleus is such that the six carbon atoms, or 
CH-groups, form a closed, ring-shaped chain, the atoms being joined alternately 





by single and double bonds :— “a0 ae, 
bb bib bl - aes 
Vee are 
= Ne 
£0, y= pale 


In benzene, C,H,, the fourth affinity of each C-atom is joined to hydrogen; in 
the benzene derivatives it is combined with other atomic “ae ar 


Derivatives of Benzene.—These may be very readily derived 
from benzene by the replacement of its hydrogen atoms. Those 
derivatives in which side-chains exist are easily deprived of these 
and then revert to benzene. 

The closed chain is characterized by great stability, being torn 
asunder, or dismembered in chemical reactions with great difficulty. 
This is a property belonging to most all benzene derivatives ; it 
distinguishes the latter from the methane derivatives. In external 
properties they are better characterized, are more readily crystal- © 
lized, and are more reactive than the fatty compounds. 

The halogens and the nitro- and sulpho-groups can readily re- 
place the hydrogen of benzene :— 

C,H,Cl CHUNG A oe H,(SO,)H. 
Y ~C,H,Cl, G H,(NO,), 9 O,H), 


“se * . e ° e 


DERIVATIVES OF BENZENE. 557 


The wnion of the halogen atoms is much firmer in the benzene, 
than in the methane derivatives; as a general thing they cannot be 
exchanged for other groups by double decomposition. The pro- 
duction of mztro-compounds by the direct action of nitric acid is 
characteristic of the benzene derivatives, whereas the fatty com- 
pounds are generally oxidized and decomposed. ° 

In the reduction of the nitro-derivatives we obtain the amzdo- 
compounds .— 

C,H,;.NH, C,H,(NH,), C,.H,(NH,);. 
Amidobenzene, Diamidobenzene, Triamidobenzene, 

The so-called azo-derivatives appear as intermediate products of 
the reaction, whereas when nitrous acid acts on the amido-deriva- 
tives the diazo-compounds result. Both classes are of exceptional 
occurrence in the methane series (p. 167). 


Benzene possesses a more negative character than the methane hydrocarbons. 
The phenyl group, C,H,, stands, as it were, between the positive alkyls, 
Cn Hon +1, and the negative acid radicals. This is evident from the slight basicity 
of the phenylamines (like C,H,;.NH,), in comparison with the alkylamines. 
Diphenylamine, (C,H,;),NH, is even a more feeble base, its salts being decom- 
posed by water. Triphenylamine, (C,H,),N, is not capable of yielding salts 
(Berichte, 20, 534). 

We discover the same in relation to the hydroxyl derivatives; these, unlike the 
alcohols, posséss a more acid character. The phenols (such as C,H,.OH, carbolic 
acid) readily form metallic derivatives with basic hydroxides; trioxy-benzene, 
C,H,(OH), (Pyrogallic acid), reacts just like an acid. 


_ By introducing hydroxyl for hydrogen into benzene we obtain 
the phenols, which may be compared to the alcohols :— 
C,H,.0H _ C,H, (OH), C,H,(OH),. 


Phenol. Dioxybenzene. Trioxybenzene. . 


These resemble the tertiary alcohols in having the group C.OH 
attached to the three carbon affinities (p. 118), hence on oxidation 
they cannot yield corresponding aldehydes, ketones or acids. 

The entrance of hydrocarbon groups, C,H,, , 1, into benzene 
produces the homologues of the latter :— 

Bidioes. -_ Madpenatiet, Dikeet Gastene =< telah ecto 


C,H,.C,H C,H,(C,H;) i. C.H,. 
Ethyl hensens, Diethyl Beakenes Propet Benassi: 


Unsaturated hydrocarbons also exist :— 


C,H,.CH=CH, C,H, CoeCH,; etc. 
Ethenyl Benzene, Acetenyl Benzene. 


In these hydrocarbons the benzene residue preserves the specific 
properties of benzene; its hydrogen can readily be replaced by 


558 ORGANIC CHEMISTRY. 


halogens and the groups NO, and SO,H. On the other hand, the 
side-chains behave like the hydrocarbons of the fatty series ; their 
hydrogen can be replaced by halogens, but not by (by action of 
HNO, or H,SO,) the groups NO, and SO,H. . Different isomeric 
derivatives are possible, depending upon whether the substitution 
of the halogens (or other groups) has occurred in the benzene 
residue or the side-chains, e. g. :— 


C,H,ClCH, and C,H,.CH,Cl. 
C,H,Cl,.CH,, C,H,Cl.CH,¢l and C,H,.CHCl,. 


The halogen atoms in the benzene residue are very firmly com- 
bined and mostly incapable of double decomposition, while those in 
the side-chains react exactly as in the methane derivatives. 

The substitution of hydroxyl-for the hydrogen of the side-chains 
leads to the true alcohols of the benzene series :— 


Cats: 
C,H,.CH,.0H C,H,.CH,.CH,.0H C,H cH aL. 
Benzyl! Alcohol. ; Phenyl Ethyl! Alcohol. Tolyl ‘Aléohal. 


The primary class is oxidized to aldehydes and acids :— 


C,H,.CHO  C,H,.CH,.CHO CHA CHO’. 
Benzaldehyde, Phenyl Acetaldehyde. Tolyl Aldehyde. 


The acids can be formed by introducing carboxyl groups directly 
into benzene, or by oxidizing the homologues of the latter :— 


C,H,.CO,H C.Huce wy: efi 7C0.H),. 
Benzene Cackoxylic 2. Benzene Dicusboxyiit Acid. Bonsene "Tricarboxylic Acid. 


‘ CH, CH 
CoH CoH CH ey oe er eo. a)a, 
Toluic Acid. Pheny! Acetic Acid. Mesitylenic Bed. 


The hydrogen of the benzene residue in these acids, as well as in 
the alcohols and aldehydes, is replaceable by halogens, and the 
groups, NO,,SO;H, OH, etc. 

Furthermore, several benzene residues can unite directly, or 
through the agency of individual carbon atoms, forming higher 
hydrocarbons :— | 


C,H; C,H,.CH, CoH, CH, c, Nou, 
C,H, C.H,.CH, C,H,.CH, 5 
Diphényt: Ditolyl. Dibenzyl. Diphenyl Methane. 


he C,4Hy, Ci .Hy.. 
Naphthalene. Anthracene. Chrysene, 


DERIVATIVES OF BENZENE. 559 


Structure of the Isomerides.—Numerous cases of isomerism are 
possible among the derivatives of benzene. One variety of isomer- 
ism corresponds exactly to that observed in the fatty series ; it is 
founded in the isomerism of adjoining groups and their varying 
union with the benzene residue or in the side-chain. Thus we have 
the following isomerides of the hydrocarbon, C,H,;:— 


C.HiC.H,” “CH,CH, . CMC oat + CoH, (CeHs)s- 


Propyl Benzene. Isopropyl Benzene. Methyl Ethyl Benzene. Trimethyl Benzene. 


The products obtained by substitution in the benzene residue 
are isomeric with those derived by the same treatment of the side- 
chains :— 


C,H,Cl,.CH, C,H,Cl.CH,Cl C,H,.CHCI,. 
Cc HCH C,H,.CH,.0H C,H,.0.CH,. 
Cresol. Benzyl Alcohol. Phenyl Methyl Ether. 


The following are also isomeric :— 


/OH /O.CH /OH 
C eH co, CH, CoH CO,H CeoHs(CHs)< co.m etc. 
Giybenanic. Ester. Methyl Oxybenzoic Acid. Oxytoluic Acid. 


Another kind of isomerism is based upon the structure of the 
benzene nucleus, and is conditioned by the relative positions of the 
substituting groups, hence it is designated zsomerism of position or 
place. 

All facts known at present argue with much certainty in favor of 
the symmetrical structure of benzene, that is, that the six hydrogen 
atoms, or more correctly the six affinities of the benzene nucleus 
are of egual value (same as the four affinities of carbon). Let any 
one hydrogen atom in benzene be replaced by another atom, or 
atomic group, and every resulting compound can exist in but one 
modification ; thus there is but oe chlorbenzene, one nitrobenzene, 
one amidobenzene, one toluene, one benzoic acid, etc. The fol- 
lowing compounds are known in but one modification :— 


C,H,Cl, C,H,(NO,), C,H,.NH,, C,H,.CH,, C,H,.CO,H, etc. 


The equal value of the six affinities is indicated not only by the fact that no 
mono-derivatives, C,H ,X, can be prepared in more than one modification, but it 
can be directly proved. Thus in benzene four different hydrogen atoms (1, 2, 3, 4) 
are replaced by hydroxyl; in each case but one and the same phenol, C,H,.OH, 
results ( Ladenburg, Berichte, 7, 1684). And since two similar ortho- and ‘meta. 
positions exist in benzene (2 = 6 and 3 = 5, p. 561), the six affinities of the ben- 
zene nucleus must be equivalent. 


a 


» 


- 


B60. ORGANIC CHEMISTRY. 


4 Owing to this symmetry of the benzene nucleus, 
consisting of six carbon atoms, it can be repre- 
6 2 sented by a regular hexagon ; the numbers represent 
the six affinities, which in benzene compounds are 
saturated by other atoms or other groups.* 

5 3 Now, although the six hydrogen atoms in benzene 
are equal in value, it is obvious from the graphic 
4 representation that every di-derivative, C,H,X,, can 
exist in three modifications; their isomerism is dependent upon 
or due to the relative position of the two substituting groups. 
Indeed, nearly all di-derivatives are known in ¢hree modifications, 
but none in more than three. ‘Thus, there are three dioxybenzenes, 
three bromnitro-benzenes, three oxybenzoic acids, three toluenes, 
three dimethyl benzenes, three dicarboxylic acids, etc. The fol- 

lowing compounds are known in three modifications each :— 


/OH /Br /Br CO,H 
Coron SoH no: Cee,  SeaCon 
/CH /CO,H 


The compounds of the above series can be transformed into each 
other by various reactions ; and, indeed, so that each of the three 
isomeric modifications (in normal reaction) is transformed into the 
corresponding modification of the other body. Three isomeric 
series of di-derivatives of benzene consequently exist ; they are 
designated as the ortho, meta, and para series. We call all those 
ortho-compounds which belong to the series of phthalic acid; the 
meta or tso-compounds are those corresponding to isophthalic acid, 
and para those which correspond to parabrombenzoic acid and 
terephthalic acid. 

That an isomeric modification really belongs to one of the three 
series is determined in a purely empirical manner, either by di- 
rectly or indirectly converting it into one of the three dicarboxy- 
lic acids, Cs,H,(CO,H), (phthalic, isophthalic and terephthalic 





* The benzene formula of Kekulé, pictured on p. 556, representing the benzene 

nucleus, does not fully express the equal value of the six affinities, because accord~ 
—CX CX : 

ing tothemthe combinations || and | or the positions (1: 2) and (1: 6) 
—CX = OX 

are different. According to theory and the formula there are four isomeric di- 

derivatives, C,H,X.,, of benzene. But it has been proved that the di-derivatives 

(1, 2) and (1, 6) are identical, and that only three isomeric di-derivatives are pos- 

sible (p. 562). The hexagon does not attempt an explanation of the manner in 

which the fourth affinity of the C-atoms is combined, but it does give full expres- 

sion to the equal value of the six valences. 


DERIVATIVES OF BENZENE. 561 


acid). The relative positions of the substituting groups in the ben- 
zene nucleus have, however, been ascertained with perfect cer- 
tainty. In the ortho-compounds two adjoining hydrogen atoms 
in benzene are replaced (the positions 1: 2 or 1: 63; 1 here repre- 
sents any one of the six similar hydrogen atoms); the meta-com- 
pounds have the structure, 1: 3 or 1:53; whereas in the para- 
compounds, two opposite affinities (separated by two carbon atoms) 
are joined to other atoms (positions 1: 4). The following graphic 
representations will better explain the idea under consideration :— 


CoH 
Ortho-derivatives, Meta-derivatives. Para-derivatives. 
(1, 2) (x, 3) (x, 4) 


The following substances may be mentioned as chief representa- 
tives of the three isomeric series :— 


BE Si isl 
aes (1, 2). (1, 3)-. (1,4). 
A es 
C,H é Pyrocatechin, Resorcin, Hydroquinone, ~~ sp 
4\ OH y 
Ons 5 | On Salicylic Acid. Oxybenzoic Acid. | Paraoxybenzoic Acid, 
$4 CO ; : 
C,H cH Orthoxylene. Isoxylene. Paraxylene, 
CH ont H Phthalic Acid. Isophthalic Acid. | Terephthalic Acid. 
2 





The reasons for supposing that the isomeric di-dexivatives possess a structure 
such as indicated, are ;— 

1) Phthalic acid is ’ obtained by the oxidation of hindbalene, and the structure 
of the latter (see this) is very probably such that the two carboxyl groups in the 
acid resulting from it can only have the position (1, 2) (Graebe). 

(2) The structure of mesitylene, C,H ,(CHs)s, is ‘symmetrical ; the three methyl 
groups present in it hold the positions I, 3, 5 (see p. 566). The formation of mesi- 
tylene by the condensation of fhree molecules of acetone (A. Baeyer) proves this; 
the substitutions of mesitylene (Ladenburg, Berichte, 7, 1133) also indicate it with 
great certainty. The production of uvitic acid by the condensation of pyroracemic 
acid (p. 566) argues for the view that in it, and consequently also in mesitylene, 
the three side groups hold the positions (1, 3,5). If we replace a Cu -group in 
mesitylene by hydrogen, we obtain isoxylene, called dimethyl benzene, C, H,(CH,),, 


47 


562 ORGANIC CHEMISTRY: 


in which the two methyl groups can only have the positions (1, 3) = (1,5). When 
isoxylene is oxidized, it yields isophthalic acid, C,H $ 
xylene is oxidized, it yi phthalic aid Coy Co 


(3) It is apparent, on examining the benzene hexagon, that only a szmgle posi- 
tion (4 with reference to 1) is possible for the para-position while two similar posi- 
tions can exist for the meta- and ortho-derivatives (the positions 3 and 5, and 2 and 
6). This can be shown experimentally. It has been proved that the positions 3 
and 5 are similar with reference to I, consequently the meta-derivatives (1,3) and « 
(, 5) are identical (Anznalen, 192, 206, 222, 68). In the same manner the ortho- 

erivatives (I, 2) and (1, 6) are identical, consequently the positions 2 and 6 are 
similar (Berichte, 2, 141 and Anmalen, 192, 213)—while the para-position occurs 
but once in the benzene nucleus (see Berichte, 10,1215). It has been shown that 
paraoxybenzoic acid, parabromtoluene, and, therefore, also terephthalic occupy it. 
The latest investigations upon oxy-methyl-ethyl benzonitrile show that the positions 
2 and 6 are identical (Aerichte, 18, Ref. 148), and from the study of bromnitro- 
paratoluidine, it is concluded that this is also the case with the positions 3 and 5 
(Annalen, 234, 159). 

‘In addition to the preceding we have another means of determining the 
position, and it leads to exactly the same conclusions (Kérner). If we replace 
another hydrogen atom (by NO,) in a para compound, (e. g., paradibromben- 
zene, C,H,Br,) it is evident from the figure that but one compound can result, 
one nitroparadibrombenzene—because the positions 2, 3, 5 and 6 (those which 
the NO, can enter) are alike with reference to the para position 1,4. But 3 
igomeric mononitro derivatives are possible from metadibrombenzene (1, 3); in these 
the NO,-group occupies the positions 2, 4 (= 6) or 5. Orthodibrombenzene (1, 2) 
finally can yield 2 mononitro-derivatives; in these the NO,-group holds the positions 
3 (= 6) and4(=5). Therefore, six isomeric nitrodibrombenzenes, iC ie.” ; 
are possible ; 1 derived from the para, 3 from the meta, and 2 from ortho-dibrom- 
benzene; conversely, by the retrogressive substitution of H for NO, we discover 
that paradibrombenzene is afforded by but one-nitrodibrombenzene ; metadibrom- 
benzene by three other nitrodibrombenzenes, and the ortho-compound by two nitro- 
dibrombenzenes. K6rner executed this method of ascertaining position with much 
satisfaction and certainty with the isomeric tribrombenzenes (Gazzetta chimica 
ttal., 4, 305). The study of the six isomeric nitro- (or amido-) benzoic acids, 


CeH,C aNd.) , gave the same results (Griess, Berichte, 5, 192 and 7, 1223). 
2/2 


Further evidenct is derived from the derivatives of the three isomeric xylenes : 
metaxylene yields three nitroxylenes, three xylidines and three xylenols, the ortho- 
xylene two of each, and the para- but one. From this isoxylene and isophthalic 
acid must have the positions (1, 3), orthoxylene and phthalic acid (1, 2) and para- 
xylene and terephthalic acid (1, 4) (Berichte, 18, 2687). : 

That two adjacent carbon atoms of the benzene nucleus carry the side-groups in 
the ortho compounds is further concluded from their ability to yield so-called con- 
densations and various anhydrides (compare the phenylene diamines, thioanilines, 
coumarines, indols, phthalic acid anhydrides, etc), There are also crystallographic 
grounds favoring the idea that the meta-compounds stand between those of the 
ortho and para series (Zeztschrift f. Kryst., 1879, 171). 

The benzene hexagon not only expresses all the relations of isomerism of the 
benzene derivatives, but also abundantly illustrates their chemical and physical 
deportment. 4 


aa\> 


CONSTITUTION OF THE BENZENE NUCLEUS. 563 


If three or more hydrogen atoms of benzene be replaced, two 
cases arise: the substituting groups are like or unlike. In the first 
instance three isomerides of the tri-derivatives, ¢. g., CsH;(CHs);, 
are possible, and they occupy the positions :— 


(1, 2, 3) (1, 2, 4) and (1, 3» 5)- 


We call them adjacent (1, 2, 3) or (v) = vicinal, unsymmetrical 
(1, 2, 4) or (@) = asymmetrical, and symmetrical (1, 3, 5) or (Ss) 
tri-derivatives, 


Three isomeric structural casés exist likewise for the tetra-derivatives, with four 
similar groups, C,H,X, (analogous to the di-derivatives) :— 


(1, 2, 3, 4) (1, 2, 4; 5) (1, 2, 3, 5)- 


Adjacent, Symmetrical. Unsymmetrical. 


Only one modification is possible when there are five and six similar groups; 
thus there exists but one pentachlorbenzene, C,HCl,, and but one hexachloride, 
C,Cl,. 

When the substituting groups are unlike, the number of possible isomerides is 
far greater; they can easily be derived from the hexagon scheme. Thus, six iso- 
meric modifications correspond to the formula of dinitrobenzoic acid, C, H,(NO,),. 
CO,H :— 


(1, 2,3) (1,2,4) (1,2,5) (1,2,6) (1,3,4) (1,3, 5); 
here the carboxyl group occupies position 1. 


CONSTITUTION OF THE BENZENE NUCLEUS. 


In Kekulé’s formula the six carbon atoms are attached to each other by alter- 
nating single and double bonds, forming a closed ring, consisting of three single 
and three divalent ethylene linkages (p. 556). These assumptions give a rather 
comprehensive view of the entire behavior of the benzene derivatives :— 

1. They illustrate in the clearest manner possible the methods that have been 
employed in the synthesis of benzene derivatives (p. 565), benzene condensations, 
naphthalene, phenanthrene, etc. This has all been verified by the most recent 
syntheses (that of a-naphthol from phenylisocrotonic acid, etc). 

2. They show that only ortho-derivatives (because their side-chains are adja- 
cent) are capable of forming anhydrides, and explain many derivatives due to 
ortho-condensations. The accepted benzene formula is made quite evident from 
the manner in which the quinoline ring is formed (Marckwald, Berichte, 23, 
IOI5). 

2 Ihe assumption of three double unions offers the simplest explanation (with- 
out new theories) for the power of benzene derivatives to yield additive products 
with 2, 4 and 6 affinities (p. 567). True, this addition does not occur as readily 
With the normal benzene compounds as it does with the methane compounds, in 
which there exist ethylene unions, but it can be expressed by the ring-formula of 
the benzene nucleus, and finds analogy in the behavior of the double (divalent) 
union in phenanthrene (p. 568 and Baeyer, Anmaden, 251, and 286). Para- 
additions, it seems, do occur. These are not easily explained. The normal for- 
mula only accounts for ortho-additions (p. 568). 

4. Various physical properties argue for the presence of double unions, like 
those of ethylene, in benzene, Thus, the specific refractive powers indicate the 


- 


564 | ORGANIC CHEMISTRY. 


presence of three ethylene unions, CH—CH, in benzene compounds, and five in 
naphthalene (Briihl, Berichte, 20, 2288). Compare Nasini, Berichte, 23, Ref. 276. 
The specific volumes of the benzene derivatives appear to support this idea (p. 57 
and Berichte, 20, 771). 

Kekulé’s formula for benzene does not fully express the entire symmetry of the 
benzene nucleus. It would make the ortho-derivatives (1, 2) and (1, 6) different, 
and allow of four different di-derivatives, unless we admit Kekulé’s idea of the 
oscillations of the adjacent carbon atoms (Amma/en, 162, 86) 

For this and other reasons various benzene formulas have been proposed (see G. 
Schultz’s Chemie des Steinkohlentheers, II Aufl., p. 110), ¢. g., the octahedral 
formula of Thomsen, the Zrism formula of Ladenburg, and the diagonal formula 
of Claus. 

The authors of these three formulas do not regard double unions as present in 
the normal benzene nucleus, but contend that each carbon atom is united by a 
single bond to three other carbon atoms. The benzene nucleus, according to this 
view, contains nine single unions of carbon :— 


CH CH 


HC CH HC CH 
and 


HC CH HC CH 

















CH & 00H { 


It was thought that this last idea was definitely proved by the specific volumes 
of the benzene derivatives, and especially by their heat of combustion (Theorie 
der Bildungswarme von J. Thomsen, Berichze, 13, 1808; 14, 2944). According 
to the most recent researches the specific volumes argue strongly for the presence 
of three divalent unions in the benzene nucleus, while the conclusions drawn from 
the heat of combustion are in the opinion of Briihl unfounded (/ourn. prakt. 
Chemie (2) Bd., 35, 1). 

Ladenburg’s frvzsm formula fully accounts for all the static relations of ben- 
zene, and explains its isomeric derivatives. It, however, ignores all the double 
unions, which are proved by the partially reduced benzene nuclei of the di- and 
tetra-hydro-additive products (p. 568). It establishes a spatial orientation of 
the four affinities of the carbon atoms, which is without analogy in the paraffin 
series, and, in the opinion of its author, leaves to the formula of Kekulé the first 
place in explaining the various modes of formation and the decompositions of the 
benzene compounds (Berichée, 23, 1010). 

The diagonal formula of A. Claus, with its hexagonal ring and its diagonal or 
central linkages, explains all the isomeric relations of the derivatives of benzene 
fully as well as the hexagon formula, It has the advantage that it permits of the 
formation of either para- or ortho-additive products, because it grants the double 
carbon-linkages in both the di- and tetra-hydro-benzenes (Berichie, 20, 1422; 
Journ. pr. Chem. (2), 42, 458). But it also presents an orientation of the four 
carbon affinities that is without analogy, and introduces a peculiar central valence, 
differing from that of the two ring valences. 

Baeyer has very recently introduced a central formula, which is very similar to 
the diagonal formula, but, unlike the latter, does not admit the presence of central 
linkages. It does not attempt to account for the state or condition of the fourth 
valence of carbon, but maintains merely that it exerts a pressure directed towards 
the centre. It thus reverts to the hexagonal formula of benzene (Kekulé) which 


CONSTITUTION OF THE BENZENE NUCLEUS. 565 


makes no attempt to explain the manner in which the fourth valences are com- 
bined (Baeyer, Berichle, 23, 1775). 


Formation of Benzene Derivatives.—The compounds of benzene 
can only be obtained in exceptional cases from methane derivatives 
by synthetic reactions. As they are generally very stable on expo- 
sure to heat (especially the hydrocarbons and anilines), they are 
quite often produced by the application of a red heat to the methane 


derivatives. Thus, benzene and other hydrocarbons result by ex- . 


posing acetylene to a red heat :— 
aU Hi. => Siekia: 4C,H, = OP > ee 


Benzene. Styrolene, 


1. Liquid bromacetylene is readily polymerized, when exposed 


to light, to solid symmetrical tribrombenzene (Berichie, 18, Ref. . 


374) ?— 
3C, HBr = C,H, Br, (453, 5) 
HC = CBr HC = CBr 
Z, > 
BrC CH yield BrC CH, 
ee \ 4 
at : CBr HC — CBr 


When iodo-acetylene, C,HI, is preserved for some time it also 


becomes tri-iodobenzene, C,H;I,;. When di-iodoacetylene, C,I,, is - 
exposed to light or heat, it forms hexa-iodo-benzene, C,lI, (Be-° 


richté, 18, 2276). 

Symmetrical trimethyl benzene (mesitylene) is similarly ob- 
tained from allylene, CH;.C:CH, on distilling its sulphuric acid 
solution :— 

3CH:C.CH, = C, H,(CH;),. 


The polymerization of crotonylene, CH,.C: C.CH, (p. 89), occurs even more 
readily, since shaking it with sulphuric acid suffices for its conversion into hexa- 
methyl benzene, C,,H,, (Berichte, 14, 2073) :— 


3CH,.C: C.CH, = C,(CH,),. 


The transposition of propiolic acid (p. 244), when exposed to light, into trimesic 
acid (symmetrical benzene tricarboxylic acid (Berichte, 19, 2185) is due to the 
same polymerization :— 


3HC:C.CO,H — C,H,(CO,H), (1, 3, 5). 


2. The formation of benzene compounds from ketones (by Aydro- 
lytic condensation) is very interesting. The condensation here is 
probably analogous to that of crotonaldehyde from aldehyde (p. 
194), and mesityl oxide from acetone (p. 207). Symmetrical tri- 
methyl benzene (mesitylene) is formed rather abundantly on dis- 
tilling acetone with sulphuric acid :— 


566 ORGANIC CHEMISTRY... 


3CO(CH,), = C,H, (CH,), + 3H,0, or 


CH, CH, 
ay a 
co. CH, C—CH 
Bera yd is 
CH, .{ CO~CH,. yield. ¢; HO’ - G—CH, + 3H,0. 
Sante A 
BO cH. C—CH 
rl 
3 CH, 
3 Molecules Acetone. t Molecule Mesitylene. 


We can obtain in a similar manner symmetrical triethyl benzene, C,H,(C,H,)., 
from methyl-ethyl ketone, CH,.CO.C,H,, tripropyl benzene, C,H,(C,H,),, 
from methyl-propyl ketone, CH ,.CO.C,H.,, and triphenyl benzene, C,H,(C,H,), 
from methyl-phenyl ketone, CH,.CO.C,H,. 

Analogous condensations are the following :— 

Formo-acetic ester, CHO.CH,.CO,R, to trimesic ester, €,H,(CO,R),; acet- 
aldehyde to symmetrical triacetyl benzene, C,H,(CO.CHs), (p. 323) ; pyroracemic 
acid to uvitic acid, C,H,.(CH,).(CO,H), (reduction of the carboxyl group to 
CH,); aceton-oxalic ester to symmetrical oxytoluic acid, CgH,(CH,)(OH)CO,H 


(p- 341). 
Another rather remarkable condensation is that of the ortho-diketones. to 


quinogens and quinones (p. 326). 


3. Another synthetic method employed in the production of 
benzene derivatives depends upon condensation, analogous to that 
observed in the formation of aceto-acetic ester (p. 334). It occurs 
in the action of sodium upon various acid esters, when sodium 
ethylate or alcohol is split off, and, therefore, may be termed an 
ester condensation. 

Succino-succinic ester (quinone tetrahydro-dicarboxylic ester) (p. 342) is formed 
by the action of sodium upon ethyl succinic ester :— 

RO,C.CH, + RO.CO.CH, = RO,C.CH.CO.CH, 
+ 2ROH. 


| | | 
CH,.CO.OR * < CH COCR CH,.CO.CH.CO,R 
Again, upon heating sodium malonic ester phloroglucintricarboxylic ester re- 


sults (p. 409) :— ‘ 
RO,.C.CHNa RO.CO.CHNa.CO,R RO,C.CH.CO.CH.CO,R 


CHNa.CO.OR d 
CO.OR a O.CH.CO +. 3RONa. 
CO,R 
CO,R 
3 Molecules Sodium Malonic Ester. Phloroglucin- 


tricarboxylic Ester. 
Similarly, acetone dicarboxylic ester yields, on heating its sodium compound, 
dioxyphenylaceto-dicarboxylic ester, which can easily be converted into orcinol 
(Berichte, 19, 1446) :— 
200CHT COR Lat HL Os {cdm, + ROH + H,0. 
In this reaction there occurs first an ester, then a ketone condensation. 
The ester of trimesic acid is produced when sodium acts upon a mixture of 
‘ 


ADDITIVE PRODUCTS. 567 


acetic ester and formic ester, water and sodium ethylate splitting off at the same 
time. 

4. When hexyl iodide, C,H;,I, and ICI, are heated together the two terminal 
C-atoms unite, and the product is hexachlorbenzene, C,Cl,, and when heated with 
bromine hexabrombenzene results, even at 200° C. 

_ Another interesting synthesis is that of benzene hexacarboxylic acid, 

(C,(CO,H),) = C,,H,O};., mellitic acid, by the oxidation of graphite or charcoal 
with potassium permanganate, and that of the potassium derivative of hexaoxyben. 
zene, C,(OH),,upon heating CO with potassium (Nietzki, Berichte, 18, 1836) :— 


6CO + 6H = C,0,H,. 





The normal benzene nucleus, formed as above, is very stable: It is broken 
only when exposed to exceptionally energetic reactions. The following decompo- 
sitions are effected quite readily, and are, therefore, worthy of mention: the con- 
version of proto-catechuic acid and pyrocatechol into dioxytartaric acid by nitrous 
acid ; benzene into trichloraceto-acrylic acid and maleic acid (p. 344) by chloric 
acid, and gallic acid, salicylic acid and phenol into isotrichlorglyceric acid (p. 
461). Chlorine changes phlorglucin quite easily into dichloracetic acid and tetra- 
chloracetone (p. 205), while potassium chlorate and hydrochloric acid decompose 
chloranilic acid into tetrachloracetone and tetrachlordiacetyl (p. 327). 

The intermediate transposition of various chlorine derivatives, by the action of 
chlorine, into keto-derivatives of pentamethylene is rather peculiar (p. 520). 

All benzene compounds are decomposed when oxidized by energetic reagents, 
such as chromic acid, etc. 





Additive Products.—Many benzene derivatives are able to com- 
bine directly with 2, 4 and 6 atoms of chlorine, bromine, hydro- 
gen, etc. Here the three double bonds of the carbon atoms, as in 
the ethylenes, in all probability, change to single bonds :— 


C,H, .Cl,.. C,H, Cli Ga. 


Nascent hydrogen converts the phthalic acids into di-, tetra, and 
hexa-hydrophthalic acids. The halogens are added with much more 
difficulty than in the case of the alkylens and other unsaturated 
fat-bodies, although the latter sometimes take up the halogens with 
difficulty (see fumaric acid). These addition products contain the 
ring-shaped, closed benzene chain, and are the compounds, C,X,,, 
no longer able to saturate additional affinities. When the benzene 
ring is broken, hexane derivatives, C,X,, result. The addition 
products are, therefore, true benzene derivatives, and can readily 
be converted into the normal compounds, C,X, (p. 571). 


The latest researches of Baeyer prove that hexa hydrobenzene,C,H,.H,, is in 
fact identical with hexamethylene (analogous to tetra- and penta-methylene) 
(Baeyer, Annaden, 245, 131; Berichte, 21, Ref. 495) :— 


£CH,~ CH cy 


CoHoH, = CH Gy" _¢H 


* 


568 : ORGANIC CHEMISTRY, . 


Baeyer designates the normal benzenering, C,H,, in which each C-atom is com- 
bined with three affinities to carbon, as the ¢ertzary benzene ring, the added ring, 
C,H, ., as the secondary or reduced benzene ring. 

The partially reduced rings, C,H,.X, and C,H,.X,, contain one and two 
double-unions, C—C, which behave just like those of the olefines. Like the 
latter, they are readily oxidized by alkaline permanganate, whereas terephthalic 
acid is not attacked in the cold by this reagent. It might be deduced from this 
that an ordinary double-union does not occur in the normal benzene ring; fur- 
ther, that para-compounds also occur, as the additions sometimes take place at the 
para carbon atoms. Baeyer, however, thinks that these abnormalities are ex- 
plained by the like deportment of phenanthrene (the non-oxidation of its double- 
linkage) and by the molecular transpositions of the hydrogen additive products 
(Annalen, 251, 258; 256, 1, Berichte, 22, Ref. 375; 23, 231; 23, 1272). 

The additions to the ortho-, para, and meta-carbon atoms occur more con- 
veniently if we adopt the diagonal formula of Claus (/r. pf. Chem. 42, 461; 
Berichte, 20, 1424). 

Baeyer indicates the double-union in the reduced benzene nuclei, C,H ,.X, and 
C,H,-X4, by the character A, adding a number as index to show which carbon 
atom of the hexagon (p. 560) is in double union with the adjacent (next following) 
carbon atom. Thus, A%, §-Dihydro-terephthalic acid represents a para-dicarboxylic 
acid in which the second C-atom is doubly united with the third C-atom, and the 
fifth C-atom doubly linked to the sixth C-atom. A®-Tetrahydro-terephthalic acid 
is a substance in which the second carbon atom is doubly linked to the third 
carbon atom :— 


Pe ce et HS 


NCH CH > CH.CO,H, 48, §.Dihydroterephthalic acid. 
/CH. = CH \ 
Ci. btKS .ig Chay 


A. Baeyer has developed stereochemical representations as to the constitution of 
hexa-hydro-benzene derivatives, These would explain the existence of two 
isomeric hexa-hydroterephthalic acids, two hexahydromellitic acids, etc. (Baeyer, 
Annalen, 258, 1,145.) See also Sachse, Berichte, 23, 1363 (compare Herrmann, 
Berichte, 23, 2060). 


. CO,H .HC CH.CO,H, A®-Tetrahydroterephihalic acid. 





HYDROCARBONS, C,H,,_<. 


The benzene homologues are formed by substituting alkyls in 
benzene for hydrogen :— 


C,H, 7 sl eh, C,H,(CH;). CoH,(CHs)s C,H,(CH;), 
Benzene. oluene. Xylenes. Trimethyl Benzenes. Durene. 
B. P. 80.5°. EEO y Be 2 137-140°, * 163-170°. 190°. 
C,H,.C,H, C,H,.C,H, C,H,.C,H, C,H,.C,H,. 
Ethyl Benzene. Propy! Benzene. Isopropyl Benzene. Tecbutyl Benzene. 
134°. £57°. 151°, 163°. 


The entrance of the methyl group into the benzene nucleus 
elevates the boiling point about 29-26°; its introduction in the 
side-chains causes an increase of about 23-19°. The boiling points 
of isomerides of position (p. 559) usually lie near each other ; the 
ortho-compounds boil about 5°, and the meta- 1° higher than the 
para-derivatives. 


HYDROCARBONS. 569 


'Preparation.—The most important methods of preparing the 
benzene hydrocarbons are the following :— 

(1) Action of sodium upon mixtures of their bromides, and the 
bromides or the iodides of the alkyls in ccs sal"SOlutign ; reaction 
of Fittig (p. 72) :— 


C,H,Br + CH,I + 2Na = C,H, a, 











-+ Nal + NaBr, 
cm 9 Mi Nal + NaBr. 


@ alkyl iodide and ether 
(free from water and alcohol), then add metallic sodium in thin. pi 
stand for some time, after which the solution ‘is heated with Are 
upon a water bath. A few drops of acetic ether sometimes aé¢ lc 
action. Para- and ortho-derivatives, ¢. g., C,H,Br.CH, and C,H, Br,, react 
most readily. With the meta-compounds, which are not so easily" atiac 
mides are substiuted for alkyl iodides, or else benzene iodides are emplo: 
Berichte, 21, 3185, for the course of the reaction. ) ‘ 


(2) Action of the alkylogens upon benzene Bytrocatbortiggn 
the presence of aluminium chloride (zinc or ferric chloride)— 
Friedel and Crafts. % 


It is very likely that in this reaction metallo-organic compounds, ¢. g., C,H;. 
Al,Cl,, are formed, which afterwards act upon the alkylogens :— 


¢:H, +CH,Cl = C¢,H,.cH, - ae. 
C,H, -+ 2CH,Cl = C,H,(CH,), + 2HCl, ete. 


Even hexamethyl benzene, C,(CH,),, can be prepared after this manner. 
Various halogen derivatives, ¢. g., chloroform (see diphenyl methane) and acid 
chlorides (see ketones) react similarly with the hydrocarbons of the benzene 
series, 

To éffect syntheses after this style, AIC], ({-} part) is added to benzene, and 
CH,Cl or C,H,Cl is conducted into the heated mixture; or AICI], can be added 
to the benzene “compound mixed with the chloride or bromide, and heat then 
applied until the evolution of HCl has almost ceased (Berichte, 16, 1745). Car- 
bon disulphide sometimes acts very favorably as a diluent. The product i is grad- 
ually mixed with water, then digested with soda. The oil which separates is 
subjected to distillation. Consult Berichte, 14, 2624, upon the introduction of methyl 
into homologous benzenes. A table of all-the syntheses effected by AlCl], may be 
found in Annalen Chim. Phys., (6) I, 449. 

Frequently the action of the AICI, is much more complicated, inasmuch as 
syntheses are not the only products, but we also find decompositions, splitting-off 
and transference of the alkyls. Thus, from toluene we obtain benzene, xylene, 
etc., (Anschiitz, Berichte, 18, 338, 657; Friedel, Berichte, 18, Ref. 336). A tabu- 
lation of the more complex reactions can be found in Annalen, 235, 150, 299. 

The benzene nucleus may be alkylized if the HCl-salts of alkylic anilines be 
heated alone, or if the anilines and methyl alcohol be heated to 250—300°; here 
the NH, group is eliminated (Berichte, 13, 1729); or the anilines and fatty alco- 
hols can be heated with zinc chloride to 250° (Berichte, 16, 105) :— 


C,H,.NH, + C,H,.0H = CH CH + HO. 


48 


570° ORGANIC CHEMISTRY. 


Homologues of phenol (see these) are produced by heating fatty alcohols, 
phenol and zinc chloride together. The easy formation of isobutyl benzene on 
heating benzene and isobutyl alcohol with ZnCl,, deserves notice. 


(3) Dry distillation of a mixture of aromatic acids with lime or 
soda-lime (p. 71); iron filings are introduced to accelerate the 
conduction of heat. All the carboxyl groups are split off in the 
reaction and the original hydrocarbons set free :— 


C,H,.CO,H =C,H, + CO,, 
C,H,(CO,H), =C,H, + 2CO,, 
C,H,(CH,).CO,H = C,H,.CH, + CO,. 


(4) Heating the oxygen derivatives, e. g., phenols and ketones, with zinc dust, 
or with hydriodic acid and phosphorus. It is remarkable, that benzophenone, 
C,H,;.CO.C,H,, for example, is readily reduced, while the opposite is true of 
diphenyl ether, C,H,.0.C,H,. 

(5) The methods of obtaining benzenes synthetically from fatty compounds, 
especially acetylenes and ketones, have already received notice (p. 566). 

(7) Dry distillation of various, non-volatile carbon compounds, e¢. g., wood, 
resins, bituminous shales, and especially bituminous coal. When the vapors of 
volatile methane derivatives (CH,, alcohol, ether) are conducted through tubes 
heated to redness, they set hydrogen free and yield acetylene, benzene and its 
homologues, styrolene, C,H,, naphthalene, C,H, ), anthracene, etc. Petroleum 
and the tar from lignite, containing ethane hydrocarbons, do the same. A similar 
hehavior is observed with a mixture of benzene vapor and ethylene (Zerichie, 20, 


660). 


The chief and almost exclusive material in preparing benzene 
hydrocarbons is coal tar, which is made in such large quantities in 
the manufacture of gas. Distillation divides the tar into a Zgh¢ and 
heavy oil. The former boils from 60—180° and contains principally 
benzene, toluene, the three xylenes and trimethyl benzenes, as well 
as durene. As to their formation see Berichte, 18, 30923; 19, 


2513. 


To isolate these hydrocarbons, shake the light oil first with sulphuric acid, then 
with potash; wash, dry and finally fractionate over sodium. ‘The heavy oil, boil- 
ing from 160—220°, sinks in water and comprises mainly phenol, cresol and naph- 
thalene. In the portions of coal tar boiling at high temperatures, we have the 
solid hydrocarbons; naphthalene, C,,)H,, acenaphthene, C,,H,9, anthracene and 
phenanthrene, C,,H,), pyrene, C,,H,), chrysene, C,,H,,, and others. Some ben- 
zene hydrocarbons occur already formed in small amount in the naphtha varieties 
(p. 78) (for their recognition by means of bromine and AIBr,, see Beriche, 16, 
2295), and in different ethereal oils (together with aldehydes, alcohols and acids). 

Phenols, benzene, and its homologues (see Cymene, p. 577) are obtained by dis- 
tilling camphor with zinc chloride, or phosphorus sulphide. 


Properties.—The hydrocarbons of the benzene series are volatile 
liquids, insoluble in water, but soluble in alcohol and ether ; some, 
containing only methyl groups, are solids at ordinary temperatures. 
They dissolve in concentrated sulphuric acid, on application of 


BENZENE. 571 


heat, to form sulphonic acids, ¢. g., CsH;.SO,;H, from which the 
hydrocarbons can be reformed by dry distillation or by heating 
with concentrated hydrochloric acid (see benzene sulphonic acids). 


This reaction is the basis of a method for the separation of the ben- | 


zenes and marsh gas series ; it also permits of the preparation of the 
former in pure form. ‘The benzenes dissolve in concentrated nitric 
acid, forming nitro-derivatives. 

Acids are produced (aromatic acids) by oxidizing the side-chains 
of homologous benzenes with nitric acid, a chromic acid mixture, 
potassium permanganate, or ferricyanide of potassium. | Energetic 
oxidation converts benzene into carbon dioxide; only minute 
quantities of benzoic and phthalic acids are formed at the time. 

Chromyl chloride, CrO,Cl,, unites with the benzene homologues 
to form compounds which water converts into aromatic “seapeey oe 
(see these). 





HYDROBENZENES, OR BENZENE HYDRIDES. | 


The normal benzenes can take 2, 4 and 6 hydrogen atoms, forming additive 
products (p. 567). 

When heated with phosphonium iodide, they mostly yield the lower hydrides ; 
thus, toluene yields the dihydride, C,H,.H,, isoxylene, the tetrahydride, C,H, . H,, 
and mesitylene, the hexahydride, CoH, 2-H,; nearly all the benzenes, when 
acted on with hydriodic acid at 300° finally yield the hexahydrides. The latter 
are, in all probability, the so-called naphthenes, which have been isolated from 
Caucasian petroleum (Berichte, 23, Ref. 431). They are closely allied to the 
paraffins, boil about 12° lower than their corresponding norma] benzenes, and are 
very slowly attacked by cold, alkaline permanganate. The partial benzene hy- 
drides, C, H,, and C,H, 9, are readily oxidized by permanganate, and take up bro- 
mine with great ease (Berichte, 21, 836). 

The benzene hydrides dissolve upon ‘tinkige them with fuming sulphuric acid, 
with liberation of carbon dioxide and sulphur dioxide, and the formation of sulpho- 
acids of the normal benzenes. For example, octonaphthene, C,H, ,, yields m-xylene 
sulphonic acid. But other oxidizing agents frequently separate the added hydrogen 
atoms, or the hydride is completely destroyed. Fuming nitric acid, or nitro-sul- 
phuric acid, dissolves them in small amount (5 per cent.) to form nitro-derivatives 
of the normal benzenes. They are mostly burnt upon the application of heat 
(Berichte, 20, 1850). Many benzene hydrides precipitate metallic silver from 
boiling solutions of silver nitrate. 





1. Benzene, C,H,, contained in coal tar, is formed by the dry 
distillation of all benzene acids, having only CO,H side groups (p. 


57°). | 
That portion of the coal tar boiling from 80-85° is chilled by meansof a freezing 


mixture, and thesolid benzene then pressed out inthe cold. To get perfectly pure 
benzene, distil a mixture of benzoic acid (1 part) and CaO (3 parts). 


572 ORGANIC CHEMISTRY, 


Common benzene from coal tar, even the purified article, invariably contains 
thiophene, C,H,S; hence it yields the indophenin reaction (p. 529). When 
heated with sodium it gives the reaction of Na,S. Concentrated sulphuric acid 
turns it brown, and when the acid contains N,O,, the coloration is violet (Berichte, 


16, 1473): 


Benzene is a mobile, ethereal-smelling liquid, of specific gravity 
0.899 at o° (0.8799 at 20°). It solidifies about 0°, melts at +6°, 
and boils at 80.5°. It burns with a luminous flame, mixes with 
absolute alcohol and ether, and readily dissolves resins, fats, sulphur, 
iodine and phosphorus. 


Benzene Hexahydride, C,H,.H,, Hexamethylene (see above), boils at 69°; 
its specific gravity at 0° is 0.76. 


2. Toluene, C,H; = C,H;.CH,, is obtained from coal tar, and 
is produced in the dry distillation of tolu balsam and many resins. 
It is synthetically prepared by the action of sodium upon C,H;Br 
and CH,I, and by the distillation of toluic acid, sass W 

2 
with lime. It is very similar to benzene, boils at 110°.3, and hasa 
specific gravity at 0° of 0.882 (0.8656 at 20°). It does not solidify 
at —28°. Dilute nitric acid and chromic acid oxidize it to ben- 
zoic acid, C,H;,;COOH; chromyl chloride converts it into benz- 
aldehyde. | 


Ordinary, not perfectly pure, toluene contains some thiotolene;hence gives the 
anthraquinone reaction.(p. 529) (Berichte, 17, 1338). 

Toluene Dihydride, C,H,.H,, boils at 105—108°. Toluene Hexahydride, 
C,H,.H,, boils at 97°; sp. gr. 0.772 at 0°. : 


3. Hydrocarbons, C;H,) :— 
C,H,(CH,), O,HpC,B; 


3 Isomerides. t Modification. 


The three dimethyl benzenes, C,H,(CH;),, or methyl toluenes 
(ortho, meta and para), are called 

Xylenes, and occur in coal tar. Orthoxylene, with a little of 
the para variety, is produced on conducting CH,Cl into benzene 
or toluene containing AICI; (p. 569) (Berichte, 14, 2627). 


That portion of coal tar oil boiling between 136—141° contains, in addition to 
ten per cent. paraffins, variable quantities of metaxylene (as much as 85 per cent.), 
paraxylene (as high as 20 per cent.), and orthoxylene (up to 20 per cent.). When 
the mixture is boiled with dilute nitric acid (rt part NO,H and 3 parts H,O) the 
ortho- and para- varieties are oxidized to their corresponding toluic acids, C,H, 
(CH,).CO,H, while metaxylene and the paraffins are unattacked. On shaking 
crude xylene with ordinary sulphuric acid, the ortho- and meta- xylenes dissolve 
to form sulphonic acids. Only metaxylene is dissolved if 80 per cent. sulphuric 
acid be used. Sodium orthoxylenesulphonate is sparingly soluble in water. Para- 
xylene only dissolves in fuming sulphuric acid. It also volatilizes first when 
crude xylene is distilled with steam (erichte, 10, 1013; 14, 2625; 17, 444). 


a 


ef 


- 


4 


ETHYL BENZENE. 573 


* 1. Orthoxylene (1, 2) is obtained from orthobrom-toluene by means of CH,I 
and sodium, and can be prepared from toluene by means of CH,Cl and AICI, 
(Berichte, 14, 2628). Metaxylene is formed at the same time (Berichie, 18, 342). 
It boils at 142-143°. Dilute nitric acid oxidizes it to toluic acid, C,H,(CH,). 
CO,H; chromic acid decomposes it into carbon dioxide, and with potassium per- 
manganate it yields phthalic acid (Berichte, 19, 3084). 

Ortho-xylene can be nitrated by heating it for some time (6-8 hours) with a 
mixture of NO,H and SO,H,. Bromine, at 150°, converts it into ortho-xylene 
bromide, C,H,(CH,Br),, which melts at 94° (Berichte, 17, 123). On heating 
the three xylenes with PCI; in a sealed tube chlorine first enters the side-chains 
(Berichte, 19, Ref. 24). The resulting ortho-xylylene chloride, C,H,(CH,Cl),, 
has also been obtained from phthalyl alcohol. The latter melts at 54°, and boils 
at 145° under a pressure of 20 mm. 

o-Xylene Dihydride, C,H,,, is cantharene, obtained by heating cantharides 
with P,S;. Its odor is like that of turpentine. It resinifies when exposed to the 
air (Berichte, 19, 1406). : 

2. Metaxylene, or Isoxylene (1, 3), is obtained from coal tar, and is pro- 
duced from mesitylene, C,H,(CH,), (1, 3, 5), by heating mesitylenic acid, 

CO,H 

CoH, { (cit,), 
C,H,Br.CH,, but was obtained in small quantity from meta-iodo-toluene. It boils 
at 137°; its specific gravity at 0° is 0.878. It is not oxidized by ordinary nitric 
acid as readily as paraxylene, and yields isophthalic acid, C,H,(CO,H),. Iso- 
toluic and isophthalic acids result from it by the action of KMnO,. The hydrides 
are obtained by heating metaxylene or camphoric acid with HI or PH,1: C,H,,.H, 
and C,H,,).H,. 

m-Xylene Tetrahydride, boils at 119°. 

m-Xylene Hexahydride is identical with octonaphthene, from Caucasian 
petroleum. It boils at 117-118°, and when acted upon with nitric and sulphuric 
acids yields trinitro-isoxylene. 

On warming metaxylene with fuming nitric acid a dinitro-product results, which 
melts at 93°. SO,H, and NO,H yield a ¢rinitro-product, C, H(NO,),.(CH3),; 
this melts at 176°. Characteristic amido-compounds are obtained by the reduction 
of the preceding nitro-derivatives. Cold, fuming nitric acid produces the momo- 


, with lime. It could not be prepared from metabromtoluene, 


nitro compound, which melts at -+- 2° and boils at 237-239°. 


3.-Paraxylene (1, 4) is formed when camphor is distilled with ZnCl,. It is ob- 


_tained pure by the action of sodium and CH,I upon parabromtoluene, C,H, Br. 


CHsg, or better, upon paradibrombenzene, C,H,Br, (Berichte, 10, 1356). It boils 
at 136-137°; its specific gravity at 19° is0.862. Pure paraxylene solidifies in the 
cold, forming monoclinic needles, which melt at 15°. Dilute nitric acid oxidizes 
it first to paratoluic acid and subsequently to terephthalic acid, C,H,(CO,H),. 
Chromic acid converts it immediately into the latter acid. With fuming nitric acid 
it yields two isomeric dinitro-paraxylenes, C,H,(NO,),(CH,), ; the first melting 
at 93°, the second, more sparingly soluble in alcohol, at 123.5°. NO,H and 
H,SO, convert it into a trinitro-derivative, C sara) Oba 3)2» Which melts at 
137°. The reduction of these compounds produces ill-defined amido-compounds. 
Paraxylene is soluble in fuming sulphuric acid only ; its sulphonic acid forms large 
crystals, and is not very soluble. : < 

4. Ethyl Benzene, C,H,.C,H,, is produced by the action of sodium upon 
C,H,Br and C,H,Br, and hydriodic acid upon styrolene, C,H,;.C,H,, but best 
by the action of C,H,Br and AICI, upon benzene (Berichte, 22, 2662). It boils 
at 134°. Its specific gravity at 22° equals 0,866. Dilute nitric acid and chromic 
acid oxidize it to benzoic acid; CrO,Cl, converts it into phenyl acetaldehyde, 
C,H,.CH,.CHO. Ityields two liquid mononitro-products, C,H ,(NO,).(C,H;) 


574 ORGANIC CHEMISTRY, 


(1, 2) and (1, 4), by the action of fuming nitric acid. The first boils at 227°, the 
second at 245°. See p. 586 for the halogen derivatives of ethyl benzene. 


4. Hydrocarbons, C,H,. 


CH “ 
C,H,(CH,), CoH CH, C,H,-C,H,. 
Trimethyl Benzenes, Methyl Ethyl Benzenes. Propyl! Benzenes, 
3 Isomerides. 3 Isomerides. 2 Isomerides. 


(a) Trimethyl Benzenes. 

1. Mesitylene, symmetrical trimethyl benzene, C,H;(CH,;); 
(1, 3, 5), occurs in coal tar, and is produced by distilling acetone, 
or allylene with sulphuric acid. It may, also, be prepared from 
phorone (p. 566). 


Preparation.—Distil a mixture of acetone (1 volume) and sulphuric acid (1 
volume) diluted with % volume of water. It is well also to add sand. The 
distillate consists of two layers; the upper, oily layer is siphoned off, washed with 
a soda solution and fractionated. 


Mesitylene is an agreeable-smelling liquid, which boils at 163°. 
When heated with dilute nitric acid the methyl groups are success- 
ively oxidized to mesitylenic acid, uvitic acid and trimesic acid, 
C,H;(CO,H); (1, 3, 5). Chromic acid breaks it up, yielding acetic 
acid. Heated up to 280° with PH,I we get the hexa-hydride, 
C,H,,.H,, boiling at 138°, and yielding the same products as mesi- 
tylene when oxidized. Warm fuming nitric acid converts it into 
trinitromesitylene. 


LNVitromesitylene, C,H, ,(NO,), is obtained by the nitration of mesitylene in 
glacial acetic acid; it melts at 44°. Dinitromesitylene melts at 86°. The ¢rinztro- 
compound, obtained by adding mesitylene to a cold mixture of NO,H and SO,H,, 
crystallizes from benzene in large, colorless needles. It dissolves in hot alcohol, 
but not readily in ether, and melts at 232°. 

C,H,Cl(CH,), boils at 205°. C,HCI,(CH,), melts at 59° and boils at 244°. 
C,Cl,(CH,), melts at 204°. 

C,H,Br(CH,), solidifies at o° and boils at 225°. C,HBr,(CH,), melts at 
60°, C, Br,(CH,)., at 224°. 

The symmetrical structure of mesitylene renders it impossible to have isomerides 
in these substitution products (Aznalen, 179, 163). 

Bromine, acting upon boiling mesitylene, produces the dromides, C,H,(CH;)o. 
CH,Br, C,H,(CH,)(CH,Br),, and C,H,(CH,Br),; the latter melts at 94° 
(Berichte, 19, Ref. 25). 

z. Pseudocumene, C,H,(CH,), (1, 3, 4), unsymmetrical trimethyl ben- 

zene, occurs with mesitylene in coal tar (boiling at 162~-168°) in about equal 
amount. It cannot, however, be separated by fractional distillation. 
* To separate these two hydrocarbons, dissolve the mixture in concentrated sul- 
phuric acid and dilute with water, when the more sparingly soluble cumene- 
sulphonic acid will separate in the form of crystals, while mesitylene-sulphonic 
acid continues in solution (Berichte, 9, 258). The hydrocarbons are obtained by 
heating the sulpho-acids with hydrochloric acid to 175° (p. 571). 

It may be synthesized by the action of sodium and CH,I upon bromparaxylene 
(1, 4) and brom-metaxylene (1, 3), hence the structure (1, 3,4). It appears in 


ISOPROPYL BENZENE. 575 


small quantities when phorone is heated with P,O, or ZnCl,. Pseudocumene 
boils at 166°. Nitric acid oxidizes it to xylic acid, so-called paraxylic acid, and 
finally to xylidic acid, C,H ,(CH,)(CO,H), (see these). 

A mixture of NO,H and H,SO, converts pseudocumene into a ¢rinitro-com- 
pound, C,(NO,),.(CH,)3,/which is not very soluble in alcohol, but crystallizes 
from benzene in thick prisms, melting at 185°. It yields, by reduction with hydro- 
gen sulphide, nitro-cumidine sulphonic acid (Berichte, 20, 966). The gradual 
addition of bromine to cold pseudocumene results in the formation of a crystalline 
monobromide (melting at 73°); the addition of any more reagent makes the prod- 
uct liquid, and it finally becomes the solid tribromide, C,Br,(CH,),, melting at 
224°. Sulphuric acid converts the crystalline symmetrical brom-cumene into the 
liquid variety (1, 2, 3,4) (Berichte, 22, 1580, 1586). 

When crude pseudocumene, from coal tar, is poured into a mixture of fuming 
NO,H and SO,H, a crystalline mass is formed; it contains three trinitro-cumenes. 
Crystallized from benzene the mesitylene derivative separates first in long needles, 
then follows the pseudocumene in thick prisms. 

Hexahydro-pseudocumene, C,H,,.H,, is the nono-naphthene, C,H,,, 
isolated from Caucasian petroleum. It boils at 135-138°. Its sp. gr. is 0.7812. 
It forms pseudocumene sulphonic acid by solution in fuming sulphuric acid. 
Bromine converts it into tribrom-pseudocumene (Berichte, 23, Ref. 431). 

3. Hemimellithene, C,H,(CH,), (1, 2, 3), adjacent trimethyl benzene, is 
obtained from a-isodurylic acid, C,H,(CH,),.CO,H, and boils at 168-170°. It 
is contained in coal tar (Berichte, 19, 2517), and may be synthesized by the action 
of metallic sodium and methyl iodide upon brom-m-xylene. 


(4) Ethyl Toluenes, C,H KH: o-Ethyl Toluene, from o-bromtoluene by 


means of ethyl bromide and sodium, boils at 160° C. The (1, 4)-compound from 
parabromtoluene; boils at 161-162°, and when oxidized yields paratoluic and tere- 
phthalic acids. The (1, 3)-ethyl toluene, from metabrom-toluene, boils at 150°. 
It yields isophthalic acid on oxidation. 

(c) Propyl Benzenes, C,H,.C,H,. Normal propyl benzene, obtained from 
C,H, Br, propyl iodide or bromide and sodium, or from benzyl chloride, C,H,. 
CH,Cl, by the action of zinc ethide, boils at 157°; its specific gravity is 0.881 at 
o°. In the cold bromine converts it into parabrom-propyl benzene, C,H ,Br. 
C,H,, boiling at 220°. Normal cumic acid is obtained from this by the action of 
sodium and CO, (Berichte, 15, 698). If it be treated while hot, with bromine, we 
get (y-dibrom-propyl-benzene, C,H,.CHBr.CHBr.CH, (Berichte, 17, 709). 
Propyl benzene yields phenyl-propionic aldehyde, C,H;.CH,.CH,.CHO, when 
acted upon with chromy! chlo: ide. 

Isopropyl Benzene, C,H,.C,H,, called Cumene, is made by distilling cumic 
acid with lime, and by the action of AlBr, upon a mixture of benzene with iso- 
propyl bromide or normal propyl bromide. In the latter instance the normal 
propyl group sustains a transposition (p, 577). Normal and isopropyl! chlorides 
also yield it. Its production from benzal chloride, C,H,.CHCI,, by means of 
zinc methide, proves that the isopropyl group is present in it. Cumene boils at_ 
153°; its specific gravity is 0.879 at 0°. Parabrom-cumene, C,H,Br.C,H,, yields 
common cumic acid, C,H,(C,H,).CO,H, with sodium and CO,. In the animal 
organism normal propyl benzene is oxidized to benzoic acid, while isopropyl ben- 
zene yields propyl phenol (Berichte, 17, 2551). 

Nitric acid or the chromic acid mixture oxidizes both propyl benzenes to ben- 
zoic acid. 


576 ORGANIC CHEMISTRY. 


4. Hydrocarbons, CyyHy,:— 


C,H Coke ey | 
C,H,(CH,),- C,H, { (ci), CoHy{ Cy? CoH chy,’ Cu. u,. 
3 Isomerides. 6 Isomerides. 3 Isomerides, 6Isomerides. 4 Isomerides. 


(2) Tetramethyl Benzenes, C,H,(CH,),. Symmetrical Durene (1, 2, 4, 5) 
is formed from brom-pseudo cumene, C,H,Br(CH,),, and dibromisoxylene, 
C,H,Br,(CH,),, by means of CH,I and sodium; and from toluene by CH,Cl 
and AICl, (Anmalen, 216, 200). It is present also in coal tar (Berichte, 18, 
3034). It is crystalline, possesses a camphor-like odor, melts at 79-80° and boils 
at 190°. Nitric acid oxidizes it to durylic and cumidic acids, C,H,(CH,),. 
(CO,H), (the symmetrical constitution of durene is concluded from this (Berichte, 
11, 31). Monobrom-durene, C,HBr(CH,),, melts at 61°, and boils at 263°. 
It sustains a peculiar transposition into dibrom-durene and pentamethylbenzene, 
when it is shaken with ordinary sulphuric acid (Berichte, 20, 2837). Dibrom- 
durene melts at 199°; dinitrodurene, C,(NO,),(CH,),, at 205°. Durene is but 
slightly dissolved on shaking with concentrated sulphuric acid. When it is heated 
to 100° it sustains a peculiar transformation with the production of hexamethyl 
benzene, the sulphonic acids of prehnitol, pseudocumene and isoxylene, which can 
be separated by means of their amides (Berichte, 20, 902). Penta-methyl and 
penta-ethyl benzene undergo similar transpositions (p. 578). 

Unsymmetrical Isodurene (1, 3, 5, CH,) is obtained from brom-mesitylene 
with CH,I and Na, and from mesitylene by means of CH,Cl and AICl,, together 
with durene (Berichte, 18, 338). It boils at 195° and does not solidify in the 
cold. Dibromisodurene melts at 209°, dinitrotsodurene at 156°. The oxidation 
of isodurene with nitric acid yields three isodurylic acids, C,H,(CH,),.CO,H 
(Berichte, 15, 1853), and at last mellophanic acid. 

Adjacent tetramethyl benzene, called Prehnitol (1, 2, 3, 4), is produced by the 
action of methyl iodide and metallic sodium upon brompseudocumene and dibrom- 
metaxylene (Zerichte, 21, 2821), and on warming durene with concentrated sul- 
phuric acid ie above). It is separated from its sulpho-acid by heating with hydro- 
chloric acid (Berichte, 21,904). It is a liquid, boiling at 204°. It can only be 
soldified by a freezing mixture; it then melts at —4°C. Its oxidation by nitric 
acid produces prehnitylic acid, C,H,(CH,),.CO,.H (Berichte, 19, 1214) and 
phrenitic acid, C, H,(CO,H),. 

The tetramethyl benzene (Berichte, 19, 1553), derived from brompseudocumene, 
' is probably identical with prehnitol. ( (CH,) 

(4) Symmetrical Ethyldimethyl Benzene, C,H, {¢ H. ” (1; 3; 5), is pro- 
2.5 


duced (simultaneously with methyl diethyl benzene) by distilling a mixture of di- 
_ methyl ketone and methyl ethyl ketone with sulphuric acid (p. 566). It boils at 
185° and is converted into mesitylenic and uvitic acids by nitric acid. MMethy/- 


diethyl Benzene, C,H, { (C, it ) (1, 3, 5), which is formed at the same time, 
boils at 198—200°. an 578 

Two isomeric Ethyldimethyl Benzenes (Laurenes) are obtained by heating 
camphor with ZnCl, or iodine, They boil at 183-190° (see Berichte, 23, 983, 
2349). 

(c) Diethyl Benzenes, C,H,(C,H,),. 0-Diethyl Benzene, from o-dichior- 
benzene and ethyl bromide, boils at 184°. #-Diethyl Benzene is (with the para) 
obtained by the action of AIC], upon benzene and ethylbromide. It boils at 182°, 
and when oxidized with nitric acid yields m-ethylbenzoic acid and isophthalic 
acid. #-Diethyl Benzene, from /-bromethyl benzene and Z-dibrombenzene, 
boils at 181°, It yields f-ethylbenzoic acid and terephthalic acid. 


PARA-CYMENE. 577 


(d) Methylpropyl Benzenes, C,H, { Ci: Those of the six possible 
isomerides, having the normal propyl group, ‘are designated cymenes and those 
with the isopropyl group, zsocymenes. : 

Orthocymene (1, 2) is formed from orthobromtoluene and propyl iodide, by 
the action of sodium, and boils at 181-182°. 

Metacymene (I, 3) is formed from metabromtoluene and propyl iodide, and 
boils at 176-177°. Metaisocymene (1, 3) occurs in resin and is formed from 
toluene and isopropyl iodide in the presence of AICI,. It boils at 171-175° and 
is oxidized to isophthalic acid by chromic acid. Consult Berichte, 16, 2748, and 
Annalen, 235, 275, for the sulphonic acids. 


Para-cymene, CH. Cn (1, 4) methyl normal propyl 
ot 


benzené. This is usually called cymene and occurs in Roman 
caraway oil (from Cuminum cyminum), together with cumic alde- 
hyde, and in other ethereal oils. It is produced on heating thy- 
mol and carvacrol, 
C,H,(OH).(CH,).C,H,, 

with P,S;, or with PCl, and sodium amalgam; also by heating 
camphor, C,H,.O, and some of its isomerides with P,S; (along with 
meta-isocymene, Berichte, 16, 791 and 2259), or with P,O, (in pure 
state). Whencamphor is heated with ZnCl,, it gives rise to a series 
of benzene homologues, but, as it seems, no cymene, Berichte, 16, © 
624 and 2555). Cymene is obtained from turpentine oil and other 
terpenes, C,,H,,, by the withdrawal of two hydrogen atoms. This 
is effected by heating with SO,H, or, better, with iodine, or by the 
action of alkalies or aniline upon the dibromide, C,,H,,Br.. The 
production of cymene on boiling cumic alcohol, C,H,(C,H;). 
CH,.OH (having the isopropyl group), with zinc dust is especially 
interesting. A transformation of the isopropyl group takes place. 
Cymene may be synthetically prepared from parabrom-toluene, 
C,H,Br.CH;, by means of normal propyl iodide and sodium. 


: & : 

Preparation.—Take a mixture of equal parts of camphor and P,O, and heat 

until the réaction ceases. The cymene produced is poured off, again boiled with 

a little P,O; and then distilled over sodium (Anma/en, 172, 307). Or, shake 

Roman caraway-oil with a concentrated sodium bisulphite solution, which also dis- 

solves the cumic aldehyde contained in the oil. The oil is separated and then 
fractionated. 


Cymene is a pleasantly-smelling liquid, that boils at 175-176° ; 
its specific gravity at o° is 0.8722. It exhibits a characteristic 
absorption spectrum. It dissolves in concentrated sulphuric acid on 
warming, and forms a sulphonic acid. The characteristic barium 
salt,- (CjoH,;SO;).Ba +- 3H,0O, crystallizes in shining leaflets. 


Dilute nitric acid or the chromic acid mixture oxidizes cymene to paratoluic 
acid, C,H,(CH,).CO,H; and terephthalic acid ; whereas in the animal organism 


578 _ ORGANIC CHEMISTRY. © 


or upon shaking with caustic soda and air, it is, strange to say, converted into cu- 
mic acid, C,H,(C,H,).CO,H (with theisopropyl group). The propy! group is con- 
verted into the isopropyl group. Similarly, the same oxy-propyl-sulpho-benzoic acid, 


C,H,(C,H,.OH) { mane as that obtained from para-isocymene sulphonic acid, 
3 


is produced by the action of MnO,K upon cymene sulphonic acid. The latter 
contains the normal propyl group, which was changed tothe isopropyl] group, then 
further oxidized to oxy-isopropyl, (CH,),.C(OH). Nitrocymene and nitroiso- 


cymene, CoH(NO,) Ct yield the same nitro-oxy-isopropyl benzoic acid, 


eH, (NO) 6A OH (Berichte, 21, 2231). 

On the other hand, ethyl propyl benzene, isopropyl-propyl benzene, acetopropyl 
benzene, C,H Rew Hs (Berichte, 21, 2224), and allied compounds are oxid- 
ized to normal cumic acid, C,H,(C,H,).CO,H, and the propyl group remains 
undisturbed. In oxidations of this character, the rearrangement of the propyl to 
the isopropyl group takes place, if the second group oxidized is methyl, but not 
when ethyl, propyl and acetyl are oxidized (see Fileti, Berichte, 20, Ref. 168 ; 
Widmann, Serichle, 22, 2280; 23, 3081). 

When concentrated nitric acid acts upon cymene, the product is not nitrocymene, 
but Z-tolylmethylketone (Berichte, 19, 558; 20, Ref. 373). 

Para-isocymene (1, 4) could not be made from parabrom-toluene and iso- 
propyl iodide, but may be prepared from parabrom-cumene, C,H,Br.C,H,, by 
means of methyl iodide and sodium. It resembles paracymene in odor and boils at 

. 171-172°; its specific gravity is 0.870 at 0°. 

(e) Butyl Benzenes, C,H,.C,H,. ormal butyl benzene boils at 180°. 
Lsobutyl benzene at 167°. They are obtained from brom-benzene by means of the 
butyl bromides, and from benzyl chloride, C,H,;.CH,Cl, by propyl and isopropyl 
iodides. When benzene is quickly heated to 300° with isobutyl alcohol isobutyl 
benzene is formed (Berichte, 15,1425). The secondary butyl benzene, C,H ,.CH 
(CH,)C,H,, is formed from $-bromethyl benzene (p. 586) by means of zinc 
ethyl. It boils at 171°. The three butyl benzenes yield benzoic acid when they 
are oxidized. 

Tertiary Butyl Benzene, C,H,.C(CH;),, trimethyl phenyl methane, may be 
obtained from benzene by the action of isobutyl chloride and AICI, upon it. It 
boils at 168°. Bromine does not attack it even when exposed to sunlight. This 
behavior distinguishes it from its three isomerides (Berichte, 23, 2412). 





The following higher benzene homologues may be mentioned :— 

Pentamethyl Benzene, C,H(CH,),, is produced together with hexamethyl 
benzene when AICI, and methyl chloride act upon benzene, toluene, xylene, mesi- 
tylene, etc. (Berichte, 20, 896). It is crystalline, melts at 51.5° and boils at 231°. 
Concentrated sulphuric acid dissolves it, and it then undergoes a change similar 
to that of durene (p. 576); hexamethyl benzene and prehnitol sulphonic acid are 
produced :— 


2C,H(CH,), + SO,H, = C,(CH,), + C,H(CH,),.SO,H + H,0. 


Chlorsulphonic acid, SO,CIH, converts it into the sulphone and the sulpho-acid of 
pentamethyl benzene (Berichie, 20, 869). ‘The remaining H-atom can be readily 
substituted by acetyl, carboxyl, etc. (Berichte, 22, 1218). 

Isoamyl Benzene, C,H,.C,H,,, boils at 193°. Amyl Benzene, C,H,.C.H,,, 
from benzyl bromide, C,H,.CH,Br, and butyl bromide, boils at 201°. 


HALOGEN DERIVATIVES. 579 


Hexamethyl Benzene, C,(CH;), = C,H, is formed, together 
with the preceding (Berichte, 20, 896), by the polymerization of 
crotonylene, CH;.C:C.CH;, on shaking with sulphuric acid (p. 566), 
and by heating xylidene hydrochloride and methyl alcohol to 300°, 
(p. 368). It crystallizes from alcohol in plates or prisms, melts at 
169°, and boils at 264°. It does not dissolve in sulphuric acid, as 
it is incapable of forming a sulpho-acid. Potassium permanganate 
oxidizes it to benzene hexacarboxylic acid, C,(CO,H), (mellitic 
acid). 


Dipropyl Benzene, C,H,(C,H,), (1, 4), is formed from paradibrom-benzene 
and propy! iodide, and boils at 219°. When oxidized with dilute nitric acid it 
forms parapropyl benzoic acid, C,H,(C,H,).CO,H (normal cumic acid). 
Propyl-isopropyl Benzene, C,H,(C,H,)C,H,, derived from cumyl chloride, 
C,H <CHICH,), , and zinc ethyl, boils at 212°, and also yields parapropyl 
benzoic acid when oxidized with nitric acid. 

Symmetrical Triethyl Benzene, C,H,(C,H,), (1, 3, 5), is made by distilling 
ethyl-methyl ketone, C,H,.CO.CH,, with sulphuric acid (p. 566) and by the 
action of ethylene and AICI, upon benzene. It boils at 218°, and yields trimesic 
acid with chromic acid. 

v-Tetraethyl Benzene, C,H,(C,H,;), = C,,H,,. (1, 2, 3, 4), is obtained 
from benzene, C,H, Br, and AICl,, and from penta-ethyl-benzene by the action of 
sulphuric acid. It is liquid and boils at 251°. It yields phrenitic acid, C,H, 
(CO,H),, when oxidized with MnO,K. 

Normal Octyl Benzene, C,H,.C,H,, = C,,H,., from brom-benzene and 
normal octylchloride, boils at 262—264°, and solidifies in the cold. It yields ben- 
zoic acid when oxidized (Berichte, 19, 2717). 

Pentaethyl Benzene, C,H(C,H,),, from benzene by the action of ethyl 
bromide and AICl,, is a thick oil, boiling at 277°. Chlorsulphonic acid converts 
it into a sulpho-acid. When it is shaken with concentrated sulphuric acid it yields 
tetra- and hexa-ethyl benzene (Berichte, 21, 2814). 

Hexaethyl Benzene, C,(C,H,;), = C,,H35, crystallizes in large prisms, 
melting at 126°, and boils at 305°. 

Hexadecyl Benzene, C,H,;.C,,H,,, and Octodecyl Benzene, C,H;,. 
C,,H,,, are obtained by the action of hexadecyl iodide and octodecyl iodide upon 
iodobenzene. The first melts at 27°, and boils at 230° under a pressure of 15 
mm.; the second melts at 36° and boils at 249°, under a pressure of 15 mm. 
(Berichte, 21, 3181). 





HALOGEN DERIVATIVES. 


The hydrocarbons of the aromatic series are more rapidly substi- 
tuted by chlorine and bromine than the paraffins. In the benzene 
homologues the substitution occurs both in the residue and in the 
side groups :— 

C,H,Cl,.CH,, C,H,C.CH,Cl, C,H,.CHCI,. 


In the nucleus the halogen atoms are very firntly attached, and are 
not displaced by the action of KOH, silver oxide, ammonia, or 


So _ ORGANIC CHEMISTRY.’ 


sodium sulphite. The readiness with which they react with piperi- 
dine is interesting and remarkable (Berichte, 21, 2279). If nitro- 
groups enter, then the halogens become more reactive. The halo- 
gen atoms in the side-chains behave as in the fatty bodies. 

The transpositions, that various chlor- and brom-derivatives of 
the alkylbenzenes sustain when shaken with sulphuric acid, are 
worthy of note (Berichte, 23, 2318). 

The methods of forming the halogen products are perfectly 
analogous to those in the fatty-series (p. 90). 

(x) Bromine and chlorine manifest an interesting deportment 
in their substitution. In the cold and in presence of iodine,’ 
MoCl, or Fe,Cl, (also when heated), they act on the nucleus only ; 
from toluene, (C,H;.CH;),C,H,Cl.CH;,C,H,Br.CH;, and other 
products are obtained (Berichte, 13, 1216). On the other hand, 
on conducting chlorine or bromine vapors into boiling toluene 
(and its homologues), the side-chains are almost exclusively substi- 
tuted; C,H;.CH,Cl,C,H;.CHCl1, and C,H;.CCl, are obtained. Act- 
ing in the warm and cold alternately (or in presence of iodine), we 
can substitute hydrogen atoms in the side-chains or in the nucleus 
(Beilstein). 

It is only in exceptional cases that iodine acts substitingly 


(p. 91). 


Sunlight has the same effect as heat. Chlorine and bromine then, in nearly all in- 
stances, act upon the side-chains (Schramm, Berichte, 18, 608; 19, 214). Ferric 
chloride is also a carrier of bromine and chlorine (p. 91) ; it is also applicable in 
iodation (Anunalen, 231, 195). Nitrobenzene, C,H,NO,., may be substituted in 
this way. 

When the homologous benzenes are heated in sealed tubes, together with PC1,, 
the side-chains are alone substituted (Berichte, 19, Ref. 24). 

The action of chlorine and bromine slowly diminishes with the number of halogen 
atoms already introduced. For further chlorination, the substances must be heated 
with phosphorus chloride, molybdenum chloride, or iodine chloride (Berichie, 8, 
1296). In such energetic chlorinations the side-chains of the benzene homologues 
are at last severed. Thus, from toluene, xylene, cumene, cymene, etc., we finally 
obtain perchlorbenzene, C,Cl,, while the side groups disappear as CCl,. Naph- 
thalene, anthracene, phenanthrene, and many other benzene compounds behave 
similarly (Berichte, 16, 2869). A like decomposition occurs on heating with bro- 
mine containing iodine; C,Br, and CBr, are formed in this instance. Bromine 
reacts similarly, but more readily, in the presence of Al, Br, (Berichte, 16, 2891) ; 
from cymene we get C,Br;.CH, and isopropyl iodide. 


(2) Action of the phosphorus haloids upon*the phenols and aro- 
matic alcohols (p. 558); here both the hydroxyls in the nucleus 
and in the side-chains are replaced by halogens (p. 91) :— 


oh a Pel = CH? + POCI, + HCl, 
C,H,.CH,.OH + PCI, = C,H,.CH,Cl + POCI, + HCl. 


. 


BENZENE DERIVATIVES. 581 


(3) An important method, and one that is only applicable in the 
case of benzene derivatives, consists in the transformation of the 
diazo-compounds (see these). The diazo-group can be replaced by 
chlorine, bromine and iodine by various reactions. ‘This behavior 
serves to substitute the halogens for nitro-and amido-groups through 
the agency of diazo-compounds :— 

Cog i Cah» CR EB 
benzene. benzene, benzene, 

Halogen products can be obtained from substituted amido-com- 
pounds by introducing hydrogen for the amido-group through the 
diazo-derivative :— | 

C,H,Br,.NH, yields C,H,Br,. 


(4) Decomposition of substituted acids by heating them with 


lime (p. 570) :— 
C,H,CI.CO,H = C,H,Cl + CO,. 
Chlorbenzoic Acid, Chlorbenzene, 


Additive products are obtained by letting an excess of chlorine 
or bromine act upon benzene or the chlor-benzenes, in the sunlight 
(Pp. 567) :— 

C,H ,.Cl, C,H,.Cl, CgH,-Cl, 
C,H .€.Lci, C,H,C1.Cl, C,H,C1.Cl,, ete. 

Hexachlorbenzene, C,H ,Cl,, is also formed by conducting chlorine into boiling 
benzene; substitution products are produced at the same time. The additive 
products are solids, and do not volatilize without decomposition. When distilled or 


heated with alkalies, half of the added chlorine (or bromine) breaks off as hydro- 
gen chloride (or bromide) :— 


C,H,CLCl, = C,H,Cl, + 2HCl. 


Protracted action of sodium amalgam upon the alcoholic solutions of the halo- 
gens brings about the substitution of hydrogen for the halogens. Heating with 
hydriodic acid and phosphorus effects the same result. 





BENZENE DERIVATIVES. 


Monochlor-benzene, C,H,Cl, phenyl chloride (the group C,H, is called 
phenyl), is obtained from benzene, and from phenol, C,H,.OH, by the action of 
PCl, upon the latter. It boils at 132° and solidifies at —40°; its sp. gr. at 0° is 
1.128. 

Dichlor-benzenes, C,H,Cl,. In the ‘chlorination of benzene the products 
are chiefly solid para- and a little liquid ortho-dichlor-benzene. 

Paradichior-benzene (1, 4) forms monoclinic needles, melts at 56°, and boils 
at 173°. It is obtained also by the action of PCl, on para-nitraniline, para- 
chlorphenol and para-phenol-sulphonic acid. It forms a mononitro-product, 
C,H,Cl,.NO, (1, 4, NO,), melting at 55°. 


582 ORGANIC CHEMISTRY. 


Metadichlor-benzene (1, 3), from metachlor-aniline, 6-dichlor-aniline, C,H,C),. 
NH,, and common dinitro-benzene, is a liquid, and boils at 172°. Its mononitro- 
derivative melts at 32° (1, 3, 4 — NO, in 4). 

Orthodichlor-benzene (1, 2), from benzene and orthochlor-phenol, is a liquid, 
and boils at 179°; its nitro-derivative melts at 49° (1, 2, 4 — NO, in 4). 

Trichlor-benzenes, C,H,Cl,. 

Ordinary trichlor-benzene (1, 2, 4) is produced in the chlorination of benzene, 
or the three dichlor-benzenes, and is also obtained from benzene hexachloride, 
and a-dichlor-phenol. It melts at 17°, and boils at 213°. Its nitro-compound 
(1, 2, 4, 5 — NO, in 5) melts at 58°. 

Symmetrical Trichlor.benzene (1, 3, 5) is obtained from ordinary trichlor- 
aniline and from C,H,Cl.Cl,. Long needles, melting at 63.5°, and boiling at 
208°, 

The adjacent trichlor-benzene (1, 2, 3) is formed from trichlor-aniline (1, 2, 
3,4). It consists of plates which dissolve with difficulty in alcohol, melt at 54°, 
and boil at 218° (Annalen, 192, 228). 

Tetrachlor-benzenes, C,H,Cl,. 

Ordinary (symmetrical) tetrachlor-benzene (1, 2, 4, 5) is produced in the chlori- 
nation of benzene, or is obtained from the nitro-derivative of common trichlor- 
benzene (melting at 58°). It melts at 138°, and boils at 243-246°. Boiled with 
nitric acid it yields chloranil, C,Cl,0, (O, =1, 4). The unsymmetrical tetra. 
chloride (1, 3, 4, 5) = (1, 2, 4, 6) is formed from ordinary trichlor-aniline, and 
consists of needles, melting at 51°, and boiling at 246°. 

The adjacent tetrachlor-benzene (1, 2, 3,4) is formed from adjacenté trichlor- 
aniline (from metachlor-aniline), and consists of long needles, melts at 46°, and 
boils at 254° (Anna/en, 192, 236). 

Pentachlor-benzene, C,HCl1,, can only exist in one modification. It is pro- 
duced by chlorination; forms needles, which melt at 86°, and boil at 276°. 

Hexachlor-benzene, C,Cl,, is produced in the chlorination of benzene and 
other compounds (p. 580) in the presence of SbCl, or ICl,, and when CHC], or 
C,Cl, are conducted through tubes heated to redness. It melts at 226°, and boils 
at 332°. It forms perchlorphenol when heated to 250° with caustic potash (Be- 
richte, 18, 335). 

Benzene Hexachloride, C,H,Cl,, obtained by the action of chlorine upon 
benzene in sunlight, or upon boiling benzene, melts at 157°. When it is distilled, 
it decomposes into C,H,Cl, + 3HCI. See Berichte, 18, Ref. 149, for an isomeric 
hexachloride. ee} 





Monobrom-benzene, C,H, Br, from benzene and phenol, boils at 155°; its 
specific gravity at O° is 1.517. 

Dibrom-benzenes, C,H,Br,. When bromine acts upon benzene (on heat- 
ing) (Berichte, 10, 1354), it is chiefly the para- and little of the ortho- that results. 

p-Dibrom-benzene (1, 4), from benzene, parabrom-phenol and para-bromaniline, 
melts at 89°, and boils at 218°. Its mononitro-derivative (1, 4, NO,) melts at 85°. 
m-Dibrom-benzeneé (1, 3), from ordinary dinitro-benzene and dibrom-aniline, does 
not solidify at —20°, and boils at 219°. It yields two mononitro-products, one of 
which melts at 61° (1, 3, 4 — NO, in 4) (chief product), the other (1, 3, 2— NO, 
in 2), at 82.5°. 0-Dibrom-benzene (1, 2), from orthonitraniline and orthonitro- 
brom-benzene, becomes solid below 0°, melts at —1°, and boils at 224°. Its nitro- 
product (1, 2, 4 — NO, in 4) melts at 58.6°. 

Tribrom-benzenes, C,H,Br,. Kérner was the first to make a comprehen- 
sive investigation of these derivatives with respect to their relations to the three 
dibrom-benzenes, and to examine into their structure (p. 562). 


DERIVATIVES OF TOLUENE. 583 


Ordinary unsymmetrical tribrom-benzene (1, 3, 4) is obtained directly from 
benzene by the action of bromine. It results from all three dibrom-benzenes, 
hence (1, 3, 4); also from C,H,Br,, from common dibrom-phenol and from ordi- 
nary dibrom-aniline. It melts at 44°, and boils at 275°. Symmetrical tribrom- 
benzene (1, 3, 5), from tribromaniline, melts at 119.5°, and boils about 278°. 

The third adjacent tribrom-benzene (1, 2, 3) is formed like the corresponding 
trichlor-benzene, and melts at 87°. 

Tetrabrombenzenes, C,H,Br,. The common variety results from the treat- 
ment of benzene and nitro-benzene with bromine. Itmeltsat175°. Thezssym- 
metrical variety (1, 3, 5, Br) is obtained from ordinary tribromaniline and ordinary 
tribromphenol. It melts at 97—-99°, and boils near 329°. 

Pentabrombenzene, C,HBr,, the only possible modification, is obtained by 
acting on benzene with bromine. It melts near 240°. 

Hexabrombenzene, C,Br,, is formed by heating benzene (toluene. etc., p. 580) 
and bromine to 300-400°; or by heating CBr, to 300°. It consists of needles, 
almost insoluble in alcohol and ether; they melt above 310°. 

Benzene Hexabromide, C,H,Br,, is produced when bromine acts on ben- 
zene insunlight. It is a crystalline compound and decomposes, when heated, 
into unsymmetrical tribrombenzene and HBr. 

Iodo-benzene, C,H,I, is formed on heating benzene with iodine and iodic 
acid to 200°; by the action of phosphorus iodide upon phenol, and from aniline 
through the diazo-compound. It is a colorless liquid, boiling at 185°; its sp. gr. 
equals 1.69, 

Di-iodo-benzenes, C,H,I, : (1, 4) melts at 129° and boils near 280°; (I, 3) 
melts at 40.5° and boils at 282°; both crystallize in leaflets. (1, 2) crystallizes 
on cooling, melts at 27°, and boils at 286° (Berichte, 21, Ref. 349). 

Tri-iodo-benzene, C,H,I,, melts at 76° and sublimes readily. 

Fluorbenzene, C,H,FI, has been obtained from potassium fluorbenzoate. A 
liquid with an odor like that of benzene, and boiling at 85° (Berichte, 17, Ref. 
109). p-Fluortoluene, C,H ,F1.CHsg, obtained in an analogous manner, has an 
odor like that of bitter almond oil, and boils at 114°. When it oxidizes it forms 
p-fluorbenzoic acid. 

These fluorbenzenes are also formed in the action of concentrated hydrofluoric 
acid upon the benzene diazoamido-compounds with fatty residues (Berichie, 19, 
Ref. 753; 21, Ref. 96). Fluornitrobenzene, C,H ae (1, 4),melts at 
24° C. and boils at 205° C. p-Difluorbenzene, C,H,FI,, boils at 38°. 





DERIVATIVES OF TOLUENE. 


Chlortoluenes, C,H,CI.CH;. Para- and ortho-derivatives are 
produced in an almost equal amount when toluene is treated with 
chlorine and bromine (in the cold or in the presence of iodine 
(p. 580). The former is asolid and boils somewhat higher than 
the ortho-compounds. The haloid toluenes may be obtained pure 
from the amido-toluenes, by replacing the NH,-group by halogens ; 
this is accomplished through the diazo-compounds. Thus C,H, 
(NH,).CH, yields C,H,X.CH;. When heated with a chromic 
acid mixture (see aromatic acids) the para- and meta-derivatives 
(by the conversion of the CH,-group into CO,H) are oxidized to 
the corresponding substituted benzoic acids, whereas the ortho- 


584 - ORGANIC CHEMISTRY. 


derivatives are attacked with difficulty and completely destroyed. 
When boiled with dilute nitric acid, with MnO,K, or ferricyanide 
of potassium, all three isomerides (even the ortho) are oxidized to 
acids. 


Parachlortoluene, C,H,Cl.CH, (1, 4), solidifies at 0°, melts at 6.5° and boils 
at 160°. It yields parachlorbenzoic acid when oxidized with chromic acid or 
nitric acid. Ovrthochlortoluene (1, 2), from toluene and orthotoluidine, is liquid, 
and boils at 156°; chromic acid completely decomposes it. Metachlortoluene 
(1, 3) has been prepared from chlorparatoluidine, C,H,Cl(NH,).CH,, by re- 
placement of NH, by hydrogen. It boils at 150° and yields metachlorbenzoic 
acid. See Berichte, 19, 2440 for nitrochlortoluenes. 


Benzyl Chloride, C,H;.CH,Cl, a-chlortoluene is obtained by 
the chlorination of boiling toluene (p. 580), and from benzyl alco- 
hol, C,H;.CH,.OH. It boils at 176°. The chlorine atom is 
readily exchanged. It passes into benzyl alcohol when boiled with 
water (30 parts). Heated with water and lead nitrate it yields 
benzaldehyde, and by oxidation benzoic acid. 


When benzyl chloride is heated to 200° with water, the chloride, C;,H,,Cl, 
is produced, and by the distillation of this product, benzyl toluene, C,H,.CH,. 
C,H,.CH,, anthracene, C,,H;,, and other bodies are formed. 

In the nitration of C,H,.CH,Cl, C,H,;.CHCI, and C,H,.CCl,, the products 
are predominantly para-nitro-derivatives with some of the ortho. Further oxida- 
tion transforms these into nitro-benzoic acids (Berichte, 17, 385 and Annalen, 
224,100). From C,H,.CHO, C,H,.CO.CH,, C,H,.CO,H and C,H,.CN, we 
obtain meta-products principally. o- and f-Nitrobenzy] chlorides are also obtained 
by the chlorination, at a boiling temperature, of o- and g-nitrotoluenes ; the o- and 
m-chlorides are more easily produced by the action of PCI, upon o- and m-nitro- 
benzyl alcohol (Berichte, 18, 2402). 

o-Nitrobenzyl chloride, C,H,(NO,).CH,Cl, melts at 49°; the meta- at 45-47° ; 
the para at 73° C. Pyrogallol reduces the latter to nitrotoluene. For its deriva- 
tives see Berichte, 23, 337. 

Dichlortoluenes, C,H,Cl, :— 


C,H,Cl,.CH, C,H,C1.CH,Cl C,H,.CHCl,. 
Dichlortoluenes. Chlorbenzyl Chlorides. Benzal Chloride. 


The first compound must have six modifications; the six corresponding dibrom- 
toluenes have all been prepared. There must be three isomerides of the second, 
and of the third compound only one modification is possible. 
Benzal Chloride, C,H,;.CHCl, (Benzylene chloride, Chlorobenzene), is 
formed in the chlorination of boiling toluene and from oil of bitter-almonds, 
C,H,;.CHO, by means of PCl;. It is a liquid boiling at 206°, and has a sp. gr. 
1.295 at 16°. It changes to oil of bitter-almonds when exposed to a temperature 
of 120° in the presence of water. Satisfactory nitro-products have not been 
obtained by the nitration of benzalchloride or by conducting chlorine into 
p-nitrotoluene (Berichte, 18, 996). p-Nitrobenzal chloride, C,H,(NO,).CHCl,, 
has been prepared by the action of PCl, upon f-nitrobenzaldehyde. It melts at 46°. 
On heating g-nitrotoluene with bromine to 120-140°, p-Mitrobenzyl bromide, 
C,H,(NO,).CH,Br, and p-Mitrobenzal bromide, C,H,(NO,).CHBr, are readily 
formed. The first melts at 100°, and the second at 82° (Amna/len, 185, 268). 


DERIVATIVES OF TOLUENE. 585 


Trichlortoluenes, C,H,Cl, :-— 


C,H,Cl,.CH,  C,H,Cl,.CH,Cl C,H,CLCHCI,  C,H,.CCl,. 


6 Isomerides. 6 Isomerides. 3 Isomerides. 1 Modification. 


Two trichlorine derivatives, a- and B- (1, 2, 4, 5 —CH, in 1 and 1, 2, 3, 4), 
C,H,Cl,.CH,, are formed in chlorinating toluene; the a- melts at 82° and boils at 
230°; the B- melts at 41° and boils at 232° (Berichte, 18, 421). In accordance 
with its constitution diamid-a-trichlortoluene is oxidized to trichlortoluquinone. 

Benzotrichloride, C,H ;.CCl,, prepared from benzoyl chloride, C,H,.COCI, by 
action of PCl,, is a liquid, and boils at 213°. It yields benzoic acid when heated 
to 100° with water. 

Pentachlortoluene, C,Cl,.CH,, melts at 218° and boils at 301°. Further 
chlorination leads to the substitution of the methyl group, which finally is broken 
off and hexachlorbenzene, C,Cl, (p. 580), formed. 





Monobromtoluenes, C,H, Br.CH,. 
Parabromtoluene (1,4), from toluene and paratoluidine, melts at 28.5° and boils 
at 185°; it yields parabrombenzoic acid. CH 
Metabromtoluene (1, 3) is formed by acting on, C,H, { NH C.H.o. 2¢¢tpara- 
Sette’ 


toluidine, with bromine, and replacing the amido-group by hydrogen; and in a 
similar manner from acetorthotoluidine. It boils at 184°, and yields metabrom- 
benzoic acid. Ovrthobromtoluene (1, 2), obtained with the para- on treating 
toluene with bromine, and also from ortho-toluidine, boils at 182-183°; its sp. gr. 
at 20° is 1.40. A chromic acid mixture gradually destroys it; dilute nitric acid 
oxidizes it to orthobrombenzoic acid. 

Benzyl Bromide, C,H,;.CH,Br, is prepared by the action of bromine upon 
boiling toluene, and by the action of HBr upon benzyl alcohol. It is a liquid, 
which provokes tears and boils at 210°; its specific gravity = 1.438 at 22°. 

Dibromtoluenes, C,H,Br,.CH,. The six possible isomerides have been 
prepared in various ways (Berichte, 13, 970). 

Benzal Bromide, C,H,.CHBr,, from benzaldehyde, decomposes upon distilla- 
tion. 

_ 0-Brombenzyl Bromide, C,H,Br.CH,Br, from ortho-bromtoluene, melts at 
30°, and with sodium forms anthracene and phenanthrene, Chromic acid does not 
oxidize it. p-Brombenzyl Bromide, from p-bromtoluene, melts at 61°. 

Iodo-toluenes, C,H,I.CH;,. 

Paratodotoluene (1, 4), from paratoluidine, crystallizes in shining laminz, melts 
at 35° and boils at 211°. Chromic acid converts it into paraiodobenzoic acid. 
Metatodotoluene (1, 3), from liquid metatoluidine, is a liquid boiling at 207°, 
and when oxidized by chromic acid yields metaiodobenzoic acid. Orthotodo- 
toluene (1, 2), from orthotoluidine, is liquid, and boils at 205°. When oxidized 
with dilute nitric acid it becomes orthoiodobenzoic acid. 

Benzyl Iodide, C,H ,.CH,I, is obtained from benzyl chloride by the action of 
— acid at the ordinary temperature. It melts at 24° and decomposes when 

istilled. 





Ethyl Benzene Derivatives, C, H,.CH,.CH,. 
The replacement of the hydrogen in the ethyl group gives rise to two isomeric 
mono- and three isomeric di-derivatives :— 


C,H,.CH,.CH,Cl C,H,.CHBr.CH, 
a-Chlorethyl Benzene. 8 Bromethyl Benzene. 


49 


586 ORGANIC CHEMISTRY. 


The a-derivatives have also been called w-derivatives, the B- the a-derivatives. 

a-Chlorethyl Benzene is formed in the chlorination of hot ethyl benzene. It 
is an oil boiling at 200-204° C., when it decomposes into hydrochloric acid and 
styrene. Potassium cyanide converts it into a cyanide and then hydrocinnamic 
acid, ($-Chlorethyl Benzene, obtained from phenyl methyl carbinol, C,H, 
CH(OH).CH,, through the action of HCl, boils at 194° C. 

a-Bromethyl Benzene, from styrene by the action of HBr, decomposes into 
the latter and styrene on warming. The §-product is produced when ethyl ben- 
zene is brominated at a boiling temperature or in sunlight (Berichte, 18, 351), and 
also results from the action of HBr upon phenyl methyl carbinol (see wheat It 
does not react either with KCN or with CO, and sodium. 

a-Dichlorethyl Benzene, C,H,.CH,.CHC1,, from phenyl-acetaldehyde and 
PCl,, is an oil with penetrating odor. Alcoholic potash converts it into a-chlor- 
styrene (Berichte, 18, 982). $-Dichlorethyl Benzene, C,H,CCl,.CH,,. is 
formed from acetophenone, C,H,.CO.CH,, and PCl,;. a $-Dichlorethyl Ben- 
. zene, C,H,.CHCI.CH,Cl, styrene chloride, from styrene by the absorption of 
2Cl, yields a-chlorstyrene with alcoholic potash. 

a$-Dibromethyl Benzene, C,H,.CHBr.CH, Br, styrene bromide, is produced 
by the action of bromine upon styrene, and by the bromination of ethyl benzene in 
diffused light (Berichte, 18, 354). It is a solid and melts at 74°C. With alco- 
holic potash it yields 6-bromstyrene. $-Dibromethyl Benzene, C,H;.CBr,.CH,, 
formed by the bromination of ethyl benzene in sunlight, is a liquid. 

The halogen derivatives of the higher benzenes are described in connection 
with these. 





NITRO-DERIVATIVES. 


All benzene derivatives readily pass into nitro-products (p. 105) 
through the action of nitric acid, the benzene nucleus (not the side- 
chains) being substituted :— 


C,H,.CH, + NO,H = C,H,(NO,).CH, + H,0. 


The substance to be nitrated is gradually added to concentrated 
or fuming nitric acid, when it will dissolve with evolution of brown 
vapors. When this does not occur heat should be applied. On 
pouring the solution into water the nitro-products, not soluble in 
water, are precipitated. 


A mixture of nitric acid (1 part) and sulphuric acid (2 parts) acts more energet- 
ically, as the second acid combines with any water that may be formed-in the 
reaction. 


Di- and tri-nitro-compounds are the chief products. 


The nitration is considerably moderated by previously dissolving the substance 
in glacial acetic acid. The more alkyl groups there are in a benzene hydrocarbon, 
the more readily will it be nitrated. Nitric acid of sp. gr. 1.5 very frequently reacts 
more energetically than the acid of 1.535 sp. gr., because the latter contains more 
nitrogen dioxide (Berichde, 21, Ref. 51). 

\ Nitro/erivatives of substituted hydrocarbons are obtained: (1) by nitration of 


DERIVATIVES OF BENZENE. 587 


the halogen derivatives, while in the inverse action of chlorine and bromine upon 
nitro-derivatives in the heat the nitro-group is generally eliminated ; (2) by the 
action of PCI, and PBr, upon nitro-phenols, ¢. g., C,H,(NO,).OH, when the 
hydroxyl group is replaced by halogens; (3) from nitro-amido-compounds, the 
amido-group being exchanged for halogens through the agency of the diazo-com- 
pounds; (4) by the action of potassium nitrite and copper upon diazo-salts; (5) 
by decomposition of nitro-acids when heated with lime (p. 570). 


Various reducing agents convert the nitro into amido-compounds 
(p. 591). Sodium amalgam or alcoholic potash produces azo-com- 
pounds. The nitro-derivatives generally possess a faint yellow 
color; ammonia deepens the latter. The mono‘nitro-benzenes 
usually boil undecomposed ; the di-derivatives are not volatile. 





DERIVATIVES OF BENZENE, 


Nitro-benzene, C,H;.NO,, is obtained by dissolving benzene 
in a mixture of common nitric and sulphuric acids. It is a bright 
yellow liquid, possessing an odor resembling that of oil of bitter 
almonds (artificial almond oil, oil of mirbane), and a specific 
gravity at o° of 1.20. It becomes crystalline at +- 3° and boils at 
205°. 
Dinitro-benzenes, C,H,(NO,),.. The three dinitro-benzenes 
are produced, if in the nitration with fuming nitric acid, the mix- 
ture be boiled a short time. On crystallizing from alcohol, the 
meta-compound, formed in greatest quantity, separates first, whereas 
the ortho- and para-dinitro-derivatives remain in solution (Berichie, 
7,1372). For the production of o-dinitro-benzene, see Berichte 17, 
Ref. 20. 


The ortho-compound (like other ortho-dinitro-benzenes) exchanges an NO,- 
group for OH when boiled with caustic soda, forming o-nitro-phenol, C, H,(NO,). 
OH. Likewise on heating ortho-dinitro-compounds with alcoholic ammonia (and 
with anilines), we have o-nitranilines, ¢.¢., C,H,(NO,).NH,, produced. Ferri- 
cyanide of potash and caustic soda oxidize the metadinitro-benzenes to dinitro- 
phenols; they unite with aniline, yielding molecular compounds. m- and /-Dini- 
trobenzenes combine, too, with benzenes, naphthalenes, etc. (Berichte, 16, 234). 

Meta-dinitrobenzene (1,3) isobtained from common dinitrotoluene (1,2,4, CH, in 
1), and from a- and -dinitraniline; it was formerly called para. It crystallizes in 
long, colorless needles, sparingly soluble in cold alcohol, and melting at 89.9°. It 
boils at 297°. By reduction it yields (1, 3)-nitraniline and (1, 3) phenylene diamine 
(melting at 63°). When heated with potassium ferricyanide and caustic soda, it 
forms a- and (-dinitrophenol, C,H,(NO,),.OH. m-Dinitro-benzene, heated 
with alcoholic potash, has one of its nitro-groups removed with formation of 
C,H,(NO,)(O.C,H,).CN, which, heated with alcoholic potash, yields dioxy- 
ethyl benzonitrile, C,H,(O.C,H,;),CN. This fused with KOH, becomes dioxy- 
benzoic acid. When paradinitrobenzene (not ortho) is boiled with alcoholic 


588 ORGANIC CHEMISTRY. 


potassium cyanide potassium nitrite is also formed (Berichte, 17, Ref. 19). Upon 
digesting nitro-oxyethyl benzonitrile with potassium methylate, the nitro group is re- 
placed and oxyethyl-oxymethyl-benzonitrile formed: C,H,(CN) cock. (i, = 
6, CN in 1) Berichte, 18, Ref. 148. ; 

Paradinitrobenzene (1, 4) forms colorless needles, is more sparingly soluble in 
alcohol, melts at 173°, and yields (1, 4)-nitraniline and (1, 4)-phenylene diamine 
(melting at 140°). 

Orthodinitro-benzene (1, 2), formed in very small amount in nitration, crystallizes 
in plates from hot water, and melts at 118°. It yields (1, 2)-nitraniline, and (1, 2)- 
phenylenediamine (melting at 99°). 

Symmetrical Trinitrobenzene, C,H,(NO,), (1, 3, 5), is produced by heat- 
ing meta-dinitrobenzene with HNO, and pyrosulphuric acid to 140°; it crystallizes 
in white laminz or needles and melts at 121-122°. It becomes trinitrophenol 
(Picric Acid) when heated with ferricyanide of potassium and caustic soda. It 
unites with benzenes and anilines, forming molecular compounds (Berichte, 13, 
2346). -Dinitrobenzene forms unsymmetrical trinitrobenzene (1, 2, 4) (Be- 
vichte, 17, Ref. 233). 

Nitro-haloid Benzenes, C,H,X(NO,). 

Upon nitrating chlor-, brom-, and iodo-benzene, para- and ortho-mononitro 
products result; the first in larger quantity. The meta-derivatives are pre- 
pared from meta-nitraniline, C, H,(NO,).NH, (from common dinitro-benzene), by 
replacement of the amido group by halogens, effected by means of the diazo-com- 
pounds. The para- and ortho-compounds can be similarly prepared from the 
corresponding nitranilines. PCI, also converts nitro-phenols, C,H,(NO,).OH,: 
into chlornitro-derivatives. Metachlornitro-benzene is obtained by the chlorina- 
tion of nitrobenzene in the presence of iodine, or SbCl,. 

The isomeric mononitro-chlor-, brom-, and iodo-benzenes have the following 
melting points :— 


(x, 2). .  @,3)- (z, 4). 
C,H,Cl(NO,) 32.5° 44.4° 83° 
C,H, Br(NO,) 41.5° 56° 126° 
C,H,I (NO,) 49° 33° 171°. 


Meta-chlornitrobenzene occurs in two physical modifications: if rapidly cooled 
after fusion, it melts at 23.7°, but in a short time reverts to the stable miodification, 
melting at 44.4°. ; 


As may be séen above, the para-derivatives possess the highest 
melting points, and the meta- are generally higher than the ortho. 
A similar deportment is manifested by almost all di-derivatives of 
benzene (p. 598). Again, the para-compounds usually dissolve 
with more difficulty in alcohol. ‘The different behavior of chlor- 
and brom-nitrobenzenes with caustic potash and ammonia is very 
instructive. The ortho- and para-derivatives (latter with more 
difficulty than the former) yield the corresponding nitro-phenols, 
C,H,.(NO,).OH, when heated with aqueous or alcoholic potash in 
closed tubes to 120°. In this reaction the halogens are replaced by 
hydroxyl. The meta-derivatives do not react under the above con- 
ditions. ‘The ortho- and para-compounds also yield corresponding 
nitranilines, C,H,(NO,).NH,, when heated to 100° with alcoholic 


DERIVATIVES OF BENZENE. 589 


ammonia, while the (1, 3)-chlor- and brom-nitrobenzenes do not 
react (compare Gatiel cares (p. 587) and the nitranilines). 





In the nitration of the mono-haloid benzenes, as well as in the 
chlorination (bromination) of benzene (p. 580) and toluene (p. 583), — 
the para- and ortho-compounds (1, 4) and (1, 2) are almost the 
only products. So in the nitration (chlorination) of phenol, 
C,H;.OH, of toluene, C,H;.CH;, and of aniline, G, 3. NH,, the 
first derivatives are only the ortho- and para-varieties. It is only 
in the nitration (chlorination) of nitrobenzene, C,H;(NO,), ben- 
zoic acid, C,H;.CO,H, benzaldehyde, C,H;.CHO, benzonitrile, 
C,H;.CN, acetophenone, C,H;.CO.CHs;, and some additional com- 
pounds, wth negative side-chains, that the meta-dertgatives predom- 
inate in the presence of the ortho- and para-varieties. 

Thus, from benzoic acid we get | para-varietis) acid, from 
nitrobenzene meta-dinitrobenzene, C,H,(NO,), (1, 3). Benzene 
sulphonic acid, C,H;.SO;H, yields meta-benzene disulphonic acid, 
C,H,(SO;H), (1, 3). The following groups: OH, NH,, Cl and 
Br, CH, and all alkyls cause the entering, substituting group to 
assume ‘the ortho- and para-positions, and have been designated 
substituents of the first class, while the groups NO,, CO,H, CN, 
CO.CH;, SO;H, etc., are known as substituents of the second class 
(see Lellmann, Principien der org. Synthese, p. 11). Consult 
Berichte, 23, 130 upon the influence exerted by the atomic_magni- 
tude of the substituents. 

By the further substitution (chlorination, nitration) of the ortho- 
and para-di-derivatives (from compounds containing substituents of 
the first class) the replacing groups enter the para- or ortho-posi- 
tion, so that di-derivatives (1, 2) and (1, 4) yield the same tri- 
derivatives (1, 2, 4). Hence, the tendency of the tri-derivatives ts to 
Sorm the unsymmetrical combination (see Annalen, 192, 219). The 
substitution relations are more complicated in the case of the meta- 
di-derivatives (1, 3). . 

If an unsymmetrical tri-derivate (1, 2, 4) be further substituted, 
unsymmetrical tetra-derivatives (1, 2, 4, 6) are generally produced. 
Thus, from aniline, C,H;.NH,, phenol, C,H;.OH, etc., we obtain 
compounds like C,H,Cl,;. NH, and C,H,(NO,);.OH (1, 2, 4, 6—NH, 
or OH in 1), in which the entering groups occupy the meta-position 
(2, 4, 6 = 1, 3, 5) with reference to each other. By the elimina- 
tion of the OH and NH, eS in them, we obtain symmetrical 
tri-derivatives, C,H;X; (1, 3, 5 


a-Dinitro-chlorbenzene, C,H as (1, 2, 4), is obtained from (1, 2)- and 
(1, 4)-chlornitro-benzene, or from ordinary dinitrophenol, and by the direct nitra- 


590 ORGANIC CHEMISTRY. 


os of ata. It melts at 53.4°. The nitro-groups in it hold the position 
I, 3) = (2, 4). 

Fe ee C,H,Br(NO,), (1, 2, 4), is formed like the pre- 
ceding and melts at 75.3°. When boiled with a soda-solution both yield ordinary 
dinitrophenol, and with alcoholic ammonia a-dinitraniline (melting at 182°). 

The nitration of meta-chlor and bromnitro-benzene produces the isomerides 
8-chlor- and bromdinitro-benzenes, C,H,Cl(NO,),, and C,H,Br(NO,), (1, 
3,4. Cland Br occupy 1); the first exists in three modifications, which melt at 
36.3°, 37°, and 38.8° (Berichte, 9, 760); the second consists of yellow plates, 
melting at 59.4°. 

Trinitro-chlorbenzene, C,H,Cl(NO,), (1, 3,5, Cl), Picryl Chloride, is 
obtained from picric acid by the action of PCl,. It melts at 83°. It is converted 
into picramide, C,H,(NH,)(NO,),, with ammonia, and into picric acid when 
boiled with soda. 





DERIVATIVES OF TOLUENE. 


By nitration toluene yields chiefly two isomeric nitro-toluenes, 
C,;H,(NO,).CH;, the solid para-compound and the liquid ortho- 
derivative. ‘They can be separated by fractional distillation. The 
para-nitrotoluene predominates when the nitration occurs at an ele- 
vated temperature and fuming acid is employed, but at low temper- 
atures, and with nitric and sulphuric acids, the ortho-body is in 
greater quantity (about 66 per cent.). ; 


Paranitro-toluene (1, 4) forms large prisms; melts at 54° and boils at 237°. 
Chromic acid oxidizes it to paranitro-benzoic acid; paratoluidine is the product 
of its reduction. Chlorination at 150° produces paranitro-benzal chloride, C,H, 
(NO,).CHCI,, which forms /-nitro-benzaldehyde with SO,H,. 

Orthonitro-toluene (1, 2) is liquid, and boils at 223°; its specific gravity at 
23° is 1.163. It is also formed in the partial reduction of dinitro-toluene with 
ammonium sulphide, and the replacement of the NH,-group of the resulting amide 
by hydrogen. Chromic acid destroys it, but when oxidized with HNO,, MnO,K, 
or potassium ferricyanide, orthonitro-benzoic acid is the product; it yields ortho- 
toluidine by reduction. Bromine added to orthonitro-toluene at 170° produces 
dibromanthranilic acid :-— 


C,H,(NO,).CH, + 2Br, = C,H,Br,(NH,).CO,H + 2HBr. 


Metanitro-toluene (1, 3) is formed if acetparatoluidine, C,H, { NHC, 1,0, 
is nitrated, and the amido-group replaced by hydrogen. (Preparation, Berichie, 
- 22, 831.) It melts at 16° and boils at 230°. When oxidized, it yields metanitro- 
benzoic acid; when reduced, metatoluidine. 

Ordinary a Dinitro-toluene, C,H,(NO,),.CH, (1, 2, 4—CH, occupying 1), 
is obtained from toluene, and from (1, 4)- and (1, 2)-nitrotoluene on boiling with 
fuming nitric acid (together with #z-nitrotoluene, Berichte, 18, 1336). It crystal- 
lizes in long needles, melts at 71° and boils near 300°. It can be oxidized to 
dinitro-benzoic acid, from which we obtain (1, 3)-dinitro-benzene. Ammonium 
sulphide reduces the NO,-group (in 4), and forms amido-nitrotoluene. Sym- 
metrical dinitrotoluene (1, 3, 5) is formed from dinitro-paratoluidine, and melts 
at 92°. 


AMIDO-COMPOUNDS. 591 


Trinitro-toluene, C,H,(NO,),.CH, (1, 2, 4,6—CH, occupying 1), is pre- 
pared by heating toluene with nitric and sulphuric acids. It melts at $2°, and is 
oxidized with difficulty. It forms molecular compounds with benzenes and ani- 
lines (p. 588), and yields symmetrical trinitrobenzene when heated with nitric acid. 
The nitro-derivatives of the higher hydrocarbons have been mentioned with the 
latter. 





Pgs NITROSO-COMPOUNDS. 


Nitroso-benzene and nitroso-naphthalene are the only known de- 
rivatives in which the nitroso-group occupies the position of benzene- 
hydrogen. The so-called nitroso-phenols (see these), according to 
latest researches, possess a very different constitution, although they 
give the nitroso-reaction (p. 107). 


Nitroso-benzene, C,H,.NO, is produced by the action of NOC] or NOBr 
upon a solution of mercury diphenyl, (C,H, ),Hg, in benzene or carbon disulphide, 
or by letting nitrous acid act upon diphenyl tin chloride, (C,H,),SnCl,. It is only 
known in solution, and hasa sharp odor and green color. Tin and hydrochloric 
acid reduce it to aniline :— 


C,H;NO + 2H, = CzH;.NH, + H,0. 
When digested with aniline acetate, azobenzene is formed :— 
C,H;.NO + NH,.C,H, = C,H,;.N:N.C,H, + H,O. 


By oxidizing quinodioxime with alkaline potassium ferricyanide, there results a 
compound, which is very probably Dinitrosobenzene, C,H,(NO), (1, 4). It has 
a golden yellow color, is insoluble in nearly all solvents and, when heated, sub- 
limes with partial decomposition. Upon oxidation with HNO,, it yields f-dini- 
trobenzene, and when reduced, g-phenylenediamine. When boiled with HCl- 
hydroxylamine it is reconverted into quinodioxime, C,H,(N.OH), (Berichée, 20, 
615). 

 hatineoubbns: C,H,(NO),.CH,, from toluquinone-dioxime, closely 
resembles the benzene derivative. It has an odor somewhat like CIOH. It de- 
tonates when heated to 144° (Berichte, 21, 734). 





AMIDO-COMPOUNDS. 


These are produced by the substitution of amido-groups for the 
hydrogen of benzene :— 

C,H,NH C,H,(NH C,H,(NH,),- 
Amidobenzene. Diamido- ia): > ggg ME a): 

Or, they may be considered as ammonia derivatives, from which 
might be concluded the existence of primary, secondary and ter- 
tiary amines of the benzene series (p. 157) :— 

C,H,.NH, - (CoH,),NH (C,H,),N. 
iph 


Phen ylamine, enylamine, Triphenylamine. 


592 ORGANIC CHEMISTRY. 


The true analogues, ¢. g., C,5H;.CH,.NH,, of amines of the fatty 
series are obtained when the hydrogen of the side-chains is replaced 
by the amido-group. They are considered later. 

The amido-compounds of the benzene series are prepared almost 
exclusively by the reduction of nitro-derivatives. The most im- 
portant methods of reduction are :— 

(1) The action of ammonium sulphide in alcoholic solution 
(Zinin in 1842) :— 


C,H,;.NO, + 3H,S = C,H,;.NH, + 2H,O + 3S. 


The nitro-compound is dissolved in alcohol, concentrated ammonia added and 
hydrogen sulphide conducted into the hot mixture as long as sulphur is precipi- 
tated. Filter*and concentrate the filtrate. In using this reaction with the di- 
and tri-nitro-compounds only one nitro-group is reduced at first, and in this 
manner it is therefore easy to obtain intermediate products, like the nitroamido- 
compounds. It is only by continued heating that the second nitro-group is 
reduced. 

In the case of chlor-nitro-benzenes the nitro-group is only reduced by ammo- 
nium sulphide when it is not adjacent to the chlorine or another nitro-group; in 
the reverse instance sulphur will replace the chlorine or a nitro-group (Berichie, 
II, 2056 and 1156). 


(2) Action of zinc and hydrochioric acid upon the alcoholic 
solution of nitro-compounds (Hofmann) ; or iron filings and acetic 
-cor hydrochloric acid (Béchamp). The latter method is applied 
technically in the manufacture of aniline or toluidine; the reduc- 
tion is accomplished by the nascent hydrogen and the resulting 
ferrous oxide :— 


C,H,.NO, + 6FeO + H,O = C,H,.NH, + 3Fe,0,. 


(3) Action of tin and hydrochloric acid (or acetic acid) 
(Roussin) :— 


C,H,.NO, + 3Sn + 6HCl = C,H,.NH, + 3SnCl, + 2H,0. 
Stannous chloride reacts similarly :— 
C,H,.NO, + 3SnCl, + 6HCl — C,H,.NH, + 3SnCl, + 2H,0. 


This method serves also for the quantitative determination of 
the nitro-groups (Berichte, 11, 35 and 40). 


Pour fuming hydrochloric acid over the nitro-compound and gradually add the 
calculated quantity of granulated tin (1%4 Sn for 1NO,); after a little time, 
usually without heating, a violent reaction ensues, and the tin and nitro-derivative 
both dissolve. The solution contains a double salt, ¢ ¢.,(C,H,;.NH,.HCl), 
SnCl,, formed by the HCl-salt of the amide combining with tin chloride. These 
salts generally crystallize well. The tin is precipitated from the hot solution by 
hydrogen sulphide, the sulphide is filtered off and the filtrate contains the hydro- 
chloride salt of the amido-compound. Alkalies will set the latter free. Some- 


AMIDO-COMPOUNDS, 593 


times in using tin and hydrochloric acid chlorinated amido-compounds are pro- 
duced, therefore, in such cases it is advisable to substitute acetic acid. (Berichte, 
20, 1567). 


In this procedure, which is principally employed in laboratories, 
all the nitro-groups present in a compound are simultaneousl* 
reduced. The reduction can, however, be limited to single groups. 
(Kekulé), if we apply an alcoholic HCl solution and take only half 
the tin requisite for complete reduction; thus, nitraniline results 
from dinitrobenzene. Partial reduction can also be effected by the 
action of the calculated quantity of stannous chloride in alcoholic 
solution (Berichte, 19, 2161). 


Other reducing agents, finding occasional application, are: sodium arsenite, zinc 
dust (in alcoholic or ammoniacal solutions), tin and acetic acid (Berichte, 15, 
2105), and HI and phosphorus iodide. Sodium amalgam, on the other hand, 
reduces nitro- to azo-compounds. A procedure, very well adapted for unsaturated 
nitro-compounds, consists in the use of ferrous sulphate and baryta-water or 
ammonia (Berichte, ¥5, 2299). 

Only traces of amido-derivatives can be had by heating the haloid compounds, 
e. g., CgH; Br, with ammonia; the same may be remarked of the phenols. Both 
classes of compounds, however, react more readily providing nitro-groups exist in 
the benzene nucleus. Thus, when (1, 2)- and (1, 4)-chlor- and brom-nitroben- 
zenes are heated with alcoholic ammonia, the corresponding nitranilines are pro- 
duced, whereas the meta compounds do not react (p. 588). 

Amido- derivatives are similarly formed from the nitranisoles (alkylized phenols), 
when heated with aqueous or alcoholic ammonia to 180-200° (Berichte, 21 1541): 


C,H,(NO,).0.CH, + NH, = C,H,(NO,).NH, + CH,.OH. 


Here again it is the para- and ortho-compounds which react, not the meta-variety. 
The halogen atoms and oxyalkyls are more reactive in the presence of two or 
three nitro-groups. Thus a-chlor- and brom-dinitrobenzene yield dinitraniline (p. 
588); dinitroanilines are formed from the a- and (-dinitrophenols (their ethers) 
(Annalen, 174, 276; Berichte, 21, 1541) :— 


C,H,(NO,),.0.CH, + NH, =C,H,(NO,),.NH, + CH,.OH; 


and chrysanisic acid is obtained from dinitroanisic acid. 

In a few ortho-dinitro-compounds ammonia (also aniline) can replace a nitro- 
group by NH, (Laubenheimer), thus ortho-dinitrobenzene yields ortho-nitraniline, 
8-dinitrochlorbenzene yields nitroamido-chlorbenzene (p. 587). The phenols can 
also be directly transformed into amido-benzenes by heating them to 300° with 
ammonia-zine chloride (ZnCl,.NH,), especially in the presence of ammonium chlo- 
ride (Berichte, 19, 2916; 20, 1254): CgH;.OH + NH, = CgH;.NH, + H,0O. 
About 70 per cent. of amines are obtained by this method. The naphthols react 
even more readily. The divalent phenols react in like manner with aniline (Ze- 
richte, 16, 2812; 17, 2635). 





The secondary and tertiary phenylamines cannot be prepared from the primary, 
é.g., CgH;.NH,, by action of C,H,Cl or C,H, Br. The secondary are obtained 


5° 


594 ORGANIC CHEMISTRY. 


by heating the anilines with HCl-anilines (like the secondary acid amides) (p. 
a aa 
CH oNE ACL + CARON (CNH + NH,.HC. 


The tertiary phenylamines are prepared by treating the potassium compounds, 
C,H,.NK, or (C,H,;).NK, with C,H, Br :-— 


C,H,.NK, + 2C,H,Br = (C,H,),N + 2KBr. 





The amido-derivatives of the benzene hydrocarbons are organic 
bases: they combine with acids to form salts, just as the amines do, 
and are freed again by alkalies. But they are far more feeble bases 
than the alkylamines, because the phenyl group possesses a more 
negative character (p.557). They do not show an alkaline reaction. 
The secondary phenylamines, ¢. g., (C,H;),.NH, are even less basic ; 
their salts are decomposed by water, and tertiary. triphenylamine is 
not capable of producing salts. 

When negative groups enter the primary phenylamines, they 
further diminish their basic character; the salts of substituted 
anilines, like C,H;Cl,.NH, and C,H,(NO,),.NH,, are decomposed 
by water, or are not produced. 

The behavior of the phenylamines towards nitrous acid is very 
characteristic ; it is perfectly analogous to that of the alkylamines 
(p. 157). The primary phenylamines exchange the group NH, for 
OH, and form phenols :— . 


C,H,.NH, + NO,H =C,H,.0H + N, +H,0. © 


Diazo-compounds and diazoamido-derivatives (see these) are inter- 
mediate products. The secondary phenylamines, e. g., (CsH;),.NH 
and C,H;.NH.CHs, yield zz¢rosoamines (p. 164) :— 


(C,H,),NH + NO.OH = (C,H,),N.NO + H,0O; 


while from tertiary amido-derivatives we get the nitroso-products of 
the benzene nucleus:— | 


C,H,.N(CH,), yields C,H,(NO).N(CH,),. 


Only the primary phenylamines are adapted to the formation ot 
~ carbylamines and mustard oils (pp. 287 and 279). Furfurol com- 
bines with all the amido-benzene derivatives, forming intense red- 
colored compounds. 


On boiling the anilines with hydrochloric acid and concentrated nitric acid the 
amido-group is displaced and chlorbenzenes (together with chlorphenols) are pro- 
duced. With HBr or HI and nitric acid the products are bromine and iodine 
derivatives (Berichte, 18, 39). 


ra 


AMIDO-COMPOUNDS. 595 

On heating the HCl-salts of methyl and dimethyl aniline to 300°, the methyl 
group is transposed,,and we get toluidine, xylidine, etc. (p. 580). ; 
C,H,.N(CH,), yields C,H,(CH,).NH.CH, and C,H,(CH,),.NH,. 


A similar alkylizing of the benzene nucleus occurs on heating the HCl-anilines 
with alcohols to 300°, or the anilines with alcohols and ZnCl, to 280° (Berichte, 
16, 105; 18, 132). 





Aniline, C,H;.NH, 
Toluidine, C,H,.NH, 
Xylidine, C,H,.NH 
Cumidine, C,H,,.NH,. 


Aniline, C,H;.NH,, amidobenzene, was first noticed by Unver- 
dorben in 1826, in the dry distillation of indigo (crystallin), and 
later by Fritsche in the distillation of indigo with caustic potash 
(Antlin, 1841). Runge discovered (1834) it in coal-tar, and called 
it cyanole. Zinin was the first to prepare it artificially (1841), by 
reducing nitrobenzene with ammonium sulphide. It is formed in 
the dry distillation of many nitrogenous substances, for example, 
bituminous coal, bones, indigo and isatin. At present it is exclu- 
sively made by reducing nitrobenzene. 


In the preparation of aniline on a large scale, nitrobenzene is heated with iron 
filings and hydrochloric acid (p. 592). The product of the reaction is mixed with 
lime and distilled with superheated steam. In a small way the reduction is best 
executed with tin and hydrochloric acid. 


Aniline is a colorless liquid with a faint, peculiar odor, and boils 
at 183° (corr.); its specific gravity at o° is 1.036. When perfectly 
pure it solidifies on cooling, and melts at —8°. It is slightly 
soluble in water (1 part in 31 parts at 12°) but dissolves readily in 
alcohol and ether. It shows a neutral reaction with litmus. When 
heated it expels ammonia from its salts, while in the cold ammonia 
separates it from its salts. Exposed to air aniline gradually assumes 
a brown color, and resinifies. Bleaching lime imparts a purple 
color to the solution. When a pine shaving is moistened with 
aniline salts it becomes yellow in color. On adding sulphuric acid 
and a few drops of potassium chromate to aniline, a red color 
appears; later it becomes an intense blue. 


As a base aniline unites directly with acids, and also with some salts—(C,H,N),. 
SnCl,, (C,H,N),.CuSO,. Its salts crystallize well, and dissolve readily in 
water, The HCl-salt, C,H,N.HCI, forms deliquescent needles; platinic chlo- 
ride precipitates a yellow-colored double salt, (C,H,N.HCl),.PtCl,, from the 
alcoholic solution. The witrate, C,H,N.NO,H, crystallizes in large rhombic 
plates ; the oxalate, (C,H,N),.C,0,H,, obtained by mixing tht alcoholic solu- 
tions, forms rhombic prisms, 


596 , ORGANIC CHEMISTRY... 


On warming aniline with potassium, the hydrogen of the amido-group is re- 
placed with formation of the compounds C,H,.NHK and C,H,.NK,: sodium 
does not react until heated to 200°. It acts more readily providing one hydrogen 
atom of the amido-group is substituted by acid radicals (as in acetanilide, 
C,H,.NH.C,H,0O), or if halogen atoms be present in the benzene nucleus; in 
this case the halogen is reduced by the nascent hydrogen. The sodium com-. 
pounds are oxidized to azo-compounds, when they are exposed to the air. 





ANILINE SUBSTITUTION PRODUCTS. 


These are obtained: (1) By the direct substitution of aniline. 
The anilines, like the phenols, are more susceptible of substitution 
than the benzenes. The action of the halogens is so energetic that 
the reaction requires to be moderated. When chlorine or bromine 
water acts upon the aqueous solution of aniline salts, their hydrogen 
atoms are directly substituted. Nitric acid converts aniline into 
nitrophenols. ‘To get the mono- and di-substitution products, it is 
necessary to employ as points of departure the acid anilides, e. g., 
acetanilide, C,H;.NH.C,H;O; these are first substituted, and the 
substituted anilines separated from them by boiling with alkalies 
or hydrochloric acid, or with sulphuric acid. 


On allowing chlorine and bromine (in aqueous solution, or in vapor form) to act 
upon acetanilide suspended in water, only para-compounds are produced (p. 589), 
because the ortho-derivatives formed at the same time immediately pass into 
dihalogen derivatives. In the nitration of acetanilidé mono-derivatives of the 
para-, ortho- and meta-series are formed. By nitration in presence of much sul- 
phuric acid, meta-nitro-derivatives predominate (p. 589). 

The union of the amid-group and the transposition into an acid group occur 
simultaneously (giving rise to a meta-substitution product, p. 589). Chlorine and 
bromine react in the same way with aniline and toluidine in the presence of con- 
singe sulphuric acid or hydrochloric acid (Berichte, 22, 2539 and 2903; 23, 
1643). 

When ortho- and para-substituted anilines are chlorinated, they almost invariably 
furnish tri-substituted products (1, 2, 4,6), whereas the meta-series yield tetra- 
and penta-substitution products (Berichte, 15,1328). 


Iodine is capable of directly substituting the anilines, as the re- 
sulting hydriodic acid is taken up by the excess of aniline:— __ 


2C,H,.NH, + 1, = C,H,I.NH, + C,H,.NH,-HI. 


(2) By the reduction of halogen nitrobenzenes by means of tin 
and hydrochloric acid, or ammonium sulphide (p. 592) ; thus, the 
three C,H,Br.NO, yield the corresponding C,H,Br.NH,,. 

(3) The nitranilines can be prepared by heating haloid nitro- 
benzenes to 150-180° with alcoholic ammonia; or by heating the 
ethers of the nitrophenols, e. g., CsH,(NO,).O.C,H;, with aqueous 


ANILINE SUBSTITUTION PRODUCTS. 597 


ammonia. In both instances the para- and ortho-compounds, and 
not the meta-, react (p. 589). 

(4) The halogen anilines can be obtained from the nitro-anilines 
by first replacing the amido-group by halogens. This is accomplished 
through the diazo-compounds. ‘The next step is, then, to reduce 
the nitro-group :— 


/NH, 


NO, .. NO 
C,H,f NC? yields CHC t and CHC Gy 


6 *\ NH, 


The ortho-compounds are weaker bases than the para- and meta-. 


Ortho- and Meta-chloraniline, from the corresponding chlornitro benzenes, 
are liquids; the first boils at 207°; its specific gravity at O° is 1.23; the second 
boils at 230°; its specific gravity at 0° is 1.24. Parachloraniline, formed from 
(1, 4)-nitraniline and nitrochlorbenzene, and by the chlorination of acetanilide, 
crystallizes in shining, rhombic octahedra, which are somewhat soluble in hot 
water. It melts at 70-71° and boils at 230~-231°, with scarcely any decomposi- 
tion. The HCl-salt is slightly soluble in cold water. 


Ortho-bromaniline, C,H,Br.NH,, from o-(Br.NO,) and o-(NH,.NO,), crys- 
tallizes in needles, melting at 31.5° and boiling at 229°. Metabromaniline, from 
m-nitroaniline and m-bromnitrobenzene, melts at 18° and boils at 251°. Para- 
bromaniline, from /-nitraniline and /-nitrobrombenzene, is easily obtained by 
conducting bromine vapor into acetanilide. It crystallizes in ‘shining, rhombic 
octahedra, and melts at 63° (66°). The action of sodium upon the ethereal solu- 
tion produces benzidine. When distilled it breaks up into aniline, a-dibromaniline 
and a-tribromaniline. 


Ortho-iodoaniline, C,H,I.NH,, prepared by the reduction of o-nitroiodoben- 
zene, melts at 56.5°. It is very volatile (erichée, 21, Ref. 348). Metaiodoani- 
line, from m-nitraniline, forms silvery laminz, and melts at 27°. Paraiodoani- 
line is formed from /-nitroiodobenzene and by the direct action of iodine upon 
aniline, or by the action of chlor-iodine upon acetanilide. It consists of needles 
or prisms, melting at 63°, and somewhat soluble in hot water. With ethyl iodide 
it yields ethyl-aniline: C,H,I.NH, + C,H,I = C,H,.NH.C,H, + I,. 

a-Dichloraniline, C,H,Cl,.NH,, from dichloracetanilide (1, 2, 4—NH, in 1), 
crystallizes in needles, and melts at 63°. $-Dichloraniline, from nitro- (1, 4)- 
dichlorbenzene (p. 581), melts at 54° (Annalen, 196, 215). 

a-Dibromaniline, C,H, Br,.NH, (1, 2,4—NH, in 1), is obtained from dibrom- 
acetanilide and from nitro-(1, 3)-dibrombenzene (melting at 61°, p. 582) ; it melts 
at 79°. $-Dibromaniline, from nitro-(1, 4)-dibrombenzene, melts at 51-52°. 


a-Trichloraniline, C,H,Cl,.NH, (chlorine in I, 3, 5), is formed by con- 
ducting chlorine into the aqueous solution of HCl aniline. It melts at 77.5° and 
boils at 260°. It no longer combines with acids.’ Symmetrical trichlorbenzene 
is obtained from it by substituting H for NH,. {-Trichloraniline, (1, 2, 4, 5 
— NH, in 1), from nitro-(1, 2, 4)-trichlorbenzene, melts at 96.5° and boils at 
270°. 

a-Tribromaniline, C,H,Br,.NH, (bromine in I, 3, 5), is formed on conducting 
bromine vapors into aqueous HCl-aniline; it crystallizes in long needles, melts at 
119°, and forms salts with difficulty (Berichte, 16, 635). It yields symmetrical 
tribrombenzene. (-Tribromaniline (1, 2, 4,5 — NH, in 1) is obtained from 
ordinary tribrombenzene (1, 2, 4) by nitration and reduction, and does not melt, 
even at 130°. 


598 ORGANIC CHEMISTRY. | 


Nitranilines, C,H,(NO,).NH, :— 
i Fhe Ge 


C,H, NO: M. P. yi? 114° 147° 
C,H, NEE - 102° 63° 147° 
C,H, NO? ig 118° go° ny2°. 


The three nitranilines can be obtained from the three corresponding dinitro- 
benzenes, by incomplete reduction with ammonium sulphide (p. 592). Ortho- 
and para- nitranilines are also produced from the corresponding haloid nitroben- 
zenes, the ethers of nitrophenols and dinitro-benzenes, upon heating with ammo- 
nia (p. 588); also by the nitration of acetaniline. The easiest course to pursue 
in making the three compounds, is to dissolve aniline-sulphate in an excess 
of concentrated sulphuric acid, and add the calculated amount of fuming nitric 
acid. Precipitate with water and distil in a current of steam, when the ortho- and 
the meta-products pass over, while the para remains. The para and meta occur 
rather abundantly, the ortho only in small amount (Berichte, 10, 1716; 17, 261). 

Ortho-nitraniline (1, 2), is most easily obtained by heating o-nitranilinesul- 
phonic acid (from acetyl anilinesulphonic acid) with hydrochloric acid to 170° 
(Berichte, 18, 294), or by the action of ammonia upon o-nitrophenol at 160° 
(Berichte, 19,1749). It forms yellow needles, melting at 71°; it dissolves in 
water and alcohol more readily than its isomerides, and is more reactive. It yields 
(1, 2)-diamido-benzene when reduced. 

Metanitraniline (1, 3) consists of long yellow needles, melting at 114°. 
Water decomposes its salts. By reduction it yields (1, 3)-diamido-benzene. 
Para-nitraniline (1, 4) forms yellow needles or plates, melts at 147°, and yields 
(1, 4)-diamido- benzene. 

Of all the HCl-salts of the nitranilines that of o-nitraniline is most easily decom- 
posed by water, then follows -nitraniline, while the salt of metanitraniline is the 
most stable. From this it is evident that the basicity of the nitranilines succes- 
sively diminishes in the order: meta-, para-, ortho (Berichte, 17, 2719). The 
same is observed in the deportment of the aceto-nitranilines with alkalies (Berichée, 
19, 337)- 

Wie ortho- and para-nitranilines (not meta) are boiled with alkalies, they part 
with NH,, and are converted into their corresponding nitrophenols, CgH,(NO,). 
OH; the di- and tri-nitranilines react even more readily. 

Dinitranilines, C,H,(NO,),.NH,. The so-called a-dinitraniline is obtained 
from dinitrochlor- and dinitrobrom-benzene, also’ from a-dinitrophenol (its ether), 
when they are treated with ammonia in the heat. It melts at 182°, and by elimi- 
nation of the NH, yields ordinary dinitro-benzene (1, 3). Hence, its structure is 
(1, 2, 4—NH, in 1). 

B-Dinitraniline is obtained from $-dinitrophenol. It melts at 138°, and also 
yields (1, 3)-dinitro-benzene, hence its structure is (1, 2, 6—with NH, in 1). 

Trinitraniline, C,H,(NO,),.NH,, called Picramide, is obtained from picric 
acid through its ether, or by means of picryl chloride (p. 590). The latter reacts 
with ammonia, even in the cold. It forms orange-red needles, and melts at 186°. 
Its structure is analogous to that of picric acid (1, 2, 4,6—-NH, in1). It forms 
picric acid when heated with alkalies :— 


CH, (NO,),-NH, + KOH = C,H,(NO,);.OK + NH. 
NH 


Nitroso-anilines, C,H . These compounds are pro- 


UNH; 
*\No 


ALCOHOLIC ANILIDES. 599 - 


duced when the nitrophenols or quinoximes are heated with ammonium chloride 
and ammonium acetate (Berichte, 20, 2474; 21, 684) :-— 


JO ; YNH, 
CoHs\ N.OH yields CoHy< No’. 
Quinoxime. Nitrosoaniline. 


The nitroso-toluidines are similarly obtained from nitrosocresols adie 2t, 
729 

p-Nitroso-aniline, C,H,(NO)(NH,), crystallizes in steel-blue needles, melt- 
ing at 174°. Its solutions (in benzene, water) show a bright green color. It dis- 
solves in sodium hydroxide, forming a sodium salt. When boiled with this reagent 
it is again resolved into ammonia and nitrosophenol. HCl-Hydroxylamine con- 
verts it into quino-dioxime, C,H,(N.OH),. Phenylhydrazine changes it to 2- 
phenylenediamine and a nitroso-diazo-compound ( Berichte, 22, 623). 


ALCOHOLIC ANILIDES..: 


We find that, as in the amines of the fatty series, so in aniline, 
the hydrogen of the amido-group can be replaced by alcohol and 
acid radicals. The alkyl derivatives are formed in the same man- 
ner as the amines of the paraffin series (p. 157), by the action of 
the alkyl bromides and iodides upon aniline. This occurs mostly 
at ordinary temperatures. They can be directly produced by heat- 
ing HCl-anilines with the alcohols to 250°. Alkyl chlorides are 
first produced, but they subsequently act upon aniline. The alkyli- 
zation is more easily effected by using the HBr-salts (Berichie, 19, 
1939): 

The tertiary derivatives, ¢. g., CsH;.N(C,H;)., combine further 
with the alkylogens, forming ammonium compounds, which moist 
silver oxide or lime converts into ammonium hydroxides :— 


c, 11 Thy NT yields c, if TE)? }N.OH. 


The alkylic anilines can, vice versa, be re-formed. Dimethyl aniline results when 
the ammonium hfdrate or its haloid salts are distilled. This product, by further 
heating with HCl or HI to 150°, or by the distillation of its hydrochloride, regen- 
erates methyl-aniline and aniline (p. 160). When dimethyl aniline hydrochloride 
is heated to 250-300°, a rearrangement occurs, the alkyls enter the benzene nu- 
cleus, first in the para-position (4), then the ortho-positions (1) and (6). 4-Tolui- 
dine, metaxylidine and finally mesidine are produced. o-Toluidine deports itself 
similarly (Berichte, 21,640). When acetyl chloride acts upon the dialkyl anilines 
the alkyl-groups split off quite easily (Berichée, 19, 1947). 

The aniline salts form ferrocyanogen salts with potassium ferrocyanide ; these 
serve to separate the anilines (Anna/en, 190, 184). 





The methylated anilines are technically applied in the production 
of aniline dye-stuffs. They are formed on heating aniline together 
with HCl-aniline and methyl alcohol to 220°. A better course is 


600 : ORGANIC CHEMISTRY. 


to conduct CH,Cl into boiling aniline. Methyl and di-methyl 
aniline occur in both instances, together with unaltered aniline. 
Consult Berichte, 10, 795, 22, 1005, for their separation and detec- 
tion. 

Methyl Aniline, C,H;.NH(CH;), , is obtained pure from its 
nitroso-compound by reduction with tin and hydrochloric acid, or 
by the.saponification’of the acetyl derivative. The latter can be 
prepared from the sodium acetanilide, C,H;.N(Na).C,H,O, by treat- 
ment with methyl iodide (Berichte, 17, 267). It boilsat 190-191°, 
has an odor resembling that of aniline and a specific gravity at 15° 
of 0.976. Its salts (with HCl and H,SO,) do not crystallize and 
dissolve in ether. : Hence, dilute sulphuric acid in ethereal solution 
does not separate methyl aniline in crystalline form, as it does with 
aniline. Bleaching lime imparts no color to it. With acetyl chloride 
or acetic anhydride, it forms the crystalline acety/ derivative, C,Hs. 
N(CH;).C,H;O, which melts at ror®, and boils at 245°. When 
methyl aniline is heated to 330°, it is transformed into paratolui- 
dine, C,H,(CH;). NH. 


Nitroso-methyl-aniline, Cats \ N.NO, Phenyl] methyl-nitrosamine (p. 594), 
3 


is produced by the action of nitrous acid upon methyl aniline (also other second- 
ary phenylamines), or better by KNO, upon the solution of its HCl-salt. It 
separates as a brown oil, which can be extracted with ether (Aerich/e, 19, 2123 
and 18, 1997; Aznadlen, 190,151). When distilled with steam it yields a yellow, 
aromatic-smelling oil, that solidifies in the cold, and melts at 12-15°. It cannot 
be distilled alone. It shows the nitroso reaction (p. 107) and does not combine 
with acids. HgNa, or zinc dust and acetic acid reduce it to methyl phenyl 
hydrazine. It regenerates methyl aniline with zinc and sulphuric acid, tin and 
hydrochloric acid, or by gently heating with SnCl,. Reaction with anilines or an 
alcoholic potash solution accomplishes the same (Berichte, 11,757). See Berichte, 
17, 2668 upon the action of the nitrosamines upon the anilines. 

When acted on by alcoholic hydrochloric acid methyl-aniline-nitrosamine 
rearranges itself to Z-nitrosomethylaniline (Berichte, 19, 2991; 21, Ref. 
228) :— 


C,H,. . 
Chi,” >N-NO yields NO.C,H,.NH.CH,. 


p-Nitrosomethylaniline, C,H,(NO).NH.CH,, is perfectly analogous to 
p-nitrosodimethylaniline (see below). Its HCl-salt is not very stable. The free 
base forms large crystals with metallic lustre and melts at 118° C. It is soluble in 
dilute sodium hydroxide, forming the sodium compound, C,H,N,O.NaOH, from 
which it is again liberated by carbon dioxide. It therefore probably possesses a 
structure analogous to that of the nitrosophenols or quinoximes (Berich/e, 20, 532, 
1252) :— 


/NH.CH, /NHCH, yNCHs 
CAR = CoHAC | >0 or CoHAC ae 


When heated with sodium hydroxide / nitrosomethyl aniline is decomposed into 
p-nitrosophenol and methylaniline :— 


C,H,(NO).NH.CH, + H,O0 = C,H,(NO).OH + NH,CH,. 


DIMETHYL ANILINE. 601 


Metheny] amido-thiophenol and similar thiazole-like compounds are produced 
upon heating methyl and dimethyl aniline with sulphur (BerichZe, 21, 60). 


Dimethyl Aniline, C,H;.N(CH;)., is obtained pure by dis- 
tilling trimethyl-phenyl ammonium hydrate or its HCl-salt. The 
commercial article contains as much as 5 per cent. of methyl 
aniline. It is an oil boiling at 192° and solidifying at + 5°; its 
sp. gr. is 0.955. Its salts do not crystallize. It forms an acetate, 
C,H;N(CH;),.C,H,O,, with acetic acid ; this decomposes again on 
distillation. Hypochlorites do not color it. It forms C,H;.N 
(CH,),I with methyl iodide. 


Dimethyl aniline is remarkable because in it, as in the phenols, there is a re- 
active H-atom in the benzene nucleus. ‘The action of nitrous acid, or better, 
sodium nitrite, upon the HCl-salt (Berichte, 12, 523) produces the HCl-salt of 


-Nitroso-dimethyl Aniline, C,H,@ s)2 (Berichte, 20, 1252). This 
Fs oe 


forms needles, which are not very soluble in water. The free base, separated from 
its salts by sodium carbonate, crystallizes in green, metallic-like laminz, melting 
at 85°. It yields dyestuffs with phenols and anilines. _KMnQ, and ferricyanide 
of potassium oxidize it to nitro-dimethyl-aniline. Warm, dilute caustic soda 
decomposes it into dimethyl aniline and paranitroso-phenol (p. 600). 
p-Nitro-dimethyl Aniline, CgH,(NO,).N(CHs),, is obtained in the oxidation 
of the nitroso-compound and by the action of fuming nitric acid (1 mol.) upon 
dimethyl aniline in glacial acetic acid (10 parts) solution; it melts at 162°. Meta- 
nitro-dimethyl Aniline is produced together with the para-compound, It forms 
salts with acids (Berichte, 19, 545). Dinitro-dimethyl Aniline (1, 2, 4), 
obtained by further nitration (see Berichte, 19, 2123; 18, 1997), is also formed 
from a-dinitrochlorbenzene (p. 588), and trimethylamine (erichfe, 15, 1234); 
it melts at 78° and is easily decomposed by potash into dimethyl aniline and 
a-dinitrophenol. Further nitration produces trinitrophenyl methylnitramine, C,H, 
(NO,),-N(CH,).(NO,) (Berichte, 22, Ref. 343). 

p-Amido-dimethyl Aniline, C,H,(NH,).N(CHs;),, dimethyl-paraphenylene 
diamine, is formed by the tedirction of the nitroso- and nitro-compounds. It 
may be obtained by the decomposition of helianthine (Berichte, 16, 2235). 
melts at 41° and boils at 257°. In acid solution it gives a dark blue coloration 
(methylene blue) with hydrogen sulphide and ferric chloride, and answers as a 
sensitive reagent for hydrogen sulphide. 

Other groups can replace a benzene hydrogen in dimethyl aniline. For 
example, an acid chloride (of dimethyl amido-benzoic acid) and ketones are pro- 
duced by the action of COCI,. Benzoyl chloride (see Berichte, 18, 685), benzyl 
chloride and chloroxalic ester react similarly, whereas by the action of chlor- or 
iod-acetic acids or their esters a methyl group is displaced and phenylglycocoll 
results (Berichte, 17, 2661) :— 


C,H,.N(CH,), + CH,1.CO,H = C,H,.N(CH,).CH,.CO,H + CH,I. 


A methyl group is similarly split off by acetyl chloride or benzyl chloride 
P- 599 : 
Dimethyl aniline, like the phenols, forms condensation products with aldehydes 
(oil of almonds, furfurol, chloral, etc.); it combines with chlorides to yield 
phthaleines and green dyestuffs, and with benzotrichloride, C,H,.CCl,, to form 
the so-called malachite green. A condensation of several benzene groups takes 


602 ORGANIC CHEMISTRY. _ 


place, with the production of compounds which are allied to tripheny] methane 
and the aniline colors. 


Dimethyl] aniline and chloral condense to C,H <Ghiohica, , which yields 
CX Cue with alkalies (Berichte, 19, 365). 


The so-called Azylines are tetra-alkyl-para-diamido-azobenzenes (see these) : 
R,N.C,H,.N,.C,H,.NR,. They are formed when nitric oxide acts upon the 
tertiary anilines. Nitric acid converts the dialkyl anilines into nitramines, e. ¢., 
tri-nitrophenylnitramine, C,H,(NO,),.N(CH,)(NO,) (p. 164). 


- 





Ethyl Aniline, C,H,.NH.C,H,, boils at 204°; its specific gravity at 18° is 
0.954. Its ttrosamine derivative, C,H,.N(NO).C,H,, is a yellow oil, with an 
odor resembling that of bitter almonds; it does not unite with acids and cannot be 
distilled (Berichte, 8, 1641). Alcoholic hydrochloric acid converts it into p-Ni- 
troso-Ethyl Aniline, C,H,(NO).NH.C,H,., which crystallizes in green leaflets, 
melting at 78°. 

Methyl Ethyl Aniline, C,H,.N(CH,).(C,H;), boils at 201°. Its compound 
with CH,I is identical with dimethyl-aniline-ethyl iodide; methyl-ethyl aniline- 
ethyl iodide is also identical with diethyl aniline-methyl-iodide—an additional 
proof that ¢he five affinities of nitrogen have equal value (p. 166 and Berichte, 19, 
2785). Ethyl iodide is set free from all these ammonium iodides when they are 
- heated with caustic potash. 

Diethyl Aniline, C,H,.N(C,H,),, boils at 213°; its specific gravity at 18° is 
0.939. When heated with ethyl iodide it forms C,H,;.N(C,H,),I, from which 
silver oxide separates the strong ammonium base, C,H,.N(C,H;),.OH ; the latter 
decomposes on distillation into diethyl aniline, ethylene and water. The ¢roso- 


compound, UN ae forms large, green prisms, which melt at 84°, and 


yield nitroso-phenol and diethylamine, when boiled with dilute caustic soda. 
Allyl Aniline, C,H,.NH.C,H,, from aniline and allyl iodide, boils at 208°; it 
yields quinoline, C,H,N, when distilled over heated lead oxide. 


> 





The derivatives with divalent alcohol radicals are formed the same as the alkyl 
anilines. Methylene-diphenyl-diamine, (C,H;.NH),CH,, from aniline and 
methylene iodide, is a thick liquid. Aniline yields methylene aniline, C,H,. 
N:CH, (?), when acted upon by formic aldehyde. Bright crystals (Berichie, 18, 
3309, Ref. 71). 

Ethylene-diphenyl-diamine, (C,H;.NH),C,H,, from aniline and ethylene 
bromide, is crystalline, and melts at 65°. Ethylene aniline condenses with alde- 

CH,.N(C,H;) 
hydes, forming bases like | >CH.CHs, which are again resolved into 
CH,.N(C,H,) 
their components by acids (erichte, 20, 732). Isomeric ethidene-diphenyl 
diamine, (C,H,;.NH),.CH.CH,, is produced in the cold from aniline and alde- 
’ hyde. It is amorphous. Similar compounds are produced with other aldehydes, 
é. g., valeral, acrolein and. furfurol. With chloral it gives Trichlorethidene- 
diphenylamine, (C,H,;.NH),CH.CCl,, melting at 100°. Acrolein-aniline, 
ae :CH.CH:CH, (?), is amorphous and yields quinoline, C,H,N, upon distil- 
ation. 


DIPHENYLAMINE. 603 


Diethylene-diphenyl-diamine, (C,H;.N),.(C,H,),, or Diphenyl Pipera- 
zine, CHANG CH CHD N-CoHs a derivative of piperazine, C,H,,N,, is pro- 


duced when aniline is heated with ethylene bromide and caustic potash, or so- 
dium carbonate (Berichte, 22, 1387, 1778). It crystallizes from alcohol in needles 
melting at 163°. ; 





PHENYLATED PHENYLAMINES (p. 594). 


Diphenylamine, (C,H,),NH, is produced in the dry distilla- 
tion of triphenyl rosaniline (Rosaniline blue), and is prepared by 
heating aniline hydrochloride and aniline to 240° :— 


C,H,.NH,-HCl + C,H,.NH, = (C,H,),NH + NH,Cl. 


It results also upon heating aniline with phenol and ZnCl, to 260°. 
It is a pleasant-smelling, crystalline compound, melting at 54°, and 
boiling at 310° (corrected). It is almost insoluble in water, but 
readily soluble in alcohol and ether. It is a very weak base, whose 
salts are decomposed by water.. Nitric acid or sulphuric acid, con- 
taining nitrogen oxides, colors it a deep blue, and it serves in the 
preparation of various dye-stuffs. The acridines are obtained when 
diphenylamine is heated to 300° with fatty acids. 


Methyl Diphenylamine (C,H,),N.CH,, is formed by the action of methyl 
chloride upon diphenylamine. It boils at 290-295° (282°). Diphenyl nitros- 
amine, (C,H,),N.NO, is produced when ethyl nitrate acts on diphenylamine, or 
by the addition of HCl-diphenylamine to an acetic acid solution of potassium 
nitrite. Yellow plates of great brilliancy, melting at 66.5°. It dissolves with a 
deep blue color in concentrated sulphuric and hydrochloric acids. Alcoholic 
hydrochloric acid changes it to -Nitroso-diphenylamine, C,H,.NH.C,H,.NO 
(p. 600), crystallizing in green plates, which melt at 143°. It splits up into 
p-nitrosophenol, C,H,(NO).OH, and aniline when boiled with alkalies ( Berichée, 
20, 1252; 21, Ref. 227). 

f-Nitrodiphenylamine, C,H,(NO,).NH.C,H.,, from benzoyl nitro-diphenyl- 
amine, forms reddish-yellow needles, melting at 132°. o-Nitrodiphenylamine 
results from aniline and o-chlornitrobenzene. It crystallizes in leaflets melting at 
75° ( Berichte, 22, 903). ~-Dinitrodiphenylamine, [C,H,(NO,)],NH, consists 
of yellow needles with a blue schimmer, and melts at 214°. 

Various Tri- and Tetranitro-diphenylamines are produced by the action of 
chlor-dinitro- and trinitro-benzenes upon aniline and nitro-anilines. Hexanitro- 
diphenylamine, [C,H,(NO,),],NH, is formed by the direct nitration of 
diphenylamine and methyl diphenylamine. Yellow prisms melting at 238° 
(Berichte, 19, 845). It dissolves with a purple-red color, in the alkalies, forming 
salts. Its ammonium salt occurs in commerce as a brick-red powder, bearing the 
name Auranéia ; it colors wool and silk a beautiful orange. 

p-Amido-diphenylamine, C,H,.NH.C,H,(NH,), is formed by the reduc- 
tion of its nitro- or nitroso-compound (Berichte, 23, Ref. 102), and also by the 
decomposition of phenylamido-azobenzene and diphenylamidoazobenzene sulphonic 
acid (tropzoline 00) (see azo-compounds). It consists of laminze melting at 61°. 
p-Diamido-diphenylamine, [C,H,(NH,)],NH, is obtained in the reduction of 


* 


604 ORGANIC CHEMISTRY... 


the dinitro-compound, and by the decomposition of aniline black, and the reduc- 
tion of phenylene blue with zinc dust and alkali. It crystallizes from water in 
leaflets, melting at 158°. It forms quinone when oxidized; ferric chloride or 
chromic acid colors it dark green. Its tetramethyl compound is formed by the 
reduction of dimethyl phenylene green. 

Diamido-diphenylamine bears a close relation to the indamine- and indoaniline 
dyestuffs (see these). 


Dimethyl-amido-dinitro-diphenylamine, NH cee ea), is formed 
i ? ahs sean ~*~ 6 3+( Oz). 
from f-amido-dimethyl aniline and of-dinitro-chlorbenzene. It forms bronze- 


colored leaflets (Berichte, 23, 2739). 

Oxy- and Dioxydiphenylamines are formed on heating anilines with dioxy- 
benzenes (resorcin, hydroquinone) and CaCl, to 250-270°; at higher temper- 
atures, and with ZnCl, we get diphenyl-phenylenediamines, C,H,(NH.C,H,),. 
(Berichte, 16, 2812). ~-Oxydiphenylamine, from hydroquinone and aniline 
(Berichte, 17, 2431), melts at 70° and distils about 340°. When heated with sul- 
phur it yields oxythiodiphenylamine (see below). 

The oxydiphenylamines are closely allied to the indophenol dyestuffs. 

Thiodiphenylamine, HNC GPis* DS, is produced on heating diphenylamine 
with sulphur to 250° or with SCl, (Berichte, 21, 2063). It crystallizes from alco- 
hol in yellow laminz, melts at 180°, and boils near 370°. A purely synthetic 
method for its preparation consists in heating o-amidothiophenol with pyrocatechol 
to 220° :— 

NH HO NH 

CB er +: ge HO pCoHs = CHA Z ‘C,H, 4+ 2H,0; 
it follows from this that the two phenylene groups occupy the two ortho positions 
(Berichte, 19, 3255). It is neutral and does not combine with acids. Its imide 
hydrogen can be replaced by alkyls and acid radicals (Berichte, 18, 1844). Fum- 
. ees: nt Be i /C,H3(NO,)\ 
ing nitric acid converts it into a dinitro-sulphoxide, HN \.C-H.(NO,) poo: 
Z CoH (NH3)\\¢ 
\CpH3(NH2) >” 
which is also produced by heating 4-diamido-diphenylamine (p. 603) with sulphur 
(Berichte, 17, 2857)... When this product is oxidized with ferric chloride, it yields 
Lauth’s violet, which may be again reduced to the diamido-compound. 

A moderated nitration of thiodiphenylamine produces mononitrosulphoxide, 


which is reduced to amidothiodiphenylamine, nod ©sHaNs . When 
\c,H,ZNH, 

the latter is oxidized it yields a dyestuff like the violet. Similarly, -Oxydi- 

phenylamine (above), when heated with sulphur, forms an Oxythiodiphenyl- 


amine, HN CeHa\s , which may be oxidized to a dyestuff (Berichte, 17, 
2860). C,H,ZOH 


Reduction changes this to diamido-thio-diphenylamine, HN 





Triphenylamine, (C,H;),N, is obtained on heating dipotassium aniline (p. 
594) or sodium diphenylamine with brombenzene (Berichte, 18, 2156). It 
crystallizes from ether in large plates, melts at 127°, and distils undecomposed. It 
dissolves in sulphuric acid, forming a violet, then a dark green color. It cannot 
form salts with acids. By nitration it yields a trinitro-product that forms ¢riamido- 
triphenylamine, N(C,H,.NH,)3, by reduction (Berichte, 19, 759). Hexaphenyl- 
rosaniline is produced when phosgene acts upon triphenylamine. 





DIPHENYLAMINE DYES. 605 


Diphenylamine Dyes. 

Thiodiphenylamine is a chromogen, 7. ¢., a substance yielding colors, from 
which /euco-compounds of dyestuffs are obtained by the entrance of NH,, NR, or 
OH (see rosaniline). When the leuco-derivatives are oxidized (split off 2H-atoms, 
while at the same time 2N-atoms are combined) ¢o/ors are produced, the salts of 
which are the real dyes. These have been called Lauth’s dyestuffs (Bernthsen, 
Annalen, 230, 73; Berichte, 18, Ref. 705; Annalen 251,1; Berichte, 22, 390). 
The most important are :— 








H H 
6 aa ; C, poe ¥ 
a HNZ "Ss 
CBC a ot ee 
NH \N(CH,), 
Leucothionine, cece "dpa 
ue. 
NH N(CH,),- 
C,H, < q C, se a 
3) Ss Ree ss 
Kio 7 bey) fd 
one 3 6re8N 
NH.HCI N(CH,),.Cl 
| | = 
: HCl-Thionine. - Tetramethyl Thionine-hydrochloride. 
Lauth’s Violet. Methylene Blue. 


Lauth’s violet (¢hionine) can be produced from thiodiphenylamine after the 
manner above described. An easier course is that adopted by Lauth, viz., to 
oxidize an H,S-solution of #-phenylenediamine, C,H,(NH,),, with ferric 
chloride. Itis a direct color for silk and wool, but only attacks cotton after the 
latter has been mordanted. Owing to its high price it has not been used to any 
great extent. 

Methylene blue, discovered by Caro in 1877, is more important. It is formed by 
oxidizing dimethyl-s-phenylenediamine, H,N.C,H,.N(CH,),, with FeCl, in the 
presence of H,S. On adding sodium chloride and zinc chloride it is precipitated 
as the ZnCl,-double salt. This is the methylene blue or fast d/ue found in 
commerce. It dyes silk with ease, and also mordanted cotton. It is the most 
stable cotton blue. By reduction it yields its leuco-base (the HCl-salt) C,,H,, 
N,S.HCl-cetramethyldiamido-thiodiphenylamine. This reacts with methyl iodide, 
forming a methyl compound, which also results from diamido-thiodiphenylamine, 
and in this way proves the connection between methylene blue and Lauth’s violet. 

Dimethyl- and diethyl thionine (Berichte, 20, 931) result from methyl- and 
ethyl-paraphenylenediamine by oxidation in the presence of H,S :— 


NH.CH, 
C,H 
Wes SS Dimethylthionine. 
NO. 7 
\N.CH,.HCI 
| 








Oxidation of amidothiodiphenylamine and .oxythiodiphenylamine (p. 604) pro- 
duces the compounds— 


Sue a7 ce, 
CoH and NCH 
| 











Imidothiodiphenylimide. Oxythiodiphenylimide. 


606 ORGANIC CHEMISTRY. : 


See Annalen, 230, 169 for additional analogous derivatives. 
Phenazoxine, or phenoxazine, is a chromogen analogous to thiodiphenylamine. 
It is obtained by heating o-amidophenol with pyrocatechol :— 


NH, , HO NH 
é oH. OH? + Ho > Co = CHK - SCH, + 2H,0. 


Its nitro product, when reduced, yields a leuco-amide compound, which forms a 
red-violet dye upon oxidation. ethylene red is a by-product in the preparation 
of methylene blue (Anunalen, 251, 1; Berichte, 22, Ref. 390). 





ACID ANILIDES. 


An atom of hydrogen of the amido- or imid-group in the pri- 
mary and secondary anilines, can also be replaced by acid radicals. 
The resulting compounds are termed amides, and are formed 
according to methods similar to those used with the acid amides of 
the fatty series (p. 255); by the action of acid chlorides or acid 
anhydrides upon the anilines, or by heating the organic salts of’ the 
latter :— 

C,H,;.NH,.0.CO.CH, = C,H;NH.CO.CH, + H,O. 


Aniii ine  Rbeieited: Acetanilide. 


They are very stable derivatives; can usually be distilled with- 
out change, and also directly chlorinated, brominated and nitrated 
(p. 596). They are resolved into their components by digesting 
them with alkalies or heating with hydrochloric acid. The second- 
ary anilides, like secondary alkylanilides (p. 594), yield xitrosa- 
mines by the action of nitrous acid :— 


C,H, \ 


a 
CH’o SNH + NOH = Cio N— NO + H,O. 


4 

These give the nitrosamine reaction with phenol and sulphuric 
acid ; but are less stable than the nitrosamines of the secondary 
anilines. Reducing agents break off their nitroso-group. 





Formanilide, C,H,.NH.CHO, is obtained on digesting aniline with formic 
acid, or by rapidly heating it together with oxalic acid :— 
C,H,.NH, + C,0,H, = C,H,.NH.CHO + CO, + H,0O. 
It consists of prisms, readily soluble in water, alcohol and ether. It melts at 46°, 
and continues liquid for some time. Concentrated sodium hydroxide precipitates 
the crystalline compound, ad NNa, which is resolved by water into formani- 


lide and NaOH. Silver nitrate added to the alcoholic solution of the sodium 
compound, precipitates st/ver formanilide, C,H;.N:CH(OAg). When formani- 


ACID ANILIDES. 607 


lide is distilled with concentrated hydrochloric acid, benzonitrile is produced 
(small quantity) (Berichze, 18, 1001) :— 


C,H,.NH.CHO = C,H,.CN + H,0. 


Dry HCl converts formanilide at 100° into diphenyl-methenylamidine (p. 621). 
The alkyl formanilides, C,H,.NR(CHO), are produced when the alkyl iodides 
act upon sodium formanilide, or upon formanilide with NaOH (1 molecule) in 
alcoholic solution. They are odorless liquids which sustain a partial decomposition 
when distilled. They are resolved into acids and alkyl anilines when digested with 
alcoholic potash or with hydrochloric acid (Berichte, 21, 1107). The alkyl 
isoformanilides, C,H;.N:CH.OAg, compounds isomeric with the preceding, result 
when the alkyl iodides act upon silver formanilide (Berichte, 23, 2274, Ref. 659). 
P,S; changes formanilide to 7hioformanilide, C,H,.NH.CHS, which consists of 
white needles, melting at 137°, and decomposing at the same time into H,S and 
phenylisocyanide,C,H,;.NC. It is also formed when hydrogen sulphide acts upon 
phenylisocyanide (p. 260), or diphenyl-methylamidine; aniline is produced at the 
same time: C,H,.N = CH — HN. C,H, + H,S = C,H,.NH.CHS + C,H, 
NH,. Consult Berichte, 18, 2292, upon homologous thioformanilides. 

Acetanilide, C,H,.NH.CO.CH,, is produced by boiling (equal molecules) 
aniline and glacial acetic acid together for several hours (Berichte, 15, 1977); the 
solid, crystalline mass is then distilled. It melts at 114° and boils at 295°, with- 
out decomposition. It is Seluble in hot water, alcohol and ether. Sodium con- 
verts it into sodium acetanilide, C,H,;.N(Na).C,H,O. Its hydrochloride is de- 
composed by water into acetanilide and hydrochloric acid. When the salt is heated 
to 250°, it yields dipheny] ethenylamidine (p. 621), at 280°, flavaniline,C, ,.H,,N. 
and at 300°, dimethyl quinoline (Berichte, 18, 1340). o0-Amido-acetophenone, 
C,H,(NH,)CO.CH,, is produced when aniline is boiled with acetic anhydride 
and ZnCl,. Ethylaniline, together with acetic acid, is the product on heating 
acetanilide with sodium alcoholate (Berichte, 19, 1356) :— 


C,H,.NH.CO.CH, + C,H,.ONa = C,H,.NH.C,H, + (CH,).CO,Na. 


p- and o-Di-substitution products (p. 596) are produced when chlorine, bromine 
and nitric acid act upon acetanilide; they yield mono-substituted anilines by 
saponification. Monochloracetanilide (1, 4) melts at 162°, the dichlor (1, 2, 4) at 
140°, and both are formed by the action of bleaching lime (acidified with acetic 
acid) upon acetanilide. /onobrom-acetanilide (1, 4) melts at 165°; the dibrom 
(1, 2, 4) at 78°, p-Nitroacetanilide melts at 207° (Preparation, Berichte, 17, 222). 

The isomeric dromacetanilide, C,H,.NH.CO.CH,.Br (melting at 131°), yields 
indigo blue when it is fused with caustic potash. It is very probable that pseudo- 


indoxyl, C,H ite >CH,, is first produced (Berichte, 23, 57). 


Thioacetanilide, C,H,.NH.CS.CH, or CH NK Be (p. 260), is obtained 


by heating acetanilide with phosphorus pentasulphide (Berichte, 19, 1071). It 
crystallizes from water in needles, melting at 75°. It is soluble in alkalies, but is 
separated again by acids. An alkaline solution of potassium ferricyanide oxidizes 
it to ethenyl amido-thiophenol (Berichte, 19, 1072) :— 


C,H,.NH.CS.CH, + 0 = Cay. SC.CH, + H,0. 


The analogous compounds react similarly. A/kylized thioacetanilides, ¢. g.,C,H;. 
N(CH;).CS.CHg, are obtained from the acetyl compounds of the secondary ani- 


608 ORGANIC CHEMISTRY... 


lines (like acetmethyl-anilide (C,H,.N(CH,).CO.CH,), by paattag: | them with 
PS, (Berichte, 15, 528) :— 


C,H,.N(CH,).CO.CH, yields © C,H,.N(CH,).CS.CH,. 


Methyl]-thioacetanilide, melts at 58—59°, and boils at 290°. 


The derivatives of hypothetical zsothioacetantlide, ChHN:CC oa (p. 260), 


are isomeric with the above. They are obtained by the action of sodium alcoholate 
and alkyl iodides upon thioacetanilide (similar to formation of phenyl-isothio-ure- 
thanes, p. 615, and of phenyl-isothio-ureas, p. 617) :— 


/CH 
C.H,.NH.CS.CH, + CH,I = C,H,.N:Cg chy + HI. 


Methy]l-isothio-acetanilide. 
The methyl compound boils at 245°, the e¢hy/ at 250°. These decompose into 


aniline hydrochloride and thioacetic ester, CH,;.CO.SR, when shaken with hydro- 
chloric acid, 





ANILIDO-ACIDS.—PHENYLAMIBO-ACIDS. 


Anilido-formic Acid, C,H,.NH.CO,H, is carbanilic acid (p. 612). 

Anilido-acetic Acid, oe H, 'N nH, ‘CO, H, Phenyl glycocoll, Phenylgly- 
cin, is obtained from chlor- or brom-acetic acid by the action of aniline (2 molecules) 
and water (Berichte, 10, 2046; see, also, Berichte, 21, Ref. 136). It forms 
indistinct crystals, melting at 127°. 

Its alkyl esters are produced when aniline is heated with the diazo-acetic esters 
(p- 374). If the free acid be heated to r40-150°, it passes into the azhydride 
(C,H,.N.CH,.CO),, which is insoluble in water, and melts at 263°. 

It is identical with diphenyl-diacipiperazine (Berichte, 22, 1786, 1795) :— 


CO.CH, 
C,H,.NZ >N.C,H,. 
\CH,.CO 


$ 2° 
Indigo blue results upon fusing a mixture of phenylglycin and caustic potash 
‘with air access. It is very probable that pseudoindoxyl, C,H - core k le, 1S 
NH 


formed at first, but is then oxidized to indigo (Berichte, 23, 3044). 

Nitrous acid converts phenylglycin into Nitroso-phenylglycin, C,H,.N(NO). 
CH,.CO,H. This may be reduced to an amido-compound, zdentical with the phe- 
nylhydrazone of glyoxylic acid, C, Os .NH.N:CH.CO,H (p. 330). 

H,.CO 
Phenylhydantoin, C,H, ne” >, results upon heating phenylglycin 
\CO.NH 
and urea to 100°, It forms delicate needles, melting at I91°. a-Phenylhydan- 
CO.NH 
toin, C,H,;.CH <f >, is isomeric with the preceding. It may be obtained 
NH.CO 
from benzaldehyde-cyanhydrin and urea (p. 392). It melts at 178° (Berichie, 21, 
2321). 


aS 


ANILIDO-ACIDS. 609 


Indol, results upon distilling a mixture of the calcium salt of phenylglycocoll © 
and calcium formate (Berichte, 22, Ref. 579). In the same manner, o-tolindol is 
obtained from. o-tolylglycocoll (Berichte, 23, Ref. 654). 

o-Nitrophenyl Glycocoll, C,H,(NO,).NH.CH,.CO,H, formed by heating 
o-nitraniline with bromacetic acid to 130°, crystallizes in dark red prisms, melting 
at 193°. When it is reduced by tin and hydrochloric acid, it forms an amido- 
derivative. The latter condenses to oxy-dihydroquinoxaline, with separation of 
water (Berichte, 19,7) :— 


NH.CH,.CO,H NH.CH, 
HZ =CHK | 
\NH, N=C.OH 


The higher anilido-fatty acids are similarly prepared from aniline and the brom- 
fatty acids. They can (their nitriles) also be formed from the cyanhydrins of the alde- 
hydes by digesting them with aniline. Thus, ethidene cyanhydrin yields a nitrite, 
that upon saponification with hydrochloric acid becomes a-anilido-propionic acid 
(Berichte, 15, 2034) :— 


UCN UCN /C0.H 
CH,.CH¢ yields CH,.CH’ and CH,.CH¢ 
\oH \NH.C,H, NH.C,H,. 


Cc + H,O. 


The esters of the anilido-fatty acids are produced by heating diazo-fatty acid 
esters with aniline (p. 374):— 


C,H,.NH, + CH(N,).CO,R = C,H;.NH.CH,.CO,R + N,. 


a-Anilido-propionic Acid, Phenylalanine, consists of colorless laminz, melt- 
ing at 162°. They turn red on exposure to the air. 

Anil-pyroracemic Acid, C,H;.N:C(CH,).CO,H, is formed from pyro-racemic 
acid and aniline (2 molecules). Boiling water converts it into anil-uvitonic acid, 
C,, H,NO,, a derivative of quinoline, which yields methyl-quinoline, C,Hg(CH,)N, 
when distilled with lime (Beriche, 16, 2359). 

By heating aniline and aceto-acetic ester to 120-135° Acetoacetanilide, 
CH. CONC. H ? is produced. It melts at 85° (Anmalen, 236, 75). When 
warmed with sulphuric acid it splits off water and condenses to y-methyl carbostyril 
(Berichte, 21, 625). 

When aniline and aceto-acetic ester interact at the ordinary temperature there 
is formed anil-aceto-acetic ester, that may be considered as $-Phenylimido- 
crotonic Ester, CH;.C(NH.C,H,):CH.CO,.R (p. 339), or 8-Phenylamido- 


crotonic Ester, CHyNELCC GHc0 R (Berichte, 20, 1397; 21, 1965). This 
. 2 


is a thick oil. Acids and alkalies decompose it into its components. [If it is 
heated to 200° it loses alcohol and condenses to y-oxyquinaldine, C,,H,NO, and 
phenyl lutidon-carboxylic acid, C,,H,,NO, (Berichte, 20, 947 and 1398). The- 
latter is also formed on heating with methyl iodide (Berichée, 22, 83). 
Toluidines, etc., react in a similar manner with aceto-acetic esters. The products 
are tolylamidocrotonic esters, etc., which by condensation form y-oxyquinaldine - 


derivatives (Berichte, 21, 523). 
C,H,;.NH.C(CH,).CO,H, 
B-Anilido-pyrotartaric Acid, is formed when prus- 
CH,.CO,H 
sic acid and aniline act upon aceto-acetic ester (Berichte, 23, 893). It melts at 
102°, and when heated to 180° yields citraconanile (p. 611, see Berichte, 23, 542). 


51 


610 ORGANIC CHEMISTRY. ©: 


ANILIDES OF DIBASIC ACIDS. 


Oxanilide, C0, NCH” diphenyl-oxamide, is obtained by heating ani- 
line (2 molecules) with oxalic acid (1 molecule) to 180°. It consists of pearly 
leaflets, melting at 245° and boiling near 360°. It dissolves readily in benzene, 
but with difficulty in hot alcohol. 

Oxanili 4 J NPL ; a ; 

xanilic Acid, C202 OH 6°” 5, is formed by heating aniline with excess of 
oxalic acid to 140° (Berichte, 23, 1820). It crystallizes in leaflets, dissolves in 
water, reacts acid, and conducts itself like a monobasic acid. 

p-Nitro-oxanilic Acid, C,H,(NO,).NH.CO.CO,H (with some ortho-product), 
is obtained by nitrating oxanilic acid. It melts at 210°. o-Nitro-oxanilic Acid 
is more easily obtained by fusing a mixture of o-nitraniline and oxalic acid at 140°. 
- It crystallizes in yellow needles and melts at 120° (Berichte, 19, 2936). Tin and 
hydrochloric acid reduce it to o-Amido-oxanilic Acid, which loses water and 
immediately condenses to dioxyquinoxaline :— 


/NH.CO.CO,H /NH.CO 
CoHAC = C,H) {| + 1,0. 
NH, NH.CO 


In a similar manner nitro-oxalyl toluidic acid (from nitrotoluidine and oxalic 


acid), BRAC) No ts yields dioxymethylquinoxaline (Berichte, 17, 
318; 19, 671). : 


The anilides of the higher di- and poly-basic acids may be easily prepared by 
heating their anhydrides with aniline. PCl; converts them into acid anzles 
(Berichte, 21, 957) :— 


CO.NH.C,H, CO CO.NH.C,H; 
C,H, C.H,/. SN.C,H, ot a 
\co,H \co% CO.NH.C,H,. 
Succinanilic Acid. Suécinanile. Succinanilide. 
Malonanilic Acid, CH ue fe is produced by a peculiar transposi- 
2 


tion of acetylphenyl carbaminate of sodium when heated to 140° (Berich¢e 18, 
1359) :— 


C,H,;.NZ — C,H,.NH.CO.CH,.CO,Na. 


The acid crystallizes in needles, melting at 132° and decomposing into CO, and 
acetanilide. PCI, converts it into trichlorquinoline (Berichte, 17, 740; 18, 2975). 
Malonic acid and toluidine yield malon-toluidic acid, from which trichlormetbyl- 
quinoline may be obtained (Berichte, 18, 2979). 

Succinanilic Acid melts at 148°. When heated higher it decomposes into 
water and Succinanile, C,H,(CO),.N.C,H,, melting at 150°, and boiling at 
400°. 

Maleinanilide, C,H,(CO.NH.C,H,),, results upon digesting maleic acid 
with aniline. It melts at 211°. Fumaranilide, C,H,(CO.NH.C,H,)p, is pro- 
duced when aniline is heated together with malic acid. It melts at 87°. 


ee 


ANILIDES OF CARBONIC ACID. 611 


Citraconanile, C,;H,O,:N.C,H,, from citraconic and mesaconic acids with 
aniline, is also formed in the distillation of anilido-pyrotartaric acid (p. 609). It 
melts at 96° (Berichte, 23, 891). 

Phthalanile, C,H,(CO),N.C,H,, from aniline and phthalic acid, melts at 
205°. It is used in effecting different syntheses. 





ANILIDES OF CARBONIC ACID. 


Diphenyl urea, COC NH CH? carbanilide, is formed by the action of 


phosgene gas on aniline (Berichte, 16, 2301) :— 
COC], + 2C,H,.NH, = CO(NH.C,H,),:+ 2HCl; 
by the union of carbanile (p. 612) with aniline :— 
CO:N.C,H, +- NH,.C,H,:= CO(NE.C,H,),; 
by the action of mercuric oxide or alcoholic KOH upon diphenyl thio-urea 


(p. 616) :— 
CS(NH.C,H;), -+ HgO = CO(NH.C,H;), + HgS; ‘ 
and by heating aniline (3 parts) with urea (1 part) to 150-180° :— 
CO(NH,), + 2NH,.C,H, = CO(NH.C,H,), + 2NH,. 


It is most readily obtained by heating carbanilamide with aniline to 190° (Berichie, 
9, 820), or by heating diphenyl carbonate with aniline to 150-180° (Berichte 18, 
516) :-— 


CO(0.C,H,), + 2NH,.C,H, = CO(NH.C,H,), + 2C,H,.OH. 


Carbanilide consists of silky needles, easily soluble in alcohol and ether, but 
sparingly soluble in water. It melts at 235° and distils at 260°. When boiled 
with alkalies it decomposes into aniline and urea. Triphenyl-guanidine is pro- 
duced on heating it with sodium ethylate to 220° (Berichte, 16, 2301). 

Diphenyl Urea Chlorides (p. 376) (Berichte, 23, 424), are produced when 
COCI, acts upon secondary anilines, such as diphenylamine :— 


COCI,+ NH(C,H;). = coget 2 + HCl. 


Diphenyl urea Chloride, (C,H,;), N.COCI, crystallizes in white laminze, melt- 
ing at 85°. When these urea chlorides act upon benzene in the presence of AIC], 
they form the diphenylamides of aromatic acids— 


(C,H,),N.COC] + C,H, = (C,H,),N.CO.C,H, + HCl, 


which pass into acids and diphenylamine on warming with hydrochloric acid 

(synthesis of aromatic acids, Berichte, 20, 2118). Thiophosgene acts like COCI,. 

It converts the secondary anilines into 7hiourea chlorides, e. g.,(C,H,;),N-CSCl, 

and Thiocarbanilides, e@. g., ox NIGH’) (Berichte, 21,102). Diphenyl urea 
6°" 5/2 

chloride heated to 100°, with alcoholic ammonia, yields unsymmetrical diphenyl 


— 


612 ORGANIC CHEMISTRY. ©’ 


urea, CO NES oHs)o. Long needles, melting at 189°, and when distilled 


yielding diphenylamine and cyanic acid. If the chloride be heated with aniline 


Ce Hee 


we get Triphenyl urea, cot It is also produced by mixing 


phenylisocyanate with eg, it ‘crystallizes i in needles, melting at 136°. 
Mixed phenyl ureas are obtained in the same manner (erichte, 17, 2092). The 
action of diphenylamine upon diphenyl urea chloride produces tetraphenyl urea, 


cog NE. ots )o. Crystals melting at 183°. 
i" (C,H5). H. C H 
Phenylurea, CO rd an 5, Carbanilamide, is obtained like the alkylic 
ureas (p. 388): by conducting vapors of cyanic acid into aniline; CO:NH + C, 


NH POS NET. atts. and by the action of ammonia upon carbanile :— 
H. 
CO:N.C,H, + NH, = = COCNH CoH, 
It is best prepared by evaporating the aqueous solution of aniline hydrochloride 
and potassium isocyanide (Berichte, 9, 820). It forms needles easily soluble in 
hot water, alcohol and ether and melting at 144-145°. If boiled with caustic 
potash it breaks up into aniline, ammonia and cyanuric acid. 
Esters of isocyanic acid convert aniline into alkylized phenyl ureas, «. g., 
CO Goes Re ethyl phenylurea 
\.NH.C,H,’ y+ pHeny: . 
N(C,H,).CH, .. 
Glycolyl-phenylurea, co” , phenyl-hydantoin (p. 392), is 
\NH O 
obtained on heating phenylglycocoll (p. 608) to 160° with urea. It consists of 
needles, melting at 191°. 


Carbanilic Acid, Oe ioetiee ‘CoH, 5, phenyl carbamic acid, is not known in 


a free state. Its esters, called phenyl urethanes, (p. 383) result in the action of 
chlorearbonic esters upon aniline (most easily by shaking the two compounds with 
water (Berichte, 18, 978), or of carbanile upon alcohols and phenols :— 


/NH.C,H, 
0.C.,H, . ’ 





CO:NC;H, + C,H,.0H = CO 


The ethyl ester melts at 52° and boils at 237°, decomposing partially into CO:N. 
C,H, and C,H,.OH, which reunite on standing. Diphenylurea is formed on 
heating with potash or with aniline. The methyl ester melts at 47°, and is con- 
verted into amidosulphobenzoic ester when dissolved in sulphuric acid (Berichée, 
18, 980) :— 


NH 
C,H,.NH.CO,.CH, + $0,H, = C,H, | SO,H + H,0. 
H 
2 3 


The phenyl ester, C,H,.NH.CO,.C,H,, is formed when carbanile is heated 
with phenol (readily in the presence of AICl,). It melts at 124° (Berichie, 18, 
875). 

Pi tianise, CO:N.C,H,, phenyl isocyanate, is produced in the distillation of 
oxanilide, or better oxanilic esters with P,O,, also from diazobenzene salts, 
egthews x, by the action of potassium cyanate and copper (Aerichée, 23, 1225). 
It" may be most readily obtained by leading COCI, into fused aniline hydrochloride 


ANILIDES OF CARBONIC ACID. 613 


(Berichte, 17, 1284), or by heating: phenyl mustard oil to 170° with HgO (Be- | 
richte, 23, 1536). It is a mobile liquid, boiling at 163° and has a pungent odor, 
provoking tears. Carbanile is perfectly analogous to the isocyanic esters in 
chemical deportment (p. 274). It yields diphenylurea with water. With ammonia 


carbanilamide, CO RH 765, is formed; with the amines we obtain correspond- 
Ag 


ing alkyl compounds. 

It unites with polyhydric alcohols and phenols to form carbanilic esters. This is 
a reaction that can be employed in determining alcoholic hydroxyls (erichie, 18, 
2428 and 2606). 

Phenylisocyanate acts in a similar manner upon aldoximes and ketoximes (p. 
205). The hydrogen of its hydroxyl group is replaced (Berichte, 22, 3101, 3109; 
23, 2163) :— 


C,H,.CH:N.OH + CON.C,H, = C,H,.CH:N.O.CO.NH.C,H,. 


However, carbonyl compounds (with the group CO) do not react with phenyl- 
isocyanate. The reaction, therefore, can be employed for the purpose of deter- 
mining constitution (Berichte, 23, 257). 

Phenylisocyanate also reacts with the sulphydrate group SH; the CS-group is 
without action (Berichze, 23, 272). 

Diazo-amido-compounds, ¢.¢., C,H;.N,.NHR, react with phenylisocyanate. 
In so doing, the hydrogen of the amido-group is replaced (Berichte, 22, 3109). 

The preceding reactions, occurring in the absence of water (thus avoiding elec- 
trolytic dissociation), proceed in the normal way. Rearrangements do not take 
place, hence they are well adapted for the determination of constitution (Gold- 
schmidt, Berichte, 23, 2179). 

On heating phenylisocyanate with benzene and AICl,, we get benzoylanilides:— 


C,H,.N:CO + C,H, = C,H,.NH.CO.C,H,. 


Phenylisocyanate can be polymerized by heating it with potassium acetate (Be- 
richte, 18, 764), when there is formed 

Triphenylisocyanurate, (CON),(C,H,;), (p. 276). Itis also obtained upon 
heating triphenylisomelamine (p. 620) with concentrated hydrochloric acid to 150° 
C. (Berichte, 18, 3225) :— 


C,N,(C,H;),(NH), + 3H,O = C,0,N,(C,H,), + 3NH3. 


It crystallizes from alcohol in white needles, melting at 275°. Its isomeride is 
Triphenylcyanurate, C,N,(0.C,H,;),. The action of cyanogen chloride or 
cyanuric chloride upon sodium phenate, produces this :— 


3C,H,.0.Na + C,N,Cl, = C,N,(0.C,H,), + 3NaCl. 


It crystallizes in long needles, melting at 224°. 

Phenyl Isocyanide, C,H,;.NC, phenyl carbylamine, is isomeric with ben- 
zonitrile, C,H,.CN (p. 287), and is produced by the action of chloroform on 
aniline in an alcoholic solution of KOH (Berichte, 10, 1096), or by the distillation 
of diphenyl-methenyl-amidine (p. 621), and of thioformanilide, C,H,.NH.CSH. 
It is a liquid, resembling prussic acid, with pungent odor and boiling at 167° with 
partial decomposition. It is dichroic, being blue in reflected and green in trans- 
mitted light. Alkalies do not affect it, but acids convert it into aniline and formic 
acid. Heated to 220°, it passes into isomeric benzonitrile, C,H ,.CN. It combines 
with H,S, forming thioformanilide (p. 607). 


614 ORGANIC CHEMISTRY. 


Phenyl Mustard Oil, Sulpho-carbanile, CS:N.C,H, (p. 280), is obtained 
by boiling diphenyl thio-urea (p. 616) with sulphuric or concentrated hydrochloric 
acid, or, what would be best, with a concentrated phosphoric acid solution (Be- 
richte, 15, 986) :— 

NH.C,H 
CSONH CH — CS:N.C,H, + NH,.C,H,; 
and by the action of an alcoholic iodine solution (with triphenyl guanidine, Berichie, 
9, 812), or CSCI, upon aniline. It is a colorless liquid, with an odor resembling 
that of mustard oil, and boils at 222°. It is converted into benzonitrile when 
heated with reduced copper or zinc-dust :— 


C,H,.N:CS + Cu = C,H,.CN + CuS. 


On this reaction is founded a procedure to replace the group NH, by COOH, that 
is, to convert the anilines successively into thio-ureas, mustard oils, nitriles and 
acids. Benzonitrile (with aniline) is also produced by directly heating diphenyl 
thio-urea with zinc dust (Berichte, 15, 2505). 

In all its reactions, it is analogous to the mustard oils of the fatty series. If 
heated with anhydrous alcohols to 120°, or by the action of alcoholic potash, it is 
converted into phenyl-thio-urethanes (p. 386) :— 

. : me Y NEC, 
CS: N.C, + CoH, .O = PU OCH. , 


It forms phenyl-thio-ureas with ammonia, the amines and the anilines. 

Phenyl-sulphocyanate, C,H,.S.CN, is isomeric with phenyl mustard oil. 
It is formed when hydrosulphocyanic acid acts upon diazobenzene sulphate (see 
this), and cyanogen chloride upon the lead salt of methyl mercaptan :— 


(C,H,.S),Pb + 2CNC]l = 2C,H,.S.CN + PbCl,. 
It is a colorless liquid, boiling at 231°, and in its reactions is analogous to the sul- 
phocyanic esters (p. 280). 


Methenyl-amido Thiophenol, C,H ee ee, derived from ortho-amido thio- 
/SH 


phenol, C,H 4\.NH,? is a base, and is isomeric with phenyl sulphocyanate and 
phenyl mustard oils. * See Amido-phenols. 





Derivatives of Dithiocarbamic Acid (p. 386). 
Phenyl Dithiocarbamic Acid, CS on 


when potassium xanthate (p. 381) is boiled with aniline and alcohol. It consists 
of golden yellow needles. When the acid is liberated from its salts it decomposes 
into aniline and CS,. Its esters—the normal dithio-urethanes (p. 386 and Berichée, 
15, 563)—are produced by warming phenyl mustard oil with mercaptans :— 


C,H,.N:CS ++ CH,.SH — C,H,.NH.CS.S.CH,; 


oH. Its potassium salt is formed 


and from the alkyl compounds of diphenyl isothio-urea when heated with CS, (p. 
617). The methyl ester melts at 87-88°; the e¢hy/ (Phenyl dithio-urethane) at 
60°. 


ANILIDES OF CARBONIC ACID. 615 


When these dithio-urethanes are heated they decompose into phenyl mustard 
oil and mercaptans. They dissolve in alkalies, and on warming part with mer- 
captans (Berichte, 15, 1305). Completely alkylized dithio-urethanes, having the 
imide hydrogen replaced by alkyls, are formed the same as the mono-alky]l deriva- 
tives, z. ¢., by heating alkylized diphenyl-amidine-thioalkyls (p. 617) to 150° with 


CS,. Ethyl Phenyldithiourethane, Kr melts at 68.5°, and 


boils at 310°. These compounds are very stable, no longer soluble in alkalies, 
and are not desulphurized by mercuric oxide or an alkaline lead solution. They 
form so-called addition products (Berichte, 15, 568 and 1308) with methyl iodide. 
Phenyl sulphurethane and diphenyl-thio-urea (p. 618) do the same. 

An analogous compound is formed on heating diphenylamidin-thio-ethylene (p. 
618) with CS,. The product is called Ethylene-Phenyl-dithiocarbamate, 


kee 
csé \ °° (Berichte, 15, 345). 
H 





\s— g**4 . 
Derivatives of Swlphocarbamic Acid, CS¢ OH , thio-carbaminic acid, 
CO¢ on and the hypothetical zmidothiocarbonic acid, NHGCY oy (p. 384). 


Ethyl Phenylsulphocarbamate, Phenyl-thiourethane, Ce oe 
(Phenyl xanthamide) (Berich¢e, 15, 1307), is formed by heating phenyl-mustard- 
oil with alcohol (Berichte, 15, 2164) :— 


C,H,.N:CS +'C,H,.0H = C,H,.NH.CS.0.C,H,. 


It melts at 71-72°, and is resolved into phenyl-mustard-oil and alcohol when dis- 
tilled. It is soluble in alkalies, and unites with mercury, silver and lead. 

When alkyl iodides act upon these metallic compounds (not the free phenyl- 
sulphurethanes) we obtain phenyl-isothiourethanes, the alkyl derivatives of phenyl 
imtdo thto-carbonic acid (see above). The reaction is very probably analogous 
to that oe with thioacetanilides (p. 607) and the phenyl sulpho-ureas 
(p. 617) :— 

CH 
C,H,.NK.CS.0.C,H, + CH,I = CoH,.NCC SCA 5 4 KI. 
The methyl derivative is a liquid, and boils with partial decomposition at 260°, 
The e¢hy/ compound melts at 30° and boils at 278—-280°. : 

These alkyl derivatives are soluble in concentrated hydrochloric acid, and are 
precipitated by water, When heated with hydrochloric acid, they revert again to 
phenyl sulphurethane and alkyl chlorides; heated with dilute sulphuric acid to 

/ 0.GHs 


200°, aniline and thiocarbonic esters, ¢. g., COM Ss Ct.» result. 
On oxidizing phenylsulphurethane, in alkaline solution, with ferricyanide ot 


potassium, so-called ethoxyyphenyl mustard oil—a derivative of o-amido-thiophenol © . 


(see this) (Berichze, 19, 1811), is formed :— 


C.H,.NiCC Sa? +0 —C¢,Hi7* Soc nH, + 8.6. 


te Ps 
The esters of phenylthiocarbaminic acid (see above) ¢. g., eee ae 
are obtained by heating the thio- alkyl-diphenylamidines (p. 617) with dilute sul- 


phuric acid to 180° (Berichte, 15, 339). 


616 ORGANIC CHEMISTRY.» : 


The methyl ester melts at 83-84°; the ethyl ester at 73°. Warm alkalies 
resolve them into aniline, carbon dioxide and mercaptans. 

Another derivative of phenyl thio-carbaminic acid is the so-called glycolide 
* YN(Co H,).CO 
of Phenyl-mustard-oil, cog aa (p. 398), which is formed by heating 





phenyl-mustard-oil or phenyl-thio-urethane with chloracetic acid and alcohol to 
_ 160°; also by boiling diphenylthiohydantoin and (ortho) phenylthiohydantoin 

(p. 618) with hydrochloric acid (Berichte, 14, 1663). It crystallizes from water 
in laminz, melting at 148° and decomposing, on boiling with baryta, into aniline, 
carbon dioxide and thioglycollic acid. 





NH.C,H 


Phenylthiurea, CSC NH 5, Sulphocarbanilamide (p. 395), is formed by 


the union of pheny]l- scaane: oil with ammonia :— 


NH.C,H, 
CS:N.C,H, + NH, = CSN, 


It crystallizes in needles, melting at 154°, and forms a double salt with PtCl,. 
S is replaced by O and phenylurea formed on boiling with silver nitrate. 
Diphenyl-thiurea, CSC NHC? sulphocarbanilide, is produced by the 


union of phenyl-mustard-oil with aniline in an alcoholic solution :— 


NH.C,H 
CS:N.C,H, + NH,-CoH, se CSC NHC HS 
it is also obtained by boiling aniline (1 molecule) with CS, and alcoholic potash 
(1 molecule) :— 


CS, + 2NH,.C,H, = CS(NH.C,H,), + SH,; 


the product is poured into dilute hydrochloric acid, the alcohol evaporated and 
the mass crystallized from alcohol. 

Diphenylthiurea consists of colorless, shining leaflets, melting at 151° (Berichée, 
19, 1821), and readily soluble in alcohol. An alcoholic iodine solution converts 
it into sulpho-carbanile and triphenyl- -guanidine. When boiled with concentrated 
hydrochloric acid or phosphoric acid, it decomposes into phenyl-mustard-oil and 
aniline (p. 614); the mixed thiureas, containing two dissimilar benzene residues 
and resulting from the phenyl-mustard-oils and anilines (see above), undergo, 
under like treatment, a decomposition into two mustard-oils and two anilines 
(Berichie, 16, 2016). 

S is replaced by O, and the product is diphenylurea, if diphenyl thiurea be 
boiled with alcoholic soda or mercuric oxide (p. 611); monophenyl] thiurea, on 
the contrary, has hydrogen sulphide removed and becomes phenylcyanamide 
(p. 395). In a benzene solution mercuric oxide produces carbodipherylimide 

. 620). 
ee a action of alcoholic ammonia and lead oxide NH replaces S, forming 
diphenyl-guanidine (p. 395) :— 

NH.C,H, PRUG OE. 


x ; 
CSC NHC. OH. 5 yields ONAD<NH CH? 


under like circumstances triphenyl-guanidines are formed with anilines. 


SAY Fo ee ee 


ANILIDES OF CARBONIC ACID. 617 


Phenyl- and dipkenyl-thiurea are soluble in alkalies, because metallic com- 
pounds are probably formed by the replacement of hydrogen of the imide-group 
(as in the case of thioacetanilide, C, H,.NH.CS.CH, p. 607). If this be true they 
have not yet been isolated. Acids again set free the phenylureas. ‘ 

See Berichte, 17, 2088 and 3033 upon the alkyl phenyl thiureas and triphenyl 
thiureas. When the phenylthiureas are heated with amines secondary amine 
residues are displaced by primary amine residues ( BerichZe, 17, 3044). 


Tetraphenylthiurea, csZ N(CoHs)o. is obtained by heating! symmetrical 
\N(C,H; 


tetra-phenylguanidine (p. 619) with carbon disulphide. It crystallizes in long, 
shining needles, which melt at 195° (Berichie, 15, 1530). 





NH2\ 
NH= 
amidine thiohydryl, p. 394, Berichte, 21, 1860). 

The diphenyl thioalky/ derivatives (their haloid salts) are obtained by the action 
of caustic alkali and alkyl iodides upon diphenylthiurea, or better by heating the 
latter with an alcoholic solution of the alkyl iodides (bromides) (Berichte, 14, 
1489 and 1755; 21, 963; Ammalen, 211, 85) :— 


Derivatives of hypothetical Zsothiourea, C.SH (Imidothiocarbamic acid, 


Cn yO + GH =e SF cs.c.H + HL. 
Diphenyithiurea, Diphenylamidiae-thidthy? Derivative. 


Alkalies set free the bases, which are soluble in alcohol and combine with 1 
equivalent of acid to form crystalline salts. 

The methyl compound (Diphenylamidine-Thiomethyl) melts at 110°; the 
ethyl derivative at 73°. If heated with alcoholic potash it splits up into dipheny]- 
urea and potassium mercaptide :— 


C,H, NH\ __ C,H,NH\ 


and when heated to 120° with alcoholic ammonia diphenyl-guanidine (p. 619) 
and mercaptan are obtained :— 


C,H..NH\, Geka tee 
C,H, Nooo Gis + NH, = *CpH.NZONHa + C,H,.SH. 
C,H,.NX 


The alkyl derivatives yield carbo-diphenylimide CjH,.N ZE (Pp. 620), and mer- 
captan when distilled; and when heated to 180°, with dilute sulphuric acid, they 
decompose into phenylthio-carbamic esters (p. 615), and aniline :— 


C,H,.NH\ 
©. HN >CS-CHy + H,O = C,H,.NH.CO.S.CH, + C,H,.NH,. 


If heated with carbon disulphide to 160° the products are phenyl-mustard oil, and 
phenyl-dithiocarbamic esters (Berichte, 15, 338) :— 


C,H,.NH\ | 
CHwA + CS, = C,H,.NH.CS,S.CH, + C,H,.N:CS. 


52 


618 ORGANIC CHEMISTRY. 


The last two decompositions are perfectly analogous to those of the amidine: 


(Pp. 293). 
When the diphenylamidine-thioalkyls are heated with alkyl iodides, their alky!] 


Ce ia soi tr So S.C,H,. These yield dialkylic dithio- 


urethanes with carbon disulphide (p. eet 
Diphenylthiurea also reacts with benzyl chloride, C,H,.CH,Cl. Ethylene 


oH, 


derivatives result, ¢. g., 


bromide forms Diphenylamidine-thioethylene, » which car- 
H,.N=Ccs ~ 

bon disulphide converts: into ethylene-phenyl- dithiocarbaminate (p. 615). These 

compounds contain the “ five-membered ” ¢#zazo/e ring, hence they may be included 


among the thiazole (p. 554) derivatives (Berichte, 21, 1871). 





Chloracetic acid converts diphenylthiurea (Annalen, 207, 128) into :— 


C,H,.NH\ Ca OO 
C.S.CH,.CO,H and ue 
C,H,.NZ C,H,NZ CS.CH, 
Diphenyl-thiohydantoic Acid. Diphenyl-thiohydantoin, 


the diphenyl derivatives of so-called thiohydantoin and thiohydantoic acid 
(p. 397). 

Diphenylthiohydantoin, C,,;H,,N,SO (Diphenylamidine.thioglycollide), 
crystallizes from alcohol in leaflets, and melts at 176°. It decomposes, like the alkyl 
compounds (p. 617), when boiled with alcoholic potash, into diphenylurea, and 
thioglycollic acid, HS.CH,.CO,H. Boiling hydrochloric acid decomposes it into 


so-called glycolide of phenyl-mustard-oil, C,H,.N Koos CH (p. 616), and 
aniline. RIO. 
. Phenylthiohydantoic Acid, . #!2Nc.s.cH,.CO,H (Phenylamidine-thio- 


*C.H,.N7Z 
glycollic acid), is produced (analogous to the formation of amidines from amines 
and cyanalkyls, p. 293) from aniline and sulphocyanacetic acid (or chlor-acetic 
acid and ammonium-sulphocyanate) (Berichte, 14, 732) :— 


NH, 
C,H,.NH, + CN.S.CH,.CO,H = C,H,.N: Cs. CH,.cO,H, 
It is soluble in alcohol, crystallizes in needles, and melts at 148-152°. Boiling 
‘dilute sulphuric acid decomposes it into phenylurea and thioglycollic acid. 
Isomeric, so-called (ortho)-Phenylthiohydantoic Acid, C,H,,N,SO,, is 
formed (analogous to thiohydantoic acid (p. 397) from phenyl thiourea and 
ammonium chlor-acetate (Berichte, 14, 1660) :— 


oP A gN NHY 
C,H; NHS + CH,CLCO,H = C H, NH Joo ae + HCl. 


It is an amorphous mass, dissolving readily in alkalies and acids. The withdrawal of 
: | GScH., 


- water from it yields so-called (ortho)-Phenylthiohydantoin, Pa | 
gH,-N—-—CO 


~ 


GUANIDINE DERIVATIVES. 619 


which melts at 178°, and is obtained from thio-urea and chloracet-anilide, C,H,. 
NH.CO.CH,Cl. Boiling dilute hydrochloric acid converts it into the glycolide of 
pheny!-mustard oil (p. 616); ammonia is liberated simultaneously. 





The real Phenylsulphydantoins, corresponding to hydantoin in constitution, 
and isomeric with the preceding so-called phenylthiohydantoins (more correctly 
phenylamidine derivatives), are obtained by heating phenyl-mustard oil with. 
glycocoll (amido-fatty acids) (Berichte, 17, 424) :-— 


N.(C,H , 
CS:N.C,H, + NH,.CH,CO,H = CSC NH HCD 4 H,0. 
Phenylsulphydantoin. 
They are converted into the corresponding phenylsulphydantoic acids on boiling 
with alcoholic potash, and are desulphurized by boiling with lead oxide. 
e 


GUANIDINE DERIVATIVES (compare p. 294). 


Diphenyl-guanidine, BNC NH CH (Melaniline), is produced by the 





action of CNCl upon dry aniline, and by digesting cyananilide, C,H,.NH.CN, 
with aniline hydrochloride. It crystallizes in long needles, melting at 147°. It 
is a mono-acid base, forming crystalline salts. CS, transforms it into sulpho-car-. 
banilide and sulphocyanic “acid, which combines with a second molecule of 
dipheny]l-guanidine :— 


_>/NH.C,H “DSN a 
NE:CC Ni Cin’ + CS: = CK Nich’ + CNSH. 


a-Triphenyl-guanidine, CH, NOS a ete is obtained on heating di- 
: : 
phenyl-urea and diphenyl]-thiurea, alone or with reduced copper, to 140°. It is 


most readily prepared by digesting diphenyl-thiurea and aniline, with litharge or 
mercuric oxide (or by boiling with an iodine solution) :— 


/NH.C,H zs __/NH.C,H 
CNHCoH? + NHa-CoHs = CoHs-NiCQ ny Coy? + SH:. 


CS 
Triphenyl-guanidine crystallizes in rhombic prisms, melts at 143°, and is insolu- 
ble in water, sparingly soluble in ether, but readily in alcohol. It is a monacid 
base, and yields well crystallized salts. Heated with CS,, it reverts again to 
diphenyl-thiurea and phenyl mustard oil. 
Isomeric 6-Triphenyl-guanidine is obtained by heating cyananilide with HCl- 


diphenylamine :— 
/N(CoHs) 2 
C,H,.NH.CN + NH(C,H,;), = C=NH : 
\NH.C,H; 


It crystallizes in large plates, melting at 131° (see Annalen, 192, 9). It decom- 
poses into diphenylamine, phenyl mustard-oil, and sulphocyanic acid when heated 
with carbon disulphide. 


620, - ORGANIC CHEMISTRY. 


Symmetrical Tetraphenyl-guanidine, NH: CONCH i 8 is produced by the 


action of CNCI upon diphenylamine at 170°. Its crystals are insoluble in water, 
and melt at 130°. 





-CYANAMIDE DERIVATIVES (p. 289). 


Cyananilide, C,N;.NH.CN, phenyl cyanamide (p. 289), is formed on con- 
ducting CNC into a cooled ethereal solution of aniline, and by digesting phenyl- 
‘thiurea with litharge, or by heating it with lead acetate and alkali (Berichte, 
18, 3220). It is readily soluble in alcohol and ether, but dissolves with difficulty 
in water. It contains % molecule of water of crystallization. It forms needles, 
melting at 47°. When allowed to stand in a desiccator, it loses water, becomes 
liquid, and in the air reverts to the crystalline hydrate. When heated it poly- 
merizes to 7riphenyl-isomelamine. It forms phenyl-thiurea with H,S. 

Carbodiphenylimide, oa ct Hei is produced by the action of mercuric ox- 
ide upon diphenyl-thiurea in benzene “solution, when H,S is directly withdrawn 
(p. 616); or by the distillation of a-triphenyl- guanidine, “when aniline separates, 
It is a thick liquid, boiling at 330°. It polymerizes upon standing, yielding a porce- 
lanous mass, melting at 170°. When it absorbs water (boiling with alcohol), it 
yields diphenyl urea. It combines with H,S to diphenyl thiurea, and with aniline 
_ to a-triphenyl-guanidine. It forms very stable bases with orthophenylenediamine, 
C,H,(NH,), (Berichte, 22, 3186). 





Cyanuramide or Melamine Derivatives (p. 290). 

Normal Triphenylmelamine, C,N,(NH.C,H,),, is produced in the action of 
cyanuric chloride on aniline, or by heating ethyl trithiocyanuric ester with aniline 
(p. 290) to 250-300° (Berichte, 18, 3218) :— 


C,N,(S.CH,), + 3NH,.C,H, = C,N,(NH.C,H,), -+ 3CH,.SH. 


It consists of colorless needles, melting at 228°. Heated with hydrochloric acid 
to 150°, it breaks up into aniline and cyanuric acid. 

Hexaphenylmelamine, C,N,[N(C,H,;),],, melts at 300° and splits ‘Up into 
aniline and diphenylamine when heated to 200° with hydrochloric acid. It is 
formed by letting cyanuric chloride act upon diphenylamine. 

Triphenylisomelamine, C,N,(C,H,),(NH)s. On long standing, phenyl- 
cyanamide polymerizes to this compound, Heating will effect the same. Or, it is 
produced when cyanogen bromide acts on aniline. It crystallizes in thick needles 
and melts at 185°, It dissolves in hydrochloric acid and forms double salts with 
AuCl, and PtCl, On warming with hydrochloric acid, it successively loses its 
NH-groups, oxygen entering, and the sole product is the triphenyl ester of iso- 
cyanuric acid (p. 613) (Berichte, 18, 3225). In addition to the normal tripheny]l- 
“melamine and triphenylisomelamine, 2 asoalses triphenylamines are known 
( Berichte, 18, 3226; 23, 1678). 





Amidine derivatives (p. 293 and Benzenyl amidines), 

In addition to the methods mentioned (p. 293), we can also produce the phe- 
nylated amidines by permitting PCl, or HCl to act upon a mixture of aniline 
_with acid anilides :— 

C,H;.NH\ 


C,H,.NH.CHO + C,H, ‘NH, =¢ ee 'N PO REP 


Formanilide, Diphenyl-methenyl-amidine. 


PHOSPHORUS COMPOUNDS. 621 


C,H,-NH.CO.CH, + C,H,.NH, = CH NSCs + H,0, 


Acetanilide. Diphenyl-ethenyl-amidine. 


or by conducting HCl into anilides, or by heating the same with HCl-salts of the 
anilines (Berichte, 15, 208 and 2449). They are feeble bases, and yield salts with 1 
equivalent of hydrochloric acid. When boiled with aniline they are separated into 
aniline and acid anilides. 

Diphenyl-methenyl-amidine (Methenyldiphenyl-diamine) results upon heat- 
ing aniline with chloroform or formic acid to 180°, and by boiling phenyl-isocy- 
anide, C,H,.NC, with aniline. It crystallizes from alcohol in long needles, 
melts at 135° and distils at 250°, with partial decomposition into C,H,.NC and 
aniline. 

Diphenyl-ethenyl-amidine melts at 131°. 

Phenyl-ethenyl-amidine, C,H,;N:C(NH,).CH,, from acetonitrile and HCl- 
aniline (p. 293), is a liquid. 

We can also include here the so-called anhydro- and aldehydine bases (p.,628), 
which are obtained from the phenylenediamines of the ortho- series (see also 
Benzenyl-amidine).° 





PHOSPHORUS COMPOUNDS. 


There is a series of phosphorus compounds corresponding to the benzene 
amido-derivatives. ; 

Phenylphosphine, C,H,.PH,, phosphaniline, is obtained by the action of 
hydriodic acid upon phosphenyl-chloride, C,H,.PCl,. It is a liquid, boiling at 
160° in a current of hydrogen, and possessing an extremely disagreeable odor. 
It sinks in water and is insoluble in acids. When exposed to the air it oxidizes 
to phosphenyl oxide, C,H,.PH,O,—a crystalline mass easily soluble in water. 
Phenylphosphine combines with HI to the iodide, C,H,.PH,I, out of which 
water again separates phenylphosphine. 

Phosphenyl Chloride, C,H,.PCl,, is formed by conducting a mixture of 
benzene and PCI, vapors through tubes heated to redness, by heating mercury 
dipheayl with PCl,, and by the action of AlCl, upon benzene and PCl,. Itisa 
strongly refracting liquid, which fumes in the air, boils at 222°, and has a specific 
gravity 1.319 at 20°. It forms the ¢etrachloride, C,H,.PCl,, with chlorine; this 
melts at 73°. With oxygen it yields the oxychloride, C,H;.PC1,0, boiling at 
260°. When the dichloride is heated with water we obtain phenyl-hypo-phos- 
phorous acid, C,H,.PHO.OH (melting at 70°), while the tetrachloride forms 
phenylphosphinic acid, C,H,;.PO.(OH),, which melts at 158° (p. 155). 

Phosphenyl chloride converts phenylphosphine into Phospho-benzene, C, 
H,.P:P.C,H,, corresponding to azobenzene, C,H,.N:N.C,H,. 

Diphenylphosphine, (C,H,),PH, is obtained from diphenylphosphor- | 
chloride. It is an oil, boiling at 280° (Berichte, 21, 1507). Diphenylphosphor- 
chloride, (C,H,),PCI, from mercury diphenyl, and phosphenyl-chloride, boils at 
320° (Berichte, 18, 2108). 

Triphenylphosphine, (C,H,),P, is produced from C,H,.PCl,, and brom- 
benz2ne, or from PCl, and brombenzene by the action of sodium (erich/e, 18, 
Ref. 562); it crystallizes fh large plates, melts at 75° and boils at 360°. 

Triphenylphosphine readily enters into compounds of pentavalent phosphorus 
(p. 169). It forms, with bromine, the dibromide, (C,H,),PBr,, which is con- 
verted by water or alkalies into the dihydroxide, (C,H,),P(OH),. At 100° this 
passes into the oxide, (C,H,),PO. The latter melts at 153° and boils above 360°. 


622 ORGANIC CHEMISTRY. 


Triphenylphosphine and sulphur unite to the sulphide, (C,H,),PS, and with the 
alkyl iodides to phosphonium iodides, like (C,H,),P.CH,lI (Berichie, 18, 562). 
Phenoxyldiphenylphosphine, (C,H,),P.0.C,H,, is isomeric with triphenyl 
phosphine oxide. It is produced by the action of phenol upon diphenyl phosphor- 
Vv It 


chloride (see above): (C,H,),PO, isomeric with (C,H,;),P.0.C,H,. This 
isomerism proves the Zendavalence of phosphorus in the compounds PX, (Berichte, 
18, 2118). 

Toluene, xylene, and naphthalene form similar phosphorus derivatives. Analo- 
gous arsenic compounds exist. Furthermore, analogous arsenic (Berichte, 19, 
1031) and antimony compounds, ¢.g., Triphenylstibine, are known (Berichée, 18, 
Ref. 444). 





Phenyl-silico-chloride, C,H,.SiCl,, is prepared by heating mercury di- 
phenyl and SiCl, to 300°. It is a liquid which fumes in the air and boils at 
197°. Water decomposes it into the compound, C,H,.SiO.OH, which may be 
considered as benzoic acid in which the 1 carbon is replaced: by silicon, hence it 
is called silico-benzoic acid. Alcohol forms the triethyl ether, C,H,.Si(O.C, 
H,)s, boiling at 237°. Zinc-ethyl converts the chloride into ¢riethy/-phenyl- 
silicide, C,H .Si.(C,H,)5, boiling at 230°. 

Tetraphenyl Silicon, Si(C,H,),, is produced by the action of sodium upon a 
mixture of SiCl,, chlorbenzene and ether (Berichte 18, 1540; 19, 1012). Itisa 
white powder, which separates in a crystalline form from benzene. It melts at 
228° and distils beyond 300°. 





The arsenic and silicon compounds constitute the transition to the metallo- 
organic derivatives (p. 177); those containing tin, bismuth, mercury and lead are 
known in the benzene series. 

Mercury-Phenyl (C,H,),Hg, is formed by treating brombenzene in benzene 
solution, for some time, with liquid sodium amalgam; the addition of some acetic 
ether facilitates the reaction (p. 181). It crystallizes in colorless rhombic prisms, 
melts at 120°, and can be sublimed. It assumes a yellow color in sunlight. It 
dissolves readily in benzene and carbon disulphide, but with more difficulty in 
ether and alcohol; in water it is insoluble. When distilled it decomposes for the 
most part into diphenyl, benzene and mercury. Acids decompose it with forma- 
_ tion of benzene and mercury salts. Haloid compounds, e. ¢., C,H,.HglI, are 
produced by the action of the halogens. Moist silver oxide converts them into 
hydroxy! derivatives, ¢. ¢.,C,H,.Hg.OH—a crystalline, very alkaline body, which 
separates ammonia from ammonium salts. ze 

Bismuth-Triphenyl, (C,H,),Bi, is prepared by heating brombenzene and bis- 
- muth-sodium. It crystallizes, from hot alcohol, in needles or leaflets and melts at 

82° (Berichte, 20,54). When digested with concentrated hydrochloric acid it 
breaks up into bismuth-trichloride and benzene. 

Tin-Tetraphenyl, Sn(C,H,),, may be produced by the action of tin-sodium 
(25% Na) upon brombenzene. It crystallizes in colorless prisms, melting at 226°. 
It sublimes and boils above 420° (Berichte, 22, 2917). 6 

Lead-Tetraphenyl, (C,H,),Pb, is formed by heating brombenzene with lead- 
sodium and acetic ether. It is very much like the mercury-phenyl. It crystallizes 
in minute needles, melting at 225°, and decomposes above 270° (Berichte, 20, 


75?) 


. 


ANILINE HOMOLOGUES. 623 


ANILINE HOMOLOGUES. 


The aniline homologues, like aniline, are obtained by the reduc- 
tion of the nitro-derivatives of the homologous benzenes. ‘Techni- 
cally, the methylated homologues (toluidine, xylidene, cumidine) 
are prepared by heating dimethylaniline or methyltoluidine hydro- 
chlorides to 300° (p. 594). 


Toluidines, GHsCNe The three isomerides are formed by 
2 


the reduction of the three corresponding nitrotoluenes. Crude, 
commercial toluidine (p. 590), obtained by reducing common nitro- 
toluene, consists of solid para- and liquid ortho-toluidine; the 
former crystallizes out from the mixture. 


To separate orthotoluidine from any para that continues in solution, the two are 
converted into acetyl compounds by digesting them with glacial acetic acid; in 
this new form they are dissolved in 4 parts concentrated acetic acid, and 80 parts 
of water are then added. The acetparatoluidine is precipitated, while the ortho- 
body continues in solution. Technically, they are separated from each other (and 
from aniline) by the different behavior of their HCl-salts toward sodium phosphate 
(Berichte, 19, 1718, 2728). 

The following mixtures are handled in commerce: Aniline oil for 4/ve, consist- 
ing of pure aniline; aniline oil for ved, consisting of aniline, o-toluidine and 
p-toluidine in almost molecular quantities, and aniline oil for saffron, obtained from 
the distillate of the fuchsine fusion (échappés), is a mixture of aniline and o-tolu- 


idine. 


ee 

When the toluidines are directly oxidized they behave like the 
anilines and usually change to azo-compounds ; should the amido- 
group, however, contain acid radicals, these acid toluides can be 
oxidized by potassium permanganate, and by saponification yield 
amido-benzoic acids. Furthermore, the acid-toluides can be chlori- 
nated, brominated, and nitrated the same as the anilides. The 
substituting negative group always arranges itself near the amido- 
group (in the ortho- position). Substituted toluidines are obtained 
by the saponification of these toluides. 


Paratoluidine (1, 4), from solid paranitrotoluene, crystallizes in large plates, 
melts at 45°, and boils at 198°. It separates from boiling water, on cooling, in 
hydrous crystals, that sublime on exposure to the air. Bleaching lime does not 
color it. The acetyl compound, C,H,.NH.C,H,O, melts at 147°, and boils near 
306°. Formyl toluide, C,H,.NH.CHO, is produced by distilling toluidine with 
oxalic acid (p. 606); when distilled with concentrated hydrochloric acid it yields 
(1, 4)-tolunitrile, which passes into terephthalic acid. 

Methyl- and di-methyl-paratoluidine boil at 208°. 

Upon heating /-toluidine with sulphur we obtain both thiotoluidine and dehy- 
drothiotoluidine, C, ,H,,N,S—the parent substance of the primu/ines (see thio- 
toluidine and Berichte, 22, 581, 969). 

Nitrosotoluidines, C,H,(NO).NH,, may be prepared from the nitrosocresols 


* 


624 _. ORGANIC CHEMISTRY. 


by heating them with ammonium chloride and ammonium acetate (p. 599) (ZBe- 
richte, 21, 729). ~ 

Orthotoluidine (1, 2) (Pseudotoluidine) does not solidify at —20°, and boils at 
199°; its specific gravity at 16° is 1.00. Bleaching lime and hydrochloric acid 
color it violet, while a mixture of sulphuric and nitric acids gives it a blue color. 
Ferric chloride precipitates a blue compound (toluidine blue) from its hydro- 
chloric acid solution. Its acet-compound melts at 107° and when oxidized with 
potassium permanganate and saponified yields ortho-amido benzoic acid (Berichte, 
14, 263). It forms four isomeric nitro-orthotoluidines (Annalen, 228, 240) by the 
entrance of NO,. 

Metatoluidine (1, 3), from metanitrotoluene (Berichte, 22, 840) and metanitro- 
benzaldehyde ( Berichte, 15, 2009), does not solidify at —13°, has a specific gravity 
of 0.998 at 25°, and boils at 202°. Its acetyl compound melts at 65°. 

Ditolylamine, (C,H,.CH,),NH, is produced like diphenylamine (p. 603) by 
heating HCl-toluidine with toluidine. It is a crystalline compound, boiling near 
360°. 

Xylidines, C,H,(CH,),.NH,. 

The six possible isomerides are known. Three are derived from metaxylene, 
two from orthoxylene, and one from paraxylene (erich/e, 18, 2669). The com- 
mercial xylidine, obtained from dimethylaniline, serves for the preparation of red 
azo-dyestuffs, and consists chiefly of amido-paraxylene (Berichte, 18, 2664) and 
amido-metaxylene (Berichte, 18, 2919). — 

Amidotrimethyl-benzenes, C,H,(CH,),.NH,. The commercial product 
is made by heating xylidine hydrochloride with methyl alcohol to 256° under 
pressure; it serves for the preparation of red azo-dyestuffs and contains cumidine 
and mesidine (Berichte, 15, 1011, 2895). Cumidine is Pseudocumidine of the 
structure (1, 2, 4, 5—NH, in 1) (Berichie, 18, 92 and 1146); it consists mainly 
of nitropseudocumene; it melts at 63°, boils at 235°, and forms a nitrate that 
dissolves with difficulty. Pseudocumene, C,H,(CH,), (1, 3, 4), is produced by 
boiling its hydrazine compound, C,H,(CH,),.NH.NH,, with copper sulphate 
(see p. 833). Durylic acid is obtained by replacing the amido-group by bromine, 
and this by CO,H. Jesidine, amido-mesitylene, is obtained from nitro-mesity- 
lene, and boils at 227° (Berichte, 18, 2229). 

A mido-Isodurene, C,H(CH,),.NH,, is produced by heating pseudocumidine 
hydrochloride or mesidine hydrochloride with methyl alcohol. It boils at 250°. 
The replacement of its amido group by hydroxyl yields a tetramethylphenol, 
melting at 81° (Berichte, 18, 1149). 

Amido-pentamethyl Benzene, C,(CH,),.NH,, is very readily made by heating 
pseudocumidine and methyl iodide to 250° (Berichte, 18, 1821). It melts -at 
152° and boils at 277°. The replacement of its amido group gives rise to penta- 
methyl phenol, C,(CH,),.OH. 

Homologues of aniline with higher alkyls are easily obtained on heating ani- 
line with fatty alcohols and ZnCl, to 270-280° (p. 599); the alkyl assumes the 
para-position with reference to the amido group. s-Amidoethylbenzene, 
C,H,(C,H;).NH,, also obtained from nitroethyl benzene (Berichte, 17, 767, 
2800), boils at 214°. Amidopropylbenzene, C,H,(C,H,).NH,, boils at 225°, 
the isopropyl compound at 217° (Berichte, 17, 1231) (see Berichte, 21, 1157). 
Amidoisobutylbenzene, C,H,(C,H,).NH,, is easily obtained by heating ani- 
line hydrochloride to 230° with isobutyl alcohol (Berichte, 18, 1009), and boils at 
231°. Amido-octyl Benzene, C,H,(C,H,,)NH,, from normal octyl alcohol, 
melts at 19°, and boils at 310° (Bertchée, 18, 133). 


DIAMIDO COMPOUNDS, 625 


DIAMIDO COMPOUNDS. 


The diamidobenzenes or phenylene-diamines,C,H,(NH.)., 
are formed by the reduction of the three dinitrobenzenes or nitro- 
anilines (p. 598) with tin and hydrochloric acid; they can be 
obtained, also, from the six diamidobenzoic acids, C,H;(NH,).. 
CO.H, by the loss of carbon dioxide. They are also produced by 
the reduction of the nitroso compounds of the tertiary anilines, ¢. g., 
NO.C,H,.N(CH;). (p. 598). The monamines can be converted 
into the diamines by first changing them to amido-azo-compounds, 
and then decomposing the latter by reduction (p. 645). 

The diamines are colorless solids, but on exposure to the air 
they become colored. They are di-acid bases, forming well-defined 
salts. Ferric chloride imparts an intense red color to their solution. 


Diamidobenzenes or Phenylenediamines, C,H,(NH,),. 

o-Diamidobenzene (1, 2), four-sided plates, melts at 102° and boils at 252°. 
Ferric chloride imparts a dark red color to its HCl-solution. When o-diamido- 
benzene (o-phenylene diamine) is shaken with benzoyl chloride and caustic soda 
the dibenzoyl derivative is formed—C,H,.(NH.CO.C,H,), (p. 312 and Berichte, 
21,2744). Diacyl derivatives of the o-diamines are easily formed by heating with 
acid anhydrides (Berichte, 23, 1876), whereas if the free acids are employed 
ethenyl amidines are produced (p. 628). m-Phenylenediamine (1, 3), readily 
obtained from common dinitrobenzene, melts at 63° and boils at 287°. | 
dilute nitrous acid solutions are colored intensely yellow by it; it can the 
be employed for the quantitative estimation of the former in aqueous s¢ 
(Berichte, 14, 1015). It combines with carbon disulphide to produce a H 
compound, C,H,(NH),CS (Berichte, 21, Ref. 521). p-Phenylenediamine (1,4) 
melts at 147° and boils at 267°. Manganese peroxide and sulphuric ac 
convert it into quinone on boiling. If allowed to stand exposed to the air it 
oxidizes to green-red crystals, C,H,N, (Berichte, 22, Ref. 404). Its dimethyl 


compound, C,H Ni has already been described as f-amido-dimethyl- 


aniline (p. 601.) The tetramethyl derivative serves as a reagent for ozone 
(Berichte, 19, 3196). 

Diphenylated diamidobenzenes, C,H,(NH.C,H,;),, are produced by heating 
resorcinol and hydroquinone, C,H,(OH),, with aniline and CaCl, or ZnCl, (see 
dioxydiphenylamine, p. 604). 

Triamidobenzenes, 'C,H,(NH,),. The adjacent (1, 2, 3) is obtained from 
triamidobenzoic acid (from chrysanisic acid), When pure it is colorless, melts at 
103° and boils at 330°. It even reduces silver solutions in the cold, is colored 
violet then brown by ferric chloride, and dissolves in sulphuric acid, containing a 
little nitric acid, with a deep blue color. The wusymmetrical (1,2, 4) is obtained 
by the reduction of a-dinitroaniline (p. 598), and by the decomposition of 
chrysoidine (Berichte, 15, 2197); it forms a crystalline mass and is colored a 
wine red by ferric chloride (Berichte, 17, Ref. 285). When oxidized by air, it 
changes to a eurhodine dyestuff (Berichte, 22, 856). 

Tetra-amido benzenes, C,H,(NH,),. The symmetrical (1, 2, 4, 5) variety 
is formed by the reduction of dinitro-m-phenylenediamine. It oxidizes very rap- 
idly when liberated from its salts. It contains two amido-groups in the ortho- and 
para-positions, hence it exhibits all the reactions of the ortho- and para-diamines 








626 ORGANIC CHEMISTRY. 


(see below) (Berichte, 22, 440). The adjacent (1, 2, 3, 4) variety, produced by 
the reduction of diquinoyl-tetroxime, C,H,(N.OH),, is also quite easily oxidized, 
and reacts like an orthodiamine (2erichte, 22, 1649). 

Penta-amido benzene, C,H(NH,),, from trinitro-diamine, is very unstable 
on exposure to the air (Berichie, 21, 1547). 





Diamidotoluenes, Toluylene-diamines, C,H,(CH,)(NH,),. 0-p-Diamido- 
toluene (1, 2, 4—CH, in 1), obtained by the reduction of dinitrotoluene, consists of 
long needles, sparingly soluble in cold water, fusing at 99° and boiling at 280°. It 
is used in the preparation of toluylene red. 

m-p-Diamidotoluene (1, 3, 4—CH, in 1), with the 2NH,-groups in the ortho- 
position, is obtained from nitroparatoluidine, forms scales that dissolve easily in 
cold water, melt at 89° and boil at 265°. Of the ortho-diamines, this one is 
most readily prepared. o0-m-Diamido-toluene (1, 2, 3) (the two amido-groups are 
in the ortho-positions) is obtained from the corresponding nitroorthotoluidine. It 
melts at 62° and distils at 255° (Annalen, 228, 343). 0-0-Diamidotoluene (1, 2, 
6), from o-nitroorthotoluidine, melts at 103°. 





Differences between the ortho-, meta- and para-diamines.—The 
three isomeric diamines differ markedly in numerous reactions, and 
the ortho-derivatives especially are characterized by their capability 
of forming various condensation products. 


(1), The paradiamines, when digested in the warm with ferric chloride, are oxi- 
dized to quinones, ¢. ¢., C,H,O,, readily recognized by their odor. The same re- 
agent precipitates from the orthodiamines (their salts) intensely colored compounds 
of complex constitution. Thus, orthophenylenediamine yields the ruby red com- 
pound, C,,H,,N,0.2HCI (Berichte, 17, Ref. 431). 

(2) Nitrous acid (or NaNO,) converts the para-diamines (their salts) into diazo- 


compounds, ¢. v., C,H rk Nee the meta-diamines, on the contrary (as one NH, 


group is diazotized and two molecules unite), yield yellow brown azo-dyes, of the 
type of phenylene brown. The same products result from the action of the diazo- 
chlorides (see chrysoidine) upon the meta-diamines. In very acid solution, and 
when there is a constant excess of acid (nitrous) the meta-diamines are also capable 
of forming diazo derivatives (Berichte, 19, 317). The ortho-diamines, when acted 
upon by the nitrous acid, yield azimido-compounds, e.g., Azimidobenzene. 

(3) When the hydrochlorides of the three isomerides are digested with ammo- 

‘ ; ; ; ; NH,.HSCN 
- nium sulphocyanide, disulphocyanides, like C,H NH’ HSCN? are produced. 
On heating these to 120°, we discover that the orthodiamines are changed to phe- 
nylene sulphureas, C,H Had sel CS. These are not altered by digestion with an 
alkaline lead-solution (not desulphurized) ; while the derivatives, obtained from the 
meta- and para-diamines are immediately blackened by the alkaline lead solution 
(Reaction of Lellmann, Berichte, 18, Ref. 326). All diamines unite in a simi- 


lar manner with the mustard oz/s, to form phenylene disulphalkylureas (see p. 
389) -— E 

NHCS.NEGA,. 

C,H,(NH,), + 2CS:N.C,H, = CHC NH CSNHCH® 


_ ANHYDRO-BASES. 627 


If these products be fused, those from the ortho-diamines decompose into o-pheny- 
lenesulphurea and dialkylsulphureas :— 


/NH.CS.NH.GH; _ - q “NH /NH.CHs. 
4 NH.CS.NH.CGH, = CoH nH? + OS NHGH,? 


the fused mass instantly becomes crystalline, and the resulting phenylenesulphurea 
is not turned black by alkaline lead solutions. The mefa-diamine derivatives melt 
with decomposition, while those of the para-, after fusion, are completely broken 
up (Berichte, 18, Ref. 327, and 19, 808). 

The ortho-phenylene diamines yield peculiar bases by their union with carbo- 
diphenylimide (p. 620). With phosgene they form phenylene ureas, ¢. ¢., 


CoH NOOO (Berichte, 23, 1097). 


The para-diamines are also capable of yielding various dyestuffs. Mixed with 
primary amines (or phenols) and oxidized at the ordinary temperature, they are 
converted into ixdoamine and indophenol dyestuffs; at higher temperatures, the 
so-called safranines are produced. When oxidized with ferric chloride in the 
presence of H,S, all the para-diamines, containing a free NH,-group yield sul- 
phurized dyes of thio-diphenylamine (Lauth’s Dyestuffs, p. 605). 

With the diazo.compounds, the meta-diamines form azo-colors (see above) while 
quinoxaline and phenazine colors are obtained fromthe ortho diamines by the 
action of ortho-diketones, etc. 


C,H 


Condensation Products of the Orthodiamines.—The ortho-diamines, 
in which the 2NH,-groups occupy the ortho-position, are capable of 
forming peculiar compounds, in which the two nitrogen atoms of 
the amido-groups are joined by one or two carbon atoms. They 
belong partly to the quinoxalines and partly to the phenazines. 
Analogous amidines are obtained from the amidophenols and amido- 
thiophenols (see those of the ortho-series). 


Amidine derivatives, or azhydrodases of the ortho-diamines are obtained:— 

(1) By reducing the ortho-nitro acid anilides with tin and hydrochloric or acetic 
acid, the NO,-groups being converted into NH, and water eliminated at the same 
time—Anhydrobases, of Hobrecker and Hiibner (Auna/en, 209, 339) :— 


NH.CO.CH. NH 
CoH No, $+ 3H, = CHA DC.CH, + 3H,0, 
Ortho-nitro-acetanilide. Ethenyl-phenylene-amidine. 
/NH.CO.C,H <n 
CH No, 8 +3 = CHC CCH, + 3H,0. 
o-Nitro-benzanilide. Benzenyl-phenylene-amidine. 


(2) The same anhydrobases, or amidines, are directly produced from the ortho- 
diamines on heating them with acids (e. g., formic acid, acetic acid, benzoic acid, 
phthalic acid); the acid anilides formed at first (Berichte, 19, 1757), lose water 
(Berichte, 8, 677; 10, 1123) :— 


NH NH 
CoHy(CHs)C NP + CH,.CO.OH = CoHs(CH)CN DC-cH, + 2H,0. 
o-Toluylene Diamine. Toluylene-Ethenyl Amidine. 


The same products result on heating thé ortho-diamines with acetoacetic ester 
(Berichte, 19, 2977 ; 12, 953); paraphenylene diamine, on the other hand, forms 
an anilide of aceto-acetic acid (Berichte, 19, 3303). 


628 ORGANIC ‘CHEMISTRY. 


GB 3) The ortho-diamines yield similar derivatives with the aldehydes (benzalde- 
hyde, furfurol, salicylic aldehyde)—Aldehydine bases of penne (Berichte, 
11, 590) :— 

CH,.C,H - 
7 


nN“ 
; peal. 

21. 2COH.C,H, = C,H, C.C,H, + 2H,0. 
Benzaldehyde. 4 


C; HR 


If the hydrochloric acid salts of the diamines (with 2HCl) be employed in this 
reaction, one molecule of hydrochloric acid is set free, and the ortho-diamines can 
thereby ‘be reaeey distinguished from the meta- and para-diamines ( Berichte, 11, 
1650 

ts latest investigations prove the a/dehydine bases to be real amidines, inas- 
much as benzaldehydine can also be prepared. from benzenyl-phenylene amidine 
(see above) by heating with benzyl chloride, C,1H,.CH,Cl (Berichte, 19, 2025). 
The fatty aldehydes are also capable of yielding ‘analogous aldehydine bases (e- 
richte, 20, 1585). 

Condensation products are obtained when the free diamines act upon aldehydes 
(Berichte, 22, 2724). 

The phenylene amidines (anhydrobases and aldehydines) are perfectly analogous 
to the diphenylene amidines (p. 620). These are crystalline and very stable com- 
pounds. Being monacid-bases, they generally form well crystallized salts. They 
do not unite with acid chlorides or anhydrides. They combine with the alkyl- 
iodides (1 and 2 molecules) to ammonium iodides, yielding corresponding hydrox- 
' ides with caustic potash. /NH\ 

Phenylene-methenyl Amidine, ok 6H" NZ _>CH, phenylene-formamidine, 


(p. 293), from o-phenylene diamine and formic acid, melts at 167°. Phenylene- 
- ethenyl Amidine, C,H ‘dais ected CH,, phenylene-acetamidine, melts at 176°. 


4—_NZ 

Pleas C.C,H,,. melts at 280°. Benzalde- 
hydine results upon heating it with benzyl chloride (see above). An oxy-deriva- 
tive of methenyl amidine is produced on heating o-toluylene diamine with imido- 
carbonic ester (p. 384) :-— 


Phenylene benzamidine, C,H 


O.C,H, _ 


NH 
OCH = CH 77 \C.0.CH, + NH, -+ C,H,.0H. 


Cn. h Fe Sint a 


<NE 24 HNC. 


On heating the ethenyl-compound with hydrochloric acid, we get 


a7 EN c: 


Toluylene-oxy-methenyl amidine, or Toluylene Urea, C, 6-—_N= 


OH, or C ih ie 


ing o-toluylene-diamine with urea (Berichte, 19, 2652). v-Phenylene-sulphurea, 


HO (tautomeric forms), which can also be formed by heat- 
C,H ARS CS (p. 627), is analogous to o-toluylene-urea. 


__ A very interesting condensation of the ortho-diamines is that with 
glyoxal, CHO.CHO and other dicarbonyl derivatives, —.CO. 
CO.—, when they form basic compounds of the quinoxaline type: 


bal 


DIAZO-COMPOUNDS. 629 


N:CH 
Lo he bireak et ORD Gade totes EO 
= =p 
*\NH cae **\N-CH oy 


and also of that of phenazzne, CH ae (see these). 


Upon this behavior Hinsberg and K6rner have based the reaction 
for the detection of the ortho-diamines by means of phenanthra- 
quinone. A more delicate test is obtained by using croconic acid 
(Berichte, 19, 2727). 

The ortho-diamines unite with grape-sugar (Berichte, 20, 281 and 


495)- 





DIAZO-COMPOUNDS. 


The amido-group is directly replaced by hydroxyl, when nitrous 
acid acts upon the primary amido-derivatives of the marsh-gas 
series (p. 161) :— 


R.NH, + NO,H = R.OH + N, + H,O, 


The benzene amido products, on the other hand, first yield inter- 
mediate compounds—the so-called diazo-compounds—which can 
be further transformed into hydroxyl derivatives :— 
C,H,.NH,. C,H,.N,.NO,. C,H,.OH. 
Amido-benzene. Diazo-benzene Nitrate, ‘Phenol. 
We obtain either diazo- or diazo-amido compounds, according to 
the conditions of the reaction. If nitrous acid (or its vapors) be 
permitted to act on the salts of amido-derivatives in aqueous solu- 
tion, salts of the diazo-compounds are formed :— 
C,H,.NH,NO,H + NO,H = C,H,;.N, -NO; +- 2H,0. — 


Aniline Nitrate. Disuobensake Nitrate. 


If, however, we act on the free amido-derivatives, in alcoholic or 
ethereal solution, diazo-amido-compounds result :— 


2C,H,.NH, + NO,H = C,H,.N,.NH.C,H, + 2H,0. 


Dise- awiide Ssubene. 


The diazo compounds are produced at first, but they then com- 
bine with a second molecule of the free base and form diazo-amido- 
derivatives (p. 631) :— 


C,H,.N,.NO, + C,H,.NH, = C,H;,.N,.NH.C,H, + NO,H. 


Instead of using free nitrous acid (its vapors) with amido-salts, we can obtain 
the diazo-derivatives more easily and in purer form, by dissolving the amido-com- 
pounds in two equivalents of dilute nitric or sulphuric acid, and then adding an 
a amount of potassium or sodium nitrite to the solution (Berichte, 8, 
1073) :— 


C,H,.NH,.NO,H + NO,H + NO,K =C,H,.N,.NO, + 2H,O + NO,K. 


630 ORGANIC CHEMISTRY. 


To obtain the diazoamido-compounds add amy] nitrite or ethyl nitrite (1 mole- 
cule) to the ethereal solution of the amido-derivative (2 molecules) and allow the 
latter to evaporate over sulphuric acid (22d) :— 


2C,H,.NH,. + C,H,.0.NO.= C,H,.N,.NH.C,H, + H,O + C,H,.OH. 


They are more easily prepared by adding the aqueous solution of NO,K and 
KOH (1 molecule each) to the aqueous solution of the HCl-anilines (2 mole- 
cules) :— 
2C,H,.NH,.HCl + NO,K + KOH = C,H,.N,.NH.C,H, + 2KCl + 3H,0. 
It is frequently recommended to substitute sodium acetate for alkalies (Berichie, 
17,641). In this case the reaction proceeds so that the diazo-compound is formed 
by NO,K and 1 molecule of C,H,.NH,.HCl, and this immediately combines 
with the aniline liberated by the KOH and forms the diazo-amido-product (see 
amido-azo-benzene). All the above reactions must be executed in the cold. 
Nitrous acid converts the secondary aniline bases into the same diazo-com- 
pounds, the alkyl group disappearing as alcohol: — 


C,H,.NH(C,H,).NO,H + NO,H = C,H,.N,.NO, + H,O + C,H,.0H; 


whereas nitroso-compounds result if potassium nitrite be employed (p. 600). 
Further action of nitrous acid on the dissolved diazoamido-derivatives trans- 
forms them into diazo-compounds, and the latter, finally, by action of water, into 
phenols. 
Another procedure, occasionally applicable in diazotizing, consists in letting 
zinc dust and hydrochloric acid act upon the nitrate of the diazo-derivative 
(Méhlau) :— ; 


C,H,.NH,.NO,H + Zn + 3HCl = C,H,.N,Cl + ZnCl, + 3H,0. 


P. Griess first discovered the diazo-compounds early in the '60’s ; 
their constitution was explained by Kekulé. They all contain the 
diazo-group of two nitrogen atoms, which on the one side replaces 
an atom of hydrogen in benzene, and on the other is attached to a 
monovalent group, as seen in the following formulas :— 


Diazobenzene nitrate, C,H,.N=N.O.NO, 

$i, sulphate, . C,H;.N=N.O.SO,H 

M4 chloride, C.H;.N=NCl 
Potassium diazobenzene, C,H,;.N—N.OK 
Silver S C,H,.N=N.OAg 
Diazo-amidobenzene, C,H ,-N=N.NH.C, Hy 


Diazo-benzene sulphonate, C,H,;.N=N.SO,H. . 


_ The structure of the diazo-compounds is now fully proved by the. existence of 

the so-called tetrabrombenzene-diazosulphonic acid, CeBYC 58 = (Berichte, 9, 
2 

1537), and also by their relations to the hydrazines (Anma/en, 190, 100). . 


Free diazo-benzene has not been as yet prepared pure, nor ana- 
lyzed ; it, however, corresponds to the formula, C,H;.N=-N.OH. 
The diazo-chlorides form double salts with auric and platinic 
chlorides, e.g. :— 3 j 


C,H,.N,Cl.AuCl, (CH,.N,Cl),.PtCl,. 


DIAZOAMIDO-COMPOUNDS. 631 


The diazobromides also combine with two additional atoms of 
bromine, yielding perbromides :— 


C,H,.N,Br.Br,, Diazobenzene Perbromide. 


Potassium sulphite converts the sulphates into dazosulphonic 
acts :— 


C,H,.N,.SO,H + SO,K, = C,H,.N,.S0,K + SO,KH. 


These pass into hydrazines when reduced. 

The Diazoamido-compounds are also produced by the direct 
action of salts of the diazo-derivatives upon primary and secondary 
anilines (Berichte, 14, 2448) :— 


C,H,.N,.NO, + rk NH, = C,H,;.N,.NH.C,H, + Cun .NH,.HNO,, 


c 
C,H,.N,.NO, + 208 Hs NH = C,H, NiNC Ci 54 ils NH.NO,H; 


also :— 
C,H,.N,.0K + C,H,.NH,.HCI — C,H,.N,.NH.C,H, + KCl + H,0. 


This explains their formation by the action of nitrous acid upon 
the free amido-compounds (p. 630). See p. 638 for the constitu- 
tion of the diazo-amido-compounds of substituted anilines. 


They can also be obtained: wy the action of the nitroso-amines upon the primary 
amido- bodies :-— 


(C,H,),N.NO + NH,.C,H, = (C,H,),.N.N:N.C,H, + H,0. 


It is not only with the primary and secondary anilines, but also with the primary 
and secondary (not tertiary) amines of the fatty series, with which the diazo-com- 
pounds are capable of combining, thus forming mixed diazoamido compounds, 


e. Lo i— 
C,H,-.N,.NH.C,H, and C,H,.N,.N(CH,),. 


When sodium alcoholate and alkyl iodides act upon the diazo- 
amido derivatives the hydrogen of the NH-group is easily replaced 
by the alkyls. An excess of cold hydrochloric acid will reduce 
the resulting diazo-alkylamido-compounds into diazochlorides and 
alkyl anilines :— 

C,H,.N,.N(CH,).C,H, + HCl = C,H,N,cl + NHZ CMs | 
\C,H 

This is a proof of the accepted constitution of the diazoamido 

derivatives (Berichte, 19, 2034, 3239). 





The salts of the diazo-compounds are mostly crystalline, color- 
less bodies, which speedily brown on exposure to the air. They are 
readily soluble in water, slightly in alcohol, and are precipitated 


632 ORGANIC CHEMISTRY. 


from the latter solution by ether. They are generally very un- 
stable, and decompose with a violent explosion when they are 
heated, or struck a blow. 


The diazo-salts are first obtained in solution, from which it is rather trouble- 
some to get them in a solid form (p. 636). They can be obtained as solids by 
applying the aniline salts in alcoholic solution and acting upon the same with amyl 
nitrite (Berichte, 23, 2995). 


The diazo-derivatives are very reactive, and enter numerous, 
readily occurring reactions, in which nitrogen is liberated, and the 
diazo-group in the benzene nucleus directly replaced by halogens, 
hydrogen, hydroxyl, and other groups. 

(1) When the salts (sulphates are best) are boiled with water, the 
diazo-group is replaced by hydroxyl and phenols are produced :— 


C,H,-N,.NO, +, H,O = C,H,.0H + N, + NO,H, 
C,H,.N,.Br + H,O = C,H,.0H + N, + HBr, 


Mononitrophenols result upon digesting in the warm with 1 molecule of nitric 
acid (Berichte, 18, 1338). See Berichte, 20, 1137, for abnormal transpositions. 

The substitution of the diazo-group by the sulphydrate group (SH) occurs upon 
digesting diazo-benzenesulphonic acid with alcoholic potassium sulphide (Berichte, 
20, 350) :— 


N ose ae 
CoH $8,» +K,S=C.H,.C 86 x + Ne 


In the same manner, when mercaptan acts upon diazobenzenesulphonic acid, 
a compound results, which, upon standing or warming, liberates N,, and is trans- 
posed into the ethyl sulphid-derivative (Berichte, 17, 2075) :— 


VE SGA i ce ASG 
ys sONa = sHa\ sone Te 


(2) If alcohol be employed instead of water, then hydrogen will 
enter for the diazo-group, and hydrocarbons result. The alcohol 
is oxidized to aldehyde :— 


C.H,.N,.HSO, + C,H,O= C,H, + N, + S0,H, + C,H,O. 


Instead of first converting the amido- into the diazo-compounds, we can directly 
substitute H for NH,, by adding their compounds to alcohol saturated with N,O, 
(ethyl nitrite), and then applying heat. In this way diazo-derivatives appear at 
first, but they are at once decomposed by the alcohol. Sometimes it is advisable to 
dissolve the amido-derivatives in a little concentrated sulphuric acid, lead nitrous 
acid into the solution, and then decompose with alcohol (Berichte, 9, 899). It 
has occurred upon boiling with alcohol that the diazo-group was not replaced by 
hydrogen but by oxy-ethyl (O.C,H,); this was the case in slight degree with 
aniline and toluidine (Berichte, 17, 1917 ; 18, 65). If the dry diazo salt be de- 
composed with alcohol, phenol ethers are the chief products (Berichée, 21, Ref. . 
96; 22, Ref. 657). 

The replacement of the diazo-group by hydrogen is sometimes effected by its 
conversion into the hydrazine derivative and then boiling this with copper sul- 


- DIAZO-COMPOUNDS. 633 


phate or ferric chloride (see phenyl hydrazine). The reaction taking place on 
boiling the diazo-chlorides with a stannous chloride solution, is, in all probability, 
dependent upon the intermediate formation of hydrazines(Berichée, 17, Ref. 741) : 


C,H, (C,H,).N,Cl + SnGl, + H,O = C,H,(C,H,) + N, + SnOCl, + HCl. 


An analogous procedure for the replacement of the diazo-group by hydrogen con- 
sists in dissolving the diazo-compound in caustic soda and adding a solution of 
stannous oxide in sodium hydroxide (Berichte, 22, 587). 


(3) Chlorbenzenes are formed, if the PtCl,-double salts (p. 630) 
are heated alone, or, what is better, with dry soda or salt :— 


(C,H,.N,Cl),.PtCl, = 2C,H,Cl + N, + 2Cl, + Pt. 


When the diazo-perbromides are subjected to dry distillation, or 
boiled with alcohol (the latter is oxidized to aldehyde), bromben- 
zenes are formed :— 

C,H,.N,.Br, = C,H,Br + N, + Br,. 
On digesting the diazo-salts with hydriodic acid, iodobenzenes 
separate :— 
C,H,.N,.SO,H + HI = C,H,I + N, + SO,H,. 


HBr and HCI react similarly, providing the diazo-compounds contain additional 
negative groups (Berichze, 8, 1428, and 13, 964). : 

The diazo-group in the three diazocinnamic acids can be replaced by chlorine 
on boiling with concentrated HCl-acid (Berichte, 16, 2036). 

The dry sulphates of the diazo-benzoic acids deport themselves in a similar 
manner when heated with the concentrated haloid acids (Aerichée, 18, 961). 

In addition to phenols, large quantities of chlor- and brom-benzenes are pro- 
duced on boiling the benzene diazochlorides with hydrochloric or hydrobromic 
acid (Berichte, 18, 337, 1936). 


(4) Remarkable transpositions of the diazo salts have been effected 
through the agency of cuprous compounds (Reactions of Sandmeyer), 

Chlorbenzenes result upon heating diazo-chlorides, in aqueous 
solution, with a solution of cuprous chloride. At first compounds, 
containing cuprous chloride, are produced (Berichte, 19, 810), but 
these rapidly undergo further decomposition :— 


C,H,.N,Cl.Cu,Cl, = C,H,Cl + N, + Cu,Cl,. 


The yield is greater, if the solution of the diazo-chloride be allowed to gradually 
run into the boiling HCl-solution of cuprous chloride (Berichte, 17,1633; 23, 
1880). Or cuprous chloride is added to the HCl-solution of the amide, the liquid 
then heated to boiling, and sodium nitrite added (Berichte, 17, 2651). In this 
way amidophenols yield chlorphenols, and phenylenediamines yield dichlorben- 
zenes. By adding potassium bromide, the diazo-group is replaced by bromine and 
bromphenols are formed. Sandmeyer’s method is especially adapted for the for- _ 
mation of chlorine and bromine derivatives. The fluorine and iodine derivatives 
are better prepared from diazo-amido compounds (Berichte, 21, Ref. 97). 


53 ' 


O34 ORGANIC CHEMISTRY. 


The diazo-group can be replaced by the nitro-group, forming 
nitro-benzenes. ‘This may be accomplished by adding the diazo- 
benzene nitrite solution to freshly precipitated cuprous oxide (Be- 
richte, 20, 14953; 23, 1630) :— 


C,H,.N,.NO, = C,H,(NO,) + N,. 


If copper sulphate be mixed with potassium cyanide, and the di- 
- azochloride solution added to it, the diazo-group will be displaced 
by the cyanogen group and nitriles will result :— 


C,H,;.N,Cl + CNK =C,H,;.CN + N, + KCl. 
; ae Y/NH, .- 
Thus the three isomeric nitroanilines, C,H «NO 2, yield three nitrocyanides, 
2 


CHC No, , which can be further converted into the three nitrobenzoic acids, 


C,H,(NO,).CO,H. Likewise, the three amido-benzoic acids, C,H Cnet” H, 


can be transformed into the three phthalic acids, C,H,(CO,H), (Berichée, 18, 
1492). Thus aniline yields nitrobenzene (Berichte, 20, 1495). 

Sulphocyanides (Rhodanides) result when the diazo-salts are boiled with potas- 
sium and cuprous sulphocyanides (Berichée, 23, 738, 770) :— 


C,H,.N,Cl + CN.SK = C,H,.SCN + N, + KCL. 


A modification in Sandmeyer’s method, which frequently is of 
practical advantage, consists in using reduced copper, as a substitute 
for cuprous chloride (Gattermann, Berichte, 23, 1219; compare 
Berichte, 23, 1881). In this way it is also possible to introduce the 
group N:CO thus forming phenylsocyanates, if a potassium cyanate 
solution and copper powder be added to the diazo-salt (Berichie, 
a3, 2223) °-— 

C,H;.N,Cl + CNOK =C,H,.N:CO + N, + KCl. 

If copper powder or zinc dust acts upon diazo-benzene sulphate diphenyl results 

(Berichte, 23, 1227). Upon boiling diazo-benzene sulphonic acids with copper 


powder and formic acid hydrogen replaces the diazo-group and benzene sulphonic 
acids are formed (Berichte, 23, 1632). 


The diazo-amido-compounds, e. g., CsH;.N,.NH.C,H;, diazo- 
amidobenzenes, are generally yellow-colored, neutral bodies which 
do not combine with acids. ‘They are insoluble in water, but dis- 
solve in alcohol, ether and benzene. As a general thing they are 
more stable than the diazo-compounds, and do not often change 
color on exposure to air; yet they undergo reactions analogous to 
those of the diazo-derivatives. In so doing they are resolved into 
their components: the amido-compound breaks off, while the 
diazo-group sustains the corresponding transformation :— 


CgH,.N,.NH.C oHiy + @HBr = CoH Br +N, + C,H,.NH,.HBr, 
C,H,.N,.NH.C,H, + H,O = C,H s-OH + N, + C,H,.NH,. 


DIAZO-COMPOUNDS. 635 


Phenol and aniline are also produced by boiling with concentrated hydrochloric. 
acid. By using cold, concentrated hydrochloric acid the immediate action is the 
decomposition into diazo-chloride and aniline. The reaction is especially adapted 
to the formation of fluorine derivatives (p. 583). 


Nitrous acid converts the amido- into the diazo-group :— 
C,H,-.N,.NH.C,H, + NO,H + 2NO,H = 2C,H,.N,.NO, + 2H,0. 


On boiling the alcoholic solution with sulphurous acid, the diazo- 
group is replaced by the sulpho-group, with formation of benzene- 
sulphonic acids (Berichte, 9, 1715) :— 


C,H,-N,.NH.C,H, + 2S0,H, = C,H,.SO,H + N, + NH.,.C,H,.SO,H,. 


The diazo-derivatives of the substituted amides react similarly. 
Therefore the conversion through the diazo- or diazoamido-com- 
pounds is an excellent means of transforming amido-derivatives 
(and also nitro-) into the corresponding halogen- and oxy-com- 
pounds. Thus, we successively obtain from the three isomeric 
nitranilines the following derivatives belonging to the three 
series :— 


NO NO NO NO 
CoHa{ NEF CHiN g C.Hid Be 2 or CoH. { On" and 


NH N,.X Br OH 
C.Hy{ 5, 2 CoHy 4 3: CoHa{ Br or CeH{ Or 





Conversion of Diazo- into Azo0-Compounds.—Besides the changes 
described the diazo-compounds exhibit other noteworthy reactions. 
While they form diazo-amido-derivatives with primary and second- 
ary anilines (p. 631), they yield amido-azo-derivatives with tertiary 
anilines (p. 642), as the diazo-group encroaches upon a new ben- 
zene nucleus :— 


C,H,.N,.NO, + C,H,.N(CH,), — C,H,.N,.C,H,.N(CH,), + NO,H. 
Dimethylamido-azobenzene, 

They act in the same manner on the phenols, the phenolsulphonic 
acids and phenylenediamines, C,H,(NH,),, of the meta-series, pro- 
ducing various classes of coloring substances (the chrysoidines and 
tropzolines), which belong to the group of azo-compounds (p. 640). . 

In an analogous manner, the diazo-amido compounds are trans- 
posed into azo-derivatives by simply standing, or through the action 
of anilines (p. 642) :— 


C,H,.N,.NH.C,H, yields C,H,.N,.C,H,.NH,. 


Diazoamido-benzene, Amido-azo-benzene, 


636 _ ORGANIC CHEMISTRY. 


* For the relations of the diazo- to the hydrazine derivatives, see 
latter. 


Reactions of the Diazo-Compounds.—All, even the diazo-amido-compounds, 
give intense colorations (reaction of Liebermann), if added to a mixture of phenol 
and concentrated sulphuric acid. The nitroso-compounds (and also the nitrites) 
do the same. When an alcoholic solution of meta-diamido-benzene (or other 
meta-diamido derivatives) is added to a similar solution of the diazo-derivatives, 
red or brown colorations result; the diazoamido-bodies react under these condi- 
tions only after the addition of acetic acid (Berichte, 9, 1309). The resulting 
azo-derivatives belong to the chrysoidines (p. 643). 


Diazobenzene Nitrate, C,H;.N,.NO,, is formed by the action 
of nitrous acid upon an aqueous or alcoholic solution of aniline 
nitrate, or upon an ethereal solution of diazo-amidobenzene (in 
presence of nitric acid). 


Preparation.—Pour a little water over the aniline nitrate. Cool the flask with 
ice from the outside and conduct in nitrous acid (from As,O, and HNO,, specific 
gravity 1.35 (see Berichte, 18, Ref. 116) until all the substance has dissolved and 
potassium hydroxide, added to a small portion of the mixture, does not separate 
aniline. The dark solution is then filtered and alcohol and ether added, when 
diazobenzene nitrate is precipitated as a crystalline mass. Or, potassium nitrite 
may be allowed to act upon aniline nitrate (p. 629). The solid salt is more easily 
obtained by using alcohol and amyl nitrite (p. 632). 


Diazobenzene nitrate forms long, colorless needles, and when 
dry is rather stable. It browns in moist air and decomposes rapidly. 
When heated it explodes with violence. 


Diazobenzene sulphate, C,H,;.N,.SO,H, is similarly obtained from aniline sul- 
phate. It is advisable to add sulphuric acid (diluted with 2 volumes of water), 
alcohol (3 volumes) and then ether to the solution of diazobenzene nitrate. The 
sulphate then separates out at the bottom of the aqueous solution. After a second 
treatment with alcohol and ether, and evaporation under an air pump, it can be 
obtained crystalline. It consists of colorless needles or prisms, which dissolve 
readily in water. It explodes at 100°. It is, perhaps, also better in this case to 
use alcohol and amy] nitrite for the precipitation of the salt (p. 632). 

Diazobenzene Sulphonic Acid, C,H;.N,.SO,H. Its potassium salt is obtained 
by adding diazobenzene nitrate to a cold, neutral or feebly alkaline solution of 
potassium sulphite. The liquid solidifies to a crystalline mass of C,H,;.N,.SO;K 
(Annalen, 190, 73). Acid potassium sulphite forms potassium benzene-hydra- 
zine-sulphonate, C,H,.N,.H,.SO, 

Diazobenzene Bromide, C,H,.N,Br, separates in white laminz, if bromine be 
added to the ethereal solution of diazo-amido-benzene. Tribrom-aniline remains 
‘in solution. Ether precipitates the bromide from its alcoholic solution. 

Diazobenzene Perbromide, C,H,.N,Br,, is precipitated from the aqueous solu- 
tion of diazobenzene nitrate or sulphate, by bromine in HBr-acid or NaBr. It 
is a dark-brown oil, which quickly becomes crystalline. It is insoluble in water 
_ and ether, and crystallizes from cold alcohol in yellow laminz. Continued wash- 
ing with ether converts it into the diazo-bromide. 

The Platinum Double Salt, (C,H,.N,Cl),.PtCl, is precipitated in yellow 


DIAZO-AMIDO-BENZENE. ‘639 


prisms on adding a hydrochloric acid solution of PtCl, to the solution of the 
nitrate or sulphate. It is slightly soluble in water, and deflagrates when heated. 

Potassium Diazobenzene, C,H;.N,.OK, is separated, as a yellow liquid, from 
diazobenzene nitrate, by concentrated caustic potash. It crystallizes when evapo- 
rated on the water-bath, forming white, pearly leaflets, which readily dissolve in 
water and alcohol; the aqueous solution decomposes quickly. 

Silver Diazobenzene, C,H;.N,.OAg, is precipitated as a gray compound from 
the potassium salt by silver nitrate. It explodes very violently. 

The compounds with mercury, lead, zinc, and other metals, are formed in a 
similar manner. 

Acetic acid liberates diazobenzene (p. 630) from the potassium salt in the form 
of a heavy oil. It decomposes at once. 


Diazo-amido-benzene, C,H;.N,.NH.C,H; (p.- 634), is ob- 
tained by the action of nitrous acid on the alcoholic solution of 
aniline ; by mixing diazobenzene nitrate with aniline, and by pour- 
ing a slightly alkaline sodium nitrite solution upon aniline hydro- 
chloride (p. 630). 


Dissolve aniline in alcohol (6-10 volumes), cool and conduct nitrous acid into 
the solution until a portion crystallizes on evaporation. The solution is then 
poured into water. A dark oil separates and soon becomes crystalline. It is 
washed out with cold, and then crystallized from hot alcohol. 

Another method consists in adding sodium-nitrite (1 molegule), and then sodium- 
acetate (Berichte, 17, 641; 20, 1581) to the hydrochloric acid (3 molecules) solu- 
tion of aniline (2 molecules), Caustic soda forms amido-azobenzene at once. Or 
dissolve 50 parts of aniline in 15 parts of fuming sulphuric acid and 1500 parts of 
water. To this solution add sodium nitrite, when the temperature of the liquid is 
25-30° (Berichte, 19, 1953). 


Diazo-amidobenzene consists of golden-yellow, shining laminz 
or prisms. It is insoluble in water, sparingly soluble in cold, but 
readily in hot alcohol, ether and benzene. It melts at 98°, and 
then explodes. 


It does not combine with acids, although it forms a double salt (C,,H,,N3. 
HCl),.PtCl,, with hydrochloric acid and PtCl,. It crystallizes in reddish needles. 
When the alcoholic solution is mixed with silver nitraté, the compound, C,H;. 
N,NAg.C,H,, separates in reddish needles, 

When the alcoholic solution stands, especially in the presence of a little aniline- 
hydrochloride, the diazo-amidobenzene sustains an interesting transposition, result- 
ing in the production of amido-azobenzene (p. 641). 

Substituted anilines, e. ¢.,C,H,Br.NH,, act with nitrous acid just the same as 
aniline. ‘They yield perfectly analogous diazo compounds. 

Free diazo-chlor- and diazo-brom-benzene, C,H,Br.N,.OH (p. 630), are crys- 
talline compounds. They have not been analyzed because of their instability. . 
Higher substituted anilines, such as trinitro-aniline, C,H,(NO,),.NH,, cannot: 
form diazo-derivatives. 

The aniline homologues, toluidine, xylidine, yield perfectly analogous diazo- and 
diazo-amido-compounds with perfectly similar properties. Thus, thethree toluidines 
(ortho-, meta- and para-) yield ¢hvee corresponding isomeric diazotoluidines :-— 


C,H,(CH,)NH, give C,H,(CH,).N,X. 


638 ORGANIC CHEMISTRY. 


The para-variety of the three diazo-amido toluenes, C,H ,(CH,).N,.N.C,H,. 
CH,, is alone stable. The ortho- and meta-forms (from ortho- and meta-toluidine) 
immediately pass into amido-azo-derivatives, 

It is strange that the mixed diazo-amido-compounds, which, according to their 
mode of formation, should be different, are in fact identical. Thus, diazo-benzene- 
amido-brom-benzene, C,H,.N,.NH.C,H,Br, from diazobenzene and brom-ani- 
line, is identical with diazobrombenzene-amidobenzene, C,H,Br.N,.NH.C,H,, 
from diazobrombenzene and aniline. The following are also identical :— 


C,H,.N,.NH.C,H,.CH, and  (CH,)C,H,.N,.NH.C,H,. 


: Diazobenzene-amidotoluene. Diazotoluene-amidobenzene. 
C,H,.N,.NH.C,H,.CO,H and (CO,H)C,H,.N,.NH.C,H,. 
Diazo-benzene-amidobenzoic — Diazobenzoic acid-amido 
Acid. . benzene. 


This anomalous behavior can probably be accounted for by assuming that the 
isomeric formulas are tautomeric, the hydrogen atom oscillating from the imide- to 
the diazo-group (p. 54). Another conception allows but ove of the formulas to the 
two compounds; according to this, the diazo-group and the amido-group transpose 
themselves, the former always, however, entering the para-position (Berichte, 19, 


3239) :-— 
C,H,.N,.NH.C,H,.CH, yields | C,H,.NH.N,.C,H,.CH,. 


I, 4). : 1, 4). 
Diazobenzene-g-amido- Amidobenzene-J-diazo- 
toluene. toluene. 


Experiments instituf@l to settle this question, have given contradictory results 
(Berichte, 20, 3004; 21, 1020). The results with phenyl-cyanate are probably 
more correct (p.613). This reagent combines with the diazo-amido compounds, 
and yields diazo-benzene-diphenyl ureas :— 


Sa RE 
C,H,.N,.NH.C,H, + CO:N.C,H, = CoH.NLNC CO NLC, Hy 
Diazobenzene-diphenyl Urea. 


The latter decompose into diazobenzene (its decomposition products) and di- 
phenyl ureas :— 


Oe eae a /NH.C,H 
CoH Na NC C8 Niz.c,H, + HO = CoH OH + N, + COC NTT CH’. 


The mixed diazo-amido compounds react similarly. The product obtained by 
the action of diazobenzene upon paratoluidine, and g-diazotoluene upon aniline, 
yields with phenylcyanate a compound that, on decomposing, forms phenyl-tolyl- 
urea. It is, therefore, diazobenzene-amido-toluene, C,H,.N,.NH.C,H,. The de- 
composition of its phenylcyanate may be expressed as follows :— 


JC, ae /NH.C,H, 
CHSNINC CO. Nic, H, + HhO = CoH OH +N, + COC NH CTH”. 
Diazobenzene-tolyl-phenyl Urea, ~ Pheny!-tolyl Urea. 


Other mixed diazo-amido-derivatives behave similarly. They are distinct bodies ; 
in their formation a transposition occurs, in that the cmide group attaches itself to 
the more negative radical (Goldschmidt, Berichte, 21, 1016; 22, 2578). 

On mixing diazo-benzene salts with primary and secondary amines, the products 
are mixed diazo-amido compounds containing radicals of the paraffin series. 

Diazobenzene-ethylamine, C,H,.N,.NH.C,H,, and Diazobenzene-dime- 
thylamine, C,H,.N,.N(CH,),, are yellow oils, that form very unstable salts with 
acids. : 


DIAZO-AMIDO-BENZENE. 639 


Bis-diazo-amido-derivatives are obtained by further action of diazobenzene salts 
upon the compounds with primary amines, ¢. g., (C,H,.N,).N.CHsg, bis-diazo-ben- 
zene-methylamine ( Berichte, 22, 942). 

Bisdiazo-compounds (p. 626) are formed from the diamines of the para- and 
meta-series :— j. 


CHCNH? yield CHR ect 
Para- and Meta. p- and m-Bisdiazo- 
chlorides. 


These are also termed /e¢razo-compounds. The ortho-diamines, on the other hand, 
yield the azimido-derivatives (see below). 





Diazimido- or Triazo—-compounds, C,H,.N,. These are derivatives of azo- 
N 
imide, AN . |}, recently discovered (Berichte, 23, 3023). They are produced : 
N 


(1) By the action of aqueous ammonia upon diazobenzene perbromides :— 
C,H,;.N,.Br, + 4NH,; = C,H,.N,.N + 3NH,Br. 
(2) By the action of hydroxylamine upon diazobenzene sulphate :— 
C,H,.N,.SO,H + NH,OH = C,H,.N, + H,O + SO,H,; 


and most readily and easily by the action of sodium nitrite upon the hydrochloric 
acid solution of phenylhydrazine, when the nitrosophenylhydrazine first produced 
sustains decomposition (Fischer, Azsalen, 190, 92) :— 


NH N 
rai gi NZ H ep 
CoH NC | = CoHANC || + HL0. 


Benzenediazimide. 


Triazobenzenes, like denzene-diazimide or triazo-benzene, C,H,.N,, are yellow 
oils, insoluble in water. Their odor is stupefying. They are volatile in a vacuum 
and in a current of steam. They explode at the ordinary pressure, if heated. They 
are decomposed into N, and chloranilines when boiled with hydrochloric acid (Be- 
richte, 19, 313). 

Substituted diazobenzenes yield analogous triazo-compounds. Thus, nitro-diazo- 


benzene bromide, C,H,(NO,).N,Br, yields amido-triazobenzene, C,H =< ot 
3 


which, by diazotizing, etc., forms Jzstriazobenzene, CHS nN’, or Hexazoben- 


zene. White leaflets, melting at 83°. It explodes violently, if ‘heated to a higher 
temperature (Berichte, 21, 1559). 

Nitrous acid converts hydrazobenzene sulphonic acid into 7Zriazobenzene sul- 
phonic acid ( Berichte, 21, 3409) :— 


/S0,H 


SO,H 
<NiLNH, + HNO, = C,H £20 1 2H.0. - 


4#\N3 


Another peculiar formation is that of the triazo-compounds by the action of diazo- 
salts upon hydrazines (Berichte, 20, 1528; 21, 3415). 


C,H 


640 ’ ORGANIC CHEMISTRY. _ 
‘ 
The <Azimido-compounds are isomeric with the diazimido-derivatives. They 
are produced by the action of nitrous acid upon ortho-phenylene diamines:—- 


MIEN N— 
NE’ 4+ NO,H = CoH wu’ + 2H,0. 


Azimidobenzene. 


C,H 


They behave like secondary bases; their imide hydrogen can be replaced by 
metals, acid radicals and alkyls. The alkyl derivatives can combine further with 
alkyl iodides and yield ammonium compounds (Zincke, Berichte, 22, Ref. 139; 
23, Ref. 105). 

Azimido benzene, C,H,4:N3H, isomeric with diazimido- or triazo-benzene, C, H;. 
N,, forms white needles, melting at 98.5°. 

Pseudo-azimides are intimately related to the azimido-derivatives. They are 
formed by oxidizing the ortho-amido-azo-compounds with chromic acid (Berichie, 
23, 106, 1315, 1844) :— 


NH N 
CH. FLD ts CHS | >N.C,H,. + H,0. 
‘N:N.C,H, N 
o-Amido-azo-toluene. Pseudoazimido-toluene. 


Benzoylazimide, C,H ;.CO.N, (Triazobenzoyl), is formed by.the action of ni- 
trous acid upon benzoyl hydrazine, C,H,.CO.NH.NH,. When decomposed, it 
yields benzoic acid and the remarkable compound known as 

Azoimide, HN:N,, Mydrazoic Acid. This is perfectly analogous to the haloid 
acids. It conducts itself similarly (Curtius, Berichte, 23, 3023). 





7 


. AZO-COMPOUNDS. \ 


Like the diazo-derivatives, these contain a group, consisting. of 
two nitrogen atoms; in the former the N,-group is combined with 
only one benzene nucleus; here it is attached on either side to 
benzene nuclei :— 

C,H,N,X. Cc 


; ott 5tNg. eg 
Diazo-compounds, Azo-compounds. 


In consequence, they are far more stable than the former, and do 
not react with the elimination of nitrogen. They are classified as 
azoxy-, azo-, and hydrazo-compounds. ‘They constitute, as it were, 
a transition from the nitro- to the amido-derivatives :— 


C,H,.N, C,H,.N 
C,H,.NO,. SO 


Nitrobenzene. C,H,.N”~ C,4,N 
; Azoxybenzene. Azobenzene. 
C,H,.NH 
C,H,.NH,. 
C,H,.NH Amidobenzene. 
Hydrazobenzene. 


AZO-COMPOUNDS. 641 


They are obtained according to the following methods :— 

1. By reduction of the nitro-compounds in adkafine solution. 
Amido-derivatives are formed in acid solutions. By moderated 
reduction with an alcoholic potassium hydroxide solution (Zinin), 
or zinc dust and ammonia, azoxy-compounds are produced at first 
(the alcohol is oxidized to aldehyde) :— 


2C,H,.NO, = (C.H;),N,0 + 30. 


Stronger reducing agents (sodium amalgam in alcoholic solution, 
zinc dust with sodium hydroxide) immediately form the azo- and /y- 
drazo-derivatives. In many cases the action of SnCl, in equivalent 
quantity, dissolved in NaOH (2 molecules SnCl, for 1 molecule of 
the nitro-compound), is well adapted for the preparation of the 
azo-compounds (Witt, Berichte, 18, 2912). (All the nitrobenzene 
compounds, excepting nitronaphthalene, react similarly). 


2. By the oxidation of the primary amido-derivatives in alkaline solution with 
potassium permanganate or potassium ferricyanide (BerichZe, 9, 2098). Energetic 
reducing agents convert all the azo-derivatives into amido-bodies (p. 645). 

3. By the action of sodium or potassium upon primary amido-compounds. 
Sodium amido-derivatives result and the oxygen of the air oxidizes them to azo- 
derivatives (Berichte, 10, 1802) :— 


2C,H,.NHK + 0, = (C,H,;),N, + 2KOH. 


Similarly, bromaniline yields azobenzene, as the bromine is reduced by the 
nascent hydrogen. The action of C,H;.NCl, upon aniline produces azobenzene 
(Berichte, 16, 1048). 

4. By the action of the nitroso-compounds upon the primary amines (see 
Nitrosophenol) :— 


C,H,.NH, + ON.C,H,OH = C,H,.N:N.C,H,.OH + H,0. 


Reducing agents (H,S) also further change the azoxy- to azo- and 
hydrazo-compounds; conversely, when the hydrazo- are oxidized 
(even in the air) they become azo-compounds. 

The azoxy- and azo-derivatives are solids with a yellow to brown 
color, and do not unite with acids; the hydrazo-bodies are color- 
less and when in alcoholic solution, are easily changed by acids to 
isomeric diamido-diphenyls. By the action of stannous chloride 
and a slight quantity of sulphuric acid upon the alcoholic solu- 
tion of the azo-bodies, the latter can be directly converted into 
benzidines (Berichte, 19, 2970). Because of their stability, the 
azo-compounds can be directly chlorinated, nitrated and sulpho- 
nated. 

On reducing the nitro-azo-derivatives, we obtain the amido-azo 
compounds :— 

C,H,.N,.C,H,.NO, yields C,H;-.N,-C, H,.NH,. 
Nitro-azobenzene. Amido-azobenzene, 


54 


642 ORGANIC CHEMISTRY. 


These are also obtained from the diazo-compounds by peculiar 
reactions :— 
(1) By direct transposition of the diazoamido-compounds (p. 
Bg5) | 
C,H;.N,.NH.C,H,; forms C,H,.N,.C,H,.NH,. 


Diazoamidobenzene. Amido-azobenzene. 


In the case of diazoamido-benzene, this transposition occurs on 
standing with alcohol, but more readily by the action of a slight 
quantity of aniline hydrochloride (Berichte, 19, Ref. 24). 


The group NH.C,H, is eliminated from the diazo-compound, and the diazo- 
group, N,, attaches itself to the benzene nucleus of the aniline :— 


C,H,.N,.NH.C,H, + C,H,;.NH,= C,H,.N,-C,H,.NH, + C,H,.NH,. 
a ae b a 


As aniline is regenerated here, a very slight quantity of it suffices to transform 
the diazo- into the azo-compound. That the reaction indeed occurs as indicated, 
is verified by the knowledge that other (homologous) amido-compounds act simi- 
larly upon the diazo-amido-derivatives. ‘Thus we obtain azo-derivatives from diazo- 
amido-toluene, by the action of the salts of meta- and ortho-toluidine (Aerichée, 
10, 664 and 1156) :— 


/CH cH ZC: — cy ~ Os Fa, » | 
CoH.< WN, .NH.C,H, CH, * ~® 4\NH, > 98 4N,.C,H, NH 
Para. Para. Ortho or meta. Para. Ortho or meta. 


+ NH,-C,H,.CH,. 
Para. 


This would go to prove that the reaction only occurs readily, if in the reacting 
amido-compound the position in the benzene nucleus adjacent to the amido group 
in the para place be unoccupied; the diazo group, N,, then arranges itself in the 
para-position referred to the NH, of the amido-compound. 

This explains, too, why only diazoamido compounds are obtained from para- 
toluidine by nitrous acid, whereas the ortho- and meta-toluidines (in which the 
para-position is free) immediately yield the amido-azo. derivatives (p. 638), because 
the diazoamido-bodies first produced can immediately transpose themselves. It 
was formerly thought, that in the production of azoamido-compounds, the diazo- 
group could invariably only enter the Aara-position (referred to the amido-group. ) 
This, however, occurs only with special ease in alcoholic solution. On heating 
diazoamido-paratoluene, dissolved in fused paratoluidine, to 65° with paratoluidine 
hydrochloride, a transposition will also take place with formation of ortho amido-azo- 
toluene, C,H,(CH;).N,.C,H,(CH,).NH, (melting at 118°), as the diazo-group 
enters the ovtho-position (referred to amido group) (Berichte, 17, 77). The diazo 
compounds behave in a similar manner with phenols (p. 643). 

Diazobenzene-ethylamine and dimethylamine (p. 638) react like the diazo-amido- 
compounds with aniline hydrochloride, the alkylamines breaking off at the same 
time :— 


C,H,.N,.N(CH,), + C,H,.NH, = C,H,.N,.C,H,.NH, + NH(CH,),. 


(2) By the action of the diazo-compounds upon the tertiary ani- 


~ AZO-COMPOUNDS. 643 


lines (diazoamido-derivatives first result from the primary and sec- 
ondary anilines, p. 635) :— 


C,H,.N,.NO, + C,H,.N(CH,), = CeH,-N2.CgH,N(CH,), + NO,H. 


In this reaction also, the N,-group enters the position Jara with reference to 
the amido-group, and therefore dimethyl paratoluidine does not react (Berichte, 
10, 526). Paradiazobenzene sulphonic acid acts directly on the HCl-anilines, 
‘forming sulpho-acids of the amidoazo-compounds (BerichZe, 15, 2184). 


(3) By the action of the diazo-compounds upon the diamido- 
derivatives of the meta-series (p. 636), those of the ortho- and para- 
places not reacting (Berichte, 10, 389 and 654) :— 


NH,(! NH,(! 
C,H;.N,-NO, + CHA NHS) is CoH Ng-Cols CN + NO,H, 


The resulting compounds are dyestuffs, called chrysoidines (p. 648), 
varying in color from orange to brown. - 


The most recent research would seem to indicate that the amido-azo-compounds 
of the ortho-series are quinone-derivatives (similar to the so-called nitrosophenols), 
and, indeed, hydrazones of guinon-imides. It is probably an instance of tauto- 
merism of formulas (Berichte, 23, 497) :-— 

NH 
NH ZNH od 
CH ohana or C,H,¢ | 

\.N,.C,H s* *N.NH.C A - 
N,.C,H; S oH, \N.NH.C,H, 


o-Amido-azobenzene. o-Quinon-imide-phenyl-hydrazone. 


Arguments favoring this view, are the production of pseudo-azimides by the oxi- 
dation of the 0-amido-azo-benzenes (p. 640) and the reduction of the o-diazo-azo- 
benzenes to diazo-hydrides (Berichie, 20, 1176). 

Probably, also, the oxy-azo-compounds of the ortho-series should be regarded as 
hydrazones of the quinones (Berichte, 22, 3234; 23, 487) :— 


OH seh ZO 
CoH nc, ~ ©oH4Qn.NECH, 
o-Oxy-azobenzene. Quinone-phenyl Hydrazone. 





The diazo-derivatives react analogously with the phenols, forming 
oxyazo-compounds. With the monovalent phenols we have :— 


C,H,.N,.NO, + C,H,.OH = C,H,.N,.C,H,OH + HNO,; 
with the divalent phenols of the meta series (as resorcinol) :— 


OH H 
C,H,.N,.NO, + CHK OH = Cos Ns GH Oy 4. HNO,;- 


(1, 3). (x, 3). 
and with phenol-sulphonic acids and amidophenols of the meta 
serles :— 


C,H,-N,.NO, + C,H,¢ OH 


ne /OH 
K§0,H = Coe Ns CH so, + HNO. 


644 ORGANIC CHEMISTRY: 


They are also produced on heating the diazo-amido-benzenes with 
phenols, and with resorcinol (Berichte, 20, 372, 904. and 1577; 21, 
T1112) :— 


C,H,;.N,.NH.C,H, +. CH,.OH = C,H,.N,.C,H,.OH + C,H,.NH,. 


Or, by the molecular rearrangement induced by heating azoxyben- 
zenes with sulphuric acid (see oxy-azo-benzene, p. 646) :— 


C,H;.N 
| SO yields ‘C,H, .N,.C,H, OH. 

C,H,.N7% 

Azoxy-benzene. Oxy-azo-benzene, 


The sulpho-acids of the azo-compounds (see above) can also be 
prepared by heating the latter with concentrated or fuming sul- 
_ phuric acid (by directly su/phonating them—see benzene sulphonic 
acid). An easier course consists in letting diazo compounds act 
upon phenol sulphonic or amido-sulphonic acids, or conversely by 
combining diazobenzene sulphonic acids and amines or phenols :— 


N N,.C,H,.0OH 
Re ab: 4+ C,H,;0H = CHK 56 on 
Diazobenzene Sul- Phenol. Oxy-azobenzene Sulphonic 
phonic Acid. Acid. 


These oxyazo- and amido-azo-sulphonic acids are called ¢ropco- 
lines; many of them are applied as dyestuffs. 


* The diazo-compounds act on the phenols in aqueous solution, but more readily 
when alkali is present (diazobenzene sulphate forms only phenyl ether or phenyl 
oxide, (C,H;),0, with aqueous phenol). Ordinarily the phenol derivative is dis- 
solved in dilute alkalies and the aqueous diazo-chloride added. Occasionally it is 
advisable to apply sodium acetate instead of caustic alkalies (Berichte, 17, 641). 
Variations occur in the reaction sometimes, attributable to the quantity of alkali, 
whether it be in excess or in equivalent amount (Berichte, 17, 878). In the case 
of diazo-compounds and mono- and di-valent phenols two isomeric products, a 
and £, may arise—products soluble and insoluble in alkali (Berichte, 17, 877), 
(see Dibenzene-disazoresorcinol, p. 647). 

As in the amido-compounds, so in the phenols, the entering diazo-group prefers 
and assumes the para position with reference to the hydroxyl group (p. 642); in 
the divalent phenols, like resorcinol, it takes the para-position referred to the ove 
hydroxyl. When the y-position is occupied the diazo-group can assume the ortho- 
position, ¢. g., in f-cresol, Z- phenolsulphonic acid and £-naphthol (Berichie, 17, 
876; 21, Ref. 814). 


The amido-azo- and oxy-azo-compounds are yellow to brown in 
color, readily soluble in alcohol, and usually crystalline. The salts 
with acids and alkalies constitute what are known technically as azo- 
dyestuffs (p. 650). While the colored azo-compounds (having the 
‘chromophorus atomic group N=N) are not themselves dyes, they 
do acquire, by the entrance of the chromogenic, salt-forming groups 
OH and NH,, the character of dyestuffs (Witt, Berichte, 9, 552). 
They are decolorized by reducing agents (tin and hydrochloric 


AZOXYBENZENE, ; 645 


acid, zinc chloride, boiling with zinc dust, or upon digestion with 
ammonium sulphide), taking up four hydrogen atoms and being 
resolved into two amido-compounds. The azo-group, N=N, de- 
composes, each nitrogen atom remaining attached as NH, to a 
benzene nucleus :— | 


C,H,-N,.C,H,NH, + 2H, = C,H,.NH, + C,H,(NH,),: 


Thus, #-oxy-azobenzene is resolved into aniline and /-amido- 
phenol. This reaction, therefore, may serve for the determination 
of the constitution of azo-compounds (Berichte, 21, 3471). Such 
a decomposition occasionally takes place by heating with hydro- 
chloric acid, indulines being simultaneously produced (Bevichie, 17, 
395). Consult Berichte, 15, 2812, upon the nomenclature of the 
azo-derivatives, ‘ 


Nitrous acid converts the amido-azo-derivatives (like the amido-derivatives) into 
diazo-, ¢. g., C,H;.N,.C,H,.N.Cl, azobenzene diazochloride, which, like simple 
diazo- and amido- “derivatives, act on the phenols, forming so- called ¢etrazo-com- 
pounds, é. g.:— 


C,H,-N,.C,H,.N,.C,H,.OH. C,H,.N,-C,H,.N,.C,H,(OH),. 


a diilalaeha dai: COA g Azobenzene-azo-resorcinol. 


Such compounds can also be obtained by a second introduction of two molecules 
of a diazo-compound into phenols (resorcinol), and are also called diazo-deriva- 
tives -— 


c ts Ne Ce H,(OH), = C,H,.N,.C,H,(OH),.N,.C,H,. 
*Di enzene-diazo- Benzene-azo-resorcinol-azo-benzene, 
Resorcinol, 


Analogous compounds are also obtained from the anilines, and are called azotriple 
bases ( Berichte, 16, 2028). 

Another course, that may be pursued - in obtaining the tetrazo-derivatives, em- 
ploys the phenylene-diamines, C,H,(NH,.),, as points of departure, converting 
one and then the other amido- into a diazo group, and finally combining the pro- 
duct with phenols. Violet and blue azo-derivatives { Berichze, 17, 344, 13503 21, 
Ref, 268) are produced in this manner. 

The tetrazo-compounds from benzidine and tolidine are especially important 


(p. 652). 





Azoxybenzene, (C,H;).N,O, Azoxybenzide, is obtained by 
the reduction of nitrobenzene, or by the oxidation of amido-ben- 
zene (p. 641), the first being the preferable method. 


Add 30 parts of pure nitrobenzene to a solution of 10 parts sodium in 250 parts 
methyl alcohol and boil for five or six hours, employing a return condenser. The 
unused methyl alcohol is distilled off and the residue washed with water ( Berichée, 
15, 866, 1515). Or, 1 part of nitrobenzene is added to the boiling solution of 1 
part KOH and 9 parts alcohol. 


646 ORGANIC CHEMISTRY. 


Azoxybenzene forms long, yellow needles, easily soluble in alco- 
hol and ether, but not in water. It melts at 36°, and decomposes 
into azobenzene and aniline when distilled. It is converted into 
oxyazobenzene by digestion with sulphuric acid. 


m-Dinitroazoxybenzene, (NO,)C,H,.N,0.C,H,(NO,), is produced when 
sodium methylate acts upon m-dinitrobenzene, C,H,(NO,),. It melts at 141° 
(Berichte, 18, 2551). m-Diamidoazoxybenzene, (NH,)C,H,.N,0.C,H,.NH,, 
azoxyaniline, is obtained by the reduction of -nitraniline with zinc dust and 
caustic soda (Berichte, 21, Ref. 766). The nitration of azoxybenzene produces 
two ¢rinitroazoxybenzenes, which form trinitro-azobenzenes by partial reduction 
(Berichte, 23, Ref. 104). 


Azobenzene, (C,H;),N,, Azobenzide, is formed by the action 
of sodium amalgam upon the alcoholic solution of nitrobenzene, 
and by boiling nitrobenzene with alcoholic potash. 


A simpler procedure is to distil azoxybenzene with iron filings, or to reduce 
nitrobenzene with zinc dust and caustic potash (Anmalen, 207, 329). Or, nitro- 
benzene is added to a solution of stannous chloride (calculated amount) in sodium 
hydroxide (p. 641). 


Azobenzene forms orange-red, rhombic crystals, readily soluble 
in alcohol and ether, but sparingly soluble in water. It melts at 
68°, and distils at 293°; its vapor density confirms the molecular 
formula, C,,H,N,. It is converted into benzidine by tin and 
hydrochloric acid. When it is heated with ammonium bisulphite 
and alcohol under pressure benzidine*sulphaminic acid, NH,.C,H,. 
C,H,.NH.SO;H (p. 650) results (Berichte, 18, 1481). 


The nitration of azobenzene produces p-Witro-azo-benzene, C,H,.N,.C, Hy. 
(NO,), melting at 137°; by reduction this yields 4-amido-azo-benzene (p. 647). 
The nitration of the glacial acetic acid solution yields 0-ztro-azo-benzene, melting 
at 127° (Berichte, 18, 2157; Ref. 441). Energetic nitration gives rise to various 
dinitro- and trinitro-azo-benzenes (2b7@). 

p-Dinitroazobenzene, NO,.C,H,.N,-C,H,.NO,, melts at 206°, and is reduced 
by ammonium sulphide to a -diamido-azo- benzene (p. 648) and to diphenine (p. 
650). m-Dinitroazobenzene is an oil; ammonium sulphide changes it to m- 
diamido-azo-benzene (Berichte, 18, Ref. 627); when this decomposes m-pheny- 
lene diamine results. 

A dinitro-azobenzene, melting at 117°, has been obtained by the oxidation of 
dinitrohydrazobenzene (Berichte, 21, Ref. 400; 22, Ref. 744). 

Trinitroazobenzenes, C, »H,(NO,),N, have ‘been prepared by the partial reduc- 
tion of the two tri-nitro-azoxybenzenes. 

_ Nitrolic Acids, of unknown constitution, were formed in the reduction of 
nitrazobenzenes with ammonium sulphide in the presence of caustic potash (Ze- 
richte, 18, 1136; Ref. 628). 

p- -Oxyazobenzene, C,H,.N,.C,H,(OH), Benzeneazophenol, is obtained on 
digesting diazobenzene nitrate with barium carbonate ; by mixing the former with 
a solution of sodium phenol; by the action of para- ’ nitrosophenol upon aniline 
acetate (p. 641), and by the action of concentrated sulphuric acid upon azoxy- 


AMIDO-AZO-BENZENE. 647 


benzene (Berichte, 14, 2617), as well as by heating together phenol and diazoamido- 
benzene. It crystallizes in orange-yellow needles, and melts at 148°. 

Those oxyazo-compounds, containing a hydroxyl group in the ortho-position, 
with reference to the azo-group, are very probably quino-hydrazones. CS,, on 
application of heat causes them to decompose, thus forming carbamido-thiophenols 
(Berichte, 22, 3233). + 

Dioxyazobenzenes: /-Azophenol, C,H,(OH).N,.C,H,(OH), results: by 
fusing para-, nitro- and nitroso-phenol with caustic potash ; by the union of diazo- 
phenol nitrate with phenol, and from para-oxyazobenzene sulphonic acid ( Berichte, 
15, 3037). It consists of light brown crystals, and melts at 204°. Benzene-azo- 
resorcinol, C,H,.N,.C,H,(OH),, is produced by adding diazobenzene nitrate 
or chloride to resorcinol in aqueous or alkaline solution. It forms red needles, 
melts at 168°, and dissolves with a yellowish-red color in alkalies. Drbenzene- 
diazo-resorcinol (y, insoluble in alkalies) forms at the same time; it results from 
the decomposition of diamido-resorcinol (Berichte, 17, 880). 

The further action of a second molecule of diazobenzene chloride upon benzene- 
azo-resorcinol in alkaline solution, produces two isomeric Dibenzene-disazo- 

; CA .Wa’. 
resorcinols, 5° 3 
CH Ne 
ble in aqueous alkalies, forms red needles, melts at 214°, and dissolves in H,SO, 
with a red color. The -compound is insoluble in alkalies and dissolves in H,SO, 
with a dark blue color ( Berichte, 15, 2816; 17, 880). 

Compounds soluble and insoluble in alkalies are almost invariably produced by 
the union of diazo-derivatives with phenols. In the insoluble ones the N,-group 
seems almost always to occupy the ortho-position as compared with hydroxyl 
( Berichte, 16, 2862). 

The azobenzene-azo-resorcinols, C,H;.N,.C,H,.N,.C,H,(OH),, are iso- 
meric with the benzene-disazo-resorcinols. They form in the action of the diazo- 
chloride of amidoazo-benzene, C,H;.N,.C;H,.NH,, upon resorcinol (Berichte, 
15, 2817) (compare p. 645). 


C,H,(OH),, @and 8. The a-compound is easily solu- 





p-Amido-azo-benzene, C,H;.N,.C,H,.NH,, is obtained in the 
reduction of nitro-azo-benzene with ammonium sulphide, and by 
the molecular transposition of isomeric diazo-amido-benzene (p. 
642). 


It is best prepared by the action of a mixture of potassium nitrite (I molecule) 
and caustic potash upon aniline hydrochloride (2 molecules); the diazo-amido- 
benzene first produced in the cold is transposed by digestion into amido-azo-ben- 
zene (p. 642). 

Or, freshly prepared, moist diazo-amido-benzene is dissolved in 2~3 parts ani- 
line, #1; part aniline hydrochloride added, and the whole digested at 40° for an 
hour, and then allowed tostand 24 hours, by which time the conversion into amido- 
azo-benzene will be fully ended (Berichte, 19, 1953; 21, 1633). 

Aniline hydrochloride (1 molecule) can be dissolved in aniline (5—6 molecules), 
and mixed at 30-40° with a concentrated solution of sodium nitrite (a little less 
than one molecule) and digested from 1-2 hours at a temperature of 40°, when it 
is finally allowed to stand undisturbed for 12 hours. The addition of an excess of 
hydrochloric acid will cause a complete precipitation of the hydrochloride of amido- 
azo-benzene (7d7a). 


It crystallizes from alcohol in yellow needles or prisms, melts at 
123°, and boils above 360°. It forms crystalline salts with one 


648 ORGANIC CHEMISTRY. 


equivalent of acid ; these are yellow and violet colored, and impart 
an intense yellow to silk and wool. The HCl-salt crystallizes from 
hydrochloric acid in blue needles or scales. MnO, and sulphuric 
acid oxidize it to quinone. It is decomposed into para-diamido- 
benzene and aniline by tin.and hydrochloric acid, digestion with 
ammonium sulphide, or boiling with hydrochloric acid (p. 645). 


Commercial Aniline Yellow consists usually of amido-azo-benzene oxalate. The 
so-called Acid Yellow or Pure Yellow is a mixture of amido-azo-benzene sulphonic 
acids, and is prepared by the action of sulphuric acid on the amido azo-compound, 
or by converting sulphanilic acid, C,H,(SO,.H).NH,, into the diazo-compound, 
and then treating with aniline (Berichde, 22, 850). 

Phenyl-f-amido—azo-benzene, C,H,.N,.C,H,.NH.C,H,, is isomeric with 
induline. It is produced from diazobenzene chloride and diphenylamine. Itcon- 
sists of golden-yellow leaflets, melting at 82°. Its sulphonic acid is tropzeoline OO 

p- 651). 

{ tndutines are obtained on heating #-amido-azo-benzene or other f-amido-azo- 
derivatives with aniline hydrochlorides, whereas the o-amido-azo-compounds yield 
the eurhodines ( Berichte, 19, 441). 

Nitrous acid converts HCl-amido-azobenzene into the diazo-chloride, C,H;. 
N,.C,H,.N,Cl; the diazo-group in this can be replaced by copper sulphate and 
potassium cyanide. The resulting azo-benzene cyanide, C,H;.N,.C,H;.CN, 
melts at 10° and is changed to azobenzene carboxylic acid, C,H;.N,.C,H,.CO,H 
(Berichte, 19, 3023), by boiling alkalies. 

The disazo- or tetrazo-anilines, or phenols, result from the action of azo- 
benzene diazo-chloride, C,H;.N,.C,H,;.N,Cl, upon anilines and phenols. Disazo- 
benzene, C,H,.N,.C,H,.N,.C,H,, the basis of these derivatives, has been ob- 
tained from its amido-compound. It is very similar to azo-benzene, and melts at 
98° (Berichte, 21, 2145). 


Diamido-azo-benzene, C,,H,.N, = C,H;.N,.C,H;(NH.)., 
Benzene-azo-phenylene-diamine, is produced by the action of diazo- 
benzene-nitrate upon meta-phenylene-diamine (p. 643), and con- 
sists of yellow needles, melting at 117°. Its hydrochloric acid salt 
occurs in trade under the name chrysoidine, and dyes orange-red. 
Reduction changes it to aniline and unsymmetrical triamido-ben- 
zene, C,H;(NH,)s. 


Symmetrical #-Diamido-azo-benzene, H,N.C,H,.N,.C,H,.NH,, has been 
prepared by reducing nitroacetanilide, NO,.C,H,.NH.C,H,O, with zinc dust and 
alkali; also, from diazo-phenylene diamine, etc. (Berichte, 18, 1145), and by the 
reduction of f-dinitroazobenzene (see above) (Berichte, 18, Ref. 628). It crys- 
tallizes from alcohol in yellow needles, melting at 235°. 

Its tetra-alkylic derivatives are the so-called Azy/imes. They are formed when 
nitric oxide acts upon the tertiary anilines (dialkylanilines) (Berichze, 16, 2768) :— 


2C,H;.NR, yield R,N.C,H,.N,.C,H,.R,N, 
and in the action of the diazo-compounds of dimethyl-s-phenylene diamine (p. 625) 
upon tertiary anilines (Berichte, 18, 1143) :— 
(CH,),N.C,H,.N,Cl + C,H;N(CH,), = 
(CH,),N.C,H,.N,.C,H,N(CH;), + HCl. 


HYDRAZO-BENZENE. 649 


The azylines are red, basic dyes, which dissolve in hydrochloric acid with a 
purple-red and in acetic acid with an emerald-green color. By reduction (stan- 
nous chloride, tin and hydrochloric acid) they yield two molecules of dialkylic 
p-phenylene-diamine. They are decomposed when heated to 100° with alkyl 
iodides (4 molecules); the products in this case are tetra-alkylic para-pheny- 
lene-diamines. 


Triamido-azo-benzene, C,,H,,N,; = HjN.GHN,-GH,< Na?» is 


formed when nitrous acid acts upon metaphenylene-diamine, C,H,(NH,),. At 
first, by transformation of an amido-group, we obtain a diazo-compound, which 
further reacts on a second molecule of the diamine. It forms salts with one, two 
and three equivalents of the acids; of these the diacid are the most stable, 
while water decomposes the triacid. Its hydrochloric acid salt is commercial 
Phenylene Brown (Manchester-brown, Bismarck-brown), which is applied in dye- 
ing cotton and coloring leather. 





Azotoluenes, CH,.C,H,.N,.C,H,.CHsg. 

These are obtained, like azobenzene, from the three nitrotoluenes by the action 
of sodium amalgam or zinc dust in alkaline solution. Ovtho- and meta-azo- 
toluene form red crystals; the first melting at 137° and the latter at 55°. ara- 
azotoluene crystallizes in golden yellow needles, melting at 143°. 

The action of sodium methylate upon para-nitrotoluene produces diamidostil- 
bene, C,H,(NH,).CH:CH.C,H,(NH,) (Berichfe, 19, 3237). 

Of the three diazoamidotoluenes, C,H,.CH,.N,.NH.C,H,(CH,), the ortho- and 
meta- rearrange themselves into the corresponding amidoazotoluenes while the 
para-derivative remains unaltered (see p. 642). The azo-group takes up the para 
position with reference to the amido-group :— 


CH,.C,H,NH, yields CH,.C,H,.N,.C,H,.(CH,)NH,. 
1) 


o-Toluidine. i (1 > 3) 4- ) 
CH,.C,H,.NH, yields. CH, Ge Hy.Np.CjHy-(CH,).NH,. 
m-Toluidine, (1, 2, 4.) 


Amidoazotoluene, from o-toluidine, forms ne leaflets. It melts at 100°, 
Amidoazotoluene, from m-toluidine, melts at 80°. In paratoluidine the para- 
position is occupied; the azo-group therefore takes up the or¢ho-position with 
reference to the amido group. The resulting ortho-amidoazotoluene, with the 
amido- and azo-groups, in the ortho-position, melts at 118°. 

Ortho-amidoazo-derivatives like these exhibit a varying deportment. Chromic 
acid oxidizes them to pseudoazo-imido compounds, and when heated with aniline 
they yield exrhodines. 

See Berichte, 23, 1738 for azoxytoluenes. 


Hydrazo- benzene, C,,.H,.N, = C,H;.NH.NH.C,H; (p. 640), 
is obtained by the action of H,S and ammonia upon the alcoholic 
solution of azo-benzene, or by boiling the latter with zinc dust and 
alcohol. It is readily soluble in alcohol and ether, crystallizes in 
colorless plates, has an odor resembling that of camphor, melts at 
131°, and further decomposes into azo-benzene and aniline. When 
its alcoholic solution is exposed to the air it oxidizes to azo-ben- 
zene. Hydrazobenzene (like phenylhydrazine) unites with alde- 
hydes on heating, to form compounds known as hydrazoines. 


650 ORGANIC CHEMISTRY. 


The benzaldehyde derivative, Benzhydrazoine, ah on: hal N. CoH, 

a N.C FE; 

melts at 55° (Berichte, 19, 2239). It also unites with acetoacetic 

ester and acetone-dicarboxylic esters, forming pyrazole derivatives. 

It does not form salts with acids, but concentrated mineral acids 

occasion in it an interesting transposition, resulting in the appear- 
ance of the isomeric, basic denzidine (diamido-diphenyl) :— 


C,H,.NH.NH.C,H, forms NH,.C,H,.C,H,.NH,. 


Derivatives of benzidine are produced when it is heated with organic acids 
(Berichte, 17, 1181). In benzidine the. union of the benzene groups occurs in 
the two para-positions. With benzidine (especially in the warm) there is also 
produced isomeric o-g-diamido-diphenyl, C,H,.NH,(1, 4) 

CLF. ir (T, 2) 
Other hydrazo-compounds are similarly converted into diphenyl derivatives, but 
usually these are only such that have the para-positions, with reference to the 
imide groups, free. Thus, o- and m-hydrazotoluene yield the corresponding toli- 


dines (diamidoditolyl derivatives) :— ’ 
CH,.C,H,.NH CH CAN, 
yield , 
CH,.C,H,.NH CH, C,H,.NA. 
Ortho and meta. Tolidine. 


while / hydrazotoluene is decomposed by strong acids. The para-azo-compounds, 
however, can also be directly changed to diphenyl derivatives by the action of 
stannous chloride and sulphuric acid ( Berichte, 17, 463; 19, 2970). 

Dinitrohydrazo-benzenes, C,H,(NO,),.NH.NH.C,H,. Two isomerides 
have been obtained by acting upon dinitrochlorbenzene with phenylhydrazine 
(Berichte, 21, Ref. 571). 

p-Diamidohydrazobenzene, C,H,(NH,).NH.NH.C,H,(NH,) =C,,H,,N,, 
formerly called adiphenine, results from the action of ammonium sulphide upon 
para-dinitro-azo-benzene (Berichte, 18, 1136). It consists of yellow crystals, 
melts at 145°, and yields red colored salts with acids. Heated with ammonium 
sulphide it breaks up into 2 molecules of meta-diphenylene-diamine, AHydrazo- 
benzene-disulphonic Acid, C,,H, .N,.(SO,H),., has been obtained by the reduc- 
tion of m-nitrobenzene sulphonic acid. Hydrochloric acid converts it into ben- 
zidine disulphonic acid (Berichte, 21, Ref. 323; 23, 1053). 





Hydrazotoluenes, CH,.C,H,.NH.NH.C,H,.CHs. 

The three derivatives of this class are prepared from three azotoluenes (p. 649) 
by the action of sodium amalgam, or by heating with ammonium sulphide. The 
ortho-compound melts at 165°; the meéa is liquid, and the Jara consists of 
large plates, melting at 124°. : 

Ortho- and meta-hydrazotoluene are readily changed by mineral acids into the 
isomeric tolidines, NH ,.C,H,.C,H,.NHy. 





Azo-dyes. 

Below are mentioned some of the innumerable, complicated azo- 
compounds, which are applied technically as dyes. They are either 
azo-amido-derivatives (azo-bases) which form salts with acids, or 


AZO-DYES. 651 


azo-phenol-compounds (azo-acids) (p. 644), yielding salts with 
bases. ‘These salts represent the commercial dyes. In many cases 
the sulphonic acids of the azo-bases and azo-acids (the ¢ropeolines, 
p. 644) are better adapted for the purpose, as their alkali salts are 
very stable, and usually afford dyes which dissolve readily in water. 


The azo-dyes are made soluble by forming their alkaline bisulphite derivatives, 
which are soluble in water. These are prepared by heating the azo-compounds 
with sodium or potassium bisulphite in aqueous or alcoholic solution. On heating 
these combinations with steam or dilute alkalies they split up into their compounds 
and upon this behavior is based their application as colors for mordanted materials 
(Berichte, 18, 1479). 


Arbitrary names are assigned these dyes, with the addition of the 
letters Y (yellow), O (orange), and R (red), whose number approxi- 
mately expresses the intensity of the color. They color wool and 
silk directly, cotton after it has been mordanted. Recently violet 
and blue azo-dyes have been successfully prepared (mainly tetra- 
azo-compounds, p. 645). 


Tropzoline, O or R (Chrysoine, resorcin-yellow), C,H,(SO,H).N,.C,H,(OH),, 
Resorcin-azo-benzene sulphonic acid, is obtained from para-diazo-benzene sulphonic 
acid and resorcinol (Berichte, 11, 2195) 

Tropzoline, OO (Orange IV), C,H,(SO,H).N,.C,H,.NH.C,H,., Diphenyl- 
amine-azo-benzene sulphonic acid, is obtained from diazobenzene sulphonic acid 
and diphenylamine in alcoholic solution. It is used as an indicator in alkalimetry 
( Berichte, 16, 1989). By decomposition it yields sulphanilic acid, C,H,(NH,). 
SO,H, and amido-diphenylamine (p. 603). 

Helianthine, Methyl Orange (Oteibe III), C,H,(SO,H).N,.C,H,.N(CHg)., ° 
Dimethylaniline-azo-benzene-sul phonic acid, is formed from diazobenzene sulphonic 
acid and dimethyl aniline (Berichte 10, 528). Consult Berichte, 17, 1490, for 
another method of preparation. This and the analogous ethyl orange (from 
diethy! aniline) serve as delicate indicators in alkalimetry; mineral acids convert 
the alkaline orange-colored solution into a rose-red. CO,, H,S and acetic acid do 
not act on it in the cold (Chem. Zeit., V1, 1249; Berichte, 18, 3290). In decom- 
position helianthine yields sulphanilic acid and para-amido-dimethy] aniline (p. 
601). Monomethyl- and Mono-ethyl Orange, C,5H,(SO,H).N,.C,H,.NH(C,H;), 
are similarly prepared by the action of diazo-benzene- sulphonic acid 1 upon eane 
and ethyl-aniline. By its decomposition methyl- and ethyl-g-phenylene diamine, 
H,N.C,H,.NH.CH, (Berichte, 20, 924), are produced. 

The azo-dyes obtained from the naphthalene derivatives, are of great value. 

Tropzoline OOO, No. I (Orange I), is formed from diazobenzene sulphonic 
acid and a-naphthol. If $-naphthol, in alkaline solution, be used, then the pro- 
duct will be S-naphthol-azo-benzene sulphonic acid, CyH,(OH).N,.CgH,.SO, H. 
Its sodium salt is the B-naphthol orange (Orange II) of trade. 

Various Ponceaus and Bordeaus (R, RR, G,GG, etc.) are obtained by means 
of #-naphthol disulphonic acids from diazo- xylidines and diazo-@umidines (p. 
624). Biebrich Scarlets are obtained from the sulphonic acids of amido-azo- 
benzene, C,H;.N,.C,H,.NH, (the chlorides) with $-naphthol. They are tetrazo- - 
compounds ( Berichte, 73, 1838). Crocein Scarlet (Berichte, 15, 1352), from 
8-naphthol sulphonic acid, is also of importance. 


652 ! ORGANIC CHEMISTRY. 


Fast Brown is a disazo- or tetrazo-compound. It is the disulphonic acid ot 
a-naphthol disazobenzene, which may be prepared by the union of two molecules 
of diazo-sulphanilic acid with a-naphthol (Berichie, 21, 3241). 

Diazo-naphthalene sulphonic acid and #-naphthol combine and produce /- 
Naphtholazonaphthalene sulphonic acid, C,jH,(OH).N,.C,,H,.SO,H. The sodium 
salt of the latter is fast red or rocellin, which serves as a substitute for archil or 
cochineal. 

Thetetrazo-dyes, derived from denzidine and tolidine, are especially important, 
as they color unmordanted cotton, and the product is not affected by soap. Congo 
red, chrysamine, azo-blue, benz-azurine, Congo yellow, etc., are of this class (see 
Benzidine). 

Mixed Azo compounds. 

In this class the azo-group is linked to a benzene nucleus, and to a paraffin 
residue. 

Azo-phenyl-methyl, C,H,.N,.CH,, Benzene azomethane, is made by oxi- 
dizing a-methylphenyl hydrazine (p. 657) with mercuric oxide. It is a yellow, 
volatile oil, with a peculiar odor. It boils at 150°. Sodium amalgam reduces it 
to a-methylphenyl hydrazine (Berichte, 18, 1742). Azo-phenyl-ethyl, C,H,. 
N,.C,H,, has been similarly prepared from a-ethyl-phenyl-hydrazine. It closely 
resembles the methyl compound. It melts about 180°. 

Azo-phenyl-nitroethyl, C,H,.N,.CH(NO,).CH,, Benzene-azo-nitro— 
ethane, is obtained by the action of diazobenzene nitrate, C,H,.N,.NO,, upon 
sodium nitroethane. It crystallizes in orange colored laminz, melting at 137°. 
It behaves like an acid, dissolving in alkalies with a blood-red color, and forming 
basic salts, containing two equivalents of the bases (Berichte, 8, 1076; 9, 384). 

Compounds, regarded as mixed azo-derivatives, have been similarly prepared 
by the interaction of benzene-diazo-salts and various fatty bodies. However, a 
transposition occurs when they are produced and hydrazones result (p. 656) (see 
Japp, Annalen, 247, 190; Berichte, 21, Ref. 725; V. Meyer, Berichte, 21, 11). 

Thus, when benzene diazo-salts act upon malonic ester, the product is not the 
expected denzene-azo-malonic acid, but its isomeride, phenyl hydrazon-mesoxalic 
acid :-— 


C,H;.N,-CH(CO,H), becomes C,H,.NH.N:C(CO,H),, 


ripeness ePmalonic- Acid. Phenyl-hydrazon-mesoxalic Acid. 


as it is also formed by the action of phenyl-hydrazine upon mesoxalic acid (p. 434). 
Similarly, diazo-benzene chloride and aceto-acetic ester do not produce denzene- 
. az0-acetic ester, but the hydrazone of aceto-glyoxylic ester ( Berichte, 20, 2121): 


/CO.CH, 


C,H,.N:N.cH¢ £O-CHs becomes CoH. NELN:CC Co. RS 


\CO,R 


Benzene-diazo chloride acts upon benzoyl-acetic ester in the same manner. Ben- 
zene-azo-acetone, C,H,;.N,.CH,.CO.CH, (Berichte, 17, 2415), resulting from 
the decomposition of the ester that i is formed, is the hydrazone of pyro-racemic 
aldehyde, C, H,.NH.N:CH.CO.CH, (p. 323). 

Benzene diazo-salts displace the acetyl group of mono-alkylic aceto-acetic esters. 
In doing this, they do not form the denzene-azo-fatty acids, but the hydrazones of 

a-ketonic acids (Berichte, 20, 3398) :— 


CH CH 
CoH,.N,. CH Cop becomes C.H,.NH.NiCC C8. 


Benzene-azo-propionic Acid. Hydrazon-pyro-racemic Acid. 


HYDRAZINE COMPOUNDS, 653 


When the benzene-diazo-salts act upon the free alkyl-aceto-acetic esters, carbon 

dioxide is evolved, and hydrazones of o-diketones result (Berichte, 21, 549) :-— 

Pg dk i . mR -/ CH, 

<C0;H += C.H,.NH.N: CX Co. CH, + HCl. 
Diacetyl- hydraoie. 


C,H,.N,Cl + CH(CH,) 


However, in other cases, the action of the benzene-diazo-salts proceeds in the 
normal way. Rearrangements do not occur, and mixed azo-compounds are produced 
(Berichte, 21, 1697). Acetaldehyde reacts in this manner (p. 323) -— 


C,H,.N,Cl +CH,< CHo * = BT oa: Be Ro cho.” 


Benzene-azo-acetaldehyde. 
also, aceto-acetone, CH,.CO.CH,.CO.CHsg, and dibenzoyl-methane. The mixed 
azo-compounds, obtained from them, dissolve unaltered in alkalies, and being 
8-carbonyl derivatives, unite with phenyl-hydrazine and form hydrazones, which 
lose water and become pyrazole-derivatives (p. 327). Benzene-azo-cyanacetic 
ester, CLH,.N,.CH(CN).CO,R, is thus formed from cyanacetic ester and benzene- 
diazo-chloride (Berichte, 21, Ref. 354). 





HYDRAZINE COMPOUNDS. 


The hydrazines studied by E. Fischer in 1877 (Annalen, 190, 67) 

are intimately related to the diazo-compounds :— 
C,H,.N:N.O.NO,. C,H,.NH.NH,.HNO,. 
Diazobenzene-nitrate. "Hydrestie Nitrate. 
They are derivatives of diamide or hydrazine, H,N.NH,, which 
has only recently been obtained in a free condition (Berichte, 20, 
1632). (p. 166). . They are formed :— 

1. By the action of alkaline sulphites upon the diazo-derivatives. 
On allowing neutral potassium sulphite to act in the cold upon 
diazobenzene nitrate or hydrochloride, the yellow colored potas- 
sium salt of diazobenzene-sulphonic acid will be produced at first 
(p. 636) :— | 

C,H,.N,.NO, + SO,K, = C,H,.N,.SO,K + NO,K; 
but should the primary potassium sulphite act at 20-30°, the diazo- 
sulphonic acid will be further reduced, and colorless potassium ben- 
zene hydrazine-sulphonate will be formed immediately :— 
C,H,.N,.SO,K + H, = C,H,.N,.H,.SO,K. 

The yellow diazosulphonate can be reduced to the hydrazine 
compound by sulphurous acid, or better, with zinc dust and acetic. 
acid. 

When the sulphonate is heated with hydrochloric acid hydrazine 
hydrochloride is produced :— 

C,H,.N,-H,.SO,K + HCl + H,O= C,H,.N,H,.HCl + SO,KH; 
the alkalies separate the free hydrazine, C,H;.N,Hs. 


654 ORGANIC CHEMISTRY. 


Preparation.—In making phenyl hydrazine (benzene hydrazine) dissolve 20 
parts of aniline in 50 parts of hydrochloric acid (sp. gr. 1.19) and 80 parts water, 
and then add the equivalent amount of sodium or potassium nitrite (dissolved in 2 
parts water). The solution contains diazobenzene chloride, C,H,;.N,Cl, and is 
gradually added to a cold solution of sodium sulphite (2 molecules) ; sodium 
phenyl hydrazine sulphonate then separates, but is mixed with the yellow diazo- 
sulphonate, which is completely reduced by digestion with zinc dust (with addi- 
tion of acetic acid). The filtered, colorless solution of the hydrazine-sulphonate 
is boiled with concentrated hydrochloric acid (1% volume), and the hydrazine 
separated by means of caustic soda (Anmalen, 190, 78). A modified method for 
the preparation of phenylhydrazine will be found in the Berichze, 20, 2463. 

The suphazides, e. g., CgxH;.NH.NH.SO,.C,H,, phenyl-benzene sulphaxide, are 
prepared by the action of ‘free sulphurous acid : upon the acid solution of diazoben- 
zene salts, or by the interaction of nitrous acid, and an alcoholic aniline base super- 
saturated with SO, (Berichée, 20, 1238). These are to be regarded as benzene sul- 
phinic acid derivatives (p. 662) of the hydrazines. They are also formed when 
benzene sulphonic acid chloride, CsH,.SO,Cl, and benzene sulphinic acid, C,H,. 
SO,H, act upon phenyl hydrazine (Berichte, 18, 893). Warm alkalies resolve 
the sulphazides into benzene and benzene-sulphinic acid: C,H,.NH.NH.SO,.C, 
H, yields C,H, + N, +C,H,;.SO,H. Mercuric oxide oxidizes phenyl-benzene- 
sulphazide to benzene-sulphin-diazobenzene, C,H,.N,.SO,.C,H,, and conversely 
can be obtained from the latter (from diazobenzene nitrate and sodium benzene 
sulphinide) by reduction with zinc dust. 


2. By the action of stannous chloride and hydrochloric acid upon 
the diazo-chlorides (V. Meyer, Berichte, 16, 2976) :— 


C,H,.N,Cl + 2SnCl, + 4HCl = C,H,.N,H,.HCl + 2SnCl,. 


This procedure affords results which are especially good, if the 
hydrazine chloride (e. g., naphthyl hydrazines) dissolves with diff- 
culty (Berichte, 17, 572).. 


3. By the reduction of diazo-amido-compounds in alcoholic solution with zinc 
dust and acetic acid, when they decompose into anilines and hydrazines :— 


C,H,.N,.NH.C,H, + 2H, = C,H;.N,H, + NH,.C,H,. 


Diaz: ginido- beheene, Phenyl hydrazine. entice, 


4. By the reduction of the nitroso-amines (pp. 164 and 598) with zinc dust 
and acetic acid :— 


C,H,\. C,H;\ 
Ci’ >N.NO + 2H, = Gy DN.NH, + H,0. 
Phenyl-ethyl Nitrosamine. Phenyl-ethy! Hydrazine. 


The benzene hydrazines are very similar to those of the marsh- 
gas series, but are less basic and in consequence are only capable of 
uniting with one equivalent of acids to form salts, Generally they 
are easily fusible and boil with but slight decomposition. 

When boiled with copper sulphate or ferric chloride (Berichte, 
18, 786) the phenylhydrazines throw off nitrogen and become 
benzenes—this reaction will also serve for the replacement of the 


.PHENLYHYDRAZINE, 655 


diazo-group by hydrogen (p. 633). The liberated nitrogen also 
answers for the quantitative estimation of the hydrazines (Berichte, 
18, 3177): 

The hydrogen of the imide group in the phenylhydrazines can 
be replaced by sodium, the nitroso groups by alkyls and acid radi- 
cals; alkyl- and acid derivatives of the NH,-group (see below) are 
also known. 

Phenylhydrazones (p. 656) are produced by the union of the 
phenylhydrazines with aldehydes, ketones, aldehydic and ketonic 
acids. 

Although the hydrazines are very stable in the presence of 
reducing agents, they are readily oxidized and destroyed. They, 
therefore, reduce salts of the heavy metals and precipitate cuprous 
oxide from /eh/ing’s solution ; in this case the primary hydrazines 
and the a-alkyl derivatives react even in the cold. 

The phenyl hydrazines may be readily reconverted into diazo- 
compounds by moderated oxidation ; this is effected by the action 
of mercuric oxide upon their sulphonates :— 


C,H,.NH.NH,.HX + 20 = C,H,.N:N.X + 2H,0. 


Phenylhydrazine, C,H;.NH.NH,, is obtained from benzene 
diazochloride by reduction with sodium sulphite or stannous chlor- 
ide (p. 653). It is a colorless, peculiar-smelling oil, solidifying, 
when cooled, to plate-like crystals, melting at 23°; sp. gr. 1.091 at 
21°. It boils at 241-242° with slight decomposition (Azna/len, 236, 
198). It dissolves with great difficulty in cold water, but readily in 
alcohol and ether. It assumes a light brown color on exposure to 
the air. It serves as an important reagent for the detection of 
aldehydes and ketones (see above) and has been applied in a very 
great number of syntheses (that of antipyrine). 


Nitrous acid converts it into diazobenzene imide. When sodium nitrite acts 
upon HCl-phenylhydrazine in the cold sztroso-phenylhydrazine, C,H,.N(NO). 
NH.,, separates as a yellow-brown oil, solidifying to yellow laminz. Dilute alka- 
lies decompose this compound into water and diazo-benzene-imide. 

Metallic sodium dissolves in phenylhydrazine, forming the sodium derivative, 
C,H,.NNa.NH,. This is a yellowish red, amorphous mass. 

*Alkyls and acid residues can replace the sodium, thus producing (-phenyl- 
hydrazine derivatives (p. 657) (Berichte, 19, 2448; 22, Ref. 604). 

Substituted derivatives may be obtained from the substituted anilines (Berichte, 
22, 14). #-Bromphenylhydrazine, C,H,Br.N,H,, melts at 106° and forms 
hydrazines. o-Nitrophenylhydrazine, i. sH,(NO,). N,H,(1, 2), from o-nitrani- 
line, forms brilliant red needles, melting at 90°. Sodium amalgam reduces its 

N—CH 
formyl compound to Benzotriazine, CHK | (Berichte, 22, 2806). 
N—N 


The sulphonates are formed by the reduction of diazobenzene-sulphonic acids 
with sodium sulphite or stannous chloride (Berichte, 22, Ref. 216), and also by 


656 ORGANIC CHEMISTRY. 


the direct action of. concentrated sulphuric acid upon the phenylhydrazines 
(Berichte, 18, 3172). 

p-Hydrazine-benzenesulphonic Acid, C,H,.(NH.NH,)SO,H, is not read- 
ily soluble in water. It is used in the preparation of tartrazine (p. 492). 

The digestion of phenylhydrazine with K ,S,O,, or the addition of diazobenzene 
nitrate to a solution of potassium bisulphite, gives rise to the potassium salt of 
Benzene-hydrazine Sulphonic Acid, C,H,NH.NH.SO,H. The salt crystal- 
lizes in scales, dissolving in water with difficulty. 


Phenylhydrazones (Bervichie, 21, 984). 

Phenylhydrazones, or hydrazones, are produced by the action 
of phenylhydrazine upon carbonyl compounds, when the amido- 
group reacts with the CO-group :— 3 


C,H;.NH.NH, -+ CHO.CH, = C,H,.NH.N:CH.CH, +.H,0. 
Aldehyde Hydrazone. — 


This is confirmed by the analogous deportment of the §-alkyl phenylhydrazines 
(p. 657) -— 


C,H,.N(CH,).NH, + CO(CH,), = C,H,.N(CH,).N:C(CH,), -+ H,0; 
Acetone-methyl-phenyl Hydrazone. 


as well as by the formation of indol derivatives from the hydrazones, and by the 
behavior of benzal-phenyl hydrazone (Berichie, 20, 2487). 
The reaction proceeds in an aqueous or alcoholic solution (Berichte, 17, 573). 
A solution of 1 part HCl-phenylhydrazine with 11% parts sodium acetate in 8— 
Io parts water, is well adapted as a reagent for the compounds soluble in water. 
The aldoximes and acetoximes, or isonitroso-compounds, react in a similar 
-manner. The phenyl-hydrazine replaces the isonitroso group (Berichte, 19, 
1205) :— 


C,H,.NH.NH, + HO.N:C(CH,), = C,H,.NH.N:C(CH,), + NH,.OH. 


A peculiar formation of hydrazones is that in which benzene diazo-salts act upon 
different CH- and CH,-compounds (p. 652). The a-diketone derivatives yield 
mono- and di-hydrazones; the latter are called osazones (p. 326). The glucoses 
(aldehyde- and ketone-alcohols) deport themselves similarly, as they yield both 
hydrazones and osazones (p. 501). The (£-keto-compounds first form hydrazones 
with one molecule of phenylhydrazine, but by the exit of water, they condense to 
pyrazole- and pyrazolon-derivatives (p. 339). 

The hydrazones are usually crystalline compounds, insoluble in water. They 
are yellow or brown in color, They almost invariably decompose upon fusion, 
hence their melting points are only correct when they are heated rapidly. If di- 
gested with mineral acids they absorb water, more or less readily, and revert to 
their components, Pyroracemic acid brings about the decomposition more easily 
(Berichte, 22, Ref. 674). 

Some hydrazones are decomposed by reduction (sodium amalgam, tin and hydro- 
chloric acid, or sodium and absolute alcohol), when they yield anilines and amido 
acids (see amido-valeric acid, p. 372) (Berichte, 20, 3399). 

Nearly all phenyl hydrazones are condensed, upon heating them with concen- 
trated mineral acids, or zinc chloride, to z#do/ derivatives. Ammonia is expelled. 

The hydrazones have, in most cases, been mentioned in connection with the 
corresponding carbonyl compounds. Those of the aldehydes and ketones of the 
fat series are generally yellow oils (Annalen, 236, 126, 137). 


ALKYLIZED HYDRAZINES. 657 


Ethidene Phenyl-hydrazone, CH,CH:N,H.C,H, (isomeric with benzene- 
azo-ethane), becomes crystalline in the cold. It boils at 250°. Propidene Hy- 
drazone, C,H,.CH:N,H.C,H,, boils undecomposed under diminished pressure. 

Acetone Hydrazone, (CH,),.C:N,H.C,H ,, can also be distilled under dimin- 
ished pressure. 

Pyroracemaldehydrazone, C,H ,.NH.N:CH.CO.CH, (p. 323), formerly con- 
sidered as Benzene-azo-acetone, C,H..N,.CH,.CO.CH, (p. 652), is produced 
by the ketone decomposition of hydrazone-acetoglyoxylic ester, induced upon di- 
gesting it with alkalies (Berichte, 17, 2415). It crystallizes in yellowish-brown 
prisms, melting at 149°. Sodium ethylate and alkyl iodides, or chloracetic ester, 
displace the hydrogen of its imide group (Berichte, 29, 3398). Phenyl hydrazine 
converts it into the osazone of pyroracemic aldehyde, CH,.C(N,H.C,H.).CH(N,H. 
C,H) (p. 323), which can also be obtained from acetol and isonitroso-acetone 
(Berichte, 20, 3399). It does not react with phenyl cyanate (Berichte, 23, 496). 

Pyroracemic-acid Hydrazone, CH,.C(N,H.C,H,).CO,H (p. 332), is identi- 
cal with denzene-azo-propionic acid (p. 652). Sodium amalgam converts it into 
Hydrazido-propionic Acid, C,H »- NH.NH.CHY 66, WT 

Glyoxylic-acid Hydrazone, C,H,.NH.N:CH.CO,H, by reduction yields 
Phenylhydrazido-acetic Acid, C,H,.NH.NH,.CH,.CO,H, which can also be 
prepared by reducing nitroso-phenylglycin, CFH,.N(NO).CH,.CO,H. 





Alkylized Hydrazines :— 


C,H,.NH.NH.CH, and C,H,.N(CH,).NH,. 
a-Methyl-phenyl-hydrazine. g-Methyl- heny|-hydrazine, 


The a-derivatives are termed symmetrical, the B-compounds unsymmetrical alkyl- 
phenylhydrazines. Both isomerides are produced by the action of alkyl bromides 
upon phenylhydrazine (Anna/en, 199, 325; Berichte, 17,2844). The B-class are 
also obtained by the action of ethyl bromide upon sodium phenylhydrazine 
(Berichte, 19, 2420, 22, Ref. 664), and by the reduction of the nitrosamines 
(p. 654). The a-derivatives reduce Fehling’s solution even at the ordinary tem- 
perature (like the primary hydrazines), but the {-class only act in this way after 
warming. By oxidation (chiefly by means of mercuric oxide) the a-deriva- 
tives pass into azo-compounds, like azophenylmethyl, C,H,.N.N.CH, (p. 652), 
which by reduction revert to the original bodies. The §-derivatives, on the con- 
trary, liberate it, and become secondary anilines, or they form the ¢e/razones (see 
below). Nitrous acid causes the 6-compounds to split off the NH, group and yield 
nitrosamines, ¢. g., C,H;.N(NO).CH,. 

a-Methylhydrazine, C,H;.NH.NH(CH),, results upon distilling methyl diben- 
zoylpheny! hydrazine (p. 658) with potash. It is rather unstable. It is easily 
oxidized by mercuric oxide to azophenylethyl (Berichze, 18, 741). 

a-Ethyl-phenyl hydrazine,C,H,.NH.NH(C,H,), is produced when azo- 
phenyl-ethyl is reduced with sodium amalgam (Anna/len, 199, 330). It is a 
colorless oil. Mercuric oxide or nitrous acid will reoxidize it to azophenyl-methy]. 

B-Methyl-phenyl hydrazine, C,H,N(CH,).NH,, and S-Zthyl-phenyl hydrazine 
are obtained by the reduction of nitroso-methyl and nitroso-ethyl aniline by means 
of zinc dust (p. 654) ; the first boils about 227° (Anna/en, 236, 198), the second at 
232° (Berichte, 9, 2450). The ethyl compound unites with ethyl iodide to the 
bromide, C,H>.N(C,H,),Br.NH,, which by reduction yields diethyl-aniline 
(Berichte, 17, 2844). 

a-Allyl-phenyl hydrazine, C,H;,.NH.NH.C,H,, boils at 177° under 110 mm. 
pressure (Berichte, 22, 2233). 


55 : 


658 ORGANIC CHEMISTRY. 


hylene-phenyl hydrazine, C. 2H,(N(NH,). C,H, )., from sodium pheny] hydra- 

oie an Breet oe bromide, melts at 90° (Berichte, 22, Ref. 810 

a-Diphenyl-hydrazine, (CgH;)..N.NH., isomeric with benzene hydrazine from 
nitrosodiphenyl-amine, crystallizes in plates, melting at 34°, and boiling at 220° 
under 50 mm. pressure, or dissolves in sulphuric acid with a dark blue color. 
(Berichte, 22, Ref. 582). It forms rather insoluble diphenyl-hydrazones when 
digested with the glucoses (p. 501). 

Tetrazones. 

These are produced from the 6-alkyl-phenylhydrazines by oxidation with mer- 
curic oxide in alcoholic or ethereal solution, or by means of a dilute ferric chloride 
solution :— 


2C,H,.N(CH,).NH, + 20 = C,H,.N(CH,).N:N.N(CH,).CgH, + 2H,0. 


They are solids which undergo decomposition when fused or boiled with dilute 
acids. 

Dimethyl-diphenyl Tetrazone, CgH,.N(CH,)N,.N(CH,).C,H,, crystallizes 
in leaflets, melting at 133°. The diethyl derivative melts at 108°. The ¢e¢rapheny/ 
compound, from a-diphenylhydrazine, melts at 123°, and is colored blue by con- 
centrated acids. 

Acid Derivatives of Phenylhydrazine, or Hydrazides :— 


C,H,.NH.NH.CO.CH, and C,H,.N(CO.CH,).NH,. 
a-Acetyl Hydrazine. B-Acetyl Hydrazine. 


The a-compounds are obtained by the action of free acids, acid chlorides, acid 
anhydrides and acid esters upon phenylhydrazine. 

Free acids (especially the polyhydric oxy-acids), as well as the lactones, react 
directly upon digesting them in an acetic-acid solution (Berichte, 22, 2728). The 
hydrazides of the monobasic acids are mostly readily soluble in hot water (p. 489), 
but the dihydrazides of the polybasic acids dissolve with difficulty. Boiling alka- 
lies and baryta water decompose them all with the separation of phenylhydrazine. 
The hydrazides are distinguished from the hydrazones by the red-violet color that 
they yield with concentrated sulphuric acid and a little ferric chloride (Reaction 
of Biilow, Annalen, 236,195; Berichte, 23, 3385). 

a-Formyl-hydrazine, C,H,.NH.NH.CHO, melts at 140°; a-acetyl-hydra- 
zine, at 128°. a-Benzoyl- hydrazine melts at 168°; mercuric oxide oxidizes 
it to benzoyl-diazo-benzene, C,H;.N:N.CO.CgH, (Berichte, 19, 1203). Thie 
structure of a-benzoyl hydrazine i is proven by the methy! derivative of benzoyl- and 
dibenzoyl-hydrazine (Berichte, 18, 1739). The B-phenyl hydrazides are formed 
when acid chlorides or anhydrides act upon sodium phenylhydrazine (Berzche, 
22, Ref. 665). $-Benzoyl-hydrazine, C,H,.N(CO.C,H;).NH,, melts at 70°. 

Phosgene converts the a-phenyl hydrazides into carbizine derivatives (Berichie, 

N=CH 
21, 2456). These, probably, contain the “ring-shaped” diazole chain, | >O 
N=CH 
_ (Berichte, 23, 2821). Carbon disulphide produces ¢hio-carbizines, derivatives of 
thio-biazole, C,H,N,S. 

SO, converts phenylhydrazine into hydrazides of sulphurous acid, C,H ,.N 1H. 
SO, and (C,H;.N,H;),SO, (Berichte, 23, 475). 


SULPHO-COMPOUNDS. 659 


Homologous Phenylhydrazines. 

o-Tolyl-hydrazine, C oH,(CHs). NH.NH,, from orthotoluidine, crystallizes in 
shining leaflets melting at 59°. When digested with sulphuric acid, it becomes a 
sulpho-acid, C,H;(CH,)(N,H,).SO,H; the sulpho-group occupies ‘the para-posi- 
tion with reference to the hydrazine- -group (Berichte, 18, 3175; 19, Ref. 301). 

p-Tolyl-hydrazine, C,H,(CH,).NH.NH,, from para-toluidine, melts at 61°, 
and distils about 242°. When digested with sulphuric acid, it changes to a basic 
compound (Berichte, 19, Ref. 837). 





SULPHO-COMPOUNDS. 
The following are representatives of this class of derivatives :— 


Benzene Sulphonic Acid, C,H,.SO,H. 
« Sulphinic “ C,H °'SO, 5 
« _ Sulphone, (c: H,),SO, ‘ 
« — Disulphoxide, tes atiagltes O, , 
««  Sulphoxide, (ClH,),SO. 


The sulphonic acids of the benzene hydrocarbons (as well as of 
all other benzene derivatives) are very easily obtained by mixing 
(or digesting) the latter with concentrated or fuming sulphuric 
acid. ‘The fatty acids yield like products with more difficulty (pp. 
152 and 261) :— : / 


«Hi + .SO,H, = C,H;.S0,H Ge BLO, 
C,H, + 2S0,H, = C,H,(SO,H), + 2H,0. 


Chlorsulphonic acid, Cl.SO,.0H (Berichte, 18, 2172), acts similarly to sul- 
phuric acid. With it we can obtain the trisulpho- -acids (Berichte, 15, 307). Fur- 
ther, some sulphonic acids can be obtained from the diazo-amido-derivatives by 
means of sulphurous acid (p. 635 and Berichte, 10, 1715). 


The chloranhydrides of the sulphonic acids, ¢. g., C,H;.SO,Cl, 
are produced by letting PCI, act on the acids, or POC], upon the 
salts. Ammonia converts these into sulphamides, C,H;{SO,.NH,, ~ 
and zine and hydrochloric acid will reduce them to sulphydrates 
(thio-phenols) (p. 152) :— 


C,H,.SO,Cl + 3H, = C,H,.SH + 2H,O + HCI. 


The sulphinic acids of benzene, with the structure C,H;.SO.OH or 
“i 80, are perfectly analogous to those of the fatty series 
(p. 154). They are best prepared by the action of zinc dust upon the 
ethereal solutions of the sulphonic chlorides (Berichte, 13, 1273). 
_ They also result in the action of SO, upon benzene in the presence 
of AICI, (Berichte, a 195) BSE ays + SO,= C,H; SO,H. 


660 ORGANIC CHEMISTRY. - 


The veal esters of these acids, CSH,.SO.0.C,H,, are formed by the action of 
chlorcarbonic esters upon sulphinates (p. 154), and by the etherification of the free 
sulphinic acids with alcoholand HCl (Berichte, 18, 2506; 19, 1224). The esters 
are not very stable; alkalies saponify them, yielding sulphinates and alcohol, etc. 
The szdphones, their isomerides, ¢. ¢., (C,H;),SO,, diphenyl-sulphone (p. 142), 
are obtained by the action of SO, (or chlorsulphonic acid, CISO,H) upon benzenes 
(together with sulphonic acids): 2C,H, + SO, = (C,H,;),SO, + H,O.; by 
the distillation of sulphonic acids (together with benzenes), and by the oxidation 
of the phenyl sulphides, ¢.¢., (C,H;),S, with nitric acid. 

The benzene sulphones are formed synthetically on heating sulphonic acid with 
benzene and P,O,:C,H,;.SO,H + C,H, = C,H,.SO,.C,H, + H,O; further, 
by the action of zinc dust or aluminium chloride upon a mixture of the sulphonic 
chlorides and benzenes; mixed sulphones are also produced in this manner :— 


C,H 
G.H,.$0,0i) CH,.CHy; = CH, CH >5% + HCl. 


The same phenyl tolyl-sulphone results from benzene sulphonic acid and toluene 

as from toluene-sulphonic acid and benzene, which would prove chat both groups 

are in union with sulphur and that the latter ts sexivalent (Berichte, 11, 2181). 
Mixed sulphones, containing alkyls, are prepared from the sodium sulphinates 

by the action of the alkylogens (p. 142) :— 

C,H 

Co? >80. 4. NaBr. 


Phenyl-ethyl- 
sulphone. 


C,H,.SO,Na + C,H, Br = 


The denzene-thiosulphonic acids are formed when alkaline sulphides act upon 
the chlorides of the sulphonic acids :— 


C,H,.SO,Cl + K,S = C,H,-S0,.SK + KCL 
Potassium Benzene- 
thio-sulphonate. 


And by acting on these salts with alkylogens, esters of the thio-sulphonic acids 
(the disulphoxides) will be produced (Berichte, 20, 2079) :— 


C,H,.SO;.SK 4+ C,H,I = C,H,.SO,S.C,H, + KI. 


These are identical with the so-called alkyl-disulphoxides (p. 154). 

Phenyl esters, ¢. g., CgH,.SO,.S.C,H,;, are obtained by oxidizing the thio- 
phenols with nitric acid and by heating the sulphinic acids with water, (Aerichie, 
18, 2500). Alkalies and alkaline sulphides saponify them (p. 154 and Berichie, 
19, 3131). 

The acts sulphoxides are produced by the action of SO, or SO,Cl, upon 
benzenes in the presence of AlCl], (Berichze, 20, 191) :-— 


2C,H, + SOCI, = (C,H,),SO + 2HCl. 





The benzene sulphonic acids are perfectly analogous to those of 
the fatty series. They are very stable and are not decomposed on 
boiling with alkalies. They yield phenols when fused with 
alkalies :— : 

: “C,H,.S0,K + KHO = C,H,.0H + SO,K,. 


BENZENE-SULPHONIC ACID. 661 
When distilled with potassium cyanide (or dry yellow prussiate of 
potash) nitriles result :— 
C,H,.SO,K + CNK = C,H,.CN + SO,K,. 


Amido-compounds are produced when sodium amide acts upon 
benzene sulphonates (Berichte, 19, 903) :— 


C,H,-SO,Na + NH,Na = C,H,.NH, + SO,Na,. 


Hydrocarbons (together with phenyl sulphones) are formed when 
the free acids are subjected to distillation :— 


C,H,.SO,H = C,H, + SO,. 


This rupture is more easily accomplished by heating the acids with concentrated 
HCl to 150°, or by distilling the ammonium salt of the sulphonic acid, or a 
mixture of the lead salt with ammonium chloride (Berichte, 16, 1468). The 
decomposition results with least difficulty by conducting steam into the dry sulpho- 
acid, or its solution in concentrated sulphuric acid; superheated steam is most 
effective (Berichte, 19, 92). 

The sulphonic acids of the substituted hydrocarbons are obtained either by the 
action of sulphuric acid on the substituted hydrocarbons, or by the substitution of 
the sulphonic acids. In nitration the sulpho-group is often replaced by the nitro- 
group, just as on heating with PCI, it is sometimes substituted by chlorine :— 


C,H,C1.SO,Cl + PC], = C,H,Cl, + PCI,O + SOCl,. 


Most of the substituted benzene sulphonic acids have their sulpho-group replaced 
by hydrogen if they are heated to 150-200° with concentrated hydrochloric 
acid :-— 

C,H,Br.SO,H + H,O = C,H, Br + SO,H,. 


Nitro-benzenes and amido-benzenes result in ike manner from the nitro-benzene- 
and amido-benzene-sulphonic acids (Berichte, 10, 317). Chlorine and bromine 
occasionally effect a like replacement of the sulpho-group (Berichte, 16, 617). 

The brominated benzene-sulphonic acids can form sulpho-anhydrides, ¢. ¢., 
CH Bre sO! DO. They result from the action of pyrosulphuric acid, (SO,),0 
(OH),, upon brombenzenes (Berichze, 16, 653). 

The sulphinic acids are not very stable, and when heated or allowed to stand 
some time over sulphuric acid they split up into sulphonic acids and disu/phoxides 
(Berichte, 18, 2500). 

The air and oxidizing agents (especially BaO,) convert them into sulphonic 
acids. Their salts unite with sulphur, forming thio-sulphonates. When fused, 
they decompose into benzenes and alkaline sulphites :— 


C,H,.SO,K + KOH = C,H, + SO,K,. 





Benzene-sulphonic Acid, C,H;.SO,H. For its preparation 
equal parts of benzene and ordinary sulphuric acid are boiled for 
some time; or benzene is shaken with fuming sulphuric acid. 
Afterwards dilute with water and saturate with barium or lead car- 


662 ORGANIC CHEMISTRY. 


bonate. The free sulphonic acid is separated from its salts by 
means of sulphuric acid or hydrogen sulphide. 

Benzene sulphonic acid crystallizes in small plates, C,H;.SO,H 
-+ 114%4H,0, which are readily soluble in alcohol and water, and 
deliquesce in the air. In its dry distillation the acid yields ben- 
zene and phenylsulphone (in slight quantity), and when fused with 
caustic potash phenol is produced. 


The darium salt, (C,H,;.SO,).Ba +. H,O, forms pearly leaflets, and is sparingly 
soluble in alcohol. The ztzc salt, (C,H;.SO,).Zn + 6H,0O, crystallizes in six- 
sided plates. 

Benzene-sulpho-chloride, C,H,;.SO,Cl, is an oil, insoluble in water, but 
dissolved by alcohol and ether. Its specific gravity at 23° is 1.378. It is crystal- 
line below 0°, and boils at 247° with decomposition. It slowly reverts to the 
acid upon boiling with water. It may be obtained by gently digesting C,H;.SO,Na 
with PCI, and treating the product with water. If the chloride be digested with 
ammonia or ammonium carbonate we obtain— 

Benzenesulphamide, C,H,.SO,.NH,, which crystallizes from alcohol in 
pearly laminz. It melts at 149° and sublimes. From the alcoholic solution silver 
nitrate precipitates C,H,.SO,.NHAg. The amide hydrogen can also be re- 
placed by acid or alcohol radicals. 

Benzene Sulphinic Acid, C,H,.SO,H (its zine salt), is obtained by the 
action of zinc dust upon benzene sulphochloride. It crystallizes from hot water in 
large, brilliant prisms, and dissolves readily in alcohol and ether. It melts at 69°, 
and decomposes at 100°. In the air it oxidizes readily to benzene sulphonic acid. 
The stlver salt, C,H ,.SO,Ag, is sparingly soluble in water. 

Phenyl Ethyl Sulphone, C,H,.5O,.C,H,, is formed in the oxidation of 


henyl-ethyl-sulphide, CHS \g, with potassium permanganate, and from sodium 
pheny y!-sulp CH.'/ po p s 


benzene sulphinate with ethyl bromide (p. 660). It melts at 42° and boils above 
300°. Isomeric benzene-sulphinic ester, C,H;.SO.0.C,H,, is only known in 
mixtures (p. 659). 

Di-phenylsulphone,(C,H,),SO,, Benzene Sulphone, Sulphobenzide, is formed 
by the distillation of benzene sulphonic acid, and by the oxidation of phenyl sul- 
phide, (C,H,),S; further, from benzene sulphonic chloride, C,H,.SO,Cl, and 
mercury diphenyl. It is also obtained by the action of fuming sulphuric acid, or 
SO, upon benzene. It dissolves with great difficulty in water and crystallizes from 
alcohol in plates. It melts at 128—-129°, and distils without decomposition. It is 
converted into benzene-sulphonic acid when digested with concentrated sulphuric 
acid :-— 

(C,H,;),SO, + SO,H, = 2C,H,;.SO,H. 


When heated with PCI,, or in a current of chlorine gas, it is decomposed according 
to the equation :— 


(C,H,),SO0, + Cl, = C,H,Cl + C,H,.SO,Cl. 


C,H,Cl and its addition products are also formed when chlorine acts upon it in 
sunlight. 

Benzene disulphoxide, (C,H,),S,O, (p. 659), is produced along with benzene 
sulphonic acid on heating benzene sulphinic acid with water to 130°. It crystal- 
lizes in shining needles, and melts at 130°. It is insoluble in water but is readily 
dissolved by alcohol and ether. 


CHLORBENZENE-SULPHONIC ACIDS. - 663 


CH,.SO,.C,H, 
Ethylene Diphenyl-disulphone, | ({p. 307), is obtained from 
aCe; 
ethylene bromide and sodium benzene sulphinate. When heated with alkalies, it 
breaks down into benzene su!phinic acid and phenylsulphone-ethyl alcohol, C,H;. 
SO,.CH,.CH,.OH; chromic acid oxidizes this to phenylsulphone-acetic acid, 
C, H, SO,. CH, COOH (Berichte, 18, 155). The latter compound and its esters 
are obtained from sodium phenylsulphinate by the action of chloracetic acid. The 
hydrogen of the CH,-group in the ester is, indeed, replaceable by sodium, but zzo¢ 
by alkyls (Berichte, 22, 1447; 23, 1647). 
See Berichte, 23, 752, 1409, for analogous a@- and ¢ri-sulphones, as well as their 
decompositions, etc. 
a- and $-Phenyl-sulpho-propionic Acids, C,H,.SO,.CH(CH;).CO,H, 
have been prepared in a similar manner (erichée, 21, 89). 





SO,H 


Benzene-disulphonic Acids, C,H ‘Gi On heating benzene with fumin 
«\ SO,H: S 8 


sulphuric acid to 200° C., we get meta- and para-benzene disulphonic acids, with 
the former in predominating quantity, but by prolonged heating it passes into the 
para-variety (Berichte, 9; 550). They can be separated by means of their potas- 
sium salts. A/e¢a-disulphonic acid (1, 3) is produced by heating parabrombenzene- 
sulphonic acid with sulphuric acid to 220° and displacing the bromine with sodium 
amalgam, or from disulphanilic acid (p. 666) by means of the diazo-compound. 

Orthobenzene disulphonic acid (1, 2) is formed from meta-amido benzene sul- 
phonic acid by further introduction of the sulpho-group, and replacement of NH,, 
The melting points of the sulphochlorides and sulphamides of the three i isomeric 
disu!phonic acids are :— 


Ortho. Meta. Para. 
C,H,(SO,Cl), 105° 63° 132° 
C,H,(SO,NH,),. 233° 229° 288°. 


The corresponding dicyanides, C,H,(CN), (see nitriles), are obtained by dis- 
tillation with potassium cyanide or potassium ferrocyanide. When fused with 
potassium hydroxide, both mefa and fara acids yield resorcinol (metadioxyhen- 
zene); at lower temperatures metaphenol-sulphonie acid, C,H,(OH) SO,H, 
results at first from both acids. 

Benzene-trisulphonic Acid, C,H,(SO,H), (1, 3, 5), is easily made by heat- 
ing potassium m-benzene disulphonate with common sulphuric acid (Berichte, 21, 
Ref. 49). The free acid (from the lead salt) crystallizes in long needles with 
3H,O; its chloride melts at 184°; its amide at 306°. Fused with caustic potash 
it yields phloroglucin, C,H,(OH),, and upon heating with potassium cyanide it 
forms the nitrile, which upon saponification becomes trimesic acid, C,H,(CO,H),. 





The Chlorbenzene-sulphonic Acids, C,H,CI.SO,H, are obtained from the 
three amidobenzene-sulphonic acids, by treating their diazo- compounds with 
hydrochloric acid. The (1, 4)-acid is also produced in the action of SO,H, upon 
C,H,.Cl. The amide of the (1, 2 )-acet melts at 182°; the amide of (1, 3) acid 
at 148°; that of the (1, 4)-acid at 143°. The chloride of the (1, 4)-acid, C,H, 
C1.SO,Cl, melts at 51°; it yields (1, 4)-C,H,Cl,, when heated with PCl,. 


664 ORGANIC CHEMISTRY. 


The Brombenzene-sulphonic Acids, C,H,Br.SO,H, are obtained like the 
chlor-acids. The (1, 4)-acid is also formed on heating C,H,Br with SO,H, or 
SO,HCI; the (1, 3)-acid by heating benzenesulphonic acid with bromine to 100°, 
or by the action of Br upon C,H,SO,Ag at ordinary temperatures. They are 
very deliquescent, crystalline bodies; the para-acid melts at 88°. All three yield 
resorcinol (1, 3),-when they are fused with KOH. They form dicyanides, C,H, 
(CN),, by distilling their potassium salts with potassium cyanide or dry yellow 
prussiate of potash. Dicarboxylic acids are obtained from these. 

Nitrobenzene-sulphonic Acids, C,H,(NO,).SO,H. If nitrobenzene be dis- 
solved in fuming sulphuric acid, or benzene sulphonic acid in concentrated nitric 
acid, the three nitrobenzene sulphonic acids are produced—the (1, 4)-acid in 
largest quantity. For their separation they are converted into the amides, C,H, 
(NO,).SO,.NH,, which are then distilled. The free acids are very deliquescent 
crystalline masses. Their chlorides melt as follows: (1, 2) at 67°; (1, 3) at 60°; 
(1,4) isaliquid. The amides fuse: (1, 2) at 186°; (1,3) at 161°; (1,4) at 131°. 
Ammonium sulphide reduces them to the corresponding amidobenzene sulphonic 
acids. 





Amidobenzene-sulphonic Acids, C,H,(NH,).SO,H. They are produced 
by the reduction of the three nitrobenzene sulphonic acids with ammonium sul. 


phide. 


The para-acid, commonly called sudphanilic acid, is obtained by 
heating aniline (1 part) with fuming sulphuric acid (2 parts) to 180° 
until SO, appears. On diluting with water, the acid separates as a 
crystalline mass. Its diazo-compounds are changed by hydro- 
bromic acid into the corresponding brombenzene-sulpho acids ; by 
hydrochloric acid into chlorbenzene sulphonic acids. 


The three amido-benzene sulphonic acids dissolve with difficulty in water, 
alcohol and ether. The (1, 2)-acid either crystallizes in anhydrous rhombohedra, 
or in four-sided prisms containing 4H,O; these do not effloresce. The (1, 3)- 
acid crystallizes in delicate needles or in prisms with 144H,O, which effloresce. 
The sodium amido-benzene-sulphonates yield acetyl derivatives with acetic anhy- 
dride (Berichte, 17, 708). 

Sulphanilic Acid (1, 4) is obtained by heating (1, 4)-and (1, 2)-aniline-phe- 
nol-sulphonate :— 

/ OH fas /NH 
Mets. so Ni, Oe so hy tT els OH, 


or aniline ethyl sulphate to 200° :— 


/40.C,H i /NU : 
SO2< OH.NH,.C,H, x CeHa< so,H + C,H,.OH. 


It yields aniline and not amidophenol when fused with caustic potash. It crys- 
tallizes from hot water in rhombic plates with 1 molecule H,O; these effloresce 
in the air. They are soluble in 112 parts H,O at 15° (Berichte, 14, 1933). It 
yields a considerable quantity of quinone, when oxidized with MnO, and H,SO, or 
chromic acid. 

For nitro-aniline-sulphonic acids, consult Berichte, 21, 2579, 3220; 22, 847. 

Phenylsulphaminic Acid, C,H;.NH.SO,H (p. 164), is isomeric with the 
amidobenzene-sulphonic acids. It results from the action of chlorsulphonic acid 


TOLUENE SULPHONIC ACIDS. 665 


upon aniline, Its salts are very stable; boiling water does not decompose them. 
Boiling water containing a little acid, readily decomposes the free acid into aniline 
and sulphuric acid ( Berich/e, 23, 1653). 

Nitrous acid transforms the three amido-benzene-sulphonic acids into the anhy- 
drides of the diazobenzene-sulphonic acids (p. 630) :— 


/S0,0H / SO. 
CHAN On CoH y,? 0: 
Diazob iphonic Acid, Anhydride, 





The hydrous sulpho-acids are not known; they pass at once into anhydrides. It 
is rather remarkable that, while otherwise it is only the ortho-compcunds of the 
benzene derivatives which form inner anhydrides (p. 351), all three of the diazo- 
benzene sulpho-acids are capable of anhydride formation. 

p-Diazobenzene-sulphonic acid (its anhydride) is obtained by dissolving sul- 
phanilic acid in sodium hydroxide, adding an equivalent quantity of sodium nitrite 
and pouring the mixtureinto dilute sulphuric acid. The acid separates in needles 
that dissolve with difficulty. It exhibits all of the reactions of the diazo-compounds. 


is used in the preparation of various azo-dyes. 

m-Diazobenzene-sulphonic acid, Metanilic acid (p. 664), unites with diphenyl- 
amine to yield metanzlic yellow. 

The action of the diazo-sulphonic acid upon alcoholic H,S, is to substitute the 
diazo-group by SH, with the production of the phenolsulphonic acids, «¢. g., 
C.H,7 > 

6 4\SO,H: ' 

The benzene-diazo-sulphonic diazoamido-derivatives (the same as those of ben- 
zene carboxylic acids) are not known. 


The action of HI upon the nitro-benzene-sulphonic chlorides, CHK SS “cy 
2 


produces the su/phimido benzenes, which are nitrodiphenyl disulphides (erichie, 
21, 1099). 

Disulphanilic Acid, C,H,(NH,)(SO,H), (1, 4,2 — NH, in 1), is obtained 
by protracted heating of sulphanilic acid to 180° with concentrated sulphuric 
acid. The replacement of the amido-group produces metabenzene-disulphonic 
acid (p. 663). : 





Toluene Sulphonic Acids, C,H,(CH,).SO,H. It is chiefly the para-com- 
pound, together with some ortho- and meta- (Berichte, 17, Ref. 283), which is 
produced by the solution of toluene in sulphuric acid or by the action of chlor- 
sulphonic acid upon it. The ch/oride of the para-acid is solid and melts at 69°; 
that of the ortho-acid is liquid. When fused with alkali the para-acid yields para- 
cresol and para-oxybenzoic acid, the ortho-acid, however, ortho cresol and salicylic 
acid. When the former is oxidized with a chromic-acid mixture, it forms para- 
sulphobenzvic acid, while the latter passes into ortho-sulphobenzoic acid (Berichée, 
20, 2929). 

Mien carbonate converts the three sulphochlorides into three Zo/uene- 
sulphamides, C,H,(CH,).SO,.NH, (Berichte, 21, Ref. 100). Potassium per- 
manganate oxidizes these to the corresponding sulphamine benzoic acids, 
CHK Co? Ni (Berichte, at, 242). 

Toluene Disulphonic Acids, C,H,(CH,)(SO,H),. The six possible iso- 
merides are known (erichie, 20, 350). 


56 


666 ORGANIC CHEMISTRY. 


PHENOLS. 


The mono-, di- and tri-hydric phenols are derived by the replace- 
ment of hydrogen in the benzenes by hydroxyls :— 


C,H,.0H C,H,(OH), C,H,(OH),. 


Phenol. Dioxybenzenes. Trioxybenzenes. 


The phenols correspond to the tertiary alcohols, as they yield 
neither acids nor ketones upon oxidation. Their acid nature, dis- 
tinguishing them from alcohols, is governed by the more negative 
nature of the phenyl group (p. 557). The following are the more 
general and most important methods of forming them :— 

1. By the action of nitrous acid upon the aqueous solution of the 
amido-compounds, or by decomposing the diazo-derivatives with 
boiling water (p. 632), 


‘The sulphuric acid salts of the diazo-compounds are particularly well adapted 
to this end ; the nitric acid salts tend to yield nitro-phenols. It is best to dissolve 
the amido-derivatives in dilute sulphuric acid (2 equivalents), add aqueous potas- 
sium nitrite (1 molecule), and boil the strongly diluted solution until the disen- 
gagement of nitrogen ceases. . 


2. Fusion of the sulphonic acids with potassium or sodium 
hydroxide :— _ 
C,H,.SO,K + KOH = C,H,.0H + SO,K,, 


Cue 1 KOH ae GA Koi + S0,K,. 


Here the sulpho-group disappears as a sulphite (p. 152). 


The experiment is executed in a silver dish at higher or lower temperatures, the 
- fusion supersaturated with sulphuric acid, and the phenol extracted by shaking 
with ether. : 

In fusing sulphonic acids or phenols containing halogens, the latter are also 
replaced with formation of polyhydric phenols :— 


C,H,.CLSO,K + 2KOH = C,H,(OH), + SO,K, + KCl, 
C,H,Cl.OH + KOH = C,H,(OH), + KCL. 


Occasionally the sulpho-group splits off as sulphate and is replaced by hydrogen ; 
thus, cresolsulphonic acid yields cresol. 

3. Small quantities of phenol can be obtained from benzene by the action of 
ozone, hydrogen peroxide (palladium hydride and water), and by shaking with 
sodium hydroxide and air (Berichte, 14, 1144). 


4. The halogen benzene substitution products do not react with 
alkalies; but if nitro-groups are present at the same time, the halo- 
gens are replaced even by digesting with aqueous alkalies—this will 
occur the more readily if the nitro-groups be multiplied. For ex- 


PHENOLS. 667 


ample, ortho- and para-chlornitro-benzene (but not meta) yield the 
corresponding nitro-phenols (p. 676), when they are heated to 120° 
with sodium hydroxide; the dinitro-chlorbenzenes even react when 
boiled with carbonates, and the trinitro-chlorbenzene even with 
water. 


p-Nitrophenol-ethers, C,H,(NO,).OR, are produced on boiling 4-chlornitro- 
benzene with caustic soda and 60 per cent. alcohol; if absolute alcohol be applied 
there is simultaneous reduction and formation of chlorazobenzene (Berichie, 15, 
1005). 

Te amide-group in the nitroamido-derivatives can also be replaced by hydroxyl 
on boiling with aqueous alkalies; ortho- and para-nitranilines, C,H,(NO,).NH, 
(not meta), yield their corresponding nitrophenols, The ortho-dinitro-products 
react similarly (p. 587). 


gs. The dry distillation of salts of the oxy-acids of the benzene 
series with lime (p. 570) :— 


C,H,(OH).CO,H = C,H,.0H + CO,, 


Oxybenzoic Acid, Phenol. 
allic Acid. Pyrogallol or Pyrogallic Acid. 


6. Dry distillation of various complex carbon compounds, e. g., 
wood and coal. To isolate the phenols from the coal tar, shake 
the fraction boiling at 150—-209°, with aqueous potash, separate the 
aqueous solution from the oil containing the hydrocarbons, and 
saturate it with hydrochloric acid. The separated phenols are 
purified by fractional distillation. 


Wood-tar oils (cveasote) consist of a mixture of different phenols and their 
ethers; the portion, boiling at 180-300°, contains phenol, C,H,.OH, para-cresol, 
C,H,(CH;).OH, phlorol, C,H,(CH,),.OH, also guaiacol, C,H,(O.CH,).OH, 
creosol, CgH,(CH;).(O.CH;).OH, and the dimethyl ether of pyrogallic acid, — 
C,H,(OH),, and methyl- and propyl pyrogallol (Berichte, 14, 2005). 


7. The synthesis of the higher phenols by introduction of alkyls — 
into the benzene nucleus (p. 570) takes place readily on heating 
the phenols with alcohols and ZnCl, to 200° (Berichte, 14, 1842; 


17, 669) :— 
C,H,.0H +:C,H,.0H — C,H,(C,H,).0H + H,0. 


Alkyl ethers of the phenols are simultaneously produced; methyl alcohol 
yields methyl-phenol, C,H;.0.CH;. Magnesium chloride (Berichte, 16, 792) 
and primary alkali sulphates (Berichte, 16, 2541) possess the same condensing 
power as ZnCl,. Phenol and resorcinol condense to ketones, ¢. g., dioxybenzo- 
phenone, C,H,(OH).CO.C,H,OH (Berichte, 16, 2298), when heated with 
salicylic acid and tin chloride. 

8. Many benzene derivatives are transposed in the animal organism into phe- 
nols; thus, benzene yields phenol; brombenzene, bromphenol; aniline, amido- 
phenol and phenol hydroquinone. Different phenols are found already formed as 
phenol sulphuric acids (p. 670) in the urine of mammals, 


~ 


668 ORGANIC CHEMISTRY. 


The phenols are the analogues of the tertiary alcohols, but 
possess a more acid character (p. 666). The hydrogen ef their 
hydroxyl can be readily substituted by metals, by the action of 
bases, chiefly of the alkalies. Carbon dioxide separates the phenols 
again from these salts. ‘The entrance of negative groups into the 
benzene nucleus increases the acid nature of the phenols. Thus 
trinitrophenol manifests the properties of an acid, as it decomposes 
_carbonates. The hydroxyl-hydrogen of the phenols can also be 
replaced by alcohol and acid radicals. 

The alcohol-ethers are formed : by the action of the alkyl iodides 
upon the salts of the phenols (chiefly the silver salts), or by heating 
a mixture of the alkali salts of the phenols with an excess of alkyl 
sulphates, in aqueous or alcoholic solution (Berichte, 19, Ref. 
139) :— 

C,H,.0H + C,H,.I + KOH = C,H,.0.C,H, + KI + H,0; 


and by the dry distillation of the phenol ethers of the oxy-acids with lime :— 


O.CH 
CHK co, tf = CoH,.0.CH, + CO,. 
Anisic Acid, Methyl Phenol. 


Boiling alkalies do not alter the alcohol ethers. When, however, they are 
heated with hydriodic or hydrochloric acid, they split up into their components :— 


C,H,.0.CH, + HI = C,H,.0H + CH,I. 


The acid esters are obtained by acting with acid chlorides or 
anhydrides upon the phenols or their. salts; also by digesting the 
phenols with acids and POCI;. Osbeiling with alkalies or even 
with water, they, like all esters, breakdown into their components. 


To effect the substitution of all the hydroxyl-hydrogen atoms in the polyhydric 
phenols by acetyl groups, it is recommended to heat them with acetic anhydride 
and sodium acetate. 


Phosphorus sulphide converts the phenols into thio-phenols :— 
5C,H,.0H + P,S, = 5C,H,.SH + P,0,. 


The phosphorus haloids replace the hydroxyls of the phenols by 
halogens, forming substituted benzenes. When heated with zinc 
-dust the phenols are reduced to hydrocarbons. The anilines result 
on heating with zinc-ammonium chloride (compare p. 593). 


On adding phenols (mono- or polyhydric) to a solution of KNO, (6 per cent.) 
in concentrated sulphuric acid, intense colorations arise; with common phenol we 
get first a brown, then green, and finally a royal-blue color (Reaction of Lieber- 
mann) (see Berichte, 17, 1875). Dyes are produced in this manner; their char- 
acter is as yet unexplained. They have been called dichroines (erichie, 21, 
249). The phenols afford similar colors in the presence of sulphuric acid, with 


MONOHYDRIC PHENOLS. 669 


diazo-compounds, and nitroso-derivatives (p. 636). Ferric chloride imparts color 
to the so _— of most phenols. Mercury nitrate, containing nitrous acid, colors 
nearly all the phenols red (Reaction of Plugge) (Berichée, 23, Ref. 202). 


The hydrogen of the benzene residue in phenols can be replaced, 
further, by the halogens and groups NO,, SO;H, etc. In the alco- 
hol-ethers of the nitro-phenols (as with the acid esters) we can 
replace the OH by NH,, on heating with alcoholic ammonia 


(p. 593) :— 
C,H,(NO,).0.CH, + NH, = C,H,(NO,).NH, + CH,.OH. 


The phenols and their halogen products may be converted into 
oxy-acids by the action of sodium and carbon dioxide (see aromatic 
series) :— 2 
C,H,.0H + CO, = C,H,(OH).CO,H. 


Ble, agangpe C,H,(OH).CHO, are produced from phenols, chloroform and 
upc soda, and oxyacids (see these) from phenols and carbon tetrachloride. 
The azo yield azo-compounds with phenols—the tropzoline dyes belong to this 
clas {p- 644). Dyestuffs belonging to the aurine series, and derived from tri- 
phenylnethane, CH(C,H,), (see this), are obtained from the phenols by their 
action upon benzotrichloride, C,H,;.CCl,. The so-called phthaleins are combina- 
tions of phthalic acid and the phenols, 





MONOHYDRIC PHENOLS. 
78, Phenol, C,H,.OH. 
oe Cresols, C,H ,.CH,(OH). 
Xylenols, C,H ,(CH,),.OH, etc. 


Phenol, C,H;.OH (Benzene Phenol, Carbolic Acid, Creasote). 
This was first discovered (1834) in coal- -tar, by Runge. It is 
obtained from amidobenzene, from benzene-sulphonic acid, from 
the three oxy-benzoic acids, etc., by the methods previously de- 
scribed. It occurs already formed in Castoreum and in the urine 
of the herbivore. 

Commercial phenol is a colorless crystalline mass, which gradu- 
ally acquires a reddish color, and deliquesces on exposure to the 
air. Pure phenol crystallizes in long, colorless prisms, melts at 
42°, and boils at 183°; its specific gravity at o° is 1.084. It pos- 
sesses a characteristic odor, burning taste, and poisonous and anti- 
septic properties. It dissolves in 15 parts water at 20°, and very 
readily in alcohol, ether and glacial acetic acid. Ferric salts im- 
part a violet color to its neutral solutions. Bromine water precipi- 
tates tribromphenol from even very dilute solutions. Diphenols, 
C,,H,(OH),, derivatives of diphenyl sip sie are Peon on 
fusing phenol with caustic potash. 


670 ORGANIC CHEMISTRY. 


Potassium Phenylate or Phenoxide, C,H;.OK, is obtained by dissolving phenol 
in potassium hydroxide. It crystallizes i in delicate, readily soluble needles. CO, 
separates. phenol from it, which, therefore, is insoluble ‘in alkaline carbonates. 
Bartya, lime, and litharge form similar compounds. 

Phenacetein, Phenacetolin, CijgH,,O0, (Berichte, 15, 2907), is obtained by heat- 
ing phenol with acetic acid and zinc chloride. This compound is employed as an 
indicator in alkalimetry (Berich/e, 14, 2306). 





ACID ESTERS OF PHENOL (p. 668)—ETHEREAL SALTS. | 


Phenylsulphuric Acid, C,H;-0.SO,H, is not known in a free state; when 
liberated from its salts by concentrated hydrochloric acid, it immediately breaks 
down into phenol and sulphuric acid. Its potassium salt, C,H;.0.SO,K, forms 
leaflets, not very soluble in cold water, and occurs in the urine of herbivorous 
animals, and also in that of man and the dog after the ingestion of phenol. It is 
synthetically prepared, like other phenols, on heating potassium phenoxide with 
an aqueous solution of potassium pyrosulphate (Berichte, 9, 1715). 

The phenyl sulphuric acids are very stable in aqueous and alkaline solution; 
upon digesting with mineral acids, however, they are very rapidly decomposed. 
When potassium phenylsulphate is ‘heated in a tube it passes quietly into Z-potas- 
sium sulphonate :— 

C,H,.0.S0,.0K ~ yield noe 
gl1,;-0.SO.. yields H.C 50, OK: 


The phenol esters of phosphoric acid are produced by the action of PCI, upon 
phenol (together with chlorides) :— 


(OH) 3 ; 
PO { O.C,ft, PO{ Oi O.C,H,), 4 PO(O.C,H,)»: 


The ¢riphenyl ester is easily formed on boiling phenol with phosphorus oxy- 
chloride (Berichte, 16, 1763). It is crystalline, melts at 45°, and boils near 400°. 
Distilled with potassium cyanide it yields benzonitrile, C,H, CN. 

Consult Berichte, 18, 1700, upon the phosphoric acid esters of the higher 
phenols and their conversion into nitriles. 

At the ordinary temperature carbon dioxide converts dry sodium phenate (at 
ordinary pressure) into the sodium salt of Phenylearbonic Acid ernie 18, 
Ref. 440) :— 

- C,H,;.ONa + CO, = C,H,;.0.CO,Na. 


This is a white hygroscopic powder, decomposed again by water. When heated 
under pressure to 120-130° sodium salicylate results :— 


C,H,.0.CO,Na _ yields CHEK CO, Nar 


just as phenolsulphonic acid is obtained from phenylsulphuric acid (see above). 
When heated to 190° with sodium phenate sodium phenyl carbonate tas di- 
sodium salicylate and phenol :— 


“C,H,;.0.CO,Na ++ C,H,.ONa = C,H,(ONa).CO,Na + C,H,.0H. 


The carbonic acid ester, Pheny/ Carbonate, CO(O.C,H;)o, is produced on 
heating phenol and phosgene gas, ee to 150°. It is téadily obtained by 


PHENOL ALCOHOLIC ETHERS. 671 


leading phosgene gas into the aqueous solution of sodium phenylate (Journ. 
pract. Chem., 27, 139, Berichte, 17, 287). It crystallizes from alcohol in shining 
needles, and melts at 78°. It yields sodium salicylate (see this) when heated to 
200° with sodium hydroxide. Urea results if it be heated with ammonia, and by 
using amine bases, instead of ammonia, phenylated ureas will constitute the 
product (Berichte, 23, 694). 

Mixed carbonates containing phenol and alkyls, ¢. g., phenyl-ethyl carbonate, 
CO,(C,H,;)(C,H,), are produced by the action of chlor-formic esters upon the 
sodium salts of the phenols. 

The acetic ester, C,H,.0.C,H,O, is obtained by boiling the phosphoric ester 
with potassium acetate, and is an agreeable-smelling liquid, boiling at 190°. 
Phenyl-glycollic Acid, CH Go. iiss phenyl oxy-acetic acid (isomeric with 
mandelic acid), is produced by heating monochloracetic acid with potassium 
phenate to 150°. Long, silky needles, melting at 96°. All other phenols react 
analogously. 

The action of sodium phenate upon chloracetoacetic ester produces :— 


Phenoxyl-acetoacetic Ester, CyH.0.CHE oo , a dark oil, that is con- 
et Se 


densed by sulphuric acid, with water exit, to methylcoumarilic ester. Other 
coumarilic compounds are analogously produced (see these and Berichte, 19, — 


1291). 
Phenyl Ethyl Oxalic Ester, C,0,C oetah formed by the action of chlor- 
: . 
oxalic ester (p. 405) upon phenol, is an oil boiling at 236°, and is slowly decom- 
_posed by water into phenol, oxalic acid and alcohol. 
The succinic ester, C,H,(CO,.C,H;),, from phenol and succinyl chloride, forms 
shining leaflets, melts at 118°, and boils at 330°. 


Phenyl-allophanic Ester, COC NH'CO,.C, H, (p. 393), is produced by conduct- 


ing cyanic acid vapors into anhydrous phenol. A crystalline mass, decomposing 
at 150° into phenol and cyanuric acid, 

Phenyl-ortho-formic-ester, CH(O.C,H,),, is formed by boiling phenol with 
sodium hydroxide and chloroform (as a by-product in the formation of oxybenzal- 
dehyde). It crystallizes in white needles, melts at 71° and distils at 265°, under 
50 mm. pressure, See Berichte, 18, 1679, for the phenol silicates. 





PHENOL ALCOHOLIC ETHERS (p. 668). 


Methyl Phenyl Ether, C,H,.0.CH;, Anisol, is produced by heating phenol 
with potassium and methyl iodide or potassium methyl sulphate in alcoholic solu- 
tion; by distilling anisic or methyl salicylic acid with lime or baryta (p. 668); 
. or Ai leading methyl chloride into sodium phenoxide at 200° (Berichte, 16, 

2513). x 

It is an ethereal-smelling liquid, boiling at 152°; its specific gravity at 15° is 

0.991. Heated to 130° with hydriodic acid it decomposes into phenol and methyl 

alcohol. It is not reduced by zinc dust. 

Bromine converts it into substitution products: dromanisol, C,H,Br.O.CH,, 
boils at 223°; dibromanisol crystallizes in rhombic plates, melts at 59° and boils 
at 272°; tribromanisol melts at 87° and sublimes. Further action of bromine 
produces bromanil, C, Br,O,. 

Nitric acid converts anisol into two mono-nitroanisols (1, 4) and (1, 2). 


672 ORGANIC CHEMISTRY. 


. Ethyl Phenyl Ether, (C,H,).0 C,H,, Phenetol, is obtained from phenol 
and ethyl salicylic acid. It is an aromatic-smelling ether, boiling at 172°. The 
isoamy]! ether boils at 225°. 

Ethylene Phenyl Ether, (C,H,.0),.C,H,,is formed from ethylene bromide 
and potassium phenylate. It consists of leafleis, melting at 95°. 

Phenyl Ether, (C,H,),O, Phenyl Oxide, is produced by distilling copper 
benzoate (together with benzoic phenyl ether) and digesting diazobenzene sul- 
phate with phenol; also by heating phenol with zinc chloride to 350°, or better, 
wi h aluminium chloride (Berichte, 14, 189). It crystallizes in long needles, pos- 
sesses an odor resembling that of geraniums; melts at 28°, and boils at 252°. It 
dissolves readily in alcohol and ether. It is not reduced on heating with zinc 
dust or hydriodic acid. 





Thiophenol, C,H,.SH, phenyl mercaptan, is obtained by letting phosphorus 
pentasulphide act on phenol or sodium benzene sulphonate; or by the action of 
zinc and sulphuric acid upon C,H,.SO,Cl (p. 660). It is most readily prepared 
by distilling sodium benzene-sulphonate with potassium sulphydrate (Berichte, 17, 
2080). It is a mobile, ill-smelling liquid, boiling at 168°; its specific gravity at 
14° is 1.078. It dissolves readily in alcohol and ether. Like the mercaptans, it 
reacts readily with metallic oxides. The mercury compound, (C,H,.S),Hg, 
crystallizes frm alcohol in shining needles. Silver, mercury and lead salts pre- 
cipitate the alcoholic solution of thiophenol. 

Pheny! mercaptan combines with a-, B- and y-ketonic acids, yielding derivatives 
resembling mercaptol (p. 306and Berichte, 19, 1787). Esters of phenyl thioformic 
acid, C,H,.S.CO,R (Berichée, 19, 1228) result from the action of thiopheny ]-zinc 
and chlorcarbonic esters. 

Phenyl Dithiocarbonic Esters, C,H,.S.CS.OR, are produced when benzene 
diazo-chlorides act upon xanthic esters. ‘They decompose at 200° into COS and 
thiophenols (Berichie, 21, Ref. 915). 

Phenyl Sulphide (C,H,),S, Benzene sulphide, is formed by distilling phenol 
with P,S, (along with thiophenol), and in the dry distillation of sodium benzene 
sulphonate, as well as in the action of benzene-diazochloride upon sodium thio- 
phenate ( Berich/e, 23, 2471). A colorless liquid, with an odor resembling that of 
leeks; boils at 292°, and has a specific gravity of 1.12. Nitric acid converts it into 
phenylsulphone. 

Phenyl Disulphide (C,H,),S., results from the oxidation of thiophenol with 
dilute nitric acid, and by the action of iodine upon aqueous potassium thiophenate : 


2C,H,.SK + 1, =(C,H;),$, + 2KI; 


also, when an alcoholic solution of benzene sulpho-chloride is reduced with potas- 

sium cyanide. 

_ It erystallizes from alcohol in shining needles, melting at 60°, Nitric acid 
oxidizes it to benzene sulphonic acid; and nascent hydrogen converts it into thio- 

phenol. The same occurs by the use of K,S (Berichte, 19, 3129). 
Phenyl-disulphides, containing two different radicals, result from the action of 

bromine upon a mixture of two thiophenols (Berichze, 19, 3132; 20, 189) :— 


C,H,.SH + C,H,(CH,).SH + Br, = C,H (CH, ; <3 4 2HBr, 


PHENOL SUBSTITUTION PRODUCTS. 673 


PHENOL SUBSTITUTION PRODUCTS. 


The introduction of halogen atoms considerably increases the 
acid character of phenol; thus, trichlorphenol readily decomposes 
the alkaline carbonates. When fused with potassium hydroxide 
the halogen is replaced by the hydroxyl group (p. 667): 


C,H,CLOH + KOH = C,H,(OH), + KCl. 


In this reaction it frequently occurs that not the corresponding 
isomerides, but rather, the more stable derivative results; for ex- 
ample, all the bromphenols yield resorcinol. 

Chlorine and bromine react readily; this is exemplified in bro- 
mine precipitating tribromphenol directly upon its introduction into 
phenol solutions. The iodo-derivatives are formed by adding 
iodine and iodic acid to a dilute potassium hydroxide solution of 
phenol :— 

5C,H,O + 21, + 10,1 = 5C,H,10 4+ 3H,0, 


or by the action of iodine and mercuric oxide (p. 91). Di-iodo- 
phenol is the chief product in the latter case. 


Substituted phenols are obtained indirectly: 1, from substituted anilines by the 
replacement of NH, by OH, which may be brought about through the diazo- 
compounds; 2, from the nitrophenols by replacing the nitro-group with halogens 
(effected through the amido- and diazo-derivatives) ; 3, by distilling substituted 
oxyacids with lime or baryta :— 


OH 
{CO,H — C,H,Br.0H + CO,. 


Bromsalicylic Acid. 
Sodium amalgam causes the replacement of the halogen atoms by hydrogen. 





Chlorphenols, C,H,Cl.OH. The para- and ortho-derivatives are produced 
by leading chlorine into boiling phenol; they can be separated by fractional dis- 
tillation. The three chlor-compounds may be obtained perfectly pure from the 
corresponding chlor-anilines (from the chlor-nitro-benzenes). (1, 2)-Ch/orphe- 
nol (also produced from volatile ortho-nitro-phenol) boils at 176°, solidifies 
at —12°, and melts at +7°. It yields pyrocatechin when fused with KOH. 
(1, 3)-Chlorphenol, from (1, 3)-chlor-aniline, melts at 28.5°, and boils at 212°. 
(1, 4)-Chlorphenol (para) consists of colorless prisms, which acquire a red color 
on exposure to the air, melt at 37° (41°) and boil at 217°. Hydroquinone is 
produced when it is fused with caustic potash. The three chlorphenols have a 
very penetrating, adhering odor. 

Dichlorphenol, C,H,Cl,.OH, from phenol (1, 2, 4 — OH in 1), melts at 
43° and boils at 210°. It yields (1, 2, 4)-trichlorbenzene with PCl,. - Trichlor- 
phenol, C,H,Cl,.OH (1, 3, 5, OH) (compare p. 589), obtained by acting on 
phenol with chlorine, melts at 68°, boils at 244°, and reacts acid. Pentachlor- 
phenol, C,Cl,;.OH, formed by the chlorination of phenol in presence of SbCl,, 
melts at 187°. 


, 


674 ORGANIC CHEMISTRY. 


Bromphenols, C,H,Br.OH (Azmnalen, 234, 129). On conducting bromine 
vapors into phenol, or in brominating the glacial acetic acid solution of phenol we 
obtain chiefly (1, 4)- and (1, 2)-monobromphenol; under certain conditions it 
appears that (I, 3) is also produced. They are obtained pure from the brom- 
anilines. 

(1, 2)-Bromphenol, from (1, 2)-bromaniline and from (1, 2)-nitrophenol, is a 
liquid, boiling at 195°. (1, 3)-Bromphenol, from (1, 3)-bromaniline, melts at 32- 
33°, and boils at 236°. (1, 4)-Bromphenol is formed in largest quantity when 
phenol is treated with bromine, and has also been obtained from (1, 4)-brom- 
aniline and from bromsalicylic acid. It consists of large crystals, melting at 66° 
(66.4°) and boiling at 238°. PBr, converts it into (1, 4)-dibrombenzene. 

Dibromphenol, C,H,Br,.OH (1, 2,4 -— OH im 1), from phenol, melts at 
40°. Tribromphenol, C,H,Br,(OH) (¥, 3, 5, OH), is directly precipitated 
from aqueous phenol solutions by bromine water. It crystallizes from alcohol in 
silky needles, melting at 92°. PBr, converts it into tetrabrombenzene, melting at 
98°. Nitric acid converts it into picric acid. Tetrabromphenol, C,HBr,OH, 
melts at 120°; Pentabromphenol, C,Br,OH, at 225°. 

Iodophenols, C,H,I.OH. When phenol is acted upon by iodine and iodic 
acid three mono-iodo-phenols are said to be formed; of these the ortho- and 
meta- volatilize with steam, the para- does not (Berichte, 6, 1251). 

(1, 2)-lodophenol is obtained from (1, 2)-amido-phenol and from iodosalicylic 
acid. It is also produced when iodine acts upon sodium phenoxide (Berichze, 16, 
1897). It melts at 43° and when fused with KOH yields pyrocatechin (at 200°) 


. and resorcinol. (1, 4)-odophenol, from phenol, (1, 4)-amidophenol and (1, 4)- 


iodo-aniline, melts at $9°, and when fused with KOH forms hydroquinone at 160°, 
but resorcinol at higher temperatures. 





NITROSO-DERIVATIVES OF PHENOL, 


The nitrosophenols, analogous to the nitroso-benzenes (p. 591), 
were first made by the action of nitrous acid upon phenols, and 
again they are obtained from the quinones by the action of hydroxyl- 
amine, and may, therefore, be considered as isonitroso-derivatives 
(p. Ig), or quinoximes (see quinone). In accordance with their 
mode of formation they have the formulas of nitrosophenols or of 
quinoximes (Goldschmidt, Berichte, 7, 213, 801) :— 


OH O 
sH,Z and C,H,7 or C,H,~ | 
\No SN.OH \N.OH 


Nitrosophenol. Quinoxime. 


eg 


These formulas are probably tautomeric. The formation of quinone-dioxime 
argues in favor of the formula ascribed to quinoxime (p. 675); it is also supported 
by the deportment of the two nitrosonaphthols with hydroxylamine, and their 
ethers when reduced (see nitrosonaphthols, Berichte, 18, 571); further, by the 
action of methyl hydroxylamine upon naphthoquinones (Zerich/e, 18, 2224), by 
the feeble basic character of the nitrosophenols (Berich/e, 18, 3198), and the for- 
mation of hypochlorous esters, C,H,(O).NOCI, when acted upon by bleaching 
lime (Berichte, 19, 280). An argument in favor of the nitrosophenol formula is 
found in their oxidation to nitrophenols, and subsequent reduction to amido- 
phenols. 


NITROSOPHENOL, QUINOXIME. 675 


The so-called nitrosophenols are formed :— 
1. By the action of nitrous acid upon the phenols :-— 


C,H,.0H + NO,H = C,H,(NO).OH + H,0. 


Phenol is dissolved in a dilute alkaline hydroxide, the equivalent amount of po- 
tassium nitrite added, thé solution cooled with ice, and gradually supersaturated 
with dilute sulphuric or acetic acid (Berichte, 8, 614). 

Instead of nitrous acid we may employ the action of nitro-sulphuric acid, 
50,7 ou > upon aqueous phenols (Amma/en, 188, 353). 

In both reactions nitrous acid is liberated and occasions the production of con- 
siderable resin. Hence, it is advisable to employ the nitrites of heavy metals, 
which are decomposed by the phenols themselves (Berichte, 16, 3080). 

In many cases the action of amyl nitrite upon sodium phenoxides is adapted 
for this purpose. 

It is noteworthy that while the mono-hydric phenols yield only mono-nitroso- 
compounds, two nitroso-groups directly enter the divalent phenols of the meta- 
series (like resorcinol and orcinol). 

2. By the action of HCl-hydroxylamine upon quinones in aqueous or alcoholic 
solution. Free hydroxylamine reduces the quinones to hydroquinones (Zerichée, 
17, 2061). : 


fp-Nitrosophenol, Quinoxime, C,H,(NO).OH, or 
YO : . 5S 
eS Cn. OH Besides the general methods just mentioned, it is 
also obtained by a peculiar decomposition of nitroso-dimethyl- or 
diethyl aniline (p. 602) with sodium hydroxide :— 


_ CsH,(NO).N(CH,), + NaOH = C,H,(NO).ONa + NH(CH,),. 


It is produced, further, by the action of hydroxylamine hydro- 
chloride upon an aqueous solution of quinone, C,H,O, (see above). 


Preparation.—It is made from phenol by the action of NO,K and acetic acid 
(Berichte, 7, 967), or nitroso-sulphuric acid (Annalen, 188, 360; Berichte, 21, 
429). Its production from nitroso-dimethyl-aniline is more convenient. The 
pure (free from alcohol) hydrochloride of the latter is introduced into boiling, 
dilute sodium hydroxide, the dimethyl-amine formed is distilled off, the residue 
acidified with dilute sulphuric acid, and then shaken with ether (erichie, 7, 964, 
and 8, 622). We can easily obtain sodium nitrosophenylate by adding phenol (1 
molecule), and then amy] nitrite (1 molecule) to a concentrated solution of sodium 
ethylate (1 molecule), and allowing the whole to evaporate over sulphuric acid 
(Berichte, 17, 400). The free nitrosophenol is obtained by decomposing the 
sodium salt with dilute sulphuric acid (Berichte, 17, 803). 


Pure nitrosophenol crystallizes from hot water in colorless, deli- 
cate needles, which readily brown on exposure, and from ether it 
separates in large, greenish-brown leaflets. It is soluble in water, 
alcohol and ether, and imparts to them a bright green color. When 
heated it melts with decomposition, and deflagrates at 110-120°. 
The sodium salt crystallizes.in red needles, containing two mole- 


676 ORGANIC CHEMISTRY. — 


cules of water; salts of the heavy metals throw out dark, amorphous 
precipitates. 


Nitric acid and potassium ferricyanide in alkaline solution, oxidize /-nitroso- 
phenol to g-nitrophenol. Tin and hydrochloric acid reduce it to.f amidophenol. 
Hydrochloric acid converts it into dichloramido-phenol. With nitrous acid and 
with hydroxylamine, it yields diazo-phenol :— 


C,H,(OH)NO + NH,.OH = C,H,(OH).N,.0H + H,0. 


In a similar manner it forms azo-compounds with the amines (p. 641); these 
are obtained, too, on fusion with caustic alkali. On adding a little concentrated 
sulphuric acid to a mixture of nitrosophenol and phenol, we obtain a dark red 
coloration, which changes to dark blue upon adding caustic potash (p. 668). 

Other phenols, like naphthol, resorcinol and orcinol, yield similar nitroso-deriva- 
tives. These same products can also be prepared from the corresponding quinones, 
by the action of hydroxylamine hydrochloride (Berichte, 17, 2060). 

When hydroxylamine hydrochloride acts upon /-nitrophenol (or upon quinone 
or hydroquinone in hydrochloric acid solution) we get Quinone Dioxime, HO.N: 
C,H,: N.OH (Berichte, 20, 613), crystallizing from hot water in yellow needles. 
It is not as acid as nitrosophenol, and decomposes on heating to 240°. Stannous 
chloride and hydrochloric acid reduce it to g-phenylene diamine, and by ferri- 
cyanide of potassium it is oxidized in alkaline solution to -dinitrosobenzene 
(p. 591). The formation of quinone-dioxime confirms the assumption of nitroso- 
phenol being a mono-oxime of quinone (p. 674). 


NITRO-PRODUCTS OF PHENOL. 


The phenols, like the anilines,.are very readily nitrated. The 
entrance of the nitro-groups increases their acid character very con- , 
siderably. All nitrophenols decompose alkaline carbonates. Tri- 
nitrophenol is a perfect acid in its behavior; its chloranhydride, 
C,H,(NO,);Cl, reacts quité readily with water, re-forming trinitro- 
phenol (p. 667). The benzene nucleus of the nitrophenols is 
capable of ready substitution with the halogens; whereas the nitro- 
hydrocarbons are chlorinated with difficulty, 

Dilute nitric acid converts phenol into ortho- and para-mono- 
nitrophenol (in the cold it is chiefly the para-compound which is 
formed). 


Preparation.—Gradually add one part phenol to a cooled solution of two parts 
of nitric acid (specific gravity 1.34) in four parts of water. The oil which 
separates is washed with water. and distilled with steam, when the volatile (1, 2)- 
nitrophenol distils over, while the non-volatile (1, 4)-nitrophenol remains. It is 
extracted from the residue by boiling with water. 


o- and #-Nitrophenols are obtained by heating the corresponding 
chlor- and brom-nitrobenzenes with caustic potash to 120°, whereas 
m-nitrobenzene does not react under similar circumstances (p. 588). 
Ortho- and para-nitrophenols are likewise produced from the cor- 


- TRINITROPHENOLS. | 677 


responding nitranilines by heating with alkalies (p. 598). -Nitro- 
phenol is formed from m-nitraniline (from ordinary dinitrobenzene) 
by boiling the diazo-compound with water. See Lerichie, 19, 
2979, for the benzoyl derivatives of the nitrophenols. 


Mononitrophenols, C,H,OH(NO,). The volatile orthonztrophenol (1, 2) 
crystallizes in large yellow prisms, is but slightly soluble in water, and readily 
volatilizes with steam. It has a peculiar odor, and sweetish taste; melts at 45°, 
and boils at 214°. (1, 2)-Chlornitro-benzene is obtained from it by PCI;. Its 
sodium salt is anhydrous, and forms dark red prisms. The methyl ether, C,H, 
(NO,),O.CHg, melts at + 9°, and boils at 265°. Caustic potash does not decom- 
pose it. ; 

(1, 3)-Mitrophenol, from (1, 3)-nitraniline, is rather readily soluble in cold 
water, forms yellow crystals, melts at 96°, and is not volatilized with steam. Its 
methyl ether melts at 38° and boils at 254°. 

(1, 4)-Mitrophenol crystallizes from hot water in long, colorless needles, which 
become red on exposure. It is colorless and melts at 114°. PCI; converts it 
into (1, 4)-chlornitrobenzene. The potassium salt crystallizes in yellow needles 
with two molecules of water. The methyl ether melts at 48°, and boils at 260°; 
it forms (1, 4)-nitraniline when heated with ammonia. Nitrophenol can, on the 
one hand, be changed to quinone, on the other, into anisic acid. 
Bromine converts f-nitrophenol into dibrom-g-nitrophenol, Cg BEG" 
(1, 2, 4, 6, OH in 1), melting at 141°. This yields Dibrom-f-amido-phenol, 
when reduced with tin and hydrochloric acid. The latter (its SnCl,-salt) is 


converted by bleaching lime into dibrom-quinone-chlorimide, C.H,Br. fig 
O 


which yields indophenol dyestuffs (see quinone chlorimides) with phenols. 

a-Dinitrophenol, C,H,(NO,),.0H (1, 2, 4—OH in 1), is formed by the 
direct nitration of phenol, as well as of (1, 2)- and (1, 4)-nitrophenol; by boiling 
' a-dinitro-chlor- and dinitro-brom-benzene (p. 589) with alkalies, and (together 
with B-dinitrophenol) by oxidizing metadinitrobenzene with alkaline potassium 
ferricyanide. It crystallizes from alcohol in yellow plates, and melts at 114°. 
PCI, changes it to dinitrochlorbenzene. Its methyl ether melts at 86°, and is 
saponified by boiling alkalies. The ether is transformed into a-dinitraniline by 
heating with ammonia. From this (1, 3)-dinitrobenzene may be prepared by re- 
placing the amido group by hydrogen (through the diazo-compound). 

§-Dinitrophenol (1, 2, 6—OH in 1) is produced with the former in the nitra- 
tion of (1, 2)-nitrophenol. It yields needles, melting at 64°. By replacing its 
OH-group with hydrogen it passes into (1, 3)-dinitrobenzene. : 

Further nitration converts both dinitrophenols into picric acid. Three isomeric 
dinitrophenols are obtained by the nitration of (1, 3)-nitrophenol; these melt at 
104°, I 34° and 141°. Further action of nitric acid converts them into trinitro- 
resorcinol, 


Trinitrophenols, C,H,(NO;);.0H. Picric Acid is obtained 
by the nitration of phenol, of (1, 2)- and (1, 4)-nitrophenol, and 
of the two dinitrophenols ; also, by the oxidation of symmetrical 
trinitrobenzene with potassium ferricyanide. Its structure is there- 
fore 1, 2, 4,6(OH in 1) (p. 589). 

Picric acid is produced in the action of concentrated nitric acid 


678 ORGANIC CHEMISTRY. 


upon various organic substances, like indigo, aniline, resins, silk, 
leather and wool. 


Preparation.—Add phenol (1 part) very gradually to concentrated nitric acid, 
slightly warmed. The reaction proceeds with much energy, and disengages 
brown vapors. Next add three parts fuming nitric acid and boil for some time, 
until the evolution of vapors ceases. The resulting resinous mass is boiled with 
hot water. To purify the picric acid obtained, convert the latter into its sodium 
salt, and toits solution add sodium carbonate when sodium picrate will separate in 
a crystalline form. 


Picric acid crystallizes from hot water and alcohol in yellow leaf- 
lets or prisms which possess a very bitter taste. It dissolves in 160 
parts of cold water and rather readily in hot water. Its solution im- 
parts a beautiful yellow color to silk and wool. It melts at 122.5°, 
and sublimes undecomposed when carefully heated. The fosassium 
salt, C,H.(NO,);OK, crystallizes in yellow needles, which dissolve 
in 260 parts of water at 15°. The sodium salt is soluble in 10 parts 
water at 15°, and is separated from its solution by sodium carbon- 
ate. The ammonium salt consists of beautiful, large needles, and 
is applied in explosive mixtures. All the picrates explode very 
violently when heated or struck. 3 

Phosphorus pentachloride converts picric acid into trinitro-chlor- 
benzene, C,H,(NO,);Cl (p. 590), which reverts to picric acid on 
boiling with water. 

The methyl ester of picric acid is also produced in the nitration of anisol (p. 
671) and crystallizes in plates, melting at 65°, and subliming. Alcoholic potash 
saponifies it. The ethyl ester consists of colorless needles, which brown on expo- 
sure, and melt at 78.5°. 

Picric acid forms beautiful crystalline derivatives with many benzene hydro- 
carbons, ¢. g., benzene, naphthalene and anthracene. The benzene derivative, 
C,H,(NO,),0H.C,H,, crystallizes in needles, melting at 85-g0°. In dry air or 
with hot water it decomposes into its components. 


The so-called isopicric acid, obtained by the energetic nitration 
of (1, 3)-nitrophenol, is trinitroresorcinol, CsH(NO,);.(OH),(styph- 
-nic acid). 


Picric acid is converted by potassium cyanide into the potassium salt of zsopzr- 
purie or picrocyaminic acid, C§H,N,O,, which is not stable in a free state. To 
obtain the salt the hot solution of 1 part picric acid in 9 parts of water is poured 
gradually into a solution of two parts of potassium cyanide in four parts of water, 
at a temperature of 60°, The liquid assumes a dark red color, and when it cools 
a crystalline mass separates, which is washed with cold water and recrystallized 
from hot water. 

The potassium salt, C,H,N,O,K, crystallizes in brown leaflets with green- 
gold lustre, and serves as a substitute for archi/. It dissolves in hot water and 
alcohol with a purple red color. It explodes at.215°. The other salts of isopur- 
puric acid are obtained by double decomposition,, 


AMIDO-DERIVATIVES OF PHENOL. 679 


The dinitrophenols yield similar derivatives with potassium cyanide. 

Two isomeric Trinitrophenols ($- and y-) are obtained by nitrating the di- 
nitrophenols prepared from meta-nitrophenol and are very similar to picric acid. 
8-Trinitrophenol melts at 96°; y-trinitrophenol at 117° ( Berichée, 16, 235). 


Innumerable chlornitrophenols have been obtained by the action 
of the halogens upon the nitrophenols, or by nitration of the halo- 
gen derivatives. 





AMIDO-DERIVATIVES OF PHENOL. 


These, like the anilines, are obtained by the reduction of the 
nitrophenols. In the case of the poly-nitrated phenols, ammonium 
sulphide occasions but a partial, tin and hydrochloric acid, how- 
ever, a complete reduction of the nitro-group (p. 592). Thus, 
dinitrophenol, C,H;(NO,),.OH, yields nitro-amido-phenol, C,H;. 
(NO,)(NH),.OH, and diamido-phenol, C,H;(NH,),.OH. 

The amido-group considerably diminishes the acid character of 
the phenols. This class of derivatives no longer forms salts with 
alkalies, and only yields such compounds with the acids. Their 
amido-hydrogen, like that of the anilines, is replaced by acid 
radicals on heating with acid chlorides or anhydrides. 


1. o-Amidophenol, C,H,(NH,).OH, is produced from orthonitrophenol by 
reduction with tin and hydrochloric acid, and is precipitated from its HCl-salt by 
alkaline carbonates in colorless leaflets, which rapidly turn brown. It is more easily 
obtained by dissolving orthonitrophenol in alcoholic ammonia, and leading H,S into 
the solution, when the phenol separates in crystalline form. It melts at 170° and 
is slightly soluble in water (in 50 parts). When potassium cyanate acts upon 
the hydrochloride of orthoamidophenol, it produces oxyphenyl urea, C,H,(OH). 
NH.CO.NH,, melting at 154°. Potassium sulphocyanide forms oxypheny! thio- 
urea, C,H ,(OH).NH.CS.NH,, melting at 161°. 0-Amidophenol can form anxhy- 
dro- or ethenyl-bases ; this it does by uniting its two side-chains to a carbon atom. 
These new derivatives contain both the benzene ring and that of oxazole (p. 555). 
As they have two carbon atoms in common, they are called denzoxazoles :-— 


JON 
*\NZ 
The method pursued in producing this new class of compounds consists in heat- 


ing o-amidophenols with acids or anhydrides, Acidyl derivatives are first formed, 
but they part with water :— 


C,H CH, Benzoxazole. 


/ OH ae SON 
CHC NHcHO = CHC y DCH + H,0. 
Formyl Amido-phenol. Methenyl-amido-phenol. 


In like manner ethenylamido-phenol is derived from acetyl amido-phenol, 
Phosgene, COCI,, gives rise to the oxy-methenyl derivative (see below). 


680 ORGANIC CHEMISTRY. 


The thichydrides of the anhydro-bases are formed :— 


(1) By heating o-amidophenols with carbon disulphide. 

(2) From o-oxyazobenzene by a similar treatment ; as well as from the hydra- 
zones of ortho-quinones (Berichte, 22, 3232, 3241). 

_ The benzoxazoles are feeble bases. Their combinations with salts are unstable. 
Boiling hydrochloric acid separates them into their components. 

Methenyl Amidophenol, benzoxazole, is produced by boiling o-amido- 
phenol with formic acid. It consists of vitreous crystals, melting at 30.5°, and boil- 
ing at 182°. 

Oxymethenyl-amidophenol, or Carbonyl-Amidophenol, derived from the 
preceding, possesses an atomic grouping analogous to that of the lactams or lac- 
times (see these) :— 

N NH 
C.H,< 9 SCO ee Ged CO. 


These two formulas are probably tautomeric. The above compound is formed 
by allowing chlor-carbonic ester to act upon o-amidophenol;.and by heating oxy- 
phenyl urea (see above). NH, splits off. It sublimes in leaflets with mother-of-pearl] 
lustre ; these melt at 137° and yield an acetyl derivative, melting at 95° (Berichte, 
16, 1829). It is most readily made by conducting COC], into the benzene solution 
of o-amidophenol (erichte, 20, 177). In most reactions it conducts itself as a 
lactam (zé2d.) ; it also unites, as a CO-compound, with phenylhydrazine (Berichée, 


19, 2270). 
Two different ethers are obtained by replacing its hydrogen by alkyls :— 
N N(C,H;) 
YX 2.5 
CoHAC | C.0.CHs and CHC | >C0. 
Lactime Ether. Lactam Ether. 


The Zactime ether is produced by acting upon o-amidophenol hydrochloride with 
imido-carbonic ester (Berichte, 19, 2655). It is an oil with peculiar odor, and 
boils at 225—230°. When digested with concentrated hydrochloric acid, it breaks 
down into ethyl chloride and oxymethenyl-amido-phenol. 

The Zactam ether is formed when ethyl iodide and carbonyl-amidophenol interact 
in alkaline solution (Berichte, 19, 2268; 20,177). It melts at 29°, and when 
heated with concentrated hydrochloric acid to 180°, it is resolved into carbon di- 
oxide and ethyl-amido-phenol. 

The sz/phur compound, corresponding to oxymethenyl-amidophenol, 


NX NH 
CHC 6 SCSH or CHK Gg > CS, 
Thiohydryl-methenyl-amido- Thiocarbonyl-amido- 

phenol. phenol. 


is produced either by the action of carbon disulphide upon o-amidophenol, or of 
potassium xanthate upon the hydrochloride; further, upon heating oxyphenyl 
sulphurea (see above) (Berichte, 16, 1825; 20,178). It melts at 193-196°, and 
dissolves in alkalies and ammonia. When boiled with aniline it becomes Anilido- 


carbamido-phenol, CoH. SCNH.C.H,, melting at 173°. Amido-car- 


bamido-phenol, C,H WG ONE, isomeric with phenylene urea (Berichte, 
23, 1047), is formed on boiling oxyphenyl thiourea (p. 679) with mercuric 
oxide. It crystallizes from water in large plates, melting at 130°. The ethe- 


AMIDO-THIOPHENOL. 681 


nyl compound is a liquid, and boils at 182°. Benzenyl-amido-phenol, 
C,H ea C,H,, is produced by the reduction of benzoyl-ortho-nitrophenol, 
and when digested with hydrochloric acid yields Benzoyl-amido-phenol, 
C,H,(OH).NH.CO.C,H,,. , 

Methyl iodide (3 molecules) and potassium hydroxide change o-amidophenol 
(analogous to the formation of betaine from glycocoll, p. 316) into Trimethyl 
N(CH 

~ 

*NOo 
from water in white prisms, containing 1H,O. It tastes bitter, and dissolves easily 
in water but notin ether. It breaks up by distillation into CH,Cl and Dimethyl- 
amido-phenol, C,H,(OH).N(CH,),, which melts at 45°. Its HC\l-salt, 
C,H KOH si wae gives the base again with silver oxide. 

2. m-Amidophenol, C,H,(NH,).OH (1, 3), is obtained by the reduction of 
meta-nitrophenol with tin and hydrochloric acid. Technically, it is produced by 
heating resorcin to 200° with hydrochloric acid and ammonia (Berichée, 22, Ref. 
849). In this way the alkylamines yield the alkyl-s-amido-phenols. The latter 
can also be obtained from the dialkyl-aniline sulphonic acids (Berichte, 22, 622). 
Free-m-amidophenol is not very stable. Nitric acid converts it into resorcin. 
Dimethyl.m-amidophenol melts at 87°; diethyl-m-amidophenol boils at 280°. 
m-Amidophenol and its alkyl derivatives are employed in the preparation of 
rhodamine dyes. 

3. p-Amidophenol, C,H,(NH,).OH, is obtained by reducing /-nitrophenol 
with tin and hydrochloric acid, and by distilling amidosalicylic acid. It sublimes 
in shining leaflets, and melts at 184° with decomposition. It is oxidized to 
quinone by chromic acid, or by PbO, and sulphuric acid. Bleaching lime con- 
verts it, as well as its substitution products, into quinone chlorimides. 

p-Amidophenetol, C,H ,(NH,).0.C,H,;, Phenetidine, is the ethyl ether. It 


boils at 242°. Boiling glacial acetic acid converts it into CHGcH 
ee ok. 


-ammonium-phenol, C,H si (Berichte, 13, 246), which crystallizes 


phenacetin, which has been applied as an antipyretic. 





Amido-thiophenol, C,H,(NH,)SH, (1, 2), is obtained from ortho-nitro-ben- 
zene-sulphonic chloride, C,H,(NO,).SO,Cl, by reduction with tin and hydro- 
chloric acid; also from acetanilide, C,H,.NH.CO.CHsg, by heating with sulphur 
and fusing with caustic alkali (Berichte, 13, 1226). A better method to pursue is 
to fuse benzenyl-amidothiophenol with caustic potash (Berichte, 20, 2259). It 
crystallizes in needles; melting at 26°, and boiling at 234°. ; 

o-Amido-thiophenol (like o-amidophenol, p. 679) forms ¢hioanhydro-compounds 
by linking its two side-chains to a carbon atom. Because these derivatives con- 
tain the thiazole-ring they are called Benzothiazoles :— 


NX : 
CHK § OX, Benzothiazole. 

They bear the same relation to quinoline that thiophene bears to benzene (they 
contain an S-atom instead of the group HC : CH, hence they show similarity to 
the quinoline compounds (Berichte, 21, 2629). They are formed :— 


57 





68s ORGANIC CHEMISTRY. 


(1) By the action of acid chlorides or anhydrides upon the o-amido-thiophenols 
. 680) : 


(P a8 
/NH a SNS 
CoH gy? + CHO.OH = C,H, ¢ SCH + 2H,0. 
Methenyl Amido- 
thiophenol, Benzo- 
thiazole. 


If acetyl chloride be used the product will be ethenyl amido-thiophenol or 
benzo-methyl-thiazole. ; 
(2) By oxidizing the thioanilides with alkaline potassium ferricyanide (Berichie, 
21, 2624; 22, 905) :— 
CH. .NH.CS.CH, + 0 = CoH< ¢ SCCH, + H,0. 


Thioacetanilide. Ethenyl-amido- 
thiophenol. 


(3) By boiling the acid anilides with sulphur (in slight quantity) (Berichte, 13, 
1223; 22, 905) :— 


C,H,.NH.CO.C,H, +S =C,H,~ SCG + H,0. 
Benzanilide. Benzenyl-amido-thiophenol. 


(4) The thiohydrides of the anhydrobases may be obtained from the o-amido- 
thiophenols and CS, (Berichte, 20, 1790) :— 


Cel preetok tne gly 5 SCSH + SH,. 
Thiomethenyl-amido- 
thiophenol. 


The benzo-thiazoles are liquids that boil without decomposition. They have an 
odor like that of pyridine. Their salts are not very stable. Fused alkalies 
decompose them into their components. . 

The Methenyl-amido-thiophenol, C,H ce en, benzo-thiazole (isomeric 
with phenyl mustard oil, C,H,.N:CS, and phenyl sulphocyanate, C,H;.S.CN), is 
produced on heating amidothiophenol with formic acid. It is an oil smelling like 
pyridine, and boiling at 230°. 

Chlormethenyl-amido-thiophenol, chlorphenyl mustard-oil, C,H,NSCI, 
results from phenyl mustard-oil on heating it to 160° with PCI, :— 


C,H,.N:CS + Cl, = CHC § yeCl + HCl. 

It melts at 24°, and boils at 248°. It reverts to methenyl amidothiophenol by the 
action of tin and hydrochloric acid. The chlorine atom in it is readily adapted to 
double decompositions. The hydroxide, C,H,(SN)C.OH, oxy-phenyl mustard- 
oil, melts at 136°, and dissolves readily in alkalies. Sodium ethylate converts the 
chloride into the ethyl oxide (ethyl oxyphenyl mustard-oil), C,H,.(SN).C.O. 
C,H,. This results from the oxidation of phenyl-sulphurethane with potassium 
ferricyanide (see above). It melts at 25°, and when boiled with hydrochloric acid 
yields the hydroxide. 

The amide melts at 129°. The thiohydride, C,H,(NS)C(SH), results 


TRIAMIDOPHENOL. 683 


when the chloride is acted upon with alcoholic sodium sulphydrate and from : 
o-amidophenol and CS,. It melts at 179° (Berichte, 20, 1790). 


Ethenyl-amido-thiophenol, C,H,{§FC.CHy is obtained by boiling 
o-amido-thiophenol with acetic anhydride, and by oxidizing thioacetanilide (see 
above). It is a liquid, boiling at 238°. 

Benzenyl-amido-thiophenol, CoHAC§ VOCs, results upon heating 
phenylbenzamide with sulphur, and also in the oxidation of thiobenzanilide with 


potassium ferricyanide (see above and Berichte, 19, 1068). It crystallizes in long 
needles, melting at 114°. g 





Dinitro-amido-phenol, C, H,(NH,).(NO,),.OH, picramic acid, is obtained by 
reducing ammonium picrate in alcoholic solution with hydrogen sulphide. It 
forms red needles, which melt at 165°. It yields red-colored crystalline salts with 
bases. 

Triamidophenol, C,H,(NH,),-OH, is obtained from picric acid by the 
action of phosphorus iodide, or by tin and hydrochloric acid (Berichte, 16, 2400). 
When set free from its salts it decomposes very quickly. Its salts, with 3 equiva- 
lents of acids, crystallize well. The HI-salt, CoH, O(N, )s 311, crystallizes 
in colorless needles. These salts color water which is faintly alkaline, and even 
spring water, a beautiful blue. If ferric chloride be added to the solution of 
the hydrochloride, it will become deep blue in color, and brown-blue needles 
with metallic lustre will separate ; they are WC/-amido-di-imido-phenol, C,H,(OH) 


(NEL) Nu which dissolves in water with a beautiful blue color. 





Diazo-compounds of the Phenols, such as phenol diazochloride, C,H 


result from the action of nitrous acid upon the amido-phenols; free diazo-com- 
pounds have been obtained from the substituted amido-phenols, ¢. ¢. -— 


C,H,Cl, { ot» C,H,(NO,) { ot C,H,(NO,), { Re 


in which the second affinity of the diazo-group appears to be joined to oxygen 
(p. 630). 

Analogous sulphur-compounds, the diazo-sulphides, are formed when nitrous 
acid acts upon the o-amidothiophenols and their anhydro-compounds (Berichte, 
22, 905) :— 


CHA Sy + NO,H = CHK GSN 4+ 2H,0. 


They are very stable and crystallize well. They distil without decomposition 
under reduced pressure. 

o-Phenylene-diazosulphide, C HLT IN, is easily produced when nitrous acid 
acts upon benzenyl-amidothiophenol. It forms large plates, having a pleasant 
odor. It melts at 37°, and volatilizes with steam. 

The azo-derivatives of the phenols are produced by reduction of the nitro- 
phenols in alcoholic potassium hydroxide. solution (p. 641); further, by the action 


684 2 ORGANIC CHEMISTRY. 


of the anilines upon the nitrosophenols. They are perfectly analogous to the azo- 
‘derivatives of the benzenes (Berichte, 17, 272). 





Amidothiophenyls or Thioanilines. 
These compounds result when nitrothiophenyls are reduced. The diamido- 
phenyl sulphides are also produced from anilines by boiling the latter with 
sulphur :— 
/C,H,.NH 
oe H, .NH, 


The alkyl anilines and sulphur yield derivatives resembling the thiazoles (Berichte, 
22, 67). Sulphur chloride, or thionyl chloride, SOCI, (Berichte, 21, 2056; 23, 
552), converts the dialkylanilines into alkylic-thio-anilines. The mono-alkyl- 
anilines, by like treatment, yield Zhzony/ anilines, e. g., SO (C,H,.NH.CH,), 
(Berichte, 23, 3020). Silver nitrate and ammonia desulphurize the dialkyl-com- 
pounds, with the formation of oxydimethylanilines, e. ¢., O[C,H,.N(CH,), ], 


(Berichte, 21, 2056). 
Diamidophenyl Sulphide, S< ei Ht NE Thioaniline, results from the reduc- 


2C,H,.NH, +S, =S 24 SH,. 


tion of dinitrophenyl-sulphide (p. 672), and by heating aniline and sulphur to 150-— 
160°, then adding litharge (Berichte, 4, 384). It crystallizes from hot water in 
long ‘needles, melting at 105°. 

Thio p-toluidine, SCF H(CH,) NH” Diamidotolyl Sulphide, is obtained by 
heating /-toluidine with “sulphur and litharge to 140°. It crystallizes in large 
leaflets. melting at 103°. The sodium salts of thio- and dithio toluidine sulphonic 
acids dye unmordanted cotton (Berichte, 21, Ref. 877). 

The bi-diazo salts of thio-toluidine combine with naphthylamine- sulphonic acids 
and yield disazo dyes of a brown-red color (Berichte, 20, 664). 

Dehydrothio toluidine, C,,H,,N,S, is formed when thio-g-toluidine and sul- 
phur are heated to 185° (Berichte, 22, 423,581, 970). It crystallizes from alcohol 
in yellow needles, melting at 191°. Its alcoholic solution shows a beautiful blue 
fluorescence. Another base, very similar to the preceding, is formed at the same 
time it is produced. The sodium sulphonate of the latter is pr7mu/ine, which 
dyes unmordanted cotton yellow if it be diazotized upon the fibre. It can also 
combine with phenols and anilines. 

Benzenyl-p-m-amido-thiocresol, CH,.C,H go C,H,, results when the 

amido-group is eliminated from dehydro-thio-toluidine. It may be synthetically 
prepared by oxidizing thio-benz-toluidine, CH,.C,H,NH.CS.C,H, (p. 682) 
( Berichte, 22, 1063). 





PHENOL-SULPHONIC ACIDS. 


Ortho- and Para-phenolsulphonic Acid, C,H,(OH).SO,;H, 
are formed when phenol dissolves in concentrated sulphuric acid ; 
at medium temperatures the former is the more abundant, but 
readily passes into the para- on the application of heat. 


Preparation.—To obtain the acids, the solution of phenol in sulphuric acid 
equal parts) is diluted with water and saturated with calcium carbonate. The 
Itrate from the gypsum, containing the calcium salts, is boiled with potassium 

carbonate, thus producing potassium salts. On allowing it to crystallize the potas- 


HOMOLOGOUS PHENOLS. 685 


sium salt, C,H,(OH).SO,K, of the para-acid first separates in hexagonal plates ; 
later the ortho-salt, C,H,(OH).SO,K + 2H,0, crystallizes out in prisms, which 
soon effloresce on exposure (Annalen, 205, 64). 

The free acids can be obtained in crystalline form by the slow evaporation of 
their aqueous solution. When the aqueous ortho-acid is boiled it changes to para. 
The aqueous soijution of the ortho-acid is applied as an antiseptic under the name> 
of aseptol ( Berichte, 18, Ref. 506). The para-acid yields quinone if its sodium 
salts be oxidized with MnO, and sulphuric acid. PCI; converts it into (1, 4)- 
chlor-phenol and (1, 4)-dichlorbenzene. When the ortho-acid is fused with KOH 
at 310° it yields pyro-catechin—hence it belongs to the ortho-series; the para- 
acid does not react at 320°, and at higher temperatures yields diphenols. 

The iodation of the para-acid produces Dz-iodo-phenol sulphonic Acid, C,H, 
I,.(O0H).SO,H. This is applied as an antiseptic, bearing the name Sozo-zodol 
(Berichte, 21, Ref. 250). 

Meta-phenolsulphonic Acid (1, 3) is produced when meta-benzene-disul- 
phonic acid (p. 663) is heated to 170-180° with aqueous potassium hydroxide 
(Berichte, 9, 969). The potassium salt, C,H,(OH).SO,K + H,O, effloresces 
in the air; the free acid consists of delicate needles, and contains 2 molecules of 
H,O. Fusion with potassium hydroxide at 250° converts it into resorcinol (1, 3). 
When para-benzene-disulphonic acid is heated with caustic alkali, meta-phenol- 
sulphonic acid is also produced at first, but it yields resorcinol later. 

Phenol-disulphonic Acid, C,H,(OH).(SO,H),, results from the action of 
an excess of sulphuric acid upon phenol, also upon (1, 2)- and (1, 4)-phenol- 
sulphonic acid, hence its structure is (1,2,4—-OH in 1). It is further produced 
in the action of SO,H, upon diazobenzene sulphate. The solutions of the acid 
and its salts are colored a dark red by ferric chloride. . 

Phenol-trisulphonic Acid, C,H,(OH).(SO,H), (1, 3, 5, OH), is obtained 
when concentrated sulphuric acid and P,O; act upon phenol. It crystallizes in 
thick prisms with 3%4H,O. 





HOMOLOGOUS PHENOLS. 


1. Cresols, Ce oe Oxy-toluenes. 

The cresol contained in coal-tar appears to contain three isomer- 
ides, but they cannot be separated. They are obtained pure from 
the amido-toluenes (toluidines) by replacing the amido-group by 
hydroxyl, and from the toluene-sulphonic acids by fusion with 
potassium hydroxide. The cresols are changed to toluene when 
heated with zinc dust. Sodium and carbon dioxide produce the 
corresponding cresotinic acids, C;H;(CH;)(OH).CO,H. 


Ortho-cresol (1, 2), from ortho-toluidine and ortho-toluene-sulphonic acid, 
melts at 31°, and boils at 188°. It is obtained from carvacrol (p. 688) when 
heated with P,O,. It yields salicylic acid (1, 2) on fusion with potassium 
hydroxide; Fe,Cl,; colors it blue. For its nitro-derivatives, see Berichte, 15, 
1860, and 17, 270. 

LVitroso-o-cresol, from o-cresol by means of nitrous acid and from toluquinone 


and hydroxylamine (p. 676), melts at 134°. Consult Ze. I I, for azo- 
est LEAS 
z 


and diazo-compounds of the cresols, 
EF THE 


( UNIVERSITY. 


r* 
ty ee ee 





686 ORGANIC CHEMISTRY. 


Meta-cresol (1, 3) is formed from thymol (p. 688), when digested with phos- 
phoric anhydride :— 
C,H,O = C,H,.OH + C,H,, 


also from m-toluidine (from 7-nitrobenzaldehyde). 

Meta-cresol is a thick liquid, which solidifies when exposed to cold, melts at 
4-5° (Berichte, 18, 3443), and boils at 201°, Its benzoyl derivative, C,H,O. 
C,H;0, melts at 38°, and boils at 300°. The methyl ether is an oil boiling at 176° ; 
it is oxidized by potassium permanganate to methyl-meta-oxybenzoic acid. Meta- 
cresol yields meta-oxy-benzoic acid on fusion with caustic potash. The nitration 
of meta-cresol forms a trinitro-cresol, while the ortho- and para-derivatives only 
yield dinitro-derivatives (Berichte, 15, 1864). 


Trinitro-m-cresol, CgH,(NO,)s 644°» Melts at 106°; it is also obtained from 


nitrococcic acid. Consult Berichte, 15, 1130 and 1864, upon nitrometa-cresols. 

Para-cresol (1, 4), from solid paratoluidine, and from para-toluenesulphonic 
acid, forms colorless needles, melting at 36°, and boiling at 198°, Its odor 
resembles that of phenol; it dissolves with difficulty in water. Ferric chloride 
imparts a blue color to the aqueous solution. It yields paraoxybenzoic acid when 
fused with caustic potash. The denxzoy/ compound, C,H,O.C,H,O, crystallizes 
in six-sided plates, and melts at 70°. The ethyl ether, C,H,O.C,H,, is an 
aromatic-smelling liquid, which boils at 188°. The methyl ether boils at 174°. 
Chromic acid oxidizes it to anisic acid, C,H,(O.CH,).CO,H. 

Consult Berichte, 21, 729, upon Witrosocresols. . 

The nitration of para-cresol produces different nitro-cresols. Déuztro-cresol, 
C,H,(NO,),OH (1, 4, 2,6), is also obtained by the action of nitrous acid upon 
paratoluidine (Berichze, 15, 1859), and as potassium or ammonium salt represents 
commercial Victoria orange or Gold-yellow. It consists of yellow crystals, melt- 
ing at 84°, and is not as soluble in water as picric acid. Mixed with indigo- 
carmine it forms emera/d green (for liqueurs), and with aniline a carmine surrogate. 
Commercial Saffran-surrogate is a mixture of the potassium salts of dinitro- para- 
and ortho-cresols. 

/SH(3) 


re i -771- i ; 
p-Amido-m-thiocresol, C,H,(CH,) \NH,(4) 


amido-benzoic acid by the decomposition of dehydrothiotoluidine upon fusing it 
with alkalies. Nitrous acid converts it into a diazo-sulphide (p. 683) (Berichée, 
22, 1064). . 

Thio-cresols, C,H Ke ‘. 
tion of the chlorides of the three toluene sulphonic acids with zinc and hydro- 
chloric acid (p. 672). (1, 2)-Thiocresol melts at 15°, and boils at 188°. (1, 3)- 
Thiocresol is a liquid, and does not solidify at—10°. (1,4)-Thiocresol crystallizes 
in large leaflets, melts at 43°, and boils at 188°. 


, is produced together with /- 


Toluene sulphydrates, are obtained by the reduc- 


It is singular that the cresols, and all other higher phenols, can- 
not be oxidized with a chromic acid mixture; she OH-group pre- 
vents the oxidation of the alkyl group. If, however, the phenol 
hydrogen be replaced by alkyls or even acid groups (in the phenol 
ethers and esters), the alkyl is oxidized and oxyacids (their ether 
acids) are produced :— 


/ O0.CH 


O.CH, 
+\CH, 


vat CO,H" 


* yields CoH 


METHYL-PROPYL PHENOLS. 687 


To oxidize the homologous phenols it is advisable to employ their 
sulphuric. and phosphoric acid esters—these are easily prepared— 
and subject them to the action of an alkaline permanganate solution 
(Berichte, 19, 3304). This oxidizing agent destroys the free phe- 
nols completely. 


The oxidation of the alkyls in the sulphonic acids of the homologous benzenes 
is dependent upon the position of the sulpho-group. In general, negative atoms, 
or atomic groups, prevent the oxidation of the alkyls in the ortho-position by acid 
oxidizing agents (pp. 584 and 591), whereas alkaline oxidizers (like MnO,K) 
do the reverse, that is, first oxidize the alkyl occupying the ortho-position (4Az- 
nalen, 220, 16). 

Consult Berichte, 14, 687, on the deportment of cresols in the anima] organism. 

2. Phenols, C,H,.OH. 

The six possible xylenals, C,H,(CH,),.OH, have been prepared partly from 
the corresponding xylidinesy and partly by fusing isomeric xylene-sulphonic acids 
with potassium hydroxide. Further fusion oxidizes them to oxytoluic and oxy- 
phthalic acids. 

Ethyl Phenols, C,H,(C,H;).OH. The three isomerides have been prepared 
from the corresponding ethyl-benzene-sulphonic acids when the latter were fused 
with alkalies. The ov¢ho-compound is a liquid, boiling at 209-210°. The meta 
boils at 202—204°. The Zara is a solid, melts at 46°, and boils at 214° (Berichte, 
22, 2672). 

3. Phenols, C,H,,.OH. 

Mesitylol, C,H,(CH,),.OH, from amido-mesitylene, mesitylene sulphonic acid 
and pseudocumidine, is crystalline, melts at 68—69°, and boils at 220°. Isomeric 
Pseudocumenol, C,H,(CH,),-OH, from pseudo-cumene-sulphonic acid, consists 
of delicate needles, melting at 73°, and boiling at 232° (Berichte, 17, 2976). 

p-Propyl Phenol, C,H,(OH).C,H,, from propyl benzenesulphonic acid, boils 
at 232°. 4-Isopropyl-benzene, C,H,(C,H,).OH, from isopropy!-benzenesulphonic 
acid, melts at 61°, and boils at 229°. 


4. Phenols, C,,H,;.OH. 


Tetramethyl Phenol, C,H(CH,),.OH (1, 2, 4, 5, 6—OH in 6), dureno/, from 
durene sulphonic acid, melts at 117°, and boils at 250° (Berichte, 18, 2843). 


Methyl-propyl Phenols.—There are twenty possible isomerides. 
Thymol and Carvacrol merit notice. They occur in vegetable oils :— 


CXS (1) CFs (1) 
C,H,—C,H d C,H,—C,H, (4). 
KEY RGD. 


Both are derivatives of ordinary para-cymene (p. 577), and contain 
the normal propyl group (Berichte, 19, 245). In thymol the OH- 
group is in the meta-position with reference to the methyl group ; 
in carvacrol, however, in the ortho-position. Both decompose into 
propylene and cresols when heated with P.O; :— 


CH /CH 
C,H, (cit, ) OH = CHC GH Pay oe : 


thymol yielding meta-cresol and carvacrol para-cresol. 


688 - ORGANIC CHEMISTRY. 


Thymol exists with cymene, C,H, and thymene, C,,H,,, in oil 
of thyme (from Zhymus vulgaris), and in the oils of Ptychotis 
ajowan and Monarda punctata. ‘To obtain the thymol shake these 
oils with potassium hydroxide, and from the filtered solution pre- 
cipitate thymol with hydrochloric acid. It is artificially prepared 
from nitrocuminaldehyde, C,H;,(NO,).(C;H,).CHO, by its conver- 
sion into the dichloride, reduction of the latter to cymidine, C*H,. 
(NH,)(C;H,).CH;, by means of zinc and hydrochloric acid, 
and decomposition of the diazo-compound of the latter with water 
(Berichte, 19, 245). Thymol crystallizes in large colorless plates, 
melting at 44° and boils at 230°. It has a thyme-like odor and 
answers as an antiseptic. Ordinary cymene is obtained by distilling 
it with P,S,. 


. Iodine and caustic potash’convert thymol into zodothymo/. This has been sub- 
stituted for iodoform under the name of annidalin. 

Nitrous acid changes thymol to xitroso-thymol, C, ,H,2(NO)OH, melting at 
160°. The same compound results on treating thymoquinone with hydroxylamine 
(p. 675 and Berichte, 17, 2061). 

Carvacrol, C,,H,,.0H, Oxycymene, occurs already formed in the oil of cer- 
tain varieties of satureja; it is produced on heating isomeric carvo/, C, »H, ,O, with 
glacial phosphoric acid (Berichte, 20,12). It is artificially prepared from cymene- 
sulphonic acid by fusion with KOH, and by heating camphor with iodine (+ part) 
or ZnCl,. It is a thick oil, solidifying at low temperatures; it melts at 0°, and 
boils at 236°. Distilled with P,S,, it yields cymene and ¢hiocymene, C, )H,,.SH, 
which boils at 235°. 

Carvol, C,,H,,0 (see above), isomeric with carvacrol, is contained in oil of 
cumin. It is an oil boiling at 225°. When heated with potassium hydroxide or 
phosphoric acid it changes to the isomeric oxycymene. In its behavior it is very 
much like camphor, C,,H,,O (see this); it contains a CO-group, inasmuch as it 
combines with hydroxylamine and phenylhydrazine (Berichte, 17, 1578). Car- 
voxime, C,,H,,:N.OH, melts at 71° and is identical with nitrosohesperidine 
(Berichte, 18, 2220). According to its constitution carvol (like camphor) is a 
keto-derivative of a dihydrobenzene, and indeed of dihydrocymene. When it is 
converted into oxycymene there occurs a transposition of the reduced benzene 
nucleus into the normal, of the secondary ketone-form into the tertiary phenol- 
form (Berichte, 20, 491; 21, 473) (compare phloroglucin) :— 


7CH.CO—— ~CH — C(OH)\ 
CoH,.CO Gry Cy 7CH-CHs yields CH, CC Giz — Gly >C-CH. 


Carvol, Oxy-cymene. 


Isobutyl Phenol, C,H,(C,H,).OH, is readily obtained by heating phenol with 
isobutyl alcohol in the presence of ZnCl, (p. 667). It has also been prepared . 
from isobutyl-aniline, by means of the diazo-compound. It melts at 99°, and 
boils at 238°. : 

Pentamethyl Phenol, C,(CH,),.OH = C,,H,,0, is obtained from amido- 
pentamethyl benzene (Berichte, 18, 1827). It melts at 125°, and boils at 267°. 


PYROCATECHIN. 689 


DIHYDRIC PHENOLS. 


Pyrocatechin. 
Resorcin. 


OH 
CoH, { OH Hydroquinone, 


OH’ in. 
CoH, (CH) { on Orcin 


Homo-pyrocatechin, 


CoHs(CHy)2{ oH {Beurcniloron, 

These are obtained like the monohydric phenols, by fusing mono- 
halogen phenols, C,H,X.OH, halogen benzenesulphonic acids and 
phenolsulphonic acids with potassium hydroxide (p. 666). It must, 
however, be observed that often the corresponding dioxy-benzenes 
do not result, but in their stead (especially at higher temperatures) 
the more stable resorcinol (1, 3). They are also produced by diazo- 
tizing the amidophenols, and by the dry distillation of aromatic 
dioxyacids with lime or baryta. 

The dioxybenzenes belonging to the para-series, are capable of 
forming quinones, C,H,O,, when oxidized. 


j/ 





‘ 
Dioxybenzenes :— 


(1) Pyrocatechin, C,H,(OH), (1, 2), Oxyphenic Acid, Cate- 
dat was first obtained in the distillation of catechine (the juice of 
Mimosa catechu). It is formed by the dry distillation: of proto- 
catechuic acid, C,H,(OH),.CO,H, of catechuic and Moringa 
tannic acids, and from (1, 2)-chlor- and iodo-phenols, or (1, 2)- 
phenolsulphonic acid and many resins on fusion with potassium 
hydroxide. 


It is best prepared by heating guaiacol (from that ‘portion of beech-wood tar 
_ boiling at 195-205°) to 200° with hydriodic acid :— 


0.CH OH 
Cc H.C OH ‘i HI=C¢ oH. OH + CH,I. 


Or, ortho-phenolsulphonic acid may be fused with caustic alkalies (8 parts) to 
330-360° (Journ. pract. Chem., 20, 308). 


Pyrocatechin crystallizes from its solutions in short, rhombic 
prisms, and sublimes in shining leaflets. It is soluble in water, 
alcohol and ether. It melts at 104°, and boils at 245°. On expo- 
sure to the air its alkaline solutions assume a green, then brown and 
finally a black color, Lead acetate throws out a white precipitate, 
PbC,H,O,, from its aqueous solution ; while lime water imparts a 
green color to it if concentrated. Ferric chloride colors its solu- 
tion dark green, this changes to violet after the addition of a little 

58 


6090. ORGANIC CHEMISTRY. 


ammonia, sodium carbonate or tartaric acid. Ferric chloride zm- 
parts a green color to all ortho-dioxy-derivatives in solution, even if 
one hydrogen atom is replaced by an alkyl. Pyrocatechin reduces 
cold silyer solutions and alkaline copper solutions. The application 
of heat is required in the latter case. 


Acetyl chloride produces the acetyl derivative, C,H 4(O.C,H,0),, crystallizing 
in needles. 


The monomethyl ether, C,H, { aa Guaiacol, occurs in wood-tar and is 


produced on heating pyrocatechin with potassium hydroxide and potassium methyl 
sulphate to 180°. It is a colorless liquid, which boils at 200° and has a specific 
gravity 1.117. It dissolves with difficulty in water, readily in alcohol, ether and 
acetic acid. Ferric chloride gives its alcoholic solution an emerald green color. 
It forms crystalline salts with the alkali and alkaline earth metals. Its alkaline 
solutions reduce gold, silver and copper salts. Guaiacol decomposes into pyro- 
catechin and CH,I (also CH,.OH) when heated with hydriodic acid or fused with 
KOH. 

The dimethyl ether, C,H,(O.CH,),, is prepared by treating the potassium salt 
of the mono-methyl ether with CH,I, and by distilling dimethy]l-protocatechuic 
acid with lime. Itis a liquid, which boils at 205°. It is identical with vera/ro/, 
obtained from veratric acid. 


The carbonic ester, Cg HA 6 >CO, results from the action of chlorcarbonic ester 


upon pyrocatechin, and melts at 118°. Pyrogallol reacts similarly (Berichte, 13, 
697), while, on the other hand, the mixed carbonic acid esters, ¢.¢., C,H,(O. 
CO,.C,H,;), (Berichte, 19, 2265), are formed in the action of chlorcarbonic esters 
upon hydroquinone and resorcinol (as well as upon monohydric phenols). 


(2) Resorcin, Resorcinol, C,H,(OH), (1, 3), is produced from 
different resins (like ga/banum and asafetida) and from umbelliferon 
on fusion with caustic potash. It results in the same way from (1, 
3)-chlor-and iodophenol, from metaphenol sulphonic acid and meta- 
benzene disulphonic acid, and also from various other benzene di- 
derivatives not included in the meta-series, ¢.g., from the three 
brom-benzenhe sulphonic acids (p. 663) and from both benzene di- 
sulphonic acids (compare p. 689). 


It was formerly obtained by distilling the extract of Brazil wood; at present, 
however, it is prepared technically from crude benzene disulphonic acid (_/ourn., 
pract.Chem., 20, 319), and serves for the synthesis of different dyes. It is purified 
by sublimation and by crystallization from benzene. 


Resorcin crystallizes in rhombic prisms or plates, melts at 118° 
when perfectly pure (otherwise at 102—110°), and boils at 276°. It 
dissolves readily in water, alcohol and ether, but not in chloroform 

-and carbon disulphide. Lead acetate does not precipitate the 
aqueous solution (distinction from pyrocatechin). Silver nitrate is 
only reduced by it upon boiling ; and in the cold if ammonia be 
present. Ferric chloride colors the aqueous solution @ dark violet. 


HYDROQUINONE. , 691 


Bromine water precipitates ¢7-7bromresorcin, CsHBr,(OH),, from the 
solution. This crystallizes from hot water in needles. By heating 
resorcinol with phthalic anhydride we get fluorescein ; the homolo- 
gous metadioxybenzenes also yield fluoresceins. With diazo-com- 
pounds it forms azo-coloring substances (p. 643). 


The diacetyl compound, C,H,(O.C,H,O),, is a liquid. The diethyl ether, 
C,H,(O.C,H,),, obtained by heating resorcinol with ethyl iodide and potassium 
hydroxide, boils at 243°, the dimethyl ether at 214°. 

Nitrous acid, acting upon a diluted resorcinol solution (Berichte, 8, 633), 
produces dinitroso-resorcinol, C,H,(OH),(NO), or C,H,(O),(N.OH), (1, 3- 
2,4) (p. 674), (Berichte, 21, 1545; 23, 3193). This crystallizes with 2H,O in 
yellow brown leaflets, which detonate on heating to 115° C. (Berichte, 20, 1607). 
It occurs in commerce under the names solid green, fast green. 

Nitric acid vapors oxidize resorcinol to dinitroresorcin, C,H,(NO,),(OH),, 
melting at 142°. It yields dinitro-diamidobenzene when heated with ammonia. 
Lsodinitro-resorcin, obtained by nitration, melts at 212°. It passes, by reduction, 
into diamidoresorcin, C,H,(OH),.(NH,.), (1, 3-4, 6). The latter can also be 
easily obtained by reducing resorcin-diazobenzene with tin and hydrochloric acid 
(Berichte, 17, 881). When its ammoniacal solution is exposed to the air it oxidizes 
to Diamido-resorcinol, C,H,(OH),(NH,)., separating in steel blue needles 
(Berichte, 22, 1653). It is soluble in caustic potash, and on application of heat 
yields dioxyquinone (p. 702). 

When cold nitric acid acts on resorcinol and various gum-resins (galbanum, 
gum-ammoniac), or by nitrating metanitrophenol, we get 7Zrinitro-resorcinol, 
C,H(NO,),(OH), (Styphnic Acid, Oxypicric Acid) (Berichte, 21, 3119), which 
crystallizes in yellow hexagonal prisms or plates. It meits at 175°, and sublimes 
when carefully heated, but explodes on rapid heating. It dissolves easily in 
alcohol and ether, but with difficulty in water. Ferrous sulphate and lime water 
at first color it green, but this disappears (picric acid colors it blood-red). Trinitro- 
resorcinol is a strong dibasic acid, yielding well crystallized acid and neutral 
salts. The diethyl ester is solid, and melts at 120°. 

If resorcinol be heated with sodium nitrite it forms a deep-blue dye, soluble in 
water. Acids turn this red (Berichte, 17, 2617). It is used as an indicator under 
the name of /acmotd (Berichte, 18, Ref. 126). Nitric acid, containing nitrous 
acid, converts resorcin into two dyes: diazoresorcin and diazoresorufin ( Weselsky). 
These have also been called vesorufin or resorutamin, C,.H,NO,, and resazurin, 


C,,H,NO,. They appear to be derivatives of phenoxazine, C,H,~ Sas C.H, 
(Nietzki, Berichte, 22, 3020; 23, 718). whet: 
| 3- Hydroquinone, C,H,(OH), (1, 4); was first obtained by the 
dry distillation of quinic acid and ‘by digesting its aqueous solution 
with PbO, :— 

C,H,;,0, + O=C,H,O, + CO, + 3H,0. 
It results also on boiling the glucoside arbutin with dilute sulphuric 
acid, or by the action of emulsin :— 


CigH 60; =? H,0 rae C,H,O, + C H,,06¢. 


Arbutin. Hydroquinone, lucose. 


It is synthetically prepared by fusing (1, 4)-iodophenol with potas- 
sium hydroxide at 180°; or from oxysalicylic acid, and from para- 


ae “ORGANIC CHEMISTRY: 


amidophenol. Worthy of note is the formation of various hydro- 
quinone derivatives from succino-succinic ester (p. 566), or that of 
hydroquinone in the distillation of succinates. The most convenient 
method of preparing it consists in reducing quinone with sulphurous 
acid: C,H,O, + H,= C,H,O,. 


Preparation.—To get hydroquinone, oxidize aniline in sulphuric acid (1 part 
aniline, 8 parts SO,H, and 25 parts H,O) with pulverized Cr,O,Na, (2% parts) 
until the dark precipitate, which first forms, has dissolved to a cloudy, brown 
liquid (containing quinone and quinhydrone). Then conduct sulphurous acid 
through the solution until the reduction is complete; filter, extract the hydroqui- 
none by shaking with ether, then purify the product by recrystallization from hot 
water that has passed through animal charcoal (Berichte, 19, 1467), and contains 
sulphur dioxide. 

Hydroquinone is dimorphous, crystallizes in monoclinic leaflets and hexagonal 
prisms, which melt at 169°, and sublime in shining leaflets; it decomposes when 
quickly heated. It dissolves readily in water (in 17 parts at 15°), alcohol and 
ether. It forms crystalline compounds with H,S and SO, ; these are decomposed 
by water. Ammonia colors the aqueous solution reddish-brown. It is only in 
the presence of ammonia that lead acetate produces a precipitate in the solution 
of hydroquinone. Oxidizing agents (like ferric chloride) convert hydroquinone 
into quinone ; quinhydrone is an intermediate product. 

Hydroxylamine and hydroquinone form quino-dioxime, by the absorption of 
two hydrogen atoms (Berichte, 22, 1283). 


Methylhydroquinone, C,H Koa” is formed along with hydroquinone in 


the decomposition of arbutin with acids or emulsin; and from hydroquinone by 
heating it with caustic potash, and methyl iodide or potassium methyl sulphate 
(Berichte, 14, 1989). It crystallizes from hot water in hexagonal plates, melts at 
53°, and boils at 243°. The dimethyl ether,C,H,(O.CH;)., melts at 56°, and 
boils at 205°. The diethyl ether melts at 66°, and boils at 247°. ° 

We obtain the hydroquinone halogen substitution products by direct substitution, 
or from the substituted quinones and arbutins; and by the addition of HCl or HBr 
to quinone: C,H,O, + HCl = C,H,Cl(OH), (Amnalen, 201, 105, and 210, 
133). Two dinitro products are obtained by the nitration of diethylhydroquinone. 
They can be reduced totwo diamidohydroquinones, C,H,(NH,),(OH), (Berichie, 
23, 1211). 

When ‘ sforanil (tetrachlorquinone) is digested with a diluted solution of primary 
sodium sulphite, we get at first tetrachlor-hydroquinone, but later two Cl-atoms 
are replaced by sulpho-groups, The aqueous solution of the resulting dichlor- 


hydroquinone disulphonic acid, C,Cl, { tO, My , is colored indigo-blue by ferric 
chloride. When its alkaline solution is exposed it oxidizes to potassium euthio- 


chronate, C,(OH), {ig K),’ This is a quinone-like compound. 
3**)2 





(2) Dioxytoluenes, C,H,(CH;)(OH),. Four of the six pos- 
sible isomerides are known. For their reactions see Berichte, 15, 
2995- 

1. Orcin, Orcinol, C,H;(CH;)(OH), (1, 3, 5), is found in 
many lichens of the variety Roccel/a and Leconora, partly free and 


ISO-ORCIN, 693 


partly as orsellic acid or erythrine, and is obtained from these acids 
either by dry distillation or by boiling with lime :— 


C,H,(OH),.CO,H = C,H,(OH), + CO,. 
Orsellie Acid. Orcinol. 

It is obtained by fusing the extract of aloes with caustic potash. It can be pre- 
pared synthetically from dinitro-paratoluidine and various other toluene derivatives 
by the alteration of their side groups ( Berichte, 15, 2992). It crystallizes in color- 
less, six-sided prisms, containing one molecule of water. It dissolves easily in 
water, alcohol and ether, and has a sweet taste. It melts at 56°, when it contains 
water, but gradually loses this, and melts (dried in the dessicator) at 107°. It 
boils at 290°. Lead acetate precipitates its aqueous solution; ferric chloride 
colors it a d/we violet. Bleaching lime causes a rapidly disappearing dark violet 
coloration. It yields*azo-coloring substances with diazo-compounds, and there- 
fore has the 2OH-groups in the meta-position (p. 643). It does not form a 
fluorescein with phthalic anhydride (p. 691). 

The orcinol hydroxyl-groups can be replaced by acid and alcohol radicals. 
The dimethyl ether, C,H,(O.CH,),, is a liquid, boils at 244°, and when oxidized 
with MnO,K yields the dimethyl ether of symmetrical dioxybenzoic acid. See 
Berichte, 20, 1608, for dinitroso-orcin. 


On allowing its ammoniacal solution to stand exposed to the air 
orcinol changes to orcein, C,,H,,N,O, (Berichte, 23, Ref. 647), 
which separates out in the form of a reddish-brown amorphous 
powder. Orcein forms red lac-dyes with metallic oxides. It is the 
chief constitutent of the coloring matter archi/, which originates 
from the same lichens as orcinol through the action of ammonia 
and air. Litmus is produced from the lichens Roccella and 
Leconora, by the action of ammonia and potassium carbonate. 
The concentrated blue solution of the potassium salt, when mixed 
with chalk or gypsum, constitutes the commercial litmus. 


2. Iso-orcin, C,H,(CH,).(OH), (1, 2, 4—CH, in 1) (Cresorcin, y-orcin), is 
obtained by fusing a-toluene disulphonic acid with KOH; also from nitro-para- 
toluidine, a-toluylene diamine and amido-o-cresol (Berichte, 19, 136). It forms 
soluble needles, melting at 104°, and boiling at 270°. It gives a vio/e¢ coloration 
with ferric chloride, and forms a fluorescein with phthalic anhydride. _ 

3- Homopyrocatechin, C,H,(CH,)(OH), (1, 3, 4—CH, in 1), is formed 
from its methyl ether, creosol, when heated with hydriodic acid, and by the distil- 
lation of homoprotocatechuic acid. It has been synthetically prepared from meta- 
nitro-para-toluidine ( Berichte, 15, 2983). It is a non-crystallizable syrup; other- 
wise it is like pyrocatechin. It reduces Fehling’s solution and a silver solution, 
even in the cold, and is colored green by ferric chloride. O0.CH 

Its monomethyl ether is the so-called Creosol, C,H,(CH,) f OH 3(3) formed 
from guaiacum resin and is found in beech-wood tar. bs. (4) 

That fraction of the beech-wood tar (creasote p. 667), boiling at 220°, consists 
chiefly of creosol and phlorol. Potassium-creosol is precipitated on adding alco- 
holic potash to the ethereal solution; potassium phlorol remains dissolved (Berichte, 
10, 57; 14, 2010).. 


Creosol boils at 220°, and is very similar to guaiacol (p. 690). It 
reduces silver nitrate on warming, and in alcoholic solution is 
colored a dark green by ferric chloride. 


694 ORGANIC CHEMISTRY. 


It yields an acetate with acetic acid. Vanillinic acid may be obtained from the 
acetate by oxidizing the latter with potassium permanganate, and saponifying with 
caustic potash. Its methyl ether, CgH,(CH;)(O.CH,), (methyl creosol, dimethyl- 
homo-pyrocatechin), boils at 214-218°, and when oxidized with potassium per- 
manganate yields dimethyl-protocatechuic acid. The relations of these substances 
are seen in the following formulas (see Vanillin) :— 


CH, (1) cO,H CO,H 
C,H, O.CH, (3) C,H, 4 0.CH, C,H, {ox 
OH (4) OH OH 
Creosol. Vanillinic Acid. Protocatechuic Acid. 


4. Toluhydroquinone, C,H,(CH,)(OH), (1, 4, CH,,), is produced by the 
reduction of toluquinone (p. 704) with sulphurous acid, and from nitro-o toluidine 
(Berichte, 15, 2981). It consists of needles dissolving easily in water, alcohol 
and ether, and melting at 124°. It resembles hydroquinone very much, and with 
toluquinone yields a quinhydrone. Caustic soda colors it bluish-green, then dark 
brown. 





p-Xylohydroquinone, C,H,(CH,),(OH),, Dioxyparaxylene (1, 4, 2, 5), results 
on the reduction of xylo-quinone (p. 704), and is identical with so-called Aydro- 
philoron, obtained from phloron (zézd7). It crystallizes from hot water in pearly 
leaflets, melting at 212°. 

p-Xylo-orcinol, C,H,(CH,;),(OH), (1, 4, 3, 5) is obtained from m-dinitro- 
paraxylene ( Berichte, 19, 2318). It crystallizes from water in prisms, melting at 
163° and boiling at 277-280°. In ammoniacal air it rapidly acquires a red color. 
It is identical with de¢a-orcinol, obtained from various lichen acids (usninic acid) 
by distillation. 

Mesorcin, C,H(CH,),(OH), = C,H,,0,, dioxymesitylene, from dinitro- 
mesitylene, sublimes in shining leaflets, melts at 150°, and distils at 275°. When 
boiled with a ferric chloride solution, a methyl group splits off and oxyxyloquinone 
results (p. 704). 

Thymo-hydroquinone, C,,H,,(OH), = C,;H,(CH,)(C,H,)(OH),, has 
been obtained by the reduction of thymoquinone, and forms four. sided, shining 
prisms, melting at 139°. 





TRIHYDRIC PHENOLS. 


Pyrogallic Acid (1, 2, 3) 
C,H,(OH), + Phloroglucin (1, 3, 5) 
{ Oxyhydroquinone (1, 2, 4). 


1. Pyrogallic Acid, C,H,O,, Pyrogallol, is formed by heating 
gallic acid alone, or better, with water, to 210° :— 


C,H 21 Co.H — C,H,(OH), + CO,; 


and: by fusing the two parachlorphenol-disulphonic acids and 
hematoxylin with potassium hydroxide. It forms white leaflets or 


PYROGALLIC ACID. 695 


needles, melts at 115°, and sublimes when carefully heated. It 
dissolves readily in water, with more difficulty in alcohol and ether. 
Its alkaline solution absorbs oxygen very energetically, turns brown 
and decomposes into carbon dioxide, acetic acid and brown sub- 
stances. Pyrogallol quickly reduces salts of mercury, silver and 
gold with precipitation of the metals, while it is oxidized to acetic 
and oxalic acids. Ferrous sulphate containing ferric oxide colors 
its solution blue, ferric chloride red. Lead acetate precipitates 
white, C,H,O;.PbO. An iodine solution imparts a purple-red color 
to an aqueous or alcoholic pyrogallol solution. Gallic and tannic 
acids react similarly. 


Acetyl chloride converts pyrogallol into its ¢riacetyl ester, C,H,.(O0.C,H,0),, 
which is not very soluble in water. The dimethyl ether, C,H,(O.CH;)..OH, is 
found in that fraction of beech-wood tar boiling at 250-270°. Separated in a 
pure form from its benzoyl compound it crystallizes in white prisms, melting at 
51-52°, and boiling at 253°. When heated with hydrochloric acid it breaks up 
into pyrogallol and methyl chloride. Different oxidizing agents (potassium 
bichromate and acetic acid) convert it into carulignone, a diphenyl! derivative. 
When the acetyl derivative of the dimethyl ether is oxidized, the acetyl group 
separates and the quinone compound, C,H,(O.CH,),O,, results. The ¢riethy/ 
ether is formed on heating pyrogallol with caustic potash and potassium ethyl 
sulphate, also from triethyl-pyrogallo-carboxylic acid (see this). It melts at 39°. 
Bromine converts it into xanthogallol, C,,H,,4Br, 40, (Berichte, 21, Ref. 626). ; 
The trimethyl ether melts at 47°, and boils at 235° ( Berichte, 21, 607, 2020). yt 

2. Phloroglucin, C,H,(OH), (1, 3, 5), is obtained from different resins (cate- 
chu, kino), on fusion with caustic potash ; by the decomposition of phloretin and. 
quercetin, hesperidine, and other glucosides; by the fusion of phenol, resorcinol,” 
orcin or benzene trisulphonic acid with sodium hydroxide; also by the saponifica* 
tion and decomposition of synthetically prepared phloroglucin-tricarboxylic ester, 
C,(OH),.(CO,.C,H,;), (p. 566). 

It is most easily made by fusing resorcinol with caustic soda (Berichte, 12, 
503; 14, 954). It crystallizes in large, colorless prisms with 2H,O; these 
effloresce in the air. It loses all its water of crystallization at 110°, melts at 218°, 
and sublimes without decomposition. It has a sweetish taste, and dissolves readily 
in water, alcohol and ether. Lead acetate does precipitate it; ferric chloride 
colors its solution a dark violet. 

Chlorine oxidizes phloroglucin to dichloracetic acid and tetrachloracetone (p. 
566). One of the first intermediate products is hexachlor-triketo-hexamethylene 
(p. 703) (Berichte, 22, 1469). For the action of bromine see Serichie, 23, 1706. 


: : 


Phloroglucin, in most of its reactions (see Berichte, 23, 269), 
conducts itself like a trihydric phenol, C,H,(OH),;; on the other 
hand it unites with 3 molecules of hydroxylamine to form a “rioxime 
(see below), hence it may be considered a triketone—/¢riketo-hexame- 
thylene (p. 567) (Berichte, 19, 159). The two formulas— 


7C(OH)—CHN ZCO.CH,\ 
CHC CloH)—cH OOH and CHL Co.cH? >CO 


of which the first is derived from tertiary, the second from the sec- 


696 ORGANIC CHEMISTRY. 


ondary benzene ring (p. 568) are either tautomeric, or the latter 
represents the unstable or pseudo-form (p. 50). 


Normal ethers of phloroglucin have been obtained by heating it with alcohol 
and hydrochloric acid gas, or with ethyl iodide. The ¢rimethyl ether, C,H, 
(OCH,),, melts at 52°, and boils at 255° (Berichte, 21,603). Its triethyl ether, 
C,H,(O0.C,H,),, melts at 43°. 

The dibutyryl ester occurs in the root of Aspidium filix. It is a crystalline 
substance, which yields phloroglucin and butyric acid when fused with KOH 
(Berichte, 22, 463, Ref. 806). 

Phloroglucin-triacetyl Ester, C,H,(O.C,H,O),, melts at 106°. When phloro- 
glucin is heated with caustic potash and alkyl iodides it yields ethers, derived 
from the isomeride of triketo-hexamethylene. They are insoluble in the alkalies. 
Hexamethyl-phloroglucin, C,(CH,),O,, melts at 80° (Berichte, 22, Ref. 670; 


23, 20). 

Phloroglucin Trioxime, CL FN,O,: = CHC CIN OH} CH? bCN-OH 
(see above), separates, on standing, from aqueous phloroglucin with HCl-hydroxy- 
lamine (3 molecules) and potassium carbonate. It is a crystalline powder. At 
140° it becomes black, and at 155° explodes violently. 

3. Oxyhydroquinone, C,H,(OH), (1, 2, 4), is produced on fusing hydro- 
quinone with KOH (together with tetra- and hexaoxy-diphenyl. Berichie, 18, 
Ref. 24). It is crystalline, very soluble in alcohol and ether, and in aqueous 
solution soon acquires a dark color. It melts at 140.5°. Ferric chloride colors it 
a dark greenish-brown. Its tri-ethyl ether, C,H,(0.C,H,),, is obtained from 
trioxyethy] benzoic acid (from esculetin). It can also be prepared by ethylating 
ethoxy-hydroquinone. It melts at 34° (Berichte, 20, 1133). The trimethyl 
ether, C,H,(O.CH,),, from methoxy-quinone (p. 702), boils at 247°. 

Methy!] pyrogallol, C,H,(CH,)(OH),, and Propyl pyrogallol, C,H,(C,H,) 
(OH), occur in beech-wood tar as dimethyl ethers (p. 667); the latter is identical 

“with so-called picamar. 


TETRA- AND POLY-HYDRIC PHENOLS. 


Tetraoxybenzenes. 

(1) Symmetrical Tetraoxy-benzene, C,H,(OH), (1, 2, 4, 5), is obtained by 
reducing dioxyquinone with stannous chloride. It crystallizes in silvery needles, 
melting at 215~220°. It is oxidized to dioxyquinone (p. 702) when exposed, in 
acid solution, to the air, or by ferric chloride (Berichte, 21, 2374). 

Dichlortetraoxy-benzene, C,Cl,(OH), (the Cl-atoms in 1, 4), results in the 
reduction of chloranilic acid (p. 701) with sodium amalgam, or with tin and hydro- 
chloric acid, and by heating it with sulphurous acid. It forms colorless needles, 
dissolving readily in water. It is reoxidized to chloranilic acid on exposure to 
moist air. 

Diamido-tetraoxy-benzene, C,(NH,),(OH), (the NH, groups in 1, 4), is 
obtained by reducing nitranilic acid (p. 701) with tin and hydrochloric acid. It 
separates as HCl-salt, C,(OH),.(NH, HCl),, in long, colorless needles (Berichze, 
18, 503; I9, 2727). Ferric chloride and other oxidizing agents convert it into 
diimido-dioxy-guinone, C,.(NH,),0,(OH),, a black, crystalline precipitate, which 
nitric acid oxidizes to triquinoyl (p. 703). 

(2) Unsymmetrical Tetraoxybenzene, C,H,(OH), (1, 3, 4, 5), is only 
known in certain ethers. The dimethyl ether, C,H,(O.CH,),(OH),., is prepared 
by reducing dimethyl dioxyquinone with tin chloride. It forms brilliant crystals, 
melting at 158°. Caustic potash and methyl iodide convert it into the tetramethyl 


TETRA- AND POLY-HYDRIC PHENOLS. 697 


ether, C,H,(O.CH;),, melting at 47° and boiling at 271° (Berichte, 21, 609; 23, 
2288). 

( 3) Adjacent Tetraoxybenzene, C,H,(OH), (1, 2, 3, 4), with the two hydro- 
gen atoms in the ortho-position, is afonol, the parent substance of apio/, the 
methylene dimethyl ether of allyl apionol, C,H(C,H,) (OH), (Berichte, 23, 
2293). 

Dimethyl Apionol, C,H,(O.CH,),(OH),, is formed by heating apiolic acid 
with caustic potash to 180°. It melts at 106°, and boils at 298°. The introduction 
of methyl yields Tetramethyl Apionol, C,H,(O.CH,),, melting at 81° (Berichze, 
22, 2482). Methylene-dimethyl Apionol, C,H,(O,:CH,)(O.CH,),, Apione, 
is formed when apiolic acid loses carbon dioxide. It melts at 79°, and is volatile 
with steam (Berichte, 21, 1630, 2129). 

Hexoxybenzene, C,(OH), —C,H,O,, is obtained from triquinoxyl (p. 703) 
by reduction with stannous chloride and hydrochloric acid. It separates in the 
form of small, grayish-white needles, which acquire a reddish-violet color on expo- 
sure to the air. They are not fusible, but decompose about 200°. Concentrated 
nitric acid oxidizes it to triquinoyl. 

It forms the hexacetyl derivative, C,(O.C,H,O),, when heated with acetic 
acid and sodium acetate. Itis a crystalline mass, melting at 203° (Berichte, 18, 506). 


The hexapotassium salt of hexaoxybenzene, C,O,K,, is the so- 
called potasstum carbon monoxide, which results upon conducting 
carbon monoxide over heated potassium. It is obtained in the 
preparation of potassium. Dilute hydrochloric acid, acting upon 
the fresh mass, yields hexaoxybenzene (Berichte, 18, 1833). 





Quercite and Pinite seem to be jentahydric phenols of hexahydrobenzene, 
CLBas 

‘Quercite, C,H,,0, = C,H,(OH),, occurs in acorns. It can be extracted 
from them by means of water. Different hexoses accompany it, but they can be 
destroyed by fermentation. It has a sweet taste, dissolves in 8 parts of water, and 
crystallizes in hard prisms, melting at 235°. Five hydroxyls present in it can be 
replaced by acidyls. If quercite be heated alone or together with hydriodic acid 
various benzene products are obtained. Nitric acid oxidizes it to mucic and tri- 
oxyglutaric acids (same as sorbinose and arabinose) ( Berichte, 22, 518). 

a- and §-Pinite, C,H,,0, or C,H,,0,, occur in the resin of Pinus lamber- 
tina. The first melts about 150°, the second at 187°. Both yield rhodizonic acid 
when evaporated with nitric acid (Berichte, 23, 25). 

Inosite, C,H,,0, + 2H,O, Phaseomannite, is a hexahydric phenol of 
hexahydrobenzene. It occurs in the muscles of the heart, and in different plants 
(unripe peas and beans). It forms large crystals, that weather on exposure and 
then melt at 225°. There are six hydroxyl-groups in it that can be replaced by 
acid radicals. If heated with hydriodic acid to 170°, it yields benzene and tri- 
iodophenol. Nitric acid oxidizes it to two dioxy-, one tetraoxyquinone, and rhodi- 
zonic acid (Berichte, 20, Ref. 478; 23, Ref. 26). 

Phenose, is a hexahydric phenol of hexahydrobenzene, C,H,(OH),. It has 
been obtained by the action of a soda solution (Annalen, 136, 323) upon the 
addition product of benzene with three molecules of hypochlorous acid, 


C,H, { (OH) . It is an amorphous, readily soluble substance, deliquescing in 


3 
the air. It is very much like the glucoses, has a sweet taste and reduces Feh- 
ling’s solution—but is not capable of fermentation. 


698 ORGANIC CHEMISTRY. 


QUINONES. 


This is the designation ascribed to all derivatives of benzene in 
which 2H-atoms are replaced by 2O-atoms. They are mostly pro- 
duced by the direct oxidation of benzenes, especially the con- 
densed varieties (naphthalene, anthracene, chrysene, phenanthrene), 
with chromic acid in glacial acetic acid. These compounds, how- 
ever, do not possess uniform character, hence various quinone 
groups are noted. 

The ¢rue guinones or para-qguinones, whose prototype is ordinary 
quinone or benzoquinone, C,H,O,, are yellow colored, volatile 
compounds, having a peculiar, penetrating quinone odor, and are 
readily volatilized with steam. Reducing agents (SO,, conc-HI) 
easily convert them, with absorption of 2H-atoms, into the corres- 
ponding colorless dioxy-compounds (hydroquinones) :— 


C,H,(0O,.) + H, = C,H,(OH),, Hydroquinone (1, 4). 


Hence they oxidize readily, and may be compared to the per- 
oxides (like acetyl peroxide (C,H;O),O,). The two oxygen atoms 
take the para-position in the benzene nucleus, and the para-quinones 
therefore are readily produced by oxidation of the para-di-derivatives 
of the benzenes. . 


It is usually supposed that in the ordinary quinones the 20-atoms are linked 
by one valence to each other; it is, however, possible, that they ought to be con- 
sidered as di-ketones having 2CO-groups :— 





c O ns 
a 4» 
Be OH HC. CH 
| | or il 
HC CH | HC CH 
NA \/ 
C Co 





The fact that in the different reactions the 2O-atoms are invariably separated by 
only two monovalent atoms or groups (in the action of PCl;) forming normal ben- 
zene derivatives, C,X,; furthermore, the simple relations of the quinones to the 
quinone-chlorimides and indophenols (p. 705), argue for the first view. 3 

According to the second formula the quinones are derivatives of a reduced ben- 
zene nucleus, dihydrobenzene, C,H, (p. 568), and are to be termed diketo-dihydro- 
denzenes. In support of their ketone nature we have their ability to yield quin- 
oximes with one molecule of hydroxylamine (these are identical with the nitroso- 
phenols). A stronger proof is the production of quinon-dioxime, HO.N: 
CoH We CH DCN.OH, by the union of quinone with two molecules of hy- 
droxylamine (p. 675). The production of bromine additive products might be an 
additional argument (_/r. pr. Ch., 42, 61; Berichte, 23, 3141). 

Yet, the quinones of the benzene series are not capable of combining with 
phenylhydrazine, but are only reduced by it, while the naphthaquinones and 
phenanthraquinones form hydrazides (Berichte, 18, 786). 


| / QUINONES. 699 


Another series of quinones ( naphthaquinone, anthraquinone, phenanthraqui- 
none) mus} be considered true diketones (with 2CO-groups). They are non-vola- 
tile and odorless, and are either sara-diketones (like anthraquinone) or ortho-drke- 
tones (e.g., 8 naphthaquinone and phenanthraquinone). Sulphurous acid reduces 
the latter to the corresponding hydroquinones; they form anhydro-compounds 
with the aldehydes and ammonia. 

There exist, finally, the quinones with two nuclei, ¢.g., coerulignone, derived 
from diphenyl. In these the 2O-atoms link two benzene nuclei. 


Quinone, C,H,O,, Benzoquinone, was first obtained by distilling 
quinic acid with MnO, and sulphuricacid. It is formed from many 
benzene compounds, especially those di-derivatives belonging to 
thé para-series (¢. g., para-phenylene-diamine, amidophenol, phenol 
sulphonic acid and sulphanilic acid), when they are oxidized with 
MnO, @id sulphuric acid, or with a dilute chromic acid mixture. 

mzidine, C,,H,(NH,)., likewise yields a considerable quantity of 
quinone. Hydroquinone is oxidized to quinone even on boiling 
with*a ferric chloride solution. It is, however, best prepared 
(according en by oxidizing aniline with chromic acid. 







Preparatiogs—Oxidize aniline in sulphuric acid solution, just as was done in the 
case of hydroquinone (p. 691), adding, however, a little more sodium bichromate 
to effect the.complete oxidation to quinone, then extract with ether. A better 
course is to prepare the quinone from hydroquinone already prepared ; to this end 
dissolve the latter in as little water as possible, add two parts of sulphuric acid, 
and while cooling ingroduce the sodium bichromate solution, until the precipitate 
consists of pure yellow quinone, This is filtered at once ( Berichée, 19, 1468; com- 
pare Berichle, 20, 2283). 


Quinone crystallizes in goldén-yellow prisms, melts at 116°, and 
sublimes at medium temperatures, in shining needles. Its vapor 
density confirms the formula C,H,O,. It possesses a peculiar, pene- 
trating odor, distils readily with steam, and dissolves easily in hot 
water, alcohol and ether. It turns brown on exposure to sunlight. 
Reducing agents (SO,, Zn and HCl) convert it first into quin- 
hydrone and then into hydroquinone. PCI, changes it to para- 
dichlorbenzene, C,H,Cl,. 

Quinone forms chlor- and brom-hydroquinone with concentrated hydrochloric 
and hydrobrontic acids (p. 692). It also unites with two molecules of acetyl 
chloride tof diacetyl-chlorhydroquinone, C,H,O, + 2C,H,OC] = C,H, 
Cl(O.C,H,O HCl (Berichte, 16, 2096). Quinone yields guénoxime, C,H,O; 
N.OH ( g-pifrésophenol) and quinon-dioxime, HO.N:C,H,:N.OH (p. 675), with 
hydroxyl@mine hydrochloride. All true para-quinones show a like reaction in acid 
solution.” Their dioximes do not form anhydrides. They unite with acetic anhy- 
dride to diacetyl compounds. Di-nitrosobenzenes are produced by the oxidation 
of their alkaline solutions (also on exposure to the air). Nitric acid oxidizes 
them to di-nitrobenzenes (Berichte, 21, 428). Orthoguinones, or ortho-diketones 
(p. 698), and their monoximes, when in alkaline solution, unite with hydroxylamine 
to form dioximes, capable of yielding anhydrides (Berichte, 23, 2815). 

The quinone monoximes and phenylisocyanate unite and yield carbanilides. The 
dioximes combine with two molecules of C,H;.N:CO, and form di-carbanilides. 









- 


700 ORGANIC CHEMISTRY. 


They are partly changed to anhydrides (Berichte, 22, 3105). Of the substituted 
quinones, only those quinone or CO-groups react with phenylisocyanate, in which 
the adjacent positions (ortho) ave not replaced ( Berichte, 21, 3316, 3493). 

When the primary amines and anilines act upon the quinones, the following may 
occur :— 

(1) Either the quinone oxygen is replaced by the imide-group : NR, with the 
production of guinone-imides and guinone-diimides, e.g., C,H,O:N.C,H, and 
Cot ..0C ANC... 

(2) Or, the hydrogen of benzene is substituted. Then anz/ido-guinones result. 

_At the same time, quinone is reduced to hydroquinone (erichie, 18, 785) :— 


(x, 4). 
ze A NH.C,H, (2) 
3CoH,O, + 2C,H,.NH, = CHO, NH CH tS 


Dianilido-quinone, 


+ 2C,H,(OH),. 


Such compounds are readily obtained from oxy-quinones. Again, the oxy-quinone 
imides, Ry fe , and the quinone-amides, RO NH are sometimes tautomeric (Ze- 


richte, 23, 897). : 

Dianilido-quinone, C,,H,,N,O,, Quinone-anilide, is formed by boiling 
quinone with aniline and alcohol. It forms brownish-violet scales, with metallic 
lustre (Berichte, 16,1556). In the presence of acetic acid the product is Diani- 
lido-quinone-anilide, C,H,O(N.C,H,)(NH.C,H,), (Berichée, 18, 787), while 
by fusing quinone with aniline or, aniline hydrochloride, we obtain Dianilido- 
quinone-dianilide, C,H,(N.C,H,),.(NH.C,H,), (1, 4, 2,5) = Cg9H.,N4, Azo- 
phenine (Berichte, 21, 683; 21, Ref. 656). 

The latter is also produced by the action of aniline upon amidoazobenzene, | 
p-nitrosophenol and /-nitrosodiphenylamine (Berichte, 20, 2480). It consists of 
garnet-red needles, melting at 241°. Itdissolves with a violet color in oil of vitriol. 
It becomes blue in color at 300°. It changes to fluorindin when heated 
(Berichte, 23, 2791). The induline dyes are intimately related to azophenine. 

The quinones react similarly with the phenylene diamines (Zerichte, 23, 2793). 

Phenylhydrazine reduces the quinones of the benzene series to hydroquinones, 
whereas the naphthaquinones and phenanthraquinone yield hydrazones. 

The phenols and quinones form compounds containing 2 molecules of the mono- 
valent phenols (Azmalen, 215, 134). Phenoquinone, C,H,0,.2C,H,.OH, crys- 
tallizes in red needles, melting at 71°. It is very volatile. Caustic potash colors 
it blue, and baryta water green. An analogous compound is— 

Quinhydrone, C,,H,,0, = C,H,0,.C,H,(OH),. This is produced by the 
direct union of quinone with hydroquinone. It appears as an intermediate product 
in the reduction of quinone or in the oxidation of hydroquinone. It consists of 
green prisms or leaflets with metallic lustre, melts readily, and dissolves in hot 
water with a brown, in alcohol and ether with a green, color. When it is boiled 
with water it decomposes into hydroquinone and quinone, which distilsover. It is 
changed by oxidation to quinone, and by reduction to hydroquinone. 





Chlor- and brom-quinones are obtained by the substitution of quinone or by the 
oxidation of substituted hydroquinones (p. 692) with nitric acid. 

Trichlorquinone, C,HCI,(O,), is produced, together with tetrachlorqguinone ; 
it consists of large, yellow plates, melting at 166°. It forms tetrachlorhydro- 
quinone, C,Cl,(OH),, by heating with fuming hydrochloric acid. Fuming nitric 
acid oxidizes this product to tetrachlorquinone. 


QUINONES. 7ot 


Tetrachlorquinone, C,Cl,(O,), Chloranil, is obtained, together with trichlor- 
quinone from many benzene compounds (aniline, phenol, isatin) by the action of 
chlorine or potassium chlorate and hydrochloric acid. Its production from sym- 
metrical tetrachlorbenzene (p. 582) by boiling with nitric acid is theoretically 
interesting. : 

In order to prepare it, gradually add a mixture of phenol (1 part) with ClO,K 
(4 parts) to concentrated hydrochloric acid, diluted with an equal volume of 
water, and apply a gentle heat. At first red crystals separate out, but on the 
addition of more ClO,K these become yellow. ‘The crystalline mass consists of 
tri- and tetra-chlorquinone. To effect their separation, they are changed by SO, 
to hydroquinones (tetrachlorhydroquinone is insoluble in water) and the latter 
oxidized with nitric acid (Berichte, 10, 1792, and Anma/en, 210, 174). 

Chloranil consists of bright golden leaflets, insoluble in water, but soluble in hot 
alcohol and ether. It sublimes about 150°, in yellow leaflets. PCI, converts it 
into C,Cl,. It oxidizes and serves as an oxidizing agent in the manufacture of 
coloring matters. Chloranil dissolves with a purple-red color in dilute KOH, 
forming fotassium chloranilate, C,Cl,(O,)(OK), + H,O, which crystallizes in 
dark red needles, not very soluble in water. Acids set free chloranilic acid, 
C,Cl,(O,)(OH), + H,O, which consists of red, shining scales. Aqueous ammonia 
converts chloranil into ch/oranilamide, C,Cl,(O,)(NH,),, and chloranilamic acid, 
C,Cl,(O,).(NH,)OH, ; anes 

The brom-quinones are perfectly analogous to the chlorine derivatives. Z2¢ra- 
bromquinone, Bromanil, C,Br,O,, is obtained by heating phenol (1 part) with 10 
parts of bromine and 3 parts of iodine in 50 parts of water. It consists of golden- 
yellow, shining leaflets or thick plates, which melt and sublime. By dissolving 
tetra- or tri-bromquinone in dilute caustic potash we obtain the potassium salt of 
bromanilic acid, C,Br,(O,)(OH),, crystallizing in dark red needles or bronze- ~ 
colored leaflets. Bromanilic acid is formed by allowing bromire to act upon 
dioxyquinone-dicarboxylic acid, C,(O,)(OH),(CO,H),, and it, therefore, contains 
two bromine atoms in the para-position (Berichfe, 20, 1303 and 1997). 


bi sis GR: H) — : 
Nitranilic Acid, C,(NO,),0,(0H), = (no, eZee (OH) p CON) 


or (NOs)HCK 65 GQ SCH(NO,) (see Berichte, aa, Ref. 292), analogous to 
brom- and chloranilic acid, is formed from quinone and hydroquinone with nitrous 
acid; more readily from diacetyl-hydroquinone with fuming nitric acid, or by the 
action of sodium nitrite upon chloranil (Berichte, 22, Ref. 292). It also results 
from dioxyterephthalic and dioxyquinone-terephthalic acids by the action of fuming 
nitric acid; the two NO,- and OH-groups are, therefore, in the para-position 
(Berichte, 19, 2398 and 2727). It crystallizes with water in golden yellow needles 
or plates, melts in its water of crystallization, becomes anhydrous at 100°, and 
detonates at 170° without melting. The fotassium salt, C,(NO,),(O,)(OK),., 
forms yellow needles, soluble with difficulty in water. When nitroanilic acid is 
reduced it yields diamidotetroxybenzene (p. 696). 

We may look upon chlor-, brom- and nitranilic acids as derivatives of dioxy- 
quinone, C,H,(O,)(OH),. 





Diketo-hexamethylene, C,H,O, = COC CH? oe CH? OO. Tetrahydrogui- 


none, is a derivative of hexahydrobenzene or hexamethylene. It results upon 
expelling two molecules of carbon dioxide from succino-succinic acid. It forms 
colorless crystals, melting, at 78° (Berichée, 22, 2170). It forms a dioxime with 


702 ORGANIC CHEMISTRY. 


hydroxylamine, C,H,(N.OH),. Sodium and alcohol reduce this to -diamido 
hexamethylene,C,H,(NH,),. Phenylhydrazine converts tetrahydroquinone into 
a dihydrazone. Hydrocyanic acid converts it into the dicyanhydrin, C,H,(OH), 
(CN)., etc. (Berichte, 22, 2176). 





OXYQUINONES AND POLYQUINOYLS. 


Oxy-quinone, C,.H,(O,).OH. 
Dioxyquinone, C,H,(OH),O,. 
Tetroxyquinone, C,(OH),O,. 
Dioxydiquinoyl, C,(O,)(O,)(OH),. 
Triquinoyl, g(Oz)3- 


Oxy-quinone, C,H,(O,).OH. Its methyl ether is produced by oxidizing 
o-amido-anisol, C, H,; NH,).0.CHs, with potassium permanganate and sulphuric 
acid. It consists of yellow needles, melting at 140°. Sulphurous acid reduces it 
to methyl-oxy-hydroquinone (p. 696) ( BerichZe, 21, 606). 

Dioxyquinone, C,H,(O,)(OH), (1, 2, 4, 5), is obtained from dioxyquinone 
dicarboxylic acid, C,(O,)(OH),(CO,H), (its sodium salt), by boiling with hydro- 
chloric acid, by the oxidation of diamido-resorcin in alkaline solution (Aerichte, 
21, 2374; 22, 1288) and by the action of sulphuric acid upon dianilidoquinone 
(Berichte, 23, 904). It separates in small blackish-brown crystals, which sublime 
above 185°. It dissolves in alcohol with a deep red, in alkalies with a bright 
yellow color. Acids reprecipitate it in the form of a dark yellow crystalline 
powder. Stannous chloride reduces it to symmetrical tetraoxy-benzene (p. 696) 
and dianilidoquinone, C,H,(O,)(NH.C,H;)., is produced when it is heated with 
aniline (p. 700). Hydroxylamine hydrochloride converts it into a dioxime, C,H, 
(N.OH),(OH),, that yields diamidohydroquinone by reduction. 

Diquinoyl, C,H,(O,)(O,) (1, 2, 3, 4), is not known in a free condition. Dinitro- 
resorcin (p. 627) is its dioxime, C,H,(O,)(N.OH),, from which hydroxylamine 
a diquinoyltetroxime, C,H,(N.OH), (1, 2, 3, 4) (Berichie, 23, 2816, 
3139)- 

Tetraoxy-quinone, C,(O,)(OH),, formerly called dihydrocarboxylic acid, is 
obtained by oxidizing the aqueous solution of hexaoxybenzene (p. 697) by exposure 
to the air. It may also be obtained from diamido-dioxyquinone (Lerichze, 21, 
1853). The disodium salt, C,O,(OH),(ONa),, separates in metallic black 
needles, if the aqueous solution of hexa-oxybenzene, mixed with soda, be allowed 
to stand exposed to the air. When the salt is boiled with dilute hydrochloric 
acid, tetroxyquinone separates in black needles with a green, metallic reflex 
(Berichte, 18, 507, 1837). ‘It is not fusible, but readily soluble in hot water and 
alcohol. It is a strong dibasic acid. 

Dioxydiquinoyl, C,(O,)(O,)(OH),, called rhodizonic acid, is prepared by 
reducing triquinoyl, C,(O,)3, by digesting it with aqueous sulphurous acid 
(Berichie, 18, 513). It consists of colorless leaflets, very readily soluble in water ; 
it decomposes quite rapidly ig aqueous solution. The corresponding salts are 
obtained by saturating the aqueous solution with potassium and sodium carbonate. 
The potassium salt, C,0,(OK),, may also be made by washing potassium-hexa- 
oxy-benzené (potassium carbon monoxide, p. 697) with alcohol. It forms dark 
blue needles, dissolving in water with an intense yellow color. The sodium sat, 
if4 foe 2» consists of violet needles, or shining octahedra (Lerichée, 19, 
1838). 


LEUCONIC ACID. 7°3 


Dioxy-diquinoyl is probably a para- and ortho-diketone; its two hydroxyls 
occupy the ortho-position with reference to each other (Berich/e, 23, 3140) :— 


eh Co 
\c(OH).C(OH)7 


In consequence it yields with orthotoluylene diamine (one molecule) a diazine 
(p. 628), from which a diquinoyl can be prepared by oxidation. This is capable 
of combining further with two molecules of o-toluylene diamine and forming a 
triazine- or triphenazine-derivative (Berichte, 20, 322). 
Hexachlor-triketone, C,C1,0, = CCl Go.cch> 
chlorine acts upon a chloroform solution of phloroglucin (Berichte, 22, 1467). It 
forms colorless crystals with a disagreeable odor. It melts at 48°, and boils at 
269°. Stannous chloride reduces it to trichlorphloroglucin, C,C]l,(OH),. Water 
decomposes it into dichloracetic acid, tetrachloracetone and carbon dioxide: 
C,C1,0, + 2H,O = CHCl,.CO,H + CO(CHCI,), + CO, (Berichte, 23, 


230). 

Triquinoyl, C,0, + 8H,0 = 006 63 ep 4. 8H, 0, hexaketo-hexa- 
methylene (Berichte, 20, 322), results upon oxidizing dioxydiquinoyl and diamido- 
tetroxybenzene (p. 696) with nitric acid, It is a white, micro-crystalline powder 
(Berichte, 18, 504). It melts about 95°, giving up water and CO,. It is like- 
wise decomposed by warming it with water to 90°. Stannous chloride reduces it 
to hexa-oxy-benzene, which is oxidized in alkaline solution to tetraoxyquinone, 
C,(O,)(OH),, and dioxydiquinoyl, C,(O,),(OH), (see above). 





CO, Dioxydiquinoyl. 


CO, is produced when 





Triquinoyl, hexaoxybenzene and their derivatives, in various oxidation reac- 
tions, give off carbon dioxide and yield crocomic acid, C;H,O,, which by more 
energetic oxidation becomes leuconic acid, C;O; + 4H,O. Both substances are, 
in all probability, derivatives of pentamethylene (p. 520), and correspond to the 
formulas (Berichte, 19, 308, 772) :— 


C(OH)—CO co—Cco 
Of add. . COG) 3 
“co — C(OH) \co—co 
Croconic Acid. _Leuconie Acid. 


For the course of the transformation of the benzene ring into the pentamethylene 
ring see Berichte, 20, 1267 and 1617. 

Croconic Acid, C;H,O, = C,0,(OH),, is produced by the alkaline oxidation 
of most of the hexa substituted benzene-derivatives, ¢. g., hexaoxybenzene, dioxy- 
diquinoyl, diamido-tetroxy-benzene, etc. Triquinoyl, when boiled with water, 
decomposes into carbon dioxide and croconic acid :— 


C,0, + H,O = C;H,0; + CO,. 


Free croconic acid crystallizes with three molecules of water in sulphur-yellow 
leaflets; it loses its water of crystallization at 100°. It dissolves very readily in 
water and alcohol. Its potassium salt, C,O,K, + 3H,O, crystallizes in orange 
yellow needles. When oxidized with nitric acid or chlorine the product is— 
Leuconic Acid, C,;O, + 4H,O, Pentaketo-penta-methylene, which is recon- 
verted into croconic acid by sulphur dioxide, It is very soluble in water, but dis- 


7ot ORGANIC CHEMISTRY. 


solves with difficulty in alcohol and ether. It crystallizes in small colorless 
needles. Being a pentaketo.compound it unites with five molecules of hydroxyl- 
amine, forming the penta-oxime, C,(N.OH),. A tetroxime, C,(N.OH),O, is 
produced at the same time. Stannous chloride reduces these oximes to penta- 
amido-pentol, C,H(NH,),, and tetra-amido-oxy-pentol, C, H(OH)(NH,), 
(Berichte, 22, 916). As a diorthoketone it unites with two molecules of toluylene- 
diamine and forms the diphenazine, C,O(N,C,H,)., which as a ketone is capable 
of combining with one molecule of phenylhydrazine (Berichte, 19, 777). 





With naphthalene there is known, in addition to the ordinary a-naphthaquinone 
(corresponding to ordinary quinone), an isomeric $-naphthaquinone, which is 
an orthodiketone (CO.CO—) (p. 698). The o-Benzoquinone, C,H,O, = 
CHS CH cHD CH, corresponding to it, is only known in its halogen-derivatives. 
Tetrachlor- and Tetrabrom-o-benzoquinone, C,Br,O,, are produced by 
oxidizing tetrachlor- and tetrabrom-pyrocatechin, C,Br,(OH), (1, 2), with nitric 
acid. Both form crystals with a garnet-red color and_show a metallic lustre. The 
first melts at 132°; the second at 151° (Berichte, 20, 1778). 





The homologous quinones are quite similar to benzoquinone. 

Toluquinone, C,H,(CH,)O,, is obtained by oxidizing various amidotoluenes. 
It is most conveniently prepared by oxidizing o-toluidine (crude) with chromic 
acid (Berichte, 20, 2283), just as in the case of benzoquinone. It consists of 
golden yellow leaflets, melting at 67°; these are very volatile and have the 
quinone odor. Reduction (with SO,) converts it into tolu-hydroquinone (p. 694). 
Hydroxylamine converts it into the monoxime, C,H,(CH,)O:N.OH, identical 
with nitroso-o-cresol (p. 685), and toluquinon-dioxime, C,H,(CH,)(N.OH),, 
which is also obtained from nitrosotoluidine (p. 623) (Berichte, 21,733). It forms 
yellow needles, chars at 210°, and detonates at 234°. When it is oxidized in 
alkaline solution it yields dinitrotoluene. Aniline and toluquinone yield anilides 
(p. 700). 

Xyloquinones, C,H,(CH,),O,. The three possible isomerides are known. 

o-Xyloquinone (1, 2, O,), is obtained from amido-o-xylene by oxidation with 
K,Cr,O,. It sublimes in yellow needles, melting at 55° (Berich/e, 18, 2673). 
m-Xyloquinone (I, 3, O,) is obtained from amido-m-xylene and amidomesi- 
tylene, by the displacement of a CH,-group ( Berichie, 18, 1150). It melts at 73°. 
The oxidation of diamido- or dioxymesitylene, by chromic acid, produces oxy-m- 
xyloquinone, melting at 102°. The yellow aqueous solution is colored a deep 
violet by alkalies, or even by spring water. 

p-Xyloquinone, C,H,(CH;),0, (1, 4, O,), results by the oxidation of 
p-xylidine, or more readily from diamido-xylene (obtained by the decomposi- 
tion of amido-azo-xylidine). It is identical with Ah/oron. It is most easily 
obtained from pseudocumidine, C,H,(CH,), NH,, by oxidation with chromic 
acid (Berichte, 18, 1150), It consists of golden yellow needles, which resemble 
quinone in odor, and melt at 123°. With hydroxylamine it forms (like quinone) 
a monoxime and dioxime ( Berichte, 20, 978). 

Durenequinone, C,(CH,),0, (1, 2,4, 5,0,), is produced by oxidizing diamido- 
durene with ferric chloride or sodium nitrite. It forms long yellow needles, melt- 
ing at 111°, 


QUINONE-CHLORIMIDES. 705 


Thymo-quinone, C,H,(CH,)(C,H,)O,, Thymoil, is formed by oxidizing 
thymol or carvacrol (p. 688) with MnO, and H,SO,, or amidothymol with ferric 
chloride. It forms yellow plates, melts at 45.5°, and boils at 232°, By reduction 
it yields thymohydroquinone (p. 694). With hydroxylamine it yields a monoxime 
(nitrosothymol, p. 688). See Berichte, 22, 3268, upon iodo- and bromthymo- 
quinone. 

Two Oxythymoguinones, CyyH,(OH)O, and Diéioxythymoquinone, CH 
(OH),O,, are produced on heating bromthymoquinone with KOH. They yield 
thymodiquinone, C,)H)(O,)(O,), by oxidation (Berichze, 23, 1391; Ref. 565). 





QUINONE-CHLORIMIDES. 


These are very similar to the quinones, and possess an analogous constitution 
(p. 698). ‘We must regard them either as diketones or peroxides, in which oxygen 
is replaced by the group NCI. The latter view corresponds to the formulas :— 


O O NCl NCl 
G f ae Pri 
C,H C.F C,H CH 
NE NO ee 
Quinone Chlorimide. Quinone Dichlorimide. 


They are produced from f-amidophenols and Z-phenylene diamines (their HCl- 
salts) by oxidation with an aqueous solution of bleaching lime. The mono- 
chlorimides form the indophenol coloring matters (see below) with phenols and 
tertiary anilines, 

Quinone Chlorimide, C,H,(ONCI), produced from HCl-para-amidophenol 
with bleaching lime (Journ. pr. Chem. 23, 435), forms golden yellow crystals, 
which melt at 85°, volatilize readily with steam and smell like quinone. It is 
easily soluble in hot water, alcohol and ether. Reducing agents (also H,S) con- 
vert it into 4-amidophenol, When boiled with water it decomposes into NH,Cl 
and quinone. 

Quinone-dichlorimide, C,H,(N,Cl,), from paraphenylenediamine-hydro- 
chloride, crystallizes in needles which deflagrate at 124°, and are converted by 
reducing agents into #-phenylene-diamine. 

Dibrom-quinone-chlorimide, C,Br,H,(ONC1), from dibrom-/ nitro-phenol, 
crystallizes in dark yellow prisms, melting at 80° and decomposing at 121°. 


Trichlor-quinone-chlorimide, C,Cl],H(ONCI), from trichlor-g-amidophenoly 


forms yellow prisms, melting at 118°. 4 





Indophenols, Indoanilines and Jndoamines.—These are green to 
blue-colored dye-substances. In constitution they are analogous to 
the quinone-chlorimides and quinone-dichlorimides ; they bear a 
close genetic relation to the latter, and are obtained by allowing 
the quinone-chlorimides and -dichlorimides to act upon phenols 
and anilines :— 


0 YP NH.HC1 
C.H,¢ | | CoH | CHAS 
\N.C,H,.0H N.C,H,.N(CH,), N.C,H,.NH, 
Indo-phenol, Indo-aniline, Indo-amine, 
Quinone-phenolimide. Quinone-dimethyl-anilinimide, Phenylene Blue. 


59 


% 
* 


706 ORGANIC CHEMISTRY. 


These compounds also contain the chromophore groups O—N and 
N—N (see p. 644), which occupy the para-position in one benzene 
nucleus; they are also closely related to the thionine dyestuffs (p. 
605). They are decolorized upon reduction (the addition of 2H- 

atoms) which is true of most coloring compounds. By this action 
the chromophore group is severed, and derivatives of diphenyl- 
amine are formed, which are their leuaco-compounds (p. 605). Thus, 
by reducing (dibrom) quinone-phenolimide we obtain (dibrom) 
p-dioxydiphenylamine (p. 604), and the same treatment converts 
indoaniline into dimethylamido-oxy-diphenylamine, and phenylene 
blue into g-diamido-diphenylamine (p. 603) :— 


C,H,.0H /C,H,.0H /C,H,.NH 
pn Cott, H ett4 ESE shige ed. oni 
N\C,H,.0H NX CoH¢-N(CH,)s \C,H,.NH, 
p-Dioxydiphenylamine. Dimethyl-amido-oxy- Diamido-diphenylamine. 


diphenylamine. 


Therefore, the indophenols, indoanilines and indoamines may be 
viewed as derivatives of diphenylamine, in accordance with the fol- 
lowing formulas of like significance as those above (Nietzki, Be- 
richte, 21, 1736) :— 


gan OH néCoHe-N(CH,), a7 cally Ni, 
| heme ais Oe l wea? Babes has yada 
Indophenol. Indoauiline. Indoamine. 


The connection of the three groups is evident from the fact that the 
indoamines, by the replacement of the amido-group by oxygen, can 
be converted into indoanilines, and the latter, furthermore, into 
indophenols (Méhlau, Berichte, 16, 2843, and 18, 2915). 


(1) The indophenols, in addition to their formation from the action of quinone 
chlorimide upon phenol, are also produced by oxidizing a mixture of a para- 
amido. phenol and phenol (1 molecule of each). They dissolve in alcohol with a 
red color, and possess a phenol-like character. Their salts with the alkalies and 
ammonia dissolve in water with a d/ue color. 


Quinone-phenol-imide, NC CHO also results upon heating phenol- 
bien t 


blue with soda-lye (Berichte, 18, 2916), but owing to its instability, cannot be 


obtained in a free condition. Dibrom-quinone-phenolimide, NC CHB: 0 





Its sodium salt is produced by the action of dibromquinone-chlorimide in alcoholic 
solution upon an alkaline phenol solution. It separates in golden green crystals, 
which dissolve in water with a blue color. Free dibrom-phenolimide, separated 
from its sodium salt by acetic acid, crystallizes in dark red prisms having a metallic 
lustre; they dissolve in alcohol and ether with a fuchsine-red color, Strong 
mineral acids decompose it into dibromphenol and quinone, 


- NAPHTHOL BLUE. ~ 707 


(2) The Indo-anilines (indophenols of Witt), as 


n¢ Coe N(CHs)s and n7 CoHa-N(CH3), 
| 6 a | 0 ae 
Phenol Blue. Naphthol Blue. 


are produced: (1) by the action of quinone chlorimide upon dimethylaniline in 
alcoholic solution (see above) ; (2) by the action of nitroso- and nitro-dimethyl- 
aniline upon phenol and a- naphthol i in alkaline solution, especially in the presence 
of reducing agents (Witt, 1879) :— 


;H,.N(CH 
ON.C,H,.N(CH,), + C;H,-OH = sie Hy a)a, 


Witrusodimeth ylaniline. | 6**4° ; 
| Phenol Blue. 


(3) By the oxidation in a/ka/ine solution (with sodium hypochlorite), of a mix- 
ture of a para-phenylene diamine with a phenol, or of .a para-amido-phenol with a 
primary monamine; this is the readiest method for its preparation. Thus there is 
formed from dimethyl-g-phenylene diamine (p. 625) with a-naphthol, the so-called 
naphthol blue :— 


_ 4 /C,H,N(CH,) 
H,N.C,H,.N(CH,), + C,H,OH + 0, = “i CHO yo. 


Naphthol Blue. 


The indoanilines, in distinction to the indophenols, are feebly dasic, and are not 
capable of forming ‘salts with alkalies. They are rather stable towards the latter; 
acids quickly decompose them into quinones and the f-phenylene diamines, They 
are changed to the leuco-compounds by reduction (absorption of two hydrogen 
atoms); these dissolve readily in alkalies, and are readily reconverted (oxidized 
into indoanilines (by exposure of their alkaline solution to the air). The free indo- 
anilines have a deep-blue color, and can be applied as dyestuffs. For this purpose 
they are converted into their alkaline leuco-derivatives, which are soluble, and the 
material is impregnated or printed with these. Oxidation (by exposure to the air, 
or with K,Cr,O,), develops the color. The simplest aniline is Quinone Anilin- 

N.C,H,.NH 
KA 
diamine, C,H (NH), with phenol. Its dimethyl derivative is Quinone-di- 
N.C, H,.N(CH,), 
methyl-anilinimide, C, HK | | ; 

Phenol Blue. This sos from dimethyl-s-phenylene diamine and phenol. 
It has a greenish-blue color. When boiled with soda-lye it splits off dimethyl- 


amine and becomes quinone phenolimide. 
N.C, H,.N N(CHs > 
«J | : 
Witt), finds technical asters It is made by oxidizing dimethy]l-s-phenylene 
diamine with a-naphthol ( BerichZe, 18, 2916), or by the action of nitrosodimethyl- 
aniline upon a-naphthol. It crystallizes from alcohol in bronze-like, bluish violet 
crystals, dissolves without coloration in acids, and on standing in contact with the 
same decomposes into dimethyl-f-phenylene diamine and a- naphthoquinone. When 
reduced with SnCl,, it yields the SnCl,-double salt, which occurs in commerce as 
a paste, bearing the name “ white indopheno = J 


imide, C,H ,a violet dye, formed by the oxidation of f-phenylene 


Naphthol Blue, C,,H, , called indophenol (Koechlin and 


~ 


708 ORGANIC CHEMISTRY. 


(3) Indamines (see above). 

These arise by oxidation, in neutral solution and in the cold, of a mixture of a 
p-phenylene diamine with an aniline (Nietzki), or by the action of nitrosodimethy] 
aniline upon anilines or #-diamines (Witt). They are feeble bases, forming blue 
or green-colored salts with acids, but with an excess of the latter are very easily 
split up into quinone and the diamine. Because of their instability they find no 
application, and are only important as intermediate products in the manufacture of 
safranine dyestuffs (into which they can be readily transposed) (Berichte, 16, 464). 
The simplest indamine is— 


Phenylene Blue, C,,H,N, = N/Cslla-NHa  qnis is produced by the oxi- 
3**11**s \.C,H,.NH ° P 7 
, | 


dation of f-phenylene diamine with anilitte. Its salts are greenish-blue in color. 
It yields diamido-diphenylamine by reduction. Its tetramethyl-derivative is— 

Dimethylphenylene Green, C, H,,N, HC] = NZ Cols N(CH,), (Bind- 

yey Pte y NCeHa-N(CH,),C1 
| 

schedler’s green). This is obtained by oxidizing dimethyl paraphenylene diamine 
with dimethyl] aniline. Its salts dissolve in water with a beautiful green color, and 
impart a yellow-green color to silk. Its reduction yields tetramethyl-diamido-di- 
phenylamine (p. 604). Digestion with dilute acids resolves it into quinone and 
dimethylamine (Berichte, 16, 865). When it is boiled with soda-lye, dimethy]l- 
amine splits off and phenol blue is produced; this further separates into quinone 
phenolimide (p. 706) (Berichte, 18, 2915). 


Toluylene Blue, C,,H,,.N, = NC CHHY(NH,) NEP results from ordinary 
rgb Bi 





toluylene diamine (p. 626) by oxidizing it mixed with dimethyl] p-phenylene dia- 
mine, or by the action of HCl-nitroso-dimethylaniline. Its salts with one equivalent 
of acid are of a beautiful blue color, and are decolorized by an excess of mineral 
acids with formation of the diacid salts. It is converted into toluylene red (see this) 
on boiling with water. 

The lowest homologue of toluylene blue is produced by reducing dimethylamido- 
dinitro-diphenylamine (p. 604), and oxidizing the resulting triamido-compound 
(Berichte, 23, 2738). 


ALCOHOLS. 


The ¢rue alcohols (isomeric with the phenols) of the benzene 
series are produced by the entrance of hydroxyls into the side- 
chains of the homologous benzenes (p. 557). They are perfectly 
analogous to the fatty alcohols. By oxidation they yield aldehydes 
(or ketones) and acids :— 


C,H,.CH,.0H C,H,.CHO C,H,.CO.OH. 
Benzyl Alcohol. Benzaldehyde. Benzoic Acid. 


The methods of forming them are perfectly analogous to those of the fatty 
series. They are obtained :— 

1. By the conversion of substituted hydrocarbons, like benzyl chloride, C,H. 
CH,Cl, into acid esters, and saponifying the latter with alkalies, or by boiling the 
chlorides with water and lead oxide (p. 119), or with a soda solution :-— 


CH CHG O = C,H..CH,.OH HCl. 
Benzyl Chloride: ee. Benzyl Alcohol. T 


BENZYL ALCOHOL. 709 


2. By the action of nascent hydrogen (p. 119) on the aldehydes and ketones, 
or by heating the aldehydes, or letting them stand with alcoholic or aqueous potash, 
whereby acids are formed at the same time :— 


2C,H,.CHO + KOH = C,H,.CH,.0H + C,H,.CO,K. 


In this series we also distinguish primary, secondary and tertiary alcohols. 


Benzyl Alcohol, C,H,O = C,H;.CH,.OH, occurs as benzyl- 
benzoic ester, and benzyl-cinnamic ester in the balsams of Peru 
and Tolu, and in storax, and can be obtained from benzaldehyde 
(oil of bitter almonds) by the action of sodium amalgam or aque- 
ous potassium hydroxide (Berichte, 14, 2394), or by boiling benzyl 
chloride with a soda solution. It is a colorless liquid, with a 
faint aromatic odor, and boils at 206°; its specific gravity at 0° is 
1.062. It dissolves with difficulty in water, but readily in alcohol 
and ether. It yields benzaldehyde and benzoic acid when oxidized. 
Heated with hydrochloric acid or hydrobromic acid, the OH- 
group is replaced by halogens. Benzoic acid and toluene result on 
distilling it with concentrated potash :— 


3C,H,O + KOH = C,H,KO, + 2C,H, + 2H,0. 


The esters of benzyl alcohol are produced from it by the action of acid chlorides, 
or from benzyl chloride by boiling with organic salts. The acetic ester, C,H,O. 
C,H,O, is a liquid and boils at 206°. The oxalic ester, C,0,(C,H,),, forms 
shining leaflets, melting at 80°. 

The alcohol ethers are obtained by heating benzyl chloride with sodium alco- 
holates. The methyl ether, C,H ,O.CHg, boils at 168°; the ethyl ether at 185°. 

The dibenzyl ether, (C, H “CH.),0; is formed on heating the alcohol with 
boric anhydride, and benzyl. chloride with water to 190°. It is an oil boiling 
near 310°. 

The benzyl-phenyl ether, C,H,.CH,.0.C,H,, results when benzyl chloride is 
heated together with potassium phenolate, & H,.OK. It melts at 39°, and boils 
at 287°. 

Substituted benzyl alcohols are derived from substituted benzyl chlorides, e. z., 
C,H,Cl.CH,Cl, when they are heated with aqueous ammonia, or by means of 
acetic esters. Para-chlor-benzyl alcohol, C,H,Cl.CH,.OH, consists of long 
needles, which melt at 66°, and boil about 220°. 

o-Nitrobenzyl Alcohol, C,H,(NO,).CH,.OH, is formed by shaking o-nitro- 
benzaldehyde (crude) with concentrated sodium hydroxide (Berichte, 18, 2403), 
and crystallizes in bright yellow needles, melting at 74°. m-Nitrobenzyl Alco- 
hol, from m-nitrobenzaldehyde, is a thick, yellow oil. 

p-Nitrobenzyl Alcohol is obtained from its chloride and from nitrobenzyl 
acetic ester. It melts at 93°. 

Nitromethyl Benzene, C,H,.CH,(NO,), is obtained from nitrobenzalphtha- 
lide; it is a yellow- colored liquid, boiling at 226° (Berichte, 18, 1255; 19, 
1145). 

o Amidobenzyl Alcohol, C,H,(NH,).CH,.OH, is formed by the reduction of 
anthranil and o-nitrobenzyl alcohol with zinc dust and hydrochloric acid. It 
crystallizes in white needles, me - ers odor, and melts at 82° (Berichie, 15, 


2109). Benzylenimide, C Hi CH! oP 2 , is the anhydride of this alcohol, It 


710 ORGANIC CHEMISTRY. 


results from the reduction of o-nitrobenzyl chloride with stannous chloride. An 
analogous compound is also obtained from g-nitrobenzyl chloride (Berich/e, 19, 
1612). 

Potassium cyanate converts o-amidobenzyl alcohol into a urea, that condenses to 
a benzo-metadiazine (Berichte, 23, 2183) :— 


CH,.0H op NAL 
CH tH + H,0. 
bio SNHICONE). 0 NNO 3" 


Benzyl! Sulphydrate, C,H,.CH,.SH, Benzyl Mercaptan. This is formed by 
the action of alcoholic KSH upon benzyl] chloride. It is a liquid, with a leek-like 
odor; boils at 194°, and at 20° has a specific gravity = 1.058. Salts of the heavy 
metals precipitate mercaptides from its alcoholic solutions. On exposure it 
oxidizes to Benzyl disulphide, (C,H,,),S,, which crystallizes from alcohol in 
shining leaflets melting at 66°. Nascent hydrogen causes it to revert to benzyl 
sulphydrate. : 

Benzyl Sulphide, (C,H,.CH,),S, is formed by the action of K,S upon an 
alcoholic solution of benzyl chloride. Colorless needles, melting at 49°. Nitric 
acid oxidizes it to the oxy-sulphide, (C,H,.CH,),SO, which dissolves in hot 

water and melts at 130°. The szlphone, (C,H,.CH,).SO,, melts at 150°. 
Potassium Benzy/sulphonate, C,H;.CH,.SO,K + H,O, is formed on boiling 
benzyl chloride with potassium sulphite. The free acid is a deliquescent crystal- 
line mass; it is isomeric with toluene-sulphonic acid. . 





Alcoholic ammonia converts benzyl chloride into mono-, di-, and tri-benzyl- 
amines, which are separated by means of their hydrochloric acid salts. These 
same compounds are obtained from benzaldehyde on boiling with formamide 
(Berichte, 19, 2128; 20, 104). They result, too, when the benzothio-amides are 
reduced with zinc and hydrochloric acid :— 


C,H,.CS.NH, ++ 2H, = C,H,.CH,.NH, + SH,. 


(Berichte, 21, 51). 
Benzylamine, C,H,.CH,.NH, (Benzamine), is formed when zinc and hydro- 
chloric acid act upon benzonitrile; by the action of an alkaline bromine solution 
upon phenylacetamide, C,H,.CH,.CO.NH, (p. 160), but most readily by decom- 
posing benzylacetamide, C,H,;.CH,.NH.CO.CH, (from benzyl chloride with 
acetamide, Berichte, 19, 1286), by means of alcoholic potash. It dissolves in 
water and boils at 185°. It differs from its isomeric toluidine in being a strong 
base, that attracts carbon dioxide. 
o-Nitrobenzylamine, C,H,(NO,).CH,.NH,, obtained from o-nitrobenzyl- 
chloride (p. 584) by the saponification of its phthalimide derivative, is a strong, 
oily base (Berichte, 20, 2228). It may be reduced to o-amido-benzylamine, 
C,H,(NH,).CH,.NH, (o-benzylene-diamine), The benzene derivative of the 
latter forms a quinazoline by the production of a closed ring (Lerichie, 23, 
2810) :— 
Joa NH CH,.NH 
C,H ge Oe | 
: «\wu,.Co.c,H, iifeiee 2 bc.H, 


Dibenzylamine, (C,H,),.NH, is an oil insoluble in water. It is formed 
when PCI, acts upon dibenzylhydroxylamine (Berichte 19, 3287). 
_ Tribenzylamine, (C,H,),N, forms large plates melting at 91°, and distilling 
near 300° undecomposed (Aerichie, 19, 1027). 


+ H,0. 


CUMIN ALCOHOL. 711 


When benzyl chloride acts on aniline the products are :— 

Benzylaniline, C,H,.CH,.NH.C,H,, which also results in the reduction of 
benzylidene aniline with sodium in alcoholic solution. It melts at 32°, and 

Dibenzylaniline, (C,H,.CH,),.N.C,H,, melting at 67°. 

Benzyl derivatives of hydroxylamine (p. 166) (Ammalen, 257, 203). 

a-Benzyl-hydroxylamine, H,N.O.C,H,, is produced by decomposing 
acetoxime-benzyl ether (p. 205) and a-benzaldoximebenzyl ether with hydro- 
chloric acid. It is a colorless oil, boiling at 119° under 30 mm. pressure. Its 
hydrochloride forms silvery leaflets, subliming above 230° without previously 
melting. If it be heated with hydrochloric acid it breaks down into benzyl 
chloride, hydroxylamine and ammonium chloride. Hydriodic acid converts it 
into benzyl iodide and ammonia. : 

B-Benzyl-hydroxylamine, C,H ,.HN.OH, is obtained by decomposing 6-ben- 
zaldoximebenzy] ether (p. 718) and a@8-dibenzyl-hydroxylamine with hydrochloric 
acid. It melts at 57°, dissolves somewhat in water, and reduces Fehling’s solu- 
tion. Its hydrochloride is very readily soluble in water and alcohol... It melts at 
100-110° ( Berichte, 22, 429, 613). Hydrochloric acid does not decompose it. 
It yields bimolecular benzaldoxime (Berichte, 23, 1773) by oxidation. 

af-Dibenzyl-hydroxylamine, C,H ,.HN.O.C,H,, results upon heating a-ben- 
zyl-hydroxylamine with benzyl chloride. It is a liquid. A large quantity of 
water will decompose its hydrochloride. It becomes 6-benzyl-hydroxylamine by 
decomposition. 

$£B-Dibenzyl-hydroxylamine, (C,H,),N.OH, is produced on heating hy- 
droxylamine with benzyl chloride. It melts at 123°. Hydrochloric acid does not 
decompose it. 

Tribenzyl-hydroxylamine, (C,H,),N.O.C,H,, results when benzyl chloride 
acts upon a-dibenzyl-hydroxylamine (less readily if the 6G-variety be used). It 
is a liquid. Its hydrochloride is readily decomposed by water. With hydrochloric 
acid it yields 68-dibenzyl-hydroxylamine (Berichte, 23, Ref. 402). 





(2) Alcohols, C,H,,O. There are five isomerides. ‘ 

Tolyl Alcohols, C,H,(CH,;).CH,.OH. The ortho-body (1, 2). obtained 
from orthotoluy] aldehyde with sodium amalgam, melts at 31°, and boils at 210°, 
(Berichte, 23, 1028). The meta, from m-xylene bromide, C,H,(CH,).CH,Cl, 
boils at 217° (Berichte, 18, Ref. 66). The para, derived from paratoluyl alde- 
hyde with potassium hydroxide, melts at 59°, and boils at 217°. 

Phenyl Ethyl Alcohol, C,H,.CH,.CH,.OH, a-Tolyl alcohol, obtained 
from a-toluyl aldehyde, is a liquid boiling at 212°, has a specific gravity == 1.033 
at 20°, and when moderately oxidized yields a-toluic acid. Its acetic ester boils 
at 224°. See Berichte, 22, 1413 for the phenylethylamines, C,H,;.C,H,.NH,. 

Phenyl Methyl Carbinol, C,H,.CH(OH).CH,, is a secondary alcohol, pro- 
duced from $-brom-ethyl benzene (p. 586), and by the action of sodium amalgam 
upon acetophenone, C,H,.CO.CH,. It boils at 203°. Oxidation convertsit again 
into acetophenone. The acetic ester boils near 214°, and partly decomposes into 
acetic acid and styrol. 

(3) Phenyl Propyl Alcohol, C,H,.CH,.CH,.CH,(OH), Hydrocinnamy! Al- 
cohol, obtained from cinnamic alcohol, boils at 235°. It exists as cinnamic ester 
in storax. Secondary Phenyl-ethyl Carbinol, C,H,.CH(OH).CH,.CHg, is 
formed from phenyl-ethyl ketone, C, H,.C@.C,H,, and boils at 219°. 


(4) Cumin Alcohol, CHK Con (I, 4), contains the isopropyl-group. 





712 ORGANIC CHEMISTRY. 


It is formed from cuminic aldehyde. It boils at 246°, and yields common cymene, 
C,,H,,, when boiled with zinc dust. Its chloride, C,H,(C,H,).CH,Cl, yields the 
same product, when heated with zinc and hydrochloric acid. Boiling alcoholic 
potash or dilute nitric acid oxidizes it to cuminic acid. Its isomeride is tertiary— 


Benzyl-dimethyl Carbinol, “6 Hs ny? ake. OH, produced by acting on a-to- 


luic chloride, C,H,;.CH,.COCI, with ane a ea Long needles, which melt at 
20—22°, and boil about 225°. 





DIVALENT (DIHYDRIC) ALCOHOLS. 


Dihydric Benzylene-Glycol, C,H,.CH(OH),, would correspond to methylene 
glycol, but does not exist. Where it should occur, benzaldehyde appears (p. 298). 
Its ethers are derived from benzylene chloride, C,H,.CHCI,, through the action 
of sodium alcoholates or salts of organic acids. The dimethyl ether, C,H,.CH 
(O.CH,)., boils at 205°; the diethyl ether at 217°. The acetate, C,H,.CH 
(0.C,H,O),, is crystalline, melts at 43°, and boils with decomposition at 220°. 

Tollylene Alcohols, C,H,,0, = C,H Gy” Opp Xviylene alcohols. ‘The 
three isomerides are obtained from the three corresponding xylylene chlorides or 
bromides by boiling with a soda solution. The ortho (1, 2), called Phthalyl 
alcohol, is obtained also from phthalic acid chloride by sodium amalgam. It 
melts at 64°. A potassium permanganate solution oxidizes it to phthalic acid. 
The meta (1, 3) melts at 46°, while the ava melts at 112°. The three are 
readily soluble in water. 

Styrolene Alcohol, C,H,.CH(OH).CH,.OH, Phenyl glycol, is obtained 
from styrolene dibromide, C,H,.CHBr.CH,Br; it crystallizes from benzine, and 
benzene, in silky needles, melts at 67—-68°, and can be sublimed. It is very soluble 
in water, alcohol and ether. Dilute nitric acid oxidizes it to benzoyl carbinol. 

Phenyl Methyl Glycol, C,H,.CH(OH).CH(OH).CH,, exists in two modifi- 
cations, a and f, like hydrobenzoin. These are obtained from phenyl! dibrom- 
propane, C,H,.CHBr.CHBr CH, (from propyl benzene). The a-body melts at 
53°, the B- at 93° (Berichte, 17, 709). 


Benzoyl Carbinol, C,H;.CO.CH,.OH (Acetophenone Alco- 
hol), is a Xefone alcohol, formed from the bromide, C,H;.CO.CH,. 
Br, by its conversion into acetate, and saponification with potassium 
carbonate (Berichte, 16, 1290). It crystallizes from water and 
alcohol in large, brilliant leaflets, which contain water of crystalli- 
zation, and melt at 73-74°. It crystallizes from ether in shining 
anhydrous plates, and melts at 85-86°. 


When distilled it decomposes with formation of bitter almond oil. Being a 
ketone it forms crystalline compounds with primary alkaline sulphites. Like 
acetyl carbinol it reduces a cold ammoniacal silver or copper solution (form- 
ing benzaldehyde and benzoic acid), and is oxidized to mandelic acid (p. 321 
Berichte, 14, 2100). Nitric acid oxidizes it to benzoyl-carboxylic acid, C,H;.CO. 
CO,H. It yields cyanhydrin with CNH, which then forms a-pheny! ‘glyceric 
acid. Hydroxylamine converts it inte, the isonitroso-compound, C,H,.C(N.OH). 
CH,.OH, melting at 70°. 

It forms the hydrazone, C,H,.C(N, H. C,H,).CH,OH (melting at 112°), with 
phenylbydrazine. This compound unites with a second molecule of the reagent, 


oe 


OXY-BENZYL ALCOHOLS. . 713 


like the glucoses (p. 501), and yields the osazone, C,H;.C(N,H.C,H,;)CH(N.H. 
C,H.) (Berichte, 20, 822). : 

"The acetate, C,H,.CO.CH,.0.C,H,0, forms rhombic plates, melting at 49°; 
the denzoate melts at ahi 3 both reduce an ammoniacal silver solution, even in 
the cold. 





Oxy-alcohols or Phenol alcohols. : 

These contain, in addition to the alcoholic hydroxyl, one or 
more hydroxyl groups in combination with the benzene nucleus, 
hence they also possess the properties of the phenols. 


(1) Oxy-benzyl alcohols, CHC Ge OH. 


The ortho-compound (1, 2), Saligenin, is formed when sodium 
amalgam acts upon salicylic aldehyde, or in the decomposition of 
the glucoside salicin with dilute acids or ferments :— 

C,,H,,0, + H,O = C,H,0, + C,H, .0,. 
Salicin, Salipeninr Destress: 
It consists of pearly tables, soluble in hot water, alcohol and ether, 
melting at 82° and subliming near 100°. Lead acetate causes a 
white precipitate in its solutions, and ferric chloride produces a 
deep blue color in them. Dilute acids resinify it, forming sazretin, 
C,,H,,O;. It yields salicylic acid when oxidized. 


The glucosides of saligenin are salicin, populin and helicin fia 


/0.C,H,,0, /0.C,Hy,05 /0.C,H,,0 
CoH CH OH CoHA CH,.0.0C, yO “8 CHO 
Salicin. Popuiin. Helicin. 


Salicin, C\,H,,0,, the glucoside of saligenin, occurs in the bark and leaves of 
willows and some poplars, from which it may be extracted with water. It can 
be artificially prepared by reducing helicin with sodium amalgam. It forms 
shining crystals, which dissolve easily in hot water and alcohol, and melt at 198°, 
Its taste is bitter. 

The glucoside, Populin, C, ,H,,O,, contained in several varieties of poplar, is 
the benzoyl derivative of salicin, C,,H, (Cs H,0)O,, and can be artificially made 
by the action of benzoyl chloride, C,H -OCl, or benzoic anhydride upon salicin. 
Populin crystallizes in small prisms containing 2 molecules of water, dissolves with 
difficulty in water and possesses a sweet taste. Dilute hydrochloric acid decom- 
poses it into benzoic acid, glucose and saliretin. 

Ftelicin, C,H,(O.C H,,0;). CHO, is produced by oxidizing salicin with nitric 
acid. It can be artificially prepared from salicylic aldehyde and acetochlorhydrose. 
It dissolves with difficulty in water, crystallizes in small needles and melts at 175°. 
Dilute acids and ferments break it up into salicylic aldehyde and dextrose. It 
contains the CHO-group, hence combines with acetaldehyde to form glucose- 
cumaraldehyde, C,H,(O.C,H,,0,).CH:CH.CHO (Berichte, 18, 1958). 

Meta-oxybenzyl "Alcohol, ¢; H ,(OH).CH,.OH (1, 3), is formed from meta. oxy- 
benzoic acid by means of sodium amalgam. It melts at 67°, and boils at 300°, 


60 





714 ORGANIC CHEMISTRY. 


Ferric chloride colors it violet. It is oxidized to meta-oxybenzoic acid when fused 
_with KOH (but not with chromic acid, p. 686). 

Para-oxybenzyl Alcohol (1, 4) is produced by the action of sodium amalgam 
(in slightly acidulated alcoholic solution) upon paraoxybenzaldehyde (dioxy-hydro- 
benzoin, melting at 222°, is produced at the same time). It is readily soluble in 
water, alcohol and ether. From benzene it crystallizes in delicate needles, melting 
at 110° (Berichte, 19, 2374)... It melts at 197°. Its methyl ether is the so-called 


Anisyl Alcohol, C,H,(O.CH;).CH,.OH (1, 4), obtained from 
anisic aldehyde by alcoholic potassium hydroxide. It is but slightly 
soluble in water, crystallizes in needles, melts at 25°, and boils at 
259° without decomposition. It forms anisic aldehyde and acid 
when oxidized. 


(2) Vanillin Alcohol, C,H,,O;, and Piperonyl Alcohol, C,H,O,, are formed 
from their aldehydes, vanillin and piperonal, by acting on the solution with sodium 
amalgam. They are derivatives of homo-pyro-catechin and creosol (p. 693), and 
stand in intimate relation to proto-catechuic aldehyde. Vanillin alcohol is the 
methyl-phenol ether, piperonyl alcohol the methylene-phenol ether of protocate- 
chuic alcohol, which has not yet been prepared (see vanillin) :— 


. (CH, (1) CH,.0H CH,.0H COH 
C,H,;4 OH (3) C,H, 4 0.CH, Ce] ONC Cath} OF : 
OH (4) OH Ot s OH 


Homo-pyro- Vanillin Alcohol. Piperonyl Alcohol. Protocatechuic 
catechin. Aldehyde. 


Vanillin alcohol crystallizes in colorless prisms, melts at 115°, and dissolves easily 
in-hot water and alcohol. Piperonyl alcohol dissolves with difficulty in water, 
forms long prisms, and melts at 51°. 





TRIHYDRIC ALCOHOLS. 


Phenyl Glycerol (Stycerine), C,H,,0, = C,H,.CH(OH).CH(OH).CH,. 
OH, is obtained from the bromide of cinnamic alcohol, C,H,.CHBr.CHBr.CH,. 
OH, by long boiling with water. It is a gummy mass, easily soluble in water and 
alcohol. 

.Mesitylene Glycerol, C,H,(CH,.OH),, Mesicerine, is produced from tri- 
brom-mesitylene, C,H,(CH,Br), (melting at 94°), upon boiling with water and 
lead carbonate. It is a thick liquid. 





ALDEHYDES. 


The aldehydes of the benzene series, characterized by the group 
CHO, are perfectly analogous, as regards methods of formation and 
properties, with slight modifications, to those of the paraffin series. 
They are distinguished as monovalent aldehydes, like: 


C,H,.CHO C,H,.CH,.CHO C,H,(CH,)CHO, ete. 
Benzaldehyde. ~- Phenyl-acetaldehyde. Tolylaldehyde. 


ALDEHYDES. 715 


and divalent or dialdchydes, like phthalic aldehyde, C,H,(CHO).. 
Aldehydes of mixed function also occur, ¢. g., aldehydephenols or 
oxyaldehydes, CSH,(OH).CHO, ete. 

The monovalent aldehydes are obtained by the oxidation of the 
corresponding primary alcohols, or by the distillation of the calcium 
salts of the aromatic acids with calcium. formate (p. 187). They 
are derived from the benzene homologues by heating the halogen 
derivatives, C,H;.CHCI,, with water, especially in the presence of 
bases (like sodium carbonate, lime or lead oxide), or by boiling 
the mono-chlor-derivatives, C,H;.CH,Cl, with water, in presence 
of oxidizing agents (lead nitrate). 

A very interesting and direct conversion of homologous benzenes 
into aldehydes, is that occurring in the action of chromy] chloride, 
CrO,Cl,, and water (Etard). 


Here the benzene homologues first unite (in CS,-solution) with two molecules of 
chromyl chloride, forming brown pulverulent double compounds, ¢. ¢.,C,H,. 
CH,.(CrO, Cy which yield aldehydes when added to water (Berichde, 17, 1462 
and 1700). All the alkylic benzenes sustain this transformation; thus, from tolu- 
ene, C,H,.CHs, we obtain benzaldehyde, C,H,.CHO. The xylenes yield tolylalde- 
hydes, and the o-haloid toluenes, yield the. o-haloid benzaldehydes (Berichte, ar; 
Ref. 714). With benzenes, containing higher alkyls, the reaction is more com- 
plicated, as ketones are also produced, thus: propyl benzene, C gil; -C,H,,, yields 
benzylmethyl ketone, C,H,.CH,.CO.CH, (Berichte, 23, 1070). 


The benzaldehydes are mostly liquid bodies, which dissolve with 
difficulty in water, possess an aromatic odor, and in deportment 
are very similar to the fatty aldehydes. They do not reduce alka- 
line copper (p. 189), but do reduce silver solutions with the produc- 
tion of a metallic mirror. They differ from the fatty aldehydes in 
that they are, as a general thing, readily oxidized to alcohols and 
acids by alcoholic or aqueous alkalies (p. 708); it appears that this 
reaction is, however, only peculiar to those aldehydes in which the 
CHO-group is in direct union with the benzene nucleus. Further- 
more, they do not directly combine with ammonia (p. 189), the 
amines and hydrazines, but yield compounds with them with im- 
mediate separation of water, and in the new derivatives all the 
amide hydrogen is replaced by the aldehyde radicals :— 


3CoH,.CHO + 2NH, = (C,H,.CH),N, + 3H,0, 


ydro cisamiée. 


C,H,-CHO + H,N.C,H, = C,H,.CH:N.C,H, ++ H,0. 
Bensylidene-Aniline, 


Alcoholic potassium cyanide converts the benzaldehydes into 
benzoins (see these). Again, the benzaldehydes, like all benzene 
derivatives, readily furnish substitution preducts. An interesting 
fact is their ability to afford condensation products with the most 
heterogeneous bodies, water always disappearing (p. 194). 


600 ORGANIC CHEMISTRY. 


Thus, by condensation with the acids, aldehydes and ketones of the fatty series, 
we obtain unsaturated acids, aldehydes and ketones, e. ¢. :— 


C,H,.CH:CH.CO,H  C,H,.CH:CH.CHO  C,H,.CH:CH.CO.CH,. 


Cinnamic Acid. .Cinnamic Aldehyde. Benzylidene Acetone. 


Occasionally an aldol condensation occurs here (p. 195), with formation of oxy- 
bodies, e.g¢., C,H,.CH.(OH).CH,.CO,H, phenyl lactic acid, which give off water 
in addition. Such a condensation follows in consequence of the action of HCl- 
gas, zinc chloride, sulphuric acid and glacial acetic acid (Berichte, 14, 2460), or 
upon heating with acetic anhydride. The condensing influence (especially with 
acetone and acetaldehyde) of aqueous alkalies, ¢. ¢., dilute sodium hydroxide and 
baryta water (Berichte, 14, 2468, and 16, 2205), is particularly interesting. 

With very dilute aqueous sodium hydroxide (2%) it is possible for an aldol 
condensation to occur here, whereas if the solution be alcoholic, with 10% sodium 
hydroxide, there is an immediate separation of water (Berichte, 18, 484, 720). 

With malonic acid, the benzaldehydes form unsaturated dibasic acids, ¢. ¢., 
benzal-malonic acid, C,H,;.CH:C(CO,H),, with acetacetic esters, acetyl carbonic 
acids, ¢.g., benzal-acetacetic acid, CyHy.CHECE 65 GF” (Annalen, 218, 121, 

2 
and 223, 137). The benzaldehydes also condense with benzenes, phenols and 


anilines, forming derivatives of triphenyl methane (C,H ,),CH (see this). 





MONOVALENT ALDEHYDES. 


1. Benzaldehyde, C,H,O = C,H;.CHO, Bitter Almond 
Oil, results from the oxidation of benzyl alcohol, and by the dis- 
tillation of calcium benzoate and formate. Formerly it was pre- 
pared exclusively from its glucoside amygdalin (see below). At 
present it is made ona large scale from benzal chloride, C;H;.CHCL, 
with sulphuric acid, or by heating it under pressure with milk of 
lime, or by boiling benzyl chloride with water and lead nitrate. It 
is applied in the manufacture of benzoic and cinnamic acids, for 
preparing malachite green and other coloring substances. 


The bitter-almond oil, prepared from chlorinated toluene, invariably contains 
chlorine; for its purification it is advisable to change it to its sodium bisulphite 
compound and then fractionate. Officinal bitter-almond oil is obtained from 
amygdalin; it usually contains hydrocyanic acid, which can be removed by shaking 
it with lime and ferrous chloride. ) 


Bitter-almond oil is a colorless liquid with a pleasant odor, and 
high refractive power, and boils at 179° ; its specific gravity = 1.050 
at 15°. It is soluble in 30 parts water, and is miscible with alcohol 
and ether. It shows all the reactions of the aldehydes; when 
oxidized (even in the air) it forms benzoic acid; by reduction 
(sodium amalgam) it passes into benzyl alcohol (together with hy- 
drobenzoin). , | 


\ 


AMIDE DERIVATIVES OF BENZALDEHYDE, 717 


It forms crystalline compounds with the alkaline sulphites. CNH converts it 
into Cyanhydrin, C,H,.CH(OH).CN (mandelic nitrile) (p. 347)—a yellow oil, - 
which solidifies on cooling. PCI, conVerts it into benzal chloride, C,H,.CHCI, 
(p. 584). Benzaldehyde dissolves in fuming sulphuric acid to form a crystalline 
sulphonic acid, C,H,(CHO).SO,H, which forms salts, that crystallize well 
(Berichte, 16, 150). 

A glucoside of benzaldehyde is Amygdalin, C,H,,NO,,, occurring in the 
bitter almonds and in various plants, especially in the kernels of Pomacez and 
Amygdalacez,. and the leaves of the cherry laurel. To obtain it the bitter 
almonds are freed of oil by pressing, and then digested with boiling alcohol, the 
solution is concentrated and the fatty oil removed with ether. Amygdalin crys- 
tallizes from alcohol in white, shining leaflets; it tastes bitter, and dissolves readily 
in water and hot alcohol. It crystallizes from water in prisms, containing 3H,O. 
It yields a heptacetate when gently warmed with acetic anhydride. On boiling 
with dilute acids, or upon standing with water and emu/sin, a ferment present in 
bitter almonds, amygdalin, is decomposed into oil of bitter almonds, dextrose and 
hydrocyanic acid :— 


C,,H,,NO,, + 2H,O = C,H,O + 2C,H,,0, + CNH. 

When amygdalin is boiled with alkalies, the nitrogen is evolved as ammonia and 
amygdalic acid, C,JH,,O,3, produced ; this decomposes into mandelic acid and 
glucoses, when boiled with dilute acids. 

Hydrogen sulphide converts benzaldehyde into three isomeric ¢hiobenzaldehydes 
(C,H,S), (p. 197) (Berichte, 22, 2603). 

he following compound is a derivative of dihydrobenzene :— 

Dihydrobenzaldehyde, C,H,.CHO. This results from a peculiar transposition 
of anhydro-ecgonine (Berichte, 23, 2880). Itis an oil with a suffocating odor. It 
boils at 122° under a pressure of 120 mm. It exhibits all the properties of the 
fatty aldehydes, and reduces permanganate, and Fehling’s solution at 100°. The 
oxide of silver oxidizes it to dihydrobenzoic acid. 





AMIDE DERIVATIVES OF BENZALDEHYDE. 


The action of ammonia upon benzaldehyde or benzyldichloride, C,H,.CHC), 
(p. 715), produces Tribenzylene-diamine, C,,H,,N, = (C,H;.CH),N,, or 
Hydrobenzamide, which crystallizes from alcohol and ether in rhombic octa- 
hedra, melting at 110°. It reacts neutral, and does not combine with acids; but 
as a tertiary diamine it forms with ethyl iodide a Diammonium Jodide, C,,H,,N 
(C,H,I),, which gives rise to the ammonium oxide, C,,H,,N,(C,H;),0, with 
silver oxide; this yields crystalline salts with two equivalents of the acids. 

When hydrobenzamide is boiled with alcohol or acids oil of bitter almonds and 
ammonia result. 

Benzal-anilines are produced by heating hydrobenzamide with the anilines :— 


(C,H,.CH),N, + 3H,N.C,H, = 3C,H,.CH:N.C,H, -+ 2NH,. 


In a similar manner hydroxylamine forms benzaldoxime (Berichte, 22, 2887). 
If heated, hydrobenzamide is transposed to amarine (-Triphenyl-dihydroglyoxaline) 
(see Lophine). 

The benzaldehydes combine with amines and anilines, forming benzylidene-, or 
benzal-amines and -anilines (p. 715). Acids resolve them into their components. 


718 ORGANIC CHEMISTRY. 


Benzylidene Ethylamine, C,H,.CH:N.C,H,, is an oil, boiling at 195°. Ben- 
zylidene Aniline, C,H,.CH:N.C,H,, Benzal Aniline, crystallizes in yellow 
needles, melting at 42°. 4 

When benzaldehydes unite with the acid amides, ¢. ¢., C,H,O.NH,, the amid- 
hydrogen is not only entirely eliminated (p. 715), but two molecules of the amides 
are combined. 

The aldehydine bases, resulting from the combination of benzaldehyde, with 
o-phenylene diamines, have already received mention (p.,628). 

The benzaldehydes, like all aldehydes, unite with phenylhydrazine, forming 
phenylhydrazones (p. 656). 

Benzylidene-Phenyl-Hydrazone, C,H,.CH:N.NH.C,H,, melts at 152.5°. 

Benzahloximes. 

Benzaldoxime, C,H,.CH(NOH), is formed by the action of hydroxylamine 
upon benzaldehyde. It is a thick oil. Sulphuric or hydrochloric acid will trans- 
form it into a crystalline zsomeride, melting at 120-128° ( Berichte, 23, 1684; 22, 
432). These two compounds are readily converted into each other; they are 
soluble in alkalies. The sodium salt of the liquid a-aldoxime dissolves with diffi- 
culty in alcohol, while that of the 6-variety is very soluble. Beckmann considers 
that these isomerides differ in structure as represented in the following formulas :— 


oy 
No 


a-Benzaldoxime. B-Benzaldoxime. 


(2) C,H,.CH:N.OH and (8) C,H,.CH 


When the sodium salts are alkylized, the a-variety yields an oxygen-ether, and 
the 6-variety a nitrogen-ether :— 


i Oe 
(a) C,H,.CH:N.0.C,H, and (8) C.H,.CHY | ‘ 

O 
The two ethyl ethers and a-benzyl ether are oily liquids; 6-benzyl ether melts at 
82°. Hydrochloric acid decomposes the a-ethers into a-alkylhydroxylamines and 
the (-ethers into 6-alkylhydroxylamines (p. 711). Conversely, the two benzyl- 
hydroxylamines convert benzaldehyde into the corresponding benzaldoxime-benzyl- 
ethers. In accordance with this we find that when the a-benzy] ether is heated 
with hydriodic acid the product is benzyl iodide, while the 6-ether, under similar 
treatment, yields benzylamine (Berichte, 22, 1534). Ferricyanide of potassium 
oxidizes a- and f-aldoximes to azo-benzenyl peroxide, C,,H,,N,.O,, and dibenz- 
enyl cag C,,H,,NO, which also result from benzil dioximes (Berichée, 22, 
1590). 

But two different Cabanilido-benzaldoximes, C,H,.CH:N.O.CO.NH.C,H.,, 
have been obtained by the action of phenylisocyanate upon the two benzaldox- 
imes (Berichte, 22, 3113). It is, therefore, concluded that the oxime groups 
have similar structure : N.OH, and that the two benzaldoximes are stereochemical 
isomerides (Goldschmidt, Berichte, 22, 3101; Hantzsch, Berichte, 23, 15, 20; 
Behrend, 23, 454). This view is confirmed by the behavior of the two anisaldox- 
imes, C, H,(O.CH;).CH(N.OH), which yield, by alkylization, two different oxygen 
ethers, and indeed 6-anisaldoxime forms a nitrogen ether at thé same time. Hence, 
there are probably three zsomeric aldoximes, two stereochemical isomerides, a and 
8, and a third, structurally isomeric form, called zsoa/doxime (Goldschmidt, Ze- 
richté, 23, 2178; Behrend, Berichte, 23, 2750) :— 


C,H,.CH C,H,.CH C,H,.CH 
| Bee | 
HO.N N.OH ‘ NH% 


a-Aldoxime. B-Aldoxime. _ ~ Isoaldoxime. 


_ORTHO-NITRO ~BENZALDEHYDE. 719 


The aromatic, unsymmetrical ketones, containing two different radicals, e. ¢., 
CUS 
C,H, 
form but one). From this the isomerism of the oximes is dependent upon the 
asymmetry of the molecule in its relation to the nitrogen atom (Hantzsch, Berichte, 
23, 2322, 2750). V. Meyer, abandoning his early views as to the cause of the 
isomerism of the oximes, believes now that the same is due to the spatial con- 
figuration of hydroxylamine (Aerichze, 23, 2407). 


>CO, also yield two ketoximes each (acetophenone- and pyroracemic-acid 





SUBSTITUTION PRODUCTS OF BENZALDEHYDE. _ 


The haloid benzaldehydes are obtained by substituting the nucleus of the benzyl 
chlorides, C,H,.CH,Cl and C,H,.CHCl,. They can be prepared with less dif- 
ficulty by oxidizing the haloid cinnamic acids with potassium permanganate (Ze- 
richte, 21, Ref..253). Benzoyl chloride,C,H,.CO.Cl (p. 580), is produced when 
chlorine is conducted into benzaldehyde. 





NITROBENZALDEHYDES. 


On dissolving benzaldehyde in nitric-sulphuric acid, or in a mixture of sulphuric 
acid with nitre (calculated amount) below 30-35°, the chief product is meta-nitro- 
benzaldehyde, which separates in a crystalline form. The oil (20-25 per cent.) 
consists principally of ortho-nitrobenzaldehyde, which cannot, however, be well 
obtained in pure form (Berichte, 14,2802). o0-Nitrobenzaldehyde is obtained pure 
from o-nitrobenzaldoxime (see below), when it is oxidized with a chromic acid 
mixture (Berichte, 14, 2334); also from o-nitrocinnamic ester through the action 
of nitric acid and sodium nitrite (Berichte, 14, 2803). Lt ts best obtained from o- 
nitro cinnamic acid, by oxidizing the alkaline solution with potassium permangan- 
ate in the presence of benzene (Berichte, 17, 121). 


Ortho - nitro - benzaldehyde, C,H,(NO,).CHO, dissolves 
readily in alcohol and ether, but slightly in water, from which it 
crystallizes in long, yellowish needles. It melts at 46°, and distils 
with scarcely any decomposition. It possesses a peculiar odor, which 
is penetrating in the heat, and it distils with aqueous vapor. Potas- 
sium permanganate, or chromie acid, oxidizes it to o-nitrobenzoic 
acid ; with concentrated sodium hydroxide o-nitrobenzyl alcohol 
and:o-nitrobenzoic acid are readily produced. Potassium cyanide 
converts it into o-azoxybenzoic acid. 

o-Nitro-benzaldehyde condenses with acetone, under the influ- 
ence of a very little sodium hydroxide or baryta water (p. 730), to 
o-nitro-phenyl-lactic-methyl-ketone, C,H,(NO,).CH(OH).CH,.CO. 
CH;, which with more caustic soda immediately splits off acetic 
. acid and indigo (Berichte, 16, 2205) :— 


2C,H,,NO, + 2H,0 = C,,H;,N,0, + 2C,H,0, + 4H,0. 


720 . ORGANIC CHEMISTRY. 


It condenses in the same manner with acetaldehyde to o-nitro-phenyl-lactic 
aldehyde, C,H,(NO,).CH(OH).CH,.CHO, and o-nitrophenyl-cinnamic alde- 
hyde, C,H,(NO,).CH:CH.CHO. The first of these also forms indigo with the 
alkalies. 

With hydroxylamine, ortho-nitro-benzaldehyde yields the aldoxime, C,H, 
(NO,).CH(N.OH), melting at 95°. It results also from o0-nitro-para-amido- 
phenyl acetic acid by the action of nitrous acid, and then boiling with alcohol. 
It has been called nitroso-methyl-o-nitrobenzene (Berichte, 15, 3057). Heated 
with hydrochloric acid, it is split up into NH, and o-nitrobenzoic acid; when 
oxidized (ferric chloride) it forms o-nitrobenzaldehyde with evolution of hypo. 
nitrous oxide. 

The phenylhydrazine derivative, C,H,(NO,).CH(N,H.C,H,), crystallizes in 
red needles, melting at 153° (Anmalen, 232, 232). 

Meta-nitro-benzaldehyde, C,H,(NO,).CHO (1, 3), results from the nitra- 
tion of benzaldehyde (see above). It crystallizes from water in white needles, 
melting at 58°. When reduced it yields meta-amidobenzaldehyde, and when 
oxidized meta-nitrobenzoic acid. PCI; and reduction convert it into metatoluidine. 
It forms two aldoximes with hydroxylamine, one melting at 63°, and the other 
at 118° (Berichte, 23, 2170). The latter is identical with the so-called nitroso- 
methyl-m-nitro-benzene (Berichte, 15, 838 and 3060), obtained from 2-nitro-/- 
amidophenyl acetic acid. Ferric chloride decomposes it into N,O and m-nitro- 
benzaldehyde (Berichte; 15, 2004). 

PC], converts the aldoxime into m-nitro-benzonitrile, C,H,(NO,).CN. The 
phenylhydrazone, C,H,(NO,).CH:N,H.C,H,, consists of red needles, melting 
at 121°. 

Para-nitro-benzaldehyde, C,H,(NO,).CHO (1, 4), results when /-nitro- 
benzyl chloride, C,H,(NO,).CH,Cl, is boiled with water, and lead nitrate, or 
when sulphuric acid acts upon g-nitrobenzal chloride, C,H,(NO,).CHCI, (Ze- 
richte, 16, 2539); finally, by the oxidation of g-nitrocinnamic acid with sulphuric 
acid and nitre (Berichte, 16, 2714). It is most easily prepared by allowing 
CrO,Cl, and water to act upon £-nitro-toluene (Berichte, 19, 1061). It crystal- 
lizes from water in thin prisms, and melts at 107°. Its aldoxime, C,H,(NO,). 
CH(N.OH), melts at 128°, and decomposes into NH,.OH and # nitrobenzalde- 
hyde (Berichte, 16, 2003), when digested with acids. Its phenylhydrazone, 
C,H,(NO,).CH(N,H.C,H,), melts at 155°. 


~ AMIDOBENZALDEHYDES. 
These are obtained by the reduction of the nitrobenzaldehydes. 


Ortho-amido-benzaldehyde, C,H,(NH,).CHO (1, 2), is best 
obtained by reducing ortho-nitrobenzaldehyde with ferrous sulphate 
and ammonia (Berichte, 17, 456). It dissolves with difficulty in 
water, from which it crystallizes in silvery leaflets, melting at 40° 
to a yellowish oil. It possesses an intense odor, and volatilizes very 
readily insteam. It reduces an ammoniacal silver solution. Nitrous 
acid converts it into salicylic aldehyde. 


Its aldoxime, C,H,(NH,).CH(N.OH), results by the reduction of o0-nitroben- 
zaldoxime with ammonium sulphide. It melts at 133°, and when oxidized with 
FeC),, splits up into N,O and o-amido-benzaldehyde (Berichte, 15, 2004). 

Ortho-amido-benzaldehyde yields condensation products with aldehydes, ketones 
and acids of the fatty series (p. 710). By the withdrawalof water (and inner con- 


TOLUIC ALDEHYDES. 721 


densation) these new compounds pass into quinoline derivatives (Berichte, 16, 
1833) — 


. 1 /CH:CH.CHO _ JCHCHY 2? 
CoH. NH, =C.H,( y SCH + H,0, 
a-Amido-cinnamic Aldehyde. Quinoline. 
fo P penis 3 
se = CH a PoLHs + 110. 
o-Amido-cinnamic Ketone. a-Methyl Quinoline. 


a-Oxyquinoline (carbostyril) is produced by condensation with acetic anhydride 
and sodium acetate :— 


7 CHCH.CO.OH Portsmtaent 

H a C.OH + H,O. 

C, ‘\nuH, 6 SNe sie ne +H, 
o-Amido-cinnamic Acid. a-Oxyquinoline. 


With malonic acid it yields 2-oxyquinoline carboxylic acid (Berichte, 17, 456). 
Meta-amido-benzaldehyde, C,H,(NH,).CHO (1, 3), has not been obtained 
in a pure condition. It results in the reduction of m-nitrobenzaldehyde with stan- 
nous chloride or ferrous sulphate and ammonia; also by oxidizing its aldoxime with 
ferric chloride (Berichte, 15, 2044, and 16,1997). By diazotizing it yields m-oxy- 
benzaldehyde. Its a/doxime, C,H,(NH,).CH(N.OH), is obtained by the reduc- 
tion of #-nitrobenzaldoxime with ferrous sulphate and ammonia. It melts at 88°. 
Para-amido-benzaldehyde, C,H,(NH,).CHO (1, 4), is obtained from its 
aldoxime through the agency of acids. It crystallizes from water in leaflets, melt- 
ing at 71°; these are not very stable. Its a/doxime, C,H,(NH,).CH(N.OH), is 
_ produced by the reduction of Z-nitrobenzaldoxime, It melts at 124~—129° (Berichte, 
16, 2001). 





2. Toluic Aldehydes, C,H,(CH,).CHO. 

These can be easily obtained from the three xylenes, C,H,(CH,),, through the 
action of CrO,Cl, and water (p. 715) (Berichte, 17, 1464). The ortho- and meta- 
bodies resemble bitter-almond oil in odor. 

o-Toluic Aldehyde results from ortho-xylyl chloride, C,H,(CH,).CH,Cl. It 
boils at 200°, and readily oxidizes, on exposure to the air, to o-toluic acid. 

m-Toluic Aldehyde, obtained from meta-xylene chloride, boils at 199°, and when 
exposed, soon oxidizes to m-toluic acid. When nitrated, it yields an o-nitro- 
aldehyde; this forms methyl indigo with acetone and caustic soda. 

p-Toluic Aldehyde is obtained by the distillation of calcium paratoluate and 
formate. Its odor resembles that of peppermint; it boils at 204°, and is easily 
oxidized to #-toluic acid. 

The so-called a-Toluic Aldehyde, C,H,.CH,.CHO, Phenylacetaldehyde, 
is produced when chromyl chloride and water act upon ethyl benzene, C,H,. 
C,H, ; by distillation of a-toluate of calcium and calcium formate; by heating /- 
phenyl-lactic acid or phenyl-oxy-acrylic acid with dilute sulphuric acid; from 
so-called phenyl-a-chlor-lactic acid, CsH;.CH(OH).CHCI.CO,H, by the action 
of sodium hydroxide (Berichte, 16, 1286); or from phenyl-a-brom-lactic acid, 
C,H;.CH(OH).CHBr.CO,H, with a soda solution (Amznalen, 219, 179), and, 
finally by acting with water on a-bromstyrolene. It is an oil, boiling at 206° and 
yielding benzoic acid upon oxidation with nitric acid. PCI, converts it into a-di- 
chlorethyl benzene, C,H;.CH,,.CHCI, (p. 586). Nitration changes it into a com- 
pound which yields indol, C,H,N, when reduced or heated with zinc dust (Be- 


yaa: ORGANIC CHEMISTRY. 


richte, 17, 984). By the action of chloral and AICI], upon benzene there is 
obtained the Phenyldichloracetaldehyde, C,H,;.CCl,,CHO, which reduces 
Fehling’s and silver nitrate solutions, and oxidizes easily to the acid, C,H,.CCl,. 
CO,H (Berichte, 17, Ref. 229). 

3. Phenyl-propyl Aldehyde, C,H;.CH,.CH,.CHO, hydrocinnamic aldehyde, 
from hydrocinnamic acid, is an oil. 


4. Aldehydes, C,,H,,0: 

Cumic Aldehyde, C,H,(C,;H,).CHO, Cuminol, is the iso- 
propyl-benzaldehyde of the para-series. It occurs, together with 
cymene, C,,H,,, in Roman caraway oil, and in oil of Crcuta virosa, 
or water hemlock, etc. In order to effect its separation, shake the 
oil, boiling above 190°, with hydric sodic sulphite, press out the 
separated crystalline mass, and decompose it by distillation with 
sodium carbonate. Cuminol possesses an aromatic odor, has a 
specific gravity = 0.973 at 13°, and. boils at 235°. Dilute nitric 
acid oxidizes it to cumic acid ; chromic acid converts it into tere- 
phthalic acid. When distilled with zinc dust, the isopropyl group 
is transposed and ordinary cymene results. 


It forms two aldoximes with hydroxylamine (Berichte, 23, 2175). Its hydra- 
zone melts at 128°. 

Nitro-Cuminol, C,H,.(NO,)(C,H,).CHO, melts at 54°, and when acted upon 
by PCI,, reduced, etc., yields thymol (p. 688). é 





Dialdehydes and Aldehyde-Alcohols (p. 324). 

The aldehydes of phthalic acid, C HE CHO (ortho, meta and para), correspond- 
ing to the three acids, are produced (like the monovalent aldehydes) from the cor- 
responding xylylene chlorides, C, H,(CH,Cl), and C,H,(CHCI,), (p. 573). 

o-Phthalaldehyde is a thick oil, with an odor like that of oil of bitter almonds. 

Potassium permanganate oxidizes it quite readily to phthalic acid (Berichte, 20, 509). 
It combines with two molecules of hydroxylamine, yielding the di-aldoxime, 
C,H,(CH:N.OH),, melting at 245°. 

m-Phthalaldehyde (isophthalaldehyde) crystallizes in long needles, melting at 
89-90°. It is oxidized to isophthalic acid by KMnO, (Berichte, 20, 2005, 509). 
With hydroxylamine it forms a di-aldoxime, C,H,(CH:N.OH),, melting at 180°, 
and with acetyl chloride it yields #-dicyanbenzene, melting at 158°. ° 

p-Phthalaldehyde (triphthalaldehyde), from -xylylene-chloride by means of 
water and lead nitrate, consists of needles, soluble with difficulty in water and melt- 
ing at 115°. When oxidized it yields terephthalic acid. Ammonia converts it 
into a di-imine and a hydrobenzamide derivative (Berichte, 19, 575). Potassium 
cyanide changes it to benzoin-di-aldehyde (Berichte, 19, 1815). It yields a di- 
aldoxime with hydroxylamine, and a diacetyl ester with acetyl chloride. 

Phenyl-lactic Aldehyde, C,H,.CH(OH).CH, CHO, is an alcohol-aldehyde, 
produced by condensing benzaldehyde with acetaldehyde by means of very dilute 
soda-lye (p. 716). Acetic anhydride converts it into cinnamic aldehyde. 

The three nitrobenzaldehydes similarly yield the corresponding Nitrophenyl- 
lactic Aldehydes, C,H,(NO,).CH(OH).CH, CHO. The ortho-body is very 


ORTHO-OXYBENZALDEHYDE. aa 


unstable, and when boiled with acetic acid anhydride yields o-nitrocinnamic alde- 
hyde (p. 721). The me/a-compound crystallizes from ether in needles, and de- 
composes about 100° (Berich/e, 18, 720). The fara-compound crystallizes with 
one molecule of aldehyde, which escapes at 115° (Berichte, 18, 372). 





ALDEHYDE-PHENOLS OR OXY-ALDEHYDES. 


The oxy-aldehydes, having hydroxyl in the benzene nucleus, are 
obtained by oxidizing (p. 713) the oxy-alcohols with chromic acid. 
An important synthetic method, wherein the aldehyde group is 
directly introduced, consists in letting chloroform and an alkaline 
hydroxide act upon phenols (reaction of Reimer) :— 


C,H,.OH + CHCl, + 4KOH = CoH CHO + 3KCl -+ 3H,0. 


All the benzene oxy-derivatives (the oxyacids also) react similarly; 
hence, innumerable oxy-aldehydes have been prepared. 


To perform the reaction, dissolve the phenol and some potassium or sodium 
hydroxide in 1%-2 parts water, and while heating on a water bath, in connection 
with a return condenser, gradually add chloroform. Chloral can be substituted for 
the latter. The excess of chloroform is distilled off, the residue supersaturated 
with hydrochloric or sulphuric acid, and the separated aldehyde finally extracted 
with ether. Ortho-formic phenyl ether is-produced at the same time (p. 671). 

It is very probable the reaction proceeds in such a manner that formic acid first 
results from the action of the alkali on chloroform: CHCl, + 4KOH = CHO. 
OK + 3KCl + 2H,0 (p, 217) and as it is produced, acts on the phenol. Oxy- 
acids are obtained in the same way, when CC], is employed. In this reaction, 
very frequently the CO,H-group, occupying the para-position in the oxy-acids 
(para-oxy-benzoic acid), is exchanged for CHO (Berichie, g, 1268). 


In deportment the oxyaldehydes are perfectly analogous to the 
monovalent benzaldehydes. ‘They reduce an ammoniacal silver 
solution, but not the Fehling solution. Oxidizing agents convert 
them with difficulty into oxyacids; this is most easily accomplished 
by fusion with caustic alkalies. They dissolve in alkalies, forming 
salts ¢. g., CsH,(CHO).ONa; the alkyl iodides convert the latter 
into alkyl ethers (p. 668). They give aldoximes with hydroxyl- 
amine, 

1. Oxybenzaldehydes, C,A(OH).CHO. 

Ortho-oxybenzaldehyde (1, 2), Salicylic Aldehyde, oc- 
curs in the volatile oils of the different varieties of Spiraea. It is 
obtained by the oxidation of saligenin and salicin (p. 713), but is 
most readily prepared (together with para-oxybenzaldehyde) by 
the action of chloroform and caustic potash upon phenol (Berichte, 
10, 213). An oil, with an aromatic odor; solidifies at —20°, and 
boils at 196°; its specific gravity = 1.172 at 15°. It volatilizes 


45, ai ORGANIC CHEMISTRY. 


readily with steam. It is rather easily soluble in water ; the solution 
is colored a deep violet by ferric chloride. It colors the skin an 
intense yellow. Sodium amalgam transforms it into saligenin ; 
oxidizing agents change it to salicylic acid :— 


/OH /OH /OH 
CeHa< CH,.OH CoH4s Con CeH4< Co.0H: 
Saligenin. Salicylic Aldehyde, Salicylic Acid. | 


Salicylic aldehyde dissolves in caustic potash to form the crystalline derivative, 
C,H,(OK)CHO, from which ethers are obtained through the agency of alky!| 
iodides. The methyl ether, C,H,(O.CH,).CHO, melts at 35°, and boils at 238°; 
the ethyl ether boils at 248°. Salicyl aldoxime, C,H ,(OH).CH(N.OH), melts ai 

° 


Consult Berichte, 22, 2339, upon the nitrosalicylaldehydes, 

Meta-oxybenzaldehyde (1, 3) results together with the alcohol in the reduc- 
tion of m-oxybenzoic acid with sodium amalgam, and from m-nitrobenzaldehyde 
by reduction and diazotizing (Berichte, 15, 2044). It crystallizes from hot water 
in white needles, melts at 104°, and boils near to 240°. Its hydrazone melts at 
131°. Its nitration produces three mononitro-compounds.. A fourth /-nitro-7- 
oxybenzaldehyde has been obtained from m#-nitrobenzaldehyde, and it cannot, con- 
trary to statement (Berichte, 18, 2572) be converted into vanillin. 

Para-oxybenzaldehyde is formed from phenol, together with salicylic alde- 
hyde; also by the reduction of para-oxybenzoic acid, and by heating anisic aldehyde 
to 200° with hydrochloric acid. It is rather easily soluble in hot water, crystal- 
lizes in small needles, melts at 116°, and sublimes. Ferric chloride colors it the 
same as phenol. It yields para-oxybenzoic acid on fusion with KOH. Its a/dox- 
ime melts at 65°; its kydrazone at 178°. Its methyl] ether is the so-called— 


Anisic Aldehyde, C,H,(O.CH,).CHO, which results in oxid- 
izing various essential oils (anise, fennel, etc.) with dilute nitric 
acid, or a chromic acid mixture. A soda solution will liberate it 
from its crystalline ‘compound with sodium bisulphite. It is a 
colorless oil of specific gravity 1.123 at 15°, and boils at 248°. It 
combines with hydroxylamine to yield two al/doximes (p. 718). 


2. Dioxybenzaldehydes, C,H,O, = C,H,(OH),.CHO. 

Three of the six possible isomerides have been prepared from the dioxybenzenes, 
C,H,(OH),, by means of the chloroform reaction; likewise, six methyl dioxy- 
benzaldehydes, C,H,.(0.CH,).(OH).CHO, have been obtained from the three 
mono-methyl-dioxybenzenes (Berichte, 14, 2024). Dialdehydes also are simul- 
taneously produced in dilute solutions when CCl,H and KOH are employed. ) 

B-Resorcyl Aldehyde, C,H,(OH)(OH).CHO (1, 3, 4), obtained from resor- 
cinol, melts at 135°, and with acetic anhydride yields (according to Perkin) 
umbelliferon. Gentisin Aldehyde, C,H,(OH)(OH).CHO (1, 4, CHO), from 
hydroquinone, melts at 99°, and yields gentisinic acid on oxidation. 


Protocatechuic Aldehyde, C,H,(OH)(OH).CHO (1, 3, 4 
—CHO in 1), the parent substance of vanillin and piperonal, was 
first obtained from the latter; it is prepared synthetically from 
pyrocatechin by the chloroform reaction (Berichte, 14, 2015); also 
by heating its ethers, vanillin, isovanillin and piperonal, with dilute 


VANILLIN. 725 


hydrochloric acid to 200°, and from opianic acid. It dissolves 
readily in water, forms briNiant crystals (from toluene), and melts 
at 150°. It reduces silver solutions with the production of a mirror, 
and combines with alkaline bisulphites, Ferric chloride colors its 
aqueous solution a deep green (p. 690). 

Protocatechuic aldehyde is a derivative of homopyrocatechin (p. 
693); its acid is protocatechuic acid (see this). Its important 
ethers are vanillin, isovanillin and piperonal :— 


CHO (1) CHO (1) CHO (1) 
CaHh, | O.CH, (3) Catt, | OH 3 cat | Nc ¢3} 
OH (4) O.CH, (4 : 7, 5A) 


Vanillin. Isovanillin, Piperonal. 


The two OH groups in protocatechuic aldehyde occupy the ortho-position, but 
the CHO group the para with reference to one of the OH groups (see proto- 
catechuic acid). For the position of the methyl group in vanillin see Berichze, 9, 
1283, and 11, 125; it is intimately related to creosol (p. 693). 


Vanillin, C,H,O;, methyl protocatechuic aldehyde, is the active 
and odorous constituent of the vanilla bean pods (about two per 
cent.). It was first prepared artificially from the glucoside coni- 
ferine, by its oxidation with chromic acid (Tiemann), a procedure 
now applied technically for the obtainment of -vanillin. It is 
formed synthetically, together with an isomeric aldehyde, when 
guaiacol is acted upon by chloroform and caustic alkali (Berichte, 
14, 2021), and by oxidizing eugenol from clove-oil. 


Glycovanillin, C,H,(O.CH,)(O.C,H,,0,).CHO, the glucoside of vanillin, is 
produced when coniferine is oxidized by chromic acid. It crystallizes from dilute 
alcohol in white needles, melting at 192°. Acids or emulsin split it up into 
glucoses and vanillin (Berichte, 18, 1595, 1657). 


Vanillin crystallizes in stellate groups of needles, is soluble in 
hot water, alcohol and ether, melts at 80-81°, and sublimes. Asa 
phenol it forms salts with one equivalent of a base ; as an aldehyde 
it combines with primary alkaline sulphites. Heated with HCl to 
180° it decomposes into CH,Cl and protocatechuic aldehyde. Pro- 
tocatechuic acid results on fusion with potassium hydroxide (the al- 
dehyde group is oxidized and methyl split off), Nascent hydrogen 
converts vanillin into vanillin alcohol (p. 714); energetic oxidation 
carries it to vanillinic acid. 


Coniferine, C\,H,,O, + 2H,O, is found in the cambium of coniferous 
woods, and consists of shining needles. It effloresces in the air, and melts at 
185°. It acquires a dark blue color when moistened with phenol and hydro- 
chloric acid. Boiling acids or emulsin decompose it into glucoses and Conifery/ 
Alcohol, C,,H,,0, = C,H; (oir °)-GH.OH ; the latter melts at 75°, and is 


oxidized to vanillin (together with homovanillin) by chromic acid. 


726 ORGANIC CHEMISTRY. 


Isovanillin (see above) is obtained by oxidizing hesperitinic acid or by heating 
opianic methyl ether with hydrochloric acid. 

Dimethylprotocatechuic Aldehyde, C,H, (O.CH,),CHO Methylvanillin, is ob- 
tained from vanillin by the action of methyl iodide and potassium hydroxide. It 
is not very soluble in water, melts about 20°, and boils near 285°. It yields 
dimethylprotocatechuic acid by oxidation. 

Piperonal, C,H,O,, heliotropine, obtained by oxidizing piperic acid (see this) 
is the methylene ether of protocatechuic aldehyde (p. 724). It consists of crystals 
which dissolve with difficulty in water, melt at 37° and boil at 263°. Being an 
aldehyde it unites with primary alkaline sulphites. When oxidized it forms 
piperonylic acid, when reduced piperonyl alcohol (p. 714). 

Bi-di-oxymethylene indigo is obtained from its nitro-derivative (Berichie, 23, 
1566). 

Pci, converts it into the chloride, C,H,(O,:CCl,)CHCI,, which yields proto- 
catechuic aldehyde when boiled with water; the group CCl, splits off. 





KETONES. 


The ketones in which two benzene nuclei are joined by the 
ketonic group CO, e. g., benzophenone, C,H;.CO.C,H,, will receive 
attention later. At this point we will only consider the mixed 
ketones, containing a benzene and also an alkyl group :— 


C,H,.CO.CH,, Acetophenone. 


These are perfectly analogous to the ketones of the paraffin series, 
and are obtained by similar methods, chiefly by the distillation of 
a mixture of calcium salts of an aromatic and a-fatty acid (p. 187). 
They also result when (1) sulphuric acid (diluted 1%4 volume) acts on 
the phenylacetylenes (pp. 87 and 204) :— 


C,H,.C:CH + H,O = C,H,.CO.CH,;. 
(2) or from the benzenes on boiling with fatty acid chlorides and 


AICl;, as well as from the phenol ethers, unsaturated homologous 
benzenes being formed together with the ketones (Berichte, 23, 


1199) :— : 
C,H,.+ CH,.COCl = C,H,.CO.CH, + HCl, 
C,H,.0.CH, + CH,.CO.Cl = C,H,(O.CH,).CO.CH, + HCl; 
6°" 5 3 3 6°74 3 3 


(3) and by the decomposition of benzoyl acetic esters (p. 341) when 
they are boiled with water or sulphuric acid (30 per cent.) :— 

CO.CH. 

CyHy.CO.CHE COR *+2H,0 = 

C,H,.CO.CH, + CH,.CO,H + CO,R.OH. 


Benzoyl acetones (3-diketones) are produced at the same time as intermediate 
products (in slight amount), ¢. g., C,H,.CO.CH,.CO.CH,. ‘They dissolve in 
alkalies, and are precipitated by CO,. The nitro-benzoyl aceto-acetic esters 
deport themselves similarly (Berichte, 16, 2239; Annalen, 221, 332). Thus 
from aceto-phenone-bromide, C,H,.CO.CH,Br, we obtain bodies with aceto-acetic 


PHENYL-METHYL-KETONE. 727 


esters, from which, by decomposition, the y-dike/ones of the type C,H,.CO.CH,. 
CH,.CO.CHsg, are obtained ; these are insoluble in alkalies. 

y-Diketones like these are also formed by the action of succiny] chloride upon 
benzenes in the presence of AICI,; ketonic acid chlorides are produced simul- 
taneously ( Berichte, 20, 1374; 21, Ref. 611) :— 


CH,.COC1 CH,.0.C,H, CH,,CO,C, H, 
| yields | and | ‘ 
CH,.COC1 CH,.COCI CH,.CO.C FH, 


The benzene ketones are oils, insoluble in water, and boil with- 
out decomposition ; phenyl methyl ketone is the only one that is 
a solid. With the exception of benzyl-methyl ketone they do not 
unite with alkaline bisulphites. Nascent hydrogen converts them 
into secondary alcohols which form ketones when oxidized. 


Chromic acid transforms the ketones C,H,.COR into benzoic acid and the 
alkyl, which is further oxidized (p. 203). 

Cold potassium permanganate converts a few of them into a-ketonic acids 
(Berichte, 23, Ref. 640). Acids and acid amides (Berichte, 21, 534) are formed 
when phenylmethyl ketones are heated with yellow ammonium sulphide :— 


C,H,.CO.CH, yields C,H,.CH,.CO,H and C;H,.CH,.CO.NH,,. 


On heating benzene ketones with concentrated or fuming sulphuric acid the 
acetyl-group splits off and benzenesulphonic acids result (Berichte, 19, 2623). 

The phenyl-alkyl ketones apparently form but ome acetoxime with hydroxyl- 
amine (p. 205); whereas, the unsymmetrical ketones, having two phenyl groups, 
yield two acetoximes. All ketones form Aydrazones with phenylhydrazine. 





(1) Phenyl-methyl-ketone, C,H;.CO.CH;, Acetophenone, 
results by the action of zinc methyl upon benzoyl chloride, C,H;. 
COCI, and is obtained by distilling benzoate of calcium (100 parts) 
with calcium acetate (56 parts). The most convenient method 
consists in boiling benzene (10 parts) with acetyl chloride (1 part) 
and AICI, (2 parts). 

It crystallizes in large plates, melts at 20.5°, and boils at 202°. 


It is applied as a hypnotic under the name of hyfmone. Nascent hydrogen 
converts it into phenyl-methyl carbinol (p. 711). Chromic acid and potassium per- 
manganate oxidize it to benzoic acid, while a slight amount of phenyl-glyoxylic 
acid (Berichte, 23, 648) is produced by ferricyanide of potassium or perman- 
ganate. 

Its acetoxime, C,H;.C(N.OH).CH;, melts at 59°, and by the 
action of concentrated sulphuric acid, or of HCl in glacial acetic 
acid is converted into isomeric acetanilide :— 


C,H,-.C(N.OH).CH, yields C,H,:.NH.CO.CH,. 


728 ORGANIC CHEMISTRY. 


Other ketoximes behave in an analogous manner (transposition of 
Beckmann) (Berichte, 20, 1509, 2581; 23, 2746). 


The phenyl-hydrazone, C,H,.CH,.C:N.NH.C,H,, melts at 105°. Aceto- 
phenone affords 3-dichlorethyl benzene with PCl,. 

The chlorination of boiling acetophenone produces the so-called Acetophenone 
Chloride, C,H,.CO.CH,Cl, melting at 59°, and boiling at 245°. The dromide, 
C,H,.CO.CH, Br, results in the action of bromine on acetophenone dissolved in 
CS, (on passing CO, through the solution) (Beriche, 16, 22). It crystallizes in 
large, rhombic prisms, melting at 50°; its vapors provoke tears. The further bromi- 
nation of acetophenone in carbon disulphide solution produces Acetophenone- 
dibromide, C,H,.CO.CHBr,, melting at 37°; alcoholic ammonia converts it into 
benzamide, C, H;.CO.NH,, and KOH changes it to mandelic acid, C,H;.CH(OH). 
CO,H. With hydroxylamine, acetophenone dibromide, C,H,.CO.CHBr,, and 
monobromide yield Phenylglyoxime, C,H,.C(N.OH).CH(N.OH) (p. 207), melt- 
ing at 162° (Berichte, 22, 419). Phenylhydrazine and bromacetophenone yield 
the base (C,,H,.N,), (Berichie, 23, Ref. 501). 

Ammonia converts the chloride or bromide into zsoindo/, C,,H,4N,, identical 
with diphenylpyrazine (Berichze, 21, 19, 1278). 

The acid amides convert acetophenone into peculiar oxygen dases, in which, in 
all probability, the oxazole ring is present (Berichte, 21, 924). 

Aniline and bromacetophenone yield an anilide, which condenses to a-pheny]l- 
indol (Berichte, 21, 1071). 

In the same manner, methyl- and dimethyl-aniline produce acetophenone- 
methyl-anilide, C,H,.CO.CH,.N(CH,).C,H,; this also condenses, yielding x- 
methyl-a-phenyl indol (Berichze, 21, 2196, 2595) (see indol). 

In the action of sodium ethylate-upon a mixture of acetophenone and amyl 
nitrite, a peculiar reaction (Claisen) occurs, according to the equation— 


C,H,.CO.CH, + NO.0.C,H, = C,H,.CO.CH(N.OH) + C,H,OH, 


whereby we obtain :— 

Isonitroso-acetophenone, C,H,.CO.CH(N.OH). This crystallizes from 
alcohol in shining prisms, melting at 127° and decomposing at 155° (Berichée, 20, 
2194). It forms isoindol by reduction. 

Nitro-acetophenones, C,H,(NO,).CO.CHsg. 

The meta-body is the chief product (just as in the case of benzaldehyde) when 
acetophenone is dissolved in cold, fuming nitric acid. An isomeric oil is formed 
at the same time. The three isomerides can be prepared from the three nitro- 
benzoyl-aceto-acetic esters, which result from the action of the nitrobenzoyl chlor- 
ides, C,H ,(NO,).COCI, upon aceto-acetic esters (p. 726). 

o-Nitro-acetophenone is a yellowish oil, of peculiar odor, and does not solidify 
on cooling. Bromine converts it into a mono- and a di-bromide, from which 
indigo is obtained by the action of ammonium sulphide (Annaden, 221, 330). 

m-WNitro-acetophenone crystallizes in needles, melts at 93°, volatilizes with 
steam, and is oxidized to m-nitrobenzoic acid by potassium permanganate. 

p-Nitro-acetophenone results on digesting f-nitrophenyl-propiolic acid, 
C,H,(NO,)C:C.CO,H, with sulphuric acid; it first parts with CO, and the result- 
ing nitrophenyl-acetylene, C,H,(NO,).C: CH, absorbs water (p. 726). -Nitro- 
acetophone forms yellowish prisms, melts at 80°, and with PCI, yields f-nitro-chlor- 
styrol, C,H,(NO,).CCI:CH, (Annalen, 212, 159). 

Amido-acetophenones, C,H ,(NH,).CO.CHs3. 

o- Amido-acetophenone (1, 2) is ebtained: By reducing o-nitroacetophenone 
with tin and hydrochloric acid ; from o-amido-pheny]l acetylene, C, H,(NH,)C:CH, 
by the action of sulphuric acid; by boiling o-amidophenyl-propiolic acid with water 


BENZYL-METHYL KETONE, 729 


(Berichte, 15, 2153); and in slight quantity on heating acetanilide, C,H,;.NH. 
CO.CHs, with ZnCl, (p. 607). It isa thick, yellow oil, which boils at 242°-252°, 
and possesses a characteristic sweetish, lasting odor. A pine splinter, dipped into 
the aqueous solution of its hydrochloride, is colored an intense orange-red. It is 
very stable, and cannot form an inner condensation product. Acetic anhydride 
converts it into the acetate, C,H,(NH.C,H,O).CO.CH,; the bromides of the lat- 
ter yield zzdigo when shaken with sodium hydroxide and air (Berichte, 17, 963). 

m-Amido-acetophenone results on reducing m-nitro-acetophenone. It con- 
sists of yellow crystals, melting at 93°. ¢-Amido-acetophenone is obtained by 
reducing the g-nitro body, and also on boiling aniline with acetic anhydride and 
ZnCl, (Berichte, 18, 2688). It crystallizes in flat needles, and melts at 106°. 

Oxyacetophenones, or Ketophenols. 

These are produced when di- and tri-hydric phenols are heated with glacial 
acetic acid and ZnCl, to 169° (Berichte, 23, Ref. 43). 

a-Naphthol reacts in a similar manner (Berichte, 21, 322). Ethers of ketophe- 
nols are produced by the action of phenol ether upon acid chlorides in the presence 
of AICI, (p. 726). Alkyl benzenes are simultaneously produced (Berichte, 23, 
1199). Propionyl chloride converts phenol into phenol propionic esters and fro- 
pionyl phenol, C,H,(CO.C,H;).OH (Berichte, 22, Ref. 746). 

Resacetophenone, C,H,(OH),.CO.CHsg, from resorcinol, melts at 142°, and 
may be obtained by fusing ($-methyl umbelliferon with potassium hydroxide. 
Quinacetophenone, C,H,(OH),.CO.CH,, from hydroquinone, melts at 202°. 
Gallacetophenone, C,H,(OH),.CO.CHs, from pyrogallic acid, melts at 168°. 





(2) Phenyl-ethyl Ketone, C,H,.CO.C,H;, jpropiophenone, results when a 
mixture of calcium benzoate and propionate is distilled, or when zinc ethyl acts 
upon benzoyl chloride, C,H,;.COCI, and by the action of AlCl, upon benzene and 
propionyl chloride. It boils at 208-210°. Nascent hydrogen converts it into sec- 
ondary phenyl-propyl alcohol (p. 711); chromic acid breaks it up into benzoic 
and acetic acids. Amyl nitrite converts it into phenyl-isonitroso-ethyl ketone, 
C,H,.CO.C(N.OH).CH,, melting at 109° (Berichte, 22, 529). 

Phenyl-propyl Ketone, C,H,.CO.C,H,, obtained from calcium benzoate 
and butyrate, boils at 220-222°. Chromic acid decomposes it into benzoic and 
propionic acids. The isomeric Phenylisopropyl Ketone, C,H,.CO.C,H,, 
from calcium benzoate and isobutyrate, boils at 215°, and is converted into benzoic, 
acetic and carbonic acids by chromic acid. 

Phenylketones of the higher alkyls, like C,H,.CO.C,H, and C,H,.CO.C,H,,, 
have been prepared from mono- and di-alkylic benzoyl acetic esters, C,H ,.CO. 
CHR.CO,R and C,H,.CO.CR,.CO,R (p. 726) by a ketone decomposition in- 
duced by alcoholic potash. 

3. Benzyl-methyl Ketone, C,H,.CH,.CO.CH,, Phenyl acetone, results in 
the distillation of calcium alphatoluate and acetate, and when zinc methyl acts on 
alphatoluic chloride, C,H,.CH,.COCI. It boils at 214~216°, unites with primary 
sodium sulphite, and decomposes with chromic acid into benzoic and acetic acids. 
When its #¢ro-product is treated with zinc dust and ammonia an amido-derivative 
of the ortho series is first formed—C,H,(NH,).CH,.CO.CH,, but this loses 
water and becomes methy! ketol :— 


/CH,.CO.CH, __ /CH\ 
CHC wet = CHC yy CCH, + H,0. 


Methyl Ketol. 
61 


730 ORGANIC CHEMISTRY. 


Benzyl-ethyl Ketone, C,H,.CH,.CO.C,H,, results from a-toluic chloride by 
the action of zinc ethyl. It boils at 226°, and is oxidized by chromic acid to 
benzoic and propionic acids. 

Phenyl-ethyl-methyl Ketone, C,H,.CH,.CH,.CO.CH,, Benzyl acetone, is 
formed from calcium hydro-cinnamate and acetate, and from benzyl aceto-acetic 
ester (p. 340). It boils at 235°, and when the nitro product is reduced conden- 
sation ensues in the ortho-amido-derivative first produced, with formation of 
hydromethy! quinoline, C,)H,,N :— 


CH,.CH,.CO.CH, CH,.CH 


C,H Mit Ae) 20. S6.0H,. 
ahs a pea! gehen 
Hydromethyl Quinoline. 


An oxy-derivative of phenyl-ethyl-methyl ketone is Phenyl-lactic acid— Methyl 
Ketone, C,H;.CH(OH).CH,.CO.CH,. ‘The ortho- and para-nitro-derivatives of 
the latter are obtained by the condensation of ortho- and paranitrobenzaldehyde 
by means of very dilute sodium hydroxide (p. 723). 

o-Nitrophenyl-lactic acid-Methyl Ketone forms large crystals, melting at 
69°. When acted upon by excess of sodium hydroxide, or when boiled with 
water, it at once (by the union of two molecules and the elimination of two mole- 
cules of acetic acid) yields indigo (Baeyer, Berichte, 15, 2857) :-— 


Ring oo — C,,H,N,0, + 2CH,.CO,H + 2H,0. 
2 
Indigo. 


When heated with acetic anhydride it splits off water and becomes o-nitroben- 
zylidene acetone, C,H ,(NO,).CH:CH.CO.CH,. 

p-Nitrophenyl-lactic acid-Methyl Ketone, from -nitrobenzaldehyde, melts at 
58°, and when boiled with acetic anhydride yields f-nitrobenzylidene acetone 
(Berichte, 16, 1968). 

4. Methyl ketones of the homologous benzenes are readily obtained by the 
action of acetyl chloride or acetic anhydride upon benzenes in the presence of 
AICI, (p. 726). 

p- Tolyl-methyl-ketone, C,H ,(CH,).CO.CH,, acetyl toluene, is obtained from 
cymene by the action of concentrated nitric acid (p. 577). It is a colorless liquid, 
boiling at 224°. Nitric acid oxidizes it to paratoluic acid and chromic acid to 
terephthalic acid. See Berichte, 21, 2265, for higher tolylalkyl ketones. 

Xylyimethyl Ketones, C,H,(CH,;),.CO.CH,: The ortho (from orthoxylene) 
boils at 243°, the mefa at 228°, and the fara at 224°. 


See p. 518 for phenyl trimethylene ketone, C,H »CO.CHY es or benzoyl 
trimethylene. bo 1S 

Keton-aldehydes or Aldehyde Ketones (p. 323). 

Benzoyl Formic Aldehyde, C,H,.CO.CHO, phenyl glyoxal, is obtained from 
isonitroso-acetophenone, C,H;.CO.CH(NOH) p. 728). It crystallizes from water 
as a hydrate, melting at 73°. It volatilizes in a current of steam and provokes 
sneezing (Berichte, 22, 2557). Phenylhydrazine converts it into a hydrazone and 
an osazone. Alkalies convert it into mandelic acid, C,H,.CH(OH).CO,H. 

Toluyl Formic Aldehyde, C,H,(CH,).CO.CHO, from isonitrosotolylmethy] 
ketone, also crystallizes as a hydrate, melting about 100°. 

Benzoylaldehyde, C,H,.CO.CH,.CHO, is a B-ketone aldehyde. It is ob- 
tained by the condensation of acetophenone and formic ester by means of sodium 
’ ethylate (Claisen, p. 323): C,H,;.CO.CH, + CHO.O.C,H, = C,H,;.CO.CH,. 
CHO + C,H,;.0H. The sodium compound first forms, and from this acetic acid 


MIXED TRIKETONES. So gage 


liberates the aldehyde ketone, as a yellow, very unstable oil. It resembles the 
8 ketonaldehydes of the fatty series very much, and is colored an intense red 
by ferric chloride. It condenses with phenyl. hydrazine to diphenyl-pyrazole 
(Berichte, 21, 1135). 





Diketones (see p. 325). 

a- or Orthodiketones, C,H; CO. CO.R, are produced by replacing the isonitroso- 
group of the isonitroso ketones (p. 325). 

Benzoyl Acetyl, C,H,.CO.CO.CH,, from isonitroso-ethyl-phenyl ketone, 
C,H,.CO.C(N.OH).CH, (p. 730), isa yellow oil with a peculiar odor (Berichte, 
21, 2176; 22, 527). 

The 6- or meta-diketones, C,H ;.CO.CH,.CO.R, result from the decomposition 
of the benzoyl-acetoacetic esters (p. 726); further by a remarkable condensation, 
induced by sodium alcoholate (Claisen, Berichte, 20, 2178). Thus, benzoyl 
acetone is obtained from benzoic ester and acetone, and from acetophenone and 
acetic ester :— 


C,H,.CO.0.C,H, + CH,.CO.CH, = C,H,CO.CH,.CO.CH, + C,H,.OH. 
C,H,.CO.CH, + CH,.CO.OR = C,H,CO.CH,.CO.CH, + C,H,.0H. 


Ketonic acids are similarly produced (see these); while the formation of benzoyl 
aldehyde from acetophenone and formic ester (see below), and that of isonitroso- 
phenone are analogous (p. 728). 

The £-diketones behave like the 6-diketones of the fatty series. They dissolve 
in alkalies. This distinguishes them from the other diketones. They are colored 
an intense red by ferric chloride. They form pyrazole compounds with phenyl 
hydrazine. 

Benzoyl Acetone, C,H,.CO.CH,.CO.CH, (see above), acetyl acetophenone, 
is most readily prepared by the action of acetic ester and sodium ethylate upon 
acetophenone (Zerichie, 20, 2180). It melts at 60-61°, boils at 260-262°, and 
readily volatilizes with steam. It forms an oxime- anhydride, C,,H,NO (Berichte, 
2I, 1150) with hydroxylamine. Alkyl derivatives have not been prepared. 
o-Nitrobenzoyl Acetone, C,H,(NO,).CO.CH,.CO.CH,, from o-nitrobenzoyl 
acetic ester, melts at 55°. 

Propionyl acetophenone, C,H;.CO.CH,.CO.C,H,, etc., have been prepared 
in an analogous manner by the condensation of acetophenone with higher fatty 
acid esters (Berichte, 20, 2181). 

Phenyl-acetyl-acetone, C, ,H,,0, = C,H,.CH,.CO.CH,.CO.CH,, results 
from the decomposition of phenyl acetyl-acetoacetic ester, C,H,.CH,CO. 
CHC 60, Rs (from C,H,.CH,.COCI and acetoacetic ester). It is an oil boiling 
about 268°, It yields a pyrazole derivative with phenylhydrazine (Berichde, 18, 
2137 

following is a y-diketone (p. 328) :— 

Acetophenone-acetone, C,H,.CO.CH,.CH,.CO.CH,, is obtained from 
acetophenone aceto-acetic ester (p. 727). It is a yellow oil, insoluble in alkalies, 
and not volatile with aqueous vapor (Berichie, 17, 2758). 

Being a y-dikéetone it can split off water and yield phenylmethylfurfurane. 
P,S, converts it into phenylmethylthiophene, while ammonia-changes it to phenyl- 
methyl pyrrol (p. 329). 

The analogous ketones: diphenacyl, dibenzoyl methane, and tribenzoyl me- 
thane, will be discussed under the compounds containing several benzene nuclei. 

Mixed Triketones : Dibenzoyl Acetone, (C,H;.CO),CH.CO.CH,, from sodium 
benzoyl! acetone and benzoyl chloride, melts at 102°, The hydrogen of its CH- 


732 ORGANIC CHEMISTRY. 


group cannot be replaced by sodium or alkyls (Berichte, 21, 1153). Triacetyl 
Benzene, C,H,(CO.CH,)5(1, 3, 5), results from the condensation of acetalde- 
hyde. It melts at 163°. “Tt may be oxidized to trimesic acid (Berichte, 21, 1145). 
CO.CH. .GOC i. 
Oxalyl-diacetophenone, | ae 21, 1134), is a tetraketone. 
0.CH,.CO.C,H 





NITRILES. 


The nitriles of the benzene series, the compounds of the benzene 
nucleus with the cyanogen group, are formed, like the fatty nitriles, 
by distilling the alkali benzene sulphonates with potassium cyanide 
or yellow prussiate of potash (p. 659), and by the action of P.O, 
or PC]; upon the ammonium salts and amides of the aromatic acids 


(p. 282). 


When the halogene benzene sulphonic acids are distilled with CNK the halogen 
atoms are also replaced by cyanogen groups and we get dicyanides :— 


C,H,Br.SO,K + 2CNK = C,H,(CN), + SO,K, + BrK. 


The direct replacement of the halogens in the benzene hydrocarbons is of excep- 
tional occurrence, ¢. g., when chlor- and brom-benzene are conducted over strongly 
ignited potassium ferrocyanide, or when benzene iodide is heated to 300° with 
silver cyanide, the product being cyan-benzene. 

Further, the nitriles of both the benzene and the paraffin series are formed when 
acetyl chloride or anhydride acts on the a/doximes -— 


C,H,.CH:N.OH = C,H,.CN + H,0O. 


The methods of formation peculiar to the benzonitriles are “ie 
1. The distillation of aromatic acids with potassium sulphocyanide, or what is 
better, with lead sulphocyanide (Berichte, 17, 1766) :— 


2C,H,.CO,H ++ (CNS),Pb = 2C,H,.CN + PbS + 2CO, + H,S. 


2. To heat the phenyl mustard oils with copper, free of cuprous oxide, or with 
zinc dust :— 
C,H,.N:CS + Cu = C,H,.CN + CuS. 


The mustard oils can be easily obtained from the anilines, and in this manner 
there occurs a successive conversion of the anilines into nitriles and acids (p. 
613). 

When the diphenylthiureas (p. 616) are heated with zinc dust, both nitriles and 
anilines are produced (Berichte, 15, 2508) :— 


CS(NH.C,H,), + Zn = C,H,.CN + C,H,.NH, + ZnS. 


3. The distillation of the; formanilides (p. 606) with concentrated ° Agee 
acid or with zinc dust (Berichtex7, 73)i— 


C,H,.NH.CHO = C,H,.CN + H,0. 


BENZONITRILE. 733 


Both reactions generally yield but a small outcome, inasmuch as decompositions 
usually result (Berichte, 18, 1001). : 

4. The distillation of the triphenyl phosphates (p. 670) with potassium cyanide 
or ferrocyanide (Berichte, 16, 1771) :— 


PO(O.C,H,), + 3KCN = PO(OK), + 3C,H,.CN. 


5. The transformation of the isomeric nitriles or carbylamines (p. 613) through 
the agency of strong heat :— 


C,H,.NC yields C,H,.CN. 


6. The transformation of diazochlorides upon heating them with potassium 
cyanide and copper sulphate :-— 


C,H,.N,Cl + CNK = C,H,.CN + KCl + N,. 


In this way the three nitroanilines, after conversion into diazochlorides, have 
been changed to the corresponding nitrobenzene nitriles, C,H ,(NO,).CN. 


The benzonitriles are similar to those of the fatty series, and like 
them, when acted upon by alkalies or acids, form the corresponding 
aromatic acids. Nascent hydrogen (better sodium in alcoholic 
solution, p. 283) converts them into amines. They combine with 
alcohols and HCl, with hydroxylamine and with anilines, to form 
HCl-imido-ethers, oximido-ethers and benzenyl amidines (p. 735). 





Benzonitrile, C,H;.CN, Cyanbenzene, is isomeric with phenyl 
carbylamine, C,H;.NC (p. 613), and is best obtained from benzene 
sulphonic acid, by distillation with potassium cyanide, or by dis- 
tilling benzoic acid with lead sulphocyanide (Berichte, 17, 2767). 
It is an oil with an odor resembling that of oil of bitter-almonds, 
and boils at 191°; its specific gravity == 1.023 ato°. Like all 
nitriles it unites with the halogens, the halogen hydrides, and 
hydrogen. Acids and alkalies saponify it to benzoic acid. 


Substituted benzonitriles have been obtained from the substituted benzamines. 

The nitrobenzonitriles, C,H,(NO,).CN, are obtained from the three nitro-ani- 
lines by diazotizing and then boiling with potassium cyanide and copper sulphate 
(see above). The chief product in the nitration of benzonitrile is #-nitrobenzoni- . 
trile, melting at 115-117°. The ortho melts at 109°, and the fara at 147°. When 
saponified with sodium hydroxide, they yield the three nitrobenzoic acids. 

Polymeric nitriles, or tricyanides, derivatives of hypothetical cyanuric acid, 
C,N,H, (p. 285), containing one alkyl and two phenyl groups, are produced when 
AICI, acts upon a mixture of benzonitriles and the nitriles of fatty acids (Berichée, 
22, 803). The hydrogen tricyanide, C,N,H, (p. 285), which is their basis, is a 
‘‘ six-membered ring,” containing three C-atoms and four N-atoms. It may be 
considered an analogue of the pyridine, C;H;N, and pyrimidine, C,H,N,, rings, 
each of which contain nitrogen. The derivatives of tricyanogen are, however, 
more easily decomposed into ammonia and the constituent acids than the last- 
named compounds. 


734 ORGANIC CHEMISTRY.’ 


Methyldiphenyl Tricyanide, C,N,(C,H,),.CH,, from benzonitrile with acetyl 
chloride and AICl,, melts at 110°. It forms salts with one equivalent of acids. 
Ethyldiphenyl Tricyanide, C,N,(C,H,),.C,H,, from benzonitrile and propiony] 
chloride, melts at 67°. 

Diphenyl Tricyan Carboxylic Acid, C,N,(C,H,),.CO,H, is formed when 
methyl-diphenyl cyanide is oxidized with potassium permanganate. It melts at 
192°, whenit decomposes into CO, and diphenyl tricyanogen hydride,C, H,(C,H,),H, 
melting at 75° (Berichte, 23, 2382). 

Triphenyl Tricyanide, (C,H;.CN), = C,,H,,N,, Cyanphenine, is formed 
by polymerization of benzonitrile on dissolving it in fuming sulphuric acid, or boil- 
ing it with sodium, as well as by the action of sodium upon a mixture of cyanuric 
chloride and benzene iodide (erichte 20, Ref. 102; 22,1760), and upon heating 
benzylidene-benzamidine, C, H;.C(NH).N:CH.C,H, (p. 736) beyond its point of 
fusion. It is said to be most readily obtained from benzimido ether (p. 735) (Be- 
richte, 22,1611). Cyanphenine is almost insoluble in water, alcohol and ether, 
readily soluble in carbon disulphide, and crystallizes in needles, melting at 231°. 
Nascent hydrogen converts it into ammonia and lophine, C,,H,,N,. Itis decom- 
posed into ammonia and benzoic acid when it is heated with hydriodic acid. 


(2) Cyantoluenes, C,H Le arte Tolunitriles. The threeisomerides result from 


the three corresponding toluidines by their conversion into mustard oils, and then 
_ heating with copper (see above), or more easily by boiling their diazo-derivatives 
with potassium cyanide and copper sulphate. The ortho- and para-bodies are also 
obtained from the toluene sulphonic acids. The ortho boils at 204° (Lerichde, 19, 
756); the mefa has not yet been prepared in pure form; the fara crystallizes in 
needles, melts at 28.5°, and boils at 218°. They change to the corresponding 
toluic acids when saponified. 

o-Cyanbenzyl Chloride, C,H,(CN).CH,Cl, formed by the chlorination of 
o-cyantoluene, melts at 61°, and boils at 252° ( Berichze, 20, 2223). Aceto-acetic 
ester or malonic ester converts it into o-cyanbenzyl acetic ester. If the latter be 
saponified with hydrochloric acid, it will part with carbon dioxide and change to 
hydrindone( Berichte, 22, 2019; 23, 2479) :— 


ova /CO 
6*4\ CH,.CH,.CO,R 4“ CH, 


p-Cyanbenzyl Chloride, C,H,(CN).CH,Cl, from g-cyanbenzyl toluene, melts 
at 79°, and boils at 263°. Potassium cyanide converts it into #-cyanbenzyl cyanide, 
which yields homoterephthalic acid (erichZe, 22, 3208; 23, 1059). 

(3) Benzyl Cyanide, C,H,.CH,.CN, is isomeric with the cyan-toluenes. This 
is the chief ingredient of several cresses, and is artificially prepared from benzyl 
chloride, C,H,.CH,Cl, with potassium cyanide (Berich/e, 19, 1950). It boils at 
229°, and yields toluic acid by saponification. 

The hydrogen of the CH,-group, combined with the negative groups, C,H, and 
CN, is very readily replaced (BerichZe, 20, 534; 21, 1291). Nitrous acid, acting 
upon a sodium-ethylate solution of benzyl cyanide, produces isonitrosobenzyl cyan- 
ide, C,H,.C(N.OH).CN, melting at 129°. It dissolves with a yellow color in the 
alkalies. It forms isonitrosophenylacetic acid by saponification (erichte, 22, Ref. 
200). Sodium ethylate, acting upon benzyl cyanide and aldehydes, produces con- 
densation products, e.g., benzaldehyde yields a-phenyl-cinnamic nitrile, C,H. 
C(CH.C,H,)CN. . Anisic aldehyde, furfurol, etc., react similarly. The alkylic 
benzyl cyanides are not capable of yielding such products ( Berichie, 21, 356; 22, 
Ref. 199). 

Dec tetcodiet atom of the CH,-group can be replaced by alkyls when sodium 
ethylate and alkyl iodides act upon benzyl cyanide. Powdered caustic soda is 


42H,0 =C,H >CH,+ R.OH-+CO, +NH,. 


BENZIMIDO-ETHYL ETHER. 735 


frequently substituted for the sodium ethylate (Berich/e, 21, 1291; 21, Ref. 197). 
In the resulting mono-alkylic benzyl cyanides, C,H;.CHR.CN, the ease with 
which the second H-atom can be replaced will be dependent upon the molecular 
magnitude and the negative character of the first substituent (Berichte, 22, 1238; 
23, 2070). 

The Shiin of benzyl cyanide affords chiefly s-Nitrobenzyl cyanide, C,H, 
(NO,).CH,.CN, and slight-quantities of the o- and m-bodies (Berichle, 17, 505) ; 
the latter can also be made from o- and m-nitrobenzalcohol by means of the chlor- 
ide (Berichte, 19, 2636). The ortho crystallizes in needles from hot water and 
melts at 83°. The mea melts at 61°, and the parva at 114°. Alcoholic soda dis- 
solves the ortho with a violet color, the pera with acarmine red color, forming 
salts of the alkali metals, in which the metal may be replaced by radicals (Berichée, 
21, 2477; 22, 327). Diazobenzene chloride and the Java compound yield an 
azo- and a hydrazo-derivative. They yield condensation products with the alde- 
hydes (Berichte, 23, 3133). The Amidobenzyl Cyanides, C,H,(NH,).CH,. 
CN, result from the reduction of the nitrobenzyl cyanides with tin and hydrochloric 
acid. When diazotized, the para- and meta-compounds yield oxybenzyl cyan- 
pee C,.H,.(OH).CH,.CN, which further form oxyphenyl acetic acids, C,H,(OH),. 

H,.CO,H 

(4) Dicyanbenzenes, C,H,(CN),, result from the three brombenzene sulpho- 
nic acids, and on distilling the benzene-disulphonic acids with potassium cyanide. 
The meta-body (also obtained from isophthalamide), melts at 156°; the para- at 220°; 
the former yields isophthalic and the latter terephthalic acid. 

(5) Tolyl Cyanides, C,H,(CH,).CH,.CN. The three isomerides have been 
obtained from the three xylenes by means of the tolyl bromides, C, H,(CH, ).CH,Br. 
The CH,-group in these compounds can be readily replaced (Berichte, 21, 1331). 

(6) Xylylene Cyanides, C,H,(CH,.CN),, have been obtained from the cor- 
responding bromides. Both CH,-groups in them are easily substituted (Berichte, 
21, 72, 2318). : 





In this connection may be mentioned the zmido-ethers and oximido-ethers, also 
the denzenylamidines and benzenyloxamidines. 

The imido-ethers (their HCl-salts) result from the action of HCl upon a mixture 
of a benzonitrile with an alcohol (p. 292) :— 
ZNH.HC1 
C,H,.CN + C,H,;.0H + HCI = CoHs CC OCH. : 


All cyanides react in a like manner (BerichZe, 21, 2650), with the exception of 
those in which an ortho-position, relatively to cyanogen, is replaced by a C-group ; 
therefore, in the case of the o-dicyanides, only one cyanogen group reacts (Be- 
richte, 23,2917). Water decomposes the HCl-imido-ethers into acid esters and 
ammonium chloride. For the action of secondary amines, consult Berich/e, 23, 
2927. 

Benzimido-Ethyl Ether, C,H,.C(NH).O.C,H,, is formed by the action of 
ethyl iodide upon. silver benzamide. Its hydrochloric acid salt consists of large, 
shining prisms, and at 120° decomposes into benzamide and ethyl chloride. The 
free ether, separated by alcoholic ammonia, is a thick oil, which decomposes when 
heated or when standing into alcohol and cyanphenine.. 

The oximido ethers, or acidoximes result when hydroxylamine acts on the 
imido-ethers (p. 292) :— 


ine H, + H.N(OH).HC = C,4,.C@O Cy. + NHCL 
G, : 


C4.C ¢0.C,H; 


736 ORGANIC CHEMISTRY. 


Benzoximido-ether, C,H,.C(N.OH).O.C,H,, is a liquid, dissolving in ether, 
and solidifying to a crystalline mass. It is identical with the so-called Ethyl- 
benzo-hydroxamic Acid (Zerichte, 17, 1587), obtained from benzoyl chloride 
and hydroxylamine. 

The benzenylamidines, or benzamidines, correspond perfectly to the amidines of 
the paraffin series (p. 293), also to the ethenyl-diphenyl-amidines, and the phenylene- 
amidines or anhydro bases (p. 627). 

Phenylcyanate (p. 613) converts the amidines into diureides, e. g., 


CH c4N. CO.NH.C,H, 

irs \.NH.CO.NH.C,H, 
(Berichte, 23, 2923), while if phenyl mustard oil be employed the products will 
be amidine thioureas, C,H 5C(N H).NH.CS.NH.C,H, (Berichte, 22, 1609). 
Acid anhydrides convert them into actdyl amidines, é. 2 benzoyl benzamidine, 
C,H;.C(NH)NH.CO. C,H, (Berichte, 22,1605). The amidines combine with al- 
dehydes to alkylidene amidines, é. g., benzylidene amidine, C,H;.C(NH).N:CH. 
C,H, (Berichie, 22, 1610; 23, 2924). -Ketonic esters, as acetoacetic esters, etc., 
cause the amidines to condense to oxypyrimidines. Succino-succinic ester pro- 
duces keto-quinazolines (Berichte, 23, 2623). See Berichte, 23, 2934 for the action 
of aromatic a-oxycarboxylic acids. 
@NH 
\ NH,’ 
when alcoholic ammonia acts upon HCl-benzimido-butyl ether (p. 292.) It con- 
sists of large vitreous crystals containing two molecules of water and melts at 72°. 
When anhydrous it melts at 169° (Berichte, 22, 1607). The free benzenylamidine, 
separated by sodium hydroxide, is crystalline, melts at 75-80°, and at higher 
temperatures breaks up into 3NH, and cyanphenine. enzylidene Benzamidine 
(see above) melts at 152°, and readily yields cyanphenine. Nitrous acid converts 
it into the dinitroso-compound, C,H;.N,H(NO),. Phenylbenzenylamidine, 


C,H ees C,H,’ results from benzonitrile or thiobenzamide, C,H,.CS.NH,, 


Benzenylamidine, C,H,.C Benzamidine. Its hydrochloride is formed 


when heated with aniline hydrochloride (p. 293). It melts at 112°, and when dis- 
tilled yields benzonitrile and aniline. Symmetrical Diphenyl-benzenyl-amidine, 
C,H,.C(N.C,H,).NH.C,H,, obtained from benzanilide, C,H;.CO.NH.C,H,, or 
benzotrichloride, Cai. OGL, by means of aniline hydrochloride, melts. at 144°. 
Unsymmetrical C,H,.C(NH).N(C,H;)., from benzonitrile and diphenylamine, 
melts at 111° (Annalen, 192, 4). 

_ The Oxamidines or Amidoximes are produced: 1, by the action of hydroxyl- 
amine hydrochloride upon the benzenylamidines :— 

NH N(OH 
CHCl Nn, 4. H,N(OH).HC] = CHC iy. ) 
2, by the action of the same reagent upon the imido-ethers, when the ammonium 
chloride very likely acts on the oximido-ethers first formed (Berichte, 17, 1588 and 


1694) :— 
CHG 


+ NH,Cl; 


7 N(OH N.(OH 
COG. + NH,Cl = CHCl Nie. ) uc + C,H,.0H; 


3, from the nitriles and thioamides by direct union with hydroxylamine (Berichde, 
19, 1669) :— 


C,H,.CN -- H,N(OH) = C,H SCONE. 
C,H,.CS.NH, +. H,N(OH) = CH CON HS. 


Ferric chloride imparts a deep red color to the alcoholic solution of the amidoximes. 


ACIDS. 4934 


Benzenylamidoxime, C,H; CON,” (Berichte, 18, 1053), crystallizes 


from ether in large plates, and melts at 79-80°. It gives the isonitrile reaction 
with chloroform and potassium hydroxide. Nitrous acid changes it to benzamide, 
C,H,.CO.NH,. With acids and caustic alkalies it yields salts, ¢. 2, C,H;. 

C(N. OH)NH, “HCl and Ci, Ct TL RUN, Alkylic iodides convert. the 
latter into amidoxime- ethers, é. gz. .» C,H,.C(NH,):N(O. C, H,), which nitrous acid 


changes to ethers of benzhydroximic acid, C,H, cF ZNO pis Tiemann (Berichte, 


18, 727) considers these ethers different from Pn of benzhydroxamic acid 
(p. 746) while according to Lossen they are identical (Berichte, 22, Ref. 588). 

The amidoximes condense with the aldehydes to hydrazoximes (Berichte, 22, 
2412, 3140) :-— 


~N.OH Ag JRO Ain C7 
CoHs.CO ni, + CHO.CH, = C,H,.CC yy >CH.CH,. 


Ethylidene Benzeny]- 
hydrazoxime. 


Azoximes, ¢. g., benzenylazoxime, CoH Laer son (Berichte, 22, 2758; 


19, 1475), result from the action of chlorides or anhydrides of organic acids upon 
the amidoximes :— 


N.OH , . : JN.O 
CoHs.CO Ni + CH,.COC] = CoHs.COy C.CH, + H,O + HCl. 


Ethenyl Benzenylazoxime. 


They are also produced by the oxidation of the hydrazoximes (see above). 





ACIDS. 


The aromatic acids are derived by replacing hydrogen in the 
benzenes by carboxyls:— 


CH cod: C,H 6{ Co: 4 ae »{ Sor8 


Benzoic Acid. Toluic ‘Acids. Xylic ‘Acids, 
C,H,.CH,.CO,H C,H,.CH,.CH,.CO,H. 
Alphatoluic Acid or tH ydroctekanie or 
Phenylacetic Acid. B- Phenylpropionic Acid, 
CO,H 


CHi{co2H  CoHs(CO.H), C,H,(CO,H), C,(CO,H),. 


Benzene Dicarboxylic Benzene Tricarboxylic Benzene Tetracarboxylic _ Mellitic 
Acids, Acids, Acids. Aci 

The important general methods of forming the aromatic acids 
are :— 

1.» The oxidation of the hydrocarbons with a chromic acid mix- 
ture, potassium permanganate or dilute nitric acid. The side-chains 
are directly converted, by chromic acid, into CO,H ; the hydrocar- 
bons, C,H;.CH;, CsH;.C,H;, CsH;.C,H,, etc., all yield benzoic 
acid, C,H;.CO,H. With nitric acid it is sometimes possible to 
oxidize only the most extreme carbon atom of the side-chain. 

62 


738 ORGANIC CHEMISTRY. 


Should several side-chains chance to be present, chromic acid will 
almost invariably oxidize them all directly to CO,H. Thus, the 
xylenes, C,H,(CH;),, yield dicarboxylic acids, C,H, (CO,H),. 
Dilute nitric acid forms mono-carboxylic acids, ¢. g., ren: hd coe 
and potassium permanganate produces both varieties. Ns 


Only the Jara- and meta-derivatives (the former more readily than the latter) 
of benzenes, carrying two side-chains (the xylenes and toluic acids), are oxidized 
to acids by chromic acid, while the ortho- are either not attacked at all or are 
completely destroyed. Nitric acid, or better, potassium permanganate, oxidizes all 
(even the ortho-derivatives) to their corresponding acids. The haloid toluenes 
(p. 584), the nitro-toluenes (p. 590), and toluene sulphonic acids (p. 665) deport 
themselves similarly. The same is observed with dialkyl benzenes, where the 
entrance of a negative group hinders the oxidation of the alkyl occupying the 
ortho- place (Berichte, 15, 1022). 

In the homologous phenols the OH-group completely prevents the oxidation of 
the alkyls by the oxidizing agents mentioned; this is true, too, in all the isomer- 
ides; but it does occur in a peculiar. manner, if the phenyl hydrogen be replaced 
by alkylic groups or acid radicals (p 686). 

In the derivatives with two different alkyls (e. ¢., cymene, C,H,(CH,).(C,.H,), 
the higher alkyl is usually attacked first, by nitric acid or cnromic acid (or CrO,- 
Cl,),and converted into carboxyl (Berichée, 11, 619); while in the animal organism 
the methyl group suffers oxidation (Berichte, 16, 619). Sometimes, however, the 
methyl group is first oxidized; this occurs when dilute nitric acid isthe oxidizing 
agent ( Berichte, 19,1728). Potassium permanganate occasions at first an entrance 
of OH in the propyl group, accompanied often by a transposition (p. 346 and 
Berichte, 14, 1135). 

Potassium ferricyanide oxidizes methyl to. carboxyl, if the nitro-group occupies 
the ortho position relatively to the methyl group. This does not occur if the nitro- 
group holds the meta-position (Berichte, 22, Ref. 201, 501). 





In oxidizing the benzenes with chromic acid it is customary to employ a mix- 
ture of Cr,O,K, (2 parts) with sulphuric acid (3 parts), which is diluted with 2-3 
volumes of H,O, and apply it in the quantity necessary for oxidation (Cr,O,K, 
yields 30 and oxidizes 1CH,). The mixing is performed in a flask provided with 
a long upright tube, the whole boiled for some time, until all the chromic acid is 
reduced and the solution has acquired a pure green color. The product is dilu- 
ted with water, the solid acid filtered off and purified by dissolving in soda, etc. 
_ Soluble acids are extracted with ether; the volatile acids are distilled over with 
steam. 

When oxidizing with nitric acid, use acid diluted with 3 parts of water and boil 
for some time, in connection with a return condenser (2-3 days). To remove the 
nitro-acids which are invariably formed, the crude product is digested with tin 
and concentrated hydrochloric acid; this converts the nitro- into amido-acids, 
which dissolve in hydrochloric acid. 

Potassium permanganate often effects the oxidation at ordinary temperatures. 
The substance or (with acids) its alkaline solution, is shaken with an excess of 
permanganate; hydrated manganese dioxide separates, while the potassium salt 
of the acid produced passes into the solution. 


ACIDS. 939 


2. Oxidation of the aromatic aldehydes and alcohols. | 
3. The conversion of the nitriles (p. 211) when boiled with 
alkalies or acids :— 


C,H,.CN + 2H,0 = C,H,.CO,H + NH,, 
C,H,-CH,.CN + 2H,O = C,H,.CH,.CO,H + NH,. 


Hydrochloric acid changes the oxychlorides (obtained from the aldehydes and 
ketones with CNH) to oxy-acids (p. 347). Sometimes in this case chlorinated 
acids first form, and are converted into oxy-acids by boiling with alkalies (see 
Mandelic acid). 


4. Action of sodium and CO, upon mono-brombenzenes— 
Kekulée :— 
‘CH 


C,H,Br.CH, + CO, + 2Na = CHK CO'Na + NaBr. 


The phenols react directly with CO, and sodium, forming oxy- 


acids— Kolbe :— 


OH 
C,H,.ONa + CO, = CHK CO, Na. 


Instead of letting sodium and carbon dioxide act on the free phenols, it is better 
to expose the alkaline phenates to heat, in a current of CO,-gas (see Salicylic 
Acid). If the CO, should act further abéve 300°, oxyisophthalic acid and oxy- 
trimesic acid will result. In the substituted phenols (their ethers) the halogen 
atom is replaced by the carboxyl-group :— 


C,H,Br.0.CH, + CO, + 2Na = C,H,(O.CH,).CO,Na ++ NaBr. 


The dioxyphenols of the meta-series (resorcinol, orcinol) can be changed to 
dioxyacids when heated with ammonium carbonate or potassium (sodium) dicar- 
bonate and water to 130°, or even by merely boiling them (Berichée, 18, 3202; 
19, 2318) :-— 

C,H,(OH), + CO, = C,H,(OH),.CO,H. 


5. A similar reaction is that of sodium and esters of chlorcarbonic 
acid upon phenols and brom-hydrocarbons— Wirtz :— 


C,H,Br + CICO,.C,H, + 2Na = C,H,.CO,.C,H, ++ Na,(BrCl), 
C,H,.OK. + CICO,.C,H, = CHK C0,.C,H, + KCl. 


6. The action of phosgene gas upon benzene in the presence of 
AIC]; (p. 569); at first acid chlorides are produced, and these 
change further into benzene-ketones :— 

C,H, + COCI, = C,H,.COC] + HCl. 


Similarly, phosgene and esters of chloroxalic acid act directly upon dimethyl 
aniline (p. 601). ; 
Ethyl urea chloride, in the presence of AICl,, acts in an analogous manner upon 


74° ORGANIC CHEMISTRY. 


benzenes—the products then are derivatives of aromatic acids (Berichte, 20, 
120) :— : 
C,H, + Cl.CO.NH.C,H,; = C,H,.CO.NH.C,H, + HCl; 
Ethylbenzamide. 


urea chloride, Cl.CO.NH, (p. 376) behaves similarly (Berichte, 21, Ref. 294) :-— 
C,H, + Cl.CO.NH, = C,H;.CO.NH, + HCl; 


, Ph ai 


while diphenylurea chloride (C,H;),.N.CO.Cl (p. 611) (Berichte, 20, 2118) and 
phenylisocyanate (carbanile) (Berichte, 18, 873, 2338) may be included in the 
same category :— 


C,H, + CO.N.C,H, = C,H,.CO.NH. C,H,. 


A modification of the urea chloride process consists in the action of nascent cyanic 
acid, CONH, the benzene or phenol ether being heated with cyanuric acid 
(CONH), and AICI, (Berichte, 23, 1190) :— 


C,H, -+- CONH = C,H,.CO.NH,. 


Benzamide. 


7. Fusion of salts of sulphonic acids of the hydrocarbons, or of 
the aromatic acids with sodium formate :— 


CO,N CO,N 
CHK So!Na + CHNaO, = CHC Co'Na + SOsHNa. 


8. By heating the halogen nitro-derivatives of the hydrocarbons 
with potassium cyanide and alcohol, to 200-230° in sealed tubes :— 


B B 
CHK No, 4+ CNK = CHK CN + NO,K. 


The nitrile immediately becomes an acid. In this reaction the cyanogen group 
displaces NO,, but does not assume the same position in the benzene nucleus 
(Berichte, 8, 1418). In the same manner, when alcoholic potassium cyanide acts 
upon m#- and /-dinitrobenzene ome nitro group is replaced by CN, while an oxy- 
alkyl group enters at the same time. 


g. Action of benzyl chloride upon ethers of sodium acetoacetic 
ester, and the decomposition of the ketonic esters, formed at first, 
by alkalies (p. 212). Benzyl malonic acid, C,H;.CH,.CH(CO,H),, 
is similarly formed from sodium malonic ester; it loses CO, and be- 
comes benzyl acetic acid, C,H;,.CH,.CH,.CO,H (p. 212). 

- to. Action of sodium upon the benzyl esters of the fatty acids ; 
here, too, esters are produced at first :— 


CH, -  CH,.CH,.C,H, 
2 | +Na= | + CH,.CO,Na + H, 
CO.0.CH,.C,H, CO.0.CH,.C,H, 

Benzyl Acetic Ester. Benzyl Phenyipropionic Ester. 


ACIDS. 741 


but subsequently they yield saturated and unsaturated acids (Az- 
nalen, 193, 321, and 204, 200) :— 


C,H, C,H, C,H; 

yields | - and d 
CH,.CH,.CO,.C,H, CH,.CH,.CO,H H:CH.CO,H. 
Phenylpropionic Ester. Phesylproplouse Acid. Phenylacrylic Acid. 


Phenyl butyric and phenyl ¢fotonic acids are similarly obtained from the benzyl 
propionic esters. 


11. The direct syntheses of aromatic acids from paraffin com- 
pounds have been given upon pp. 565, 566. 

12. The special synthetic methods for oxy-acids and ketonic acids, 
as well as for the unsaturated acids, are described under these gen- 
eral headings. 

The aromatic acids occur naturally, partly i in a free state, partly 
in many resins and balsams, and in the animal organism (hippuric 
acid, tyrosine). They arise also in the decay of albuminoid bodies 
(Berichte, 16, 2313). 





The aromatic acids are crystalline solids, which generally sub- 
lime undecomposed. Most of them dissolve with difficulty in water, 
hence are precipitated from their salt solutions by mineral acids. 
Sodium amalgam or zinc dust will reduce some to aldehydes, and 
heating with concentrated hydriodic acid or phosphonium iodide 
converts them into hydrocarbons. When heated with lime or 
soda-lime, their carboxyl-groups are eliminated and hydrocarbons 
result :— 


CH, 
C,H 4 Cola = Cs H,.CH, + CO,, 


C,(CO,H), = C,H, + 6CO,. 


From the polycarboxylic acids we obtain, as intermediate pro- 
ducts, acids having fewer carboxyl-groups, e. g., phthalic acid first 
yields benzoic acid and then benzene :— 


C,H,(CO,H), = C,H,.CO,H and C,H,. 


The hydrogen of the benzene nucleus in the acids can sustain 
substitutions similar to those observed with the hydrocarbons and 
phenols. In other respects they are very similar to the fatty acids, 
and afford corresponding derivatives. 


742 ORGANIC CHEMISTRY. 


MONOBASIC ACIDS. 


Benzoic Acid, C,H,O, = C,H;.CO,H, occurs free in some 
resins, chiefly in gum benzoin (from Styrax denzoin), and in coal tar 
(Berichte 18, 615); as hippuric acid in the urine of herbivorous 
animals. In addition to the general synthetic methods it is ob- 
tained from benzotrichloride, C,H;.CCl,, when heated with water to 
150°, or by mixing with sulphuric acid; also by boiling benzyl 
chloride, C,H;.CH,Cl, with dilute nitric acid, or by acting on ben- 
zene with carbon dioxide in the presence of aluminium chloride. 


Preparation,—Gum benzoin is sublimed in an iron pan, covered with a paper 
cone. Orthe powdered resin is boiled with milk of lime, lime water (to decolorize 
the dye stuffs) added to the filtered solution of the lime salt, and the benzoic acid 
precipitated with hydrochloric acid. A more advantageous method is the pro- 
duction of the acid from hippuric acid (benzoyl glycocoll, p. 744). To accom- 
plish this, boil the latter for an hour with 4 parts of concentrated hydrochloric 
acid, and filter off the separated benzoic acid. Benzoic acid results from phthalic 
acid by heating its calcium salt to 300-350° (see above) with 1 molecule of cal- 
cium hydroxide. 


Benzoic acid crystallizes in white, shining needles or leaflets, 
melts at 120°, and distils at 250°. It volatilizes readily, and is 
carried over with steam. It dissolves with difficulty in cold water 
(1 part in 600 parts), but readily when heated. ‘The vapors possess 
a peculiar odor, which produces coughing. 

The acid yields benzene and carbon dioxide when heated with 
lime ; with excess of the latter benzophenone also results. Sodium 
amalgam converts it into benzaldehyde, hydrobenzoin and hydro- 
benzoic acid, C,H,,Q,. 


The denzoates are mostly quite readily soluble in water. Ferric chloride throws 
out a reddish precipitate of ferric benzoate from their neutral solutions. 


The potassium salt, 2C,H,KO, + H,O, crystallizes in concentrically grouped _ 


needles. The calcium salt, (C,H,O,),Ca + 3H,O, consists of shining prisms or 
needles. The si/ver salt, C,H;AgO,, crystallizes from hot water in bright leaflets. 

‘The esters of benzoic acid, as well as those of all other aromatic acids, are pre- 
pared by conducting hydrochloric acid into an alcoholic solution of the acid, and 
are aromatic-smelling liquids. They can also be obtained by shaking benzoyl 
chloride with alcohols and sodium hydroxide, until a permanent alkaline reaction 
is observed (Berichte, 19, 3218). The methyl ester, C,H,O,.CH,, boils at 199°, 
the ethyl ester at 213°, the zsoamyl ester at 261°. The zsopropyl ester boils about 
218° and decomposes into benzoic acid and propylene. The benzylic ester, 
‘C,H,.CO.0.C,H,, occurs in Peru- and Tolu-balsam,* and is formed when ben- 
zyl chloride acts upon benzal alcohol. It also results from the interaction of 
sodium or potassium ethylate and glacial acetic acid upon benzaldehyde (benzyl 





* Peru- and Tolu-balsams are thick, yellow-brown liquids, which are obtained 
from the bark of varieties of MZyroxylon. In addition to resins and some free 
benzoic and cinnamic acids they also contain benzyl-benzoic and cinnamic esters 
(Cinnamein). 


ae 


MONOBASIC ACIDS. 743 


alcohol and methyl benzoic ester are also produced) (Berichte, 20, 647). It 
crystallizes in needles, melts at 21°, and boils at 324°. The phenyl ester, 
C,H,.CO.0.C,H,, is formed from benzoyl chloride and phenol, or by fusing 
benzoic acid with phenol and POCI, (p. 668); it melts at 66°. 





Dihydrobenzoic Acid, C,H,O, = C,H,.CO,H, may be prepared by 
oxidizing dihydrobenzaldehyde with argentic oxide (Berichte, 23, 2886). It does 
not dissolve in water as readily as benzoic acid. It volatilizes with steam, and 
when cooled solidifies to a feathery crystalline mass, melting at 95°. It has an 
odor resembling that of cinnamon, and it reduces ammoniacal silver solutions. 

Hexahydrobenzoic Acid, C,H,,0, = C,H,,.COOH, Hexanaphthene Car- 
boxylic Acid. This occurs together with associated acids in the petrolic acids of 
petroleum. It is isolated by the fractional distillation of the methyl esters (Be- 
richte, 23, 870). It is a viscid oil, boiling at 215-217°. Its odor resembles that 
of baldrianic acid. 





Benzoyl Chloride, C,H,.COCI, results when benzoic acid is distilled with 
PCl,, and when chlorine acts upon boiling benzaldehyde. It is an oil witha 
penetrating odor. It boils at 199°, and is slowly converted into benzoic acid by 
water. Excess of PCI, converts it into benzotrichloride, C,H,;.CCl,. Benzoyl 
bromide, from benzoic acid with PBr,, boils at 217°-220°. 

Benzoyl Cyanide, C,H,;.CO CN, is produced when benzoyl chloride is dis- 
tilled with potassium or mercury cyanide. It crystallizes in large tables which 
melt at 34° and boil at 208°. When boiled with alkalies it changes to benzoic 
acid and potassium cyanide; concentrated hydrochloric acid converts it into ben- 
zoyl-formic acid. When phenylhydrazine acts upon benzoyl cyanide hydrocyanic 
acid is evolved and a-benzoyl phenylhydrazine results. Nitrobenzoyl cyanide 
(Berichte, 22, 329) reacts in a similar manner. 

Benzoic Anhydride, (C,H,O),O, is obtained by heating dry sodium ben- 
zoate (6 parts) to 130° with PCI,O (1 part), or upon digesting benzoyl chloride 
with lead nitrate (Berichie, 17, 1282). It consists of prisms insoluble in water, 
melts at 42°, and boils at 360°. It changes to the acid on boiling with water. 
Benzoyl Peroxide, (C,H,;O),0O,, forms large crystals, melts at 100° and defla- 
grates. 

Thiobenzoic Acid, C,H,.CO.SH, results when benzoyl chloride acts upon ~ 
alcoholic potassium sulphide. It is crystalline, melts at 24° and distils in aqueous 
vapor. Its ethv/ ester boils at 248°. When its ethereal solution is exposed to the 
air the acid rapidly changes to Benzoyl disulphide, (C,H,O),S, ; brilliant crystals, 
which melt at 128°. Benzoyl sulphide, (C,H,O),S, is obtained when benzoyl 
chloride acts upon thiobenzoic acid. It crystallizes from ether in large prisms, 
melts at 48° and decomposes when distilled. 

Dithiobenzoic Acid, C,H,.CS.SH, is obtained when C,H,.CCl, is boiled 
with alcoholic potassium sulphide; C,H,;CCl, + 2K,S = C,H,CS,K + 3KCI. 
The free acid is very unstable. The lead salt crystallizes from carbon disulphide 
in red needles. 


Amide Derivatives of Benzoic Acid. 


Benzamide, C,H,.CO.NH,, results when benzoyl chloride or benzoic ester 
acts upon alcoholic ammonia. It is best obtained by heating benzoic. acid and 
ammonium thiocyanate to 170°. It crystallizes in pearly leaflets, melts at 130°, 
and boils near 288°. It is readily soluble in hot water, alcohol and ether. 


744 ORGANIC CHEMISTRY. 


It combines with hydrochloric acid to C,H,ON.HCl. Whenit is boiled with mer- 
~ curic oxide we obtain the crystalline compound C,H;.CO.NHg. Silver benza- 
mide, C,H;.CO.NHAg or C,H;.C(NH).O.Ag, obtained by precipitating the 
aqueous solution of benzamide and silver nitrate with sodium hydroxide, is a 
brown precipitate. When digested with ethyl iodide it yields benzimido-ethyl 
ether, C,H,.C(NH).O.C,H, (p. 735) (Berichte, 23, 105,1550). Consult Berichie, 
23, 3039 for sodium benzamide. 

+ Methylene-dibenzamide, CH,(NH.CO.C,H,),, is identical with the so- 
called Azpparafin obtained in the oxidation of hippuric acid with PbO, and 
nitric acid, and results from benzonitrile and methylene dimethylate. It melts at 
233° and when heated with water is decomposed into benzamide and formalde- 
hyde. : 
Dibenzamide, (C,H;O),NH, results from the action of sulphuric acid upon 
benzonitrile. It melts at 148° and dissolves in sodium hydroxide to the salt 
(C,H;O),N.Na. 

Thiobenzamide, C,H,.CS.NH,, is formed when hydrogen sulphide is con- 
. ducted into an ammoniacal, alcoholic solution of benzonitrile (p. 260). It melts 
at 116°. Hydrochloric acid and zinc convert it into benzylamine (Berichte 21, 
53). Thiobenzanilide, C,H,;.CS.NH.C,H,, may be obtained from phenyl- 
benzenylamidine by the action of hydrogen sulphide or carbon disulphide. It 
forms yellow plates, melting at 98°. 

On mixing aniline and benzoyl chloride we get Benzanilide, C,H,.CO. 
NH.C,H;, Phenyl-benzamide, which can also be made by the action of alumi- 
nium chloride (p. 727) upon benzene and carbanile, and upon heating dipheny]l- 
ketoxime, (C,H;),C:N.OH, whereby a molecular transposition is brought about. 
It crystallizes from alcohol in leaflets, melts at 158-160°, and distils without de- 
composition. PCI; converts it into benzanilide-imidechloride, C,H;.CCI:N. 
C,H, (p. 258), which can also be obtained from diphenyl-ketoxime (C,H;), 
C:N.OH, by a transposition of the chloride (Berichte, 19, 992; 20, 504) :— 


(C,H;),Cc:NC] yields \C,H,.CCI:N.C,H,. 


From benzene the imidechloride crystallizes in large leaflets, melting at 40°, and 
boiling at 310°. Water or alcohol resolves it into hydrochloric acid and benzani- 
lide. 

Benzanilide-imidechloride, acting upon aceto-acetic ester or malonic ester, pro- 
duces compounds like C,H,.N:C(C,H POE Be anil-benzenyl-malonic 
ester, which, when heated, eliminate alcohol, and by the closing-up of the ring 
yield quinoline derivatives (Berichte, 19, 1462). 

Benzoyl Toluidines, C,H,.CO.NH.C,H,CH,, are similarly produced from 
the three toluidines with benzoyl chloride, and with PCI, yield the corresponding 
imidechlorides, C,H ,.CCl:N.C,H,, which, upon further condensation with ma- 
lonic esters, yield quinoline derivatives (Just, Berichte, 19, 979 and 1541). 


Hippuric Acid, Benzoyl glycocoll, C,H,NO; = 
CH,Z pS nde Ce) occurs in considerable amount in the urine 
\CO,H : 
of herbivorous animals, sometimes in that of man. Benzoic acid, 
cinnamic acid, toluene and other aromatic substances, when taken 
internally, are eliminated as hippuric acid. It can be obtained 
artificially by heating benzamide with monochloracetic acid :— 


C,H,.CO.NH, + CH,Cl.CO,H = C,H,.CO.NH.CH,.CO,H + HCl, 


MONOBASIC ACIDS. 745 


by the action of benzoyl chloride on silver glycocollide (Berichte, 
15, 2741), or by adding sodium hydroxide to glycocoll and shak- 
ing with benzoyl chloride (Berichte, 19, Ref. 307), and by heating 
benzoic anhydride with glycocoll (Berichte, 17, 1662). 


To prepare it boil the urine of horses with milk of lime, filter, concentrate the 


solution, and precipitate with hydrochloric acid. To purify the crude acid digest 
it with chlorine water, or dissolve it in dilute sodium hydroxide, add sodium 
hypochlorite, boil to decolorization, and then precipitate the cold solution with 
hydrochloric acid. 


Hippuric acid crystallizes in rhombic prisms, and dissolves in 600 
parts cold, and readily in hot water and alcohol. It melts at 187°, 
and about 240° decomposes into benzoic acid, benzonitrile and 
prussic acid. Phosphorus pentachloride converts it into isoquino- 
line, while its ethyl ester yields Hippuroflavin, C,H;.NO, (Be- 
richte, 21, 3321). 


‘Its stlver salt, C,H,AgNO,, crystallizes from water in silky needles. The 
ethyl ester is best obtained by digesting glycocoll ester with benzoic anhydride; 
it is crystalline, melts at 60°, and decomposes when distilled. 

Boiling acids or alkalies decompose hippuric acid into benzoic acid and glyco- 
coll. Nitrous acid converts it into benzoyl glycollic Acid, CHL CoM 
which crystallizes in fine needles. It is easily soluble in hot water, is monobasic, 
and yields salts which are readily soluble. Consult Berichte, 22, Ref. 551, for 
the condensation products obtained from hippuric acid and the aldehydes. 

Potassium chlorate and hydrochloric acid produce chlorinated hippuric acids. 
m-Nitrohippuric acid, C,H,(NO,)NOg, is obtained by adding hippuric acid to a 
mixture of nitric and sulphuric acids. It forms shining prisms, which are not 
very soluble in water, and melt about 150°. When boiled with acids it breaks up 
into glycocoll and m-nitrobenzoic acid (p. 747). 

Benzoyl Hydrazine, C,H,.CO.NH.NH,, is a derivative of diamide, N,H, 
(p. 166). It may be prepared by the action of hydrazine upon benzoyl glycollic 
ester (Berichte, 23, 3023). It crystallizes in large leaflets, melting at 112°. 
Sodium nitrite and acetic acid convert in into Benzoyl Azimide, C,H,.CO.N:N, 
(p. 640), which by boiling with sodium hydroxide, is converted into benzoic acid 
and the sodium salt of azoimide or hydrazoic acid, HN. 

Benzhydroxamic Acids (p. 260). * 

These acids are produced in the same manner as the analogous acids of the 
fatty series from the acid chlorides, esters and amides, by the action of hydroxyl- 
amine (Berichte, 22, 2856, 3070; Ref. 587) (see Berichte, 22, 1270) :— 


C,H,.CO.0.C,H, + NH,.0H = Ct Chee + C,H,.0H, 


C,H,.CO.NH, + NH,.0H = CHECK On + NH,. 


When these are heated with phenylhydrazine the oxime-group is eliminated and 
oxyhydrazones result (Berichte, 22, 3070) :— 
C,H,.C(OH).(N.OH) + NH,.NH.C,H, = 
C,H,.C(OH) (N.NH.C,H,) + H,N.OH. 


746 , ORGANIC CHEMISTRY. 


Benzhydroxamic Acid, CoH.CC Or aoe is very soluble in hot water. It 


crystallizes in leaflets and plates, melting at 125° (Berichte, 12, 1272). 
Two isomeric ethers are derived from it by the introduction of alkyls :— 


ZN.0.C,H,; ZN.OH 
CHC on and CHsCCO CH 
Alkyl Benzhydroxamic Ether. Alkyl-benzhydroxamic Acid. 


The first result when alkyl iodides and caustic alkali act upon benzhydroxamic 
acid. They are identical with the benzhydroximic acids obtained from benzeny]l- 
amidoxime by alkylization and the subsequent action of nitrous acid (Lossen, 
Berichte, 22, 588). Acids resolve them into benzoic acid and a-hydroxylamine 
ethers, H,N.OR (p. 166). 

The second class are produced when the benzoyl group is introduced into benz- 
hydroxamic acid and the product further alkylized, etc. They are identical with 
the benzoximido-ethers prepared from benzimido-ether. When the ethyl derivative 
is digested with hydrochloric acid it forms ethyl chloride and benzhydroxamic acid 
(Berichte, 22, Ref. 588). The benzhydroxamic ethers and ethylbenzhydroxamic 
acid yield the same ethyl benzhydroxamic ethylate,C,H,.C.(N.O.C,H,).0.C,H,. 


Substituted Benzoic Acids. | 

These are formed by the direct substitution of benzoic acid or 
by oxidizing substituted toluenes. The action of the halogens (or 
of hydrochloric acid and potassium chlorate ; of bleaching lime and 
of antimony chloride) upon benzoic acid is not as energetic as 
upon the hydrocarbons; the mono-substitution products of the meza 
series (p. 589) are almost the sole products. In the action of nitric 
acid small quantities of ortho- and para- compounds also result. 


» The mono-substituted toluenes of the mefa and fara series are 


readily oxidized by chromic acid to the corresponding substituted 
benzoic acids, whereas the ortho-derivatives are attacked with 
difficulty and then completely decomposed (p. 738). However, 
the ortho-compounds are oxidized to the corresponding benzoic 
acids by dilute nitric acid, or by an excess of potassium perman- 
ganate. Thus (1, 2)-brom-, iodo- and nitro-toluene yield (1, 2)- 
brom-, iodo- and nitrobenzoic acids. Furthermore, substituted 
benzoic acids can be obtained from the oxy-acids by PCI, and also 
from the amido-benzoic acids (by forming the diazo-compound and 
boiling with the haloid acids). When the halogen nitrobenzenes 
are heated with potassium cyanide substituted benzoic acids are the 
products. The ortho- melt at the lowest temperatures, are rather 
readily soluble in water, and yield easily soluble barium salts, 
whereby they can usually be quite readily separated from the meta- 
and para-derivatives. When they are fused with caustic potash 
oxy-acids result. 


Monochlorbenzoic Acids, C,H,Cl.CO,H. The ortho (1, 2)-body was 
formerly called chlorsalicylic acid, and may be obtained from salicylic acid, C,H, 
, (OH).CO,H, by the action of PCI, ; the chloride,C,H,CI.CO.Cl, formed at first, 
boils at 240° and is decomposed by boiling water. It sublimes in needles, melting 


MONOBASIC ACIDS. 747 


at 137° (they melt below 100° in water). They can also be obtained from (1, 3)- 
chlornitrobenzene by the action of potassium cyanide. Metachlorbenzoic Acid 
(1, 3) is produced by oxidizing (1, 3)-chlortoluene, and from benzoic acid by 
boiling it with hydrochloric acid and ClO,K, with HCl and MnO,, with bleaching 
lime or with SbCl, ; also from chlorhippuric acid, and from (1, 4)-chlornitroben- 
zene with potassium cyanide. It sublimes in flat needles, melting at 153°. Para- 
chlorbenzoic Acid (1, 4), called chlordracrylic acid, is obtained from (1, 4)-chlor- 
toluene; it sublimes in scales, and melts at 240°. 

Monobrombenzoic Acids, C,H,Br.CO,H. The ortho-acid, from ortho- 
bromtoluene (with nitric acid) and from orthoamidobenzoic acid (on heating the 
perbromide of the diazo-compound with alcohol), sublimes in needles and melts 
at 147-148°; its barium salt is very soluble in water. The common metabrom- 
benzoic acid, obtained from (1, 3)-bromtoluene, and by heating benzoic acid and 
bromine to 120-130° (with some I, 2-brombenzoic acid), sublimes in needles, 
melting at 155°. (1, 4)-Brombenzoic Acid, from parabromtoluene, is almost 
insoluble in water, crystallizes in needles, and melts at 251°. 

Monoiodo-benzoic Acids, C,H,I.CO,H. The ortho-acid from ortho-iodo- 
toluene (by means of nitric acid) and ortho-amidobenzoic (by decomposition of 
the diazo-compound with hydriodic acid) forms needles and melts at 159°. It 
yields salicylic acid with caustic potash. Metaiodobenzoic Acid (1,3), from meta- 
iodo-toluene and meta amidobenzoic acid, sublimes in needles, and melts at 187°; 
(1, 3)-oxybenzoic acid results when it is fused with caustic potash. Paraiodo- 
benzoic Acid (1, 4), from paraiodo-toluene, paraiodo-propyl benzene, para-amido- 
benzoic acid and g-amidoacetophenone, crystallizes from alcohol in pearly leaflets, 
sublimes in scales and melts at 265°. When fused with potassium hydroxide it 
yields paraoxybenzoic acid. 

Fluorbenzoic Acids, C,H,F1.CO,H. These are obtained by boiling the 
three diazoamido-benzoic acids with hydrofluoric acid. The ortho-acid melts at 
118°, the meta-acid at 124°, and the para-acid at 181° (Berichte, 15,1197). They 
separate out in urine as fluorhippuric acids. Dz-fluor-benzoic Acid, C,H;F1,.CO,H, 
from benzoic acid and Cr,Fl,, is in external properties very similar to benzoic acid. 
It melts at 232°. 





Nitrobenzoic Acids, C,H,(NO,).CO,H. 

Metanitrobenzoic acid is the principal product in the nitration of 
benzoic acid. The quantity of the ortho (20 per cent.) and para 
(1.8 per cent.) acids is less. 


Preparation —Gradually add sulphuric acid (4 parts) to a mixture of fusedjand 
pulverized benzoic acid (1 part) with nitre (2 parts) and apply heat to the mass 
until it melts, then pour the fused acids off from the potassium sulphate. To effect 
their separation convert them into barium salts and recrystallize; the barium salt 
of the meta-acid dissolves with great difficulty (4mmalen, 193, 202). In the nitra- 
tion of cinnamic acid g- and o-nitro-cinnamic acids are formed. ‘The oxidation of 
these yields the corrésponding nitrobenzoic acids. The nitration of hippuric acid 
gives rise to a nitrohippuric acid, which yields metanitrobenzoic acid. The nitro- 
benzoic acids can also be prepared by oxidizing the three nitrotoluenes (p. 746), 
and ortho- and para-nitrobenzyl chloride (p. 584) with potassium permanganate; 
further, by converting the three nitroanilines into three nitrobenzonitriles and saponi- 
fying the latter with alkalies (p. 634) (Berichte, 18, 1492). The ortho-acid is 
most easily prepared by oxidizing o-nitrotoluene with potassium permanganate 
(Berichte, 12, 443) and the fara-acid by oxidizing -nitrotoluene with a chromic 
acid mixture. 


748 ORGANIC CHEMISTRY. | 


(1, 2)-LVitrobenzoic Acid crystallizes in needles or prisms, melts at 147°, pos- 
sesses a sweet taste and dissolves in 164 parts of water at 16°. In the action of 
PCI, upon it there is formed, in addition to o0-nitrobenzoyl chloride, the anhydride 
of o-nitrobenzoic acid, (C,H,(NO,)CO),O, melting at 135° (Berichie, 17, 2789). 
The ordinary (1, 3)-#2¢robenzoic acid crystallizes in needles or leaflets, sublimes 
in white needles and melts at 142°. After slow cooling it melts at 135—136° and 
dissolves in 425 parts of water at 16.5°. (1, 4)-itrobenzotc acid, also obtained 
by oxidizing para-nitrotoluene, forms yellowish leaflets, melts at 240° and dissolves 
with difficulty in water. 

When the (1, 3)-brombenzoic. acid is nitrated two nitrobrombenzoic acids are 
produced, the one melting at 251°, the other, much more soluble in water, at 141°. 
In both the nitro-group is contained in the ortho-position and hence in reduction 
both yield (1, 2) = (1, 6)-amidobenzoic acid (p. 562). The halogen of the nitro- 
haloid benzoic acids is very reactive (compare p. 588, Berichte, 22, 3282), 

Dinitrobenzoic Acid, C,H,(NO,),.CO,H (1, 2, 4—CO,H in 1), is formed 
by oxidizing a-dinitro-toluene with fuming nitric acid, and consists of long prisms, 
melting at 169°. In the reduction with tin and hydrochloric acid the carboxyl 
group is split off and (1, 3)-diamidobenzene results. 

The nitration of (1, 3)-nitrobenzoic acid with nitric and sulphuric acid produces 
the symmetrical dinitrobenzoic actd (1, 3, 5), which is also obtained by oxidizing 
symmetrical dinitrotoluene. It crystallizes from water in large quadratic plates, 
melting at 205°. Its reduction affords diamidobenzoic acid which yields (1, 3)- 
diamidobenzene, when distilled with baryta. 

The nitration of (1, 2)-nitrobenzoic acid produces three dinitrobenzoic acids : 
(1, 2, 6), (1, 2, 5) and (1, 2, 4)—the latter being identical with the acid obtained 
from a-dinitrotoluene. The first acid melts at 202° and when heated decomposes 
into carbon dioxide and (1, 3)-dinitrobenzene. The second melts at 177° and when 
reduced yields a diamidobenzoic acid which affords (1, 3)-diamido-benzene when 
distilled with baryta (see the diamido-benzoic acids). 





Amido-benzoic Acids, Cg§H,(NH;).CO,H. 

These are obtained by reducing the corresponding nitrobenzoic 
acids with tin and hydrochloric acid, or with hydrogen sulphide in 
ammoniacal solution. In the latter case the amido-acid is precipi- 
tated from the solution by acetic acid. They are also formed by 
the. oxidation of the acetyl toluidines (p. 623). Dimethylated 
afiilio-acids are produced by the action of phosgene (COCI,) upon 
the dimethylanilines (p. 739): or by methylating the acids by 
heating them with alkyl iodides and caustic alkali. Like glycocoll, 
the amido-benzoic acids yield crystalline salts both with acids and 
bases. 

Ortho-amidobenzoic Acid (1, 2) also results from the two 
nitro-metabrombenzoic acids (p. 747). by. reduction, and by the 
action of sodium amalgam. It was first obtained from indigo, 
hence termed anthranilic acid. 


It is prepared by oxidizing indigo. This is effected by boiling it with manga- 


nese dioxide and sodium hydroxide (Anna/en, 234, 146), or more readily if ortho- 
nitrobenzoic acid be reduced with tin and hydrochloric acid. Also by the oxida- 


MONOBASIC ACIDS. 749 


tion of aceto-ortho-toluidine with potassium permanganate and boiling with 
hydrochloric acid. 

The formation of dibromanthranilic acid, when bromine acts upon boiling 
orthonitrotoluene (p. 590), is worthy of note. 


Anthranilic acid sublimes in long needles, is readily soluble in 
hot water and alcohol, melts at 144°, and decomposes into carbon 
dioxide and aniline when rapidly heated. Nitrous acid converts it, 
in aqueous solution, into salicylic acid. 


The inner anhydride (lactam) of ortho-amidobenzoic acid is the so-called 
Anthranil, CH NED (see Berichte, 20, 1537), obtained by the reduction of 


o-nitrobenzaldehyde with ferrous sulphate (theoretical quantity) and ammonia 
(Berichte, 15, 2572), or with tin and glacial acetic acid (Berichte, 15, 2105; 16, 
2227). It also results when o-nitro-phenyloxyacrylic acid is boiled with water 
(Berichte, 16, 2222). It is an oil which volatilizes readily with aqueous vapor, 
possesses a peculiar odor and boils with decomposition about 210°. It dissolves in 
alkalies, forming salts of anthranilic acid. o-Amidobenzaldehyde and benzalcohol 
are produced when it is reduced. Chlorcarbonic esters produce Anthranilcar- 
bonic Acid, CH, (S )co,H, or C HC NHCOye (Berichte, 22, 1676), 
which may also be obtained by oxidizing a glacial acetic acid solution of isatin 
and indigo with chromic acid (hence called isatoic acid, Berichte, 17, Ref. 488). 
It crystallizes from hot water or alcohol in colorless .needles or plates. It dissolves 
with much difficulty in most solvents, It melts about 233-240°, decomposing at 
the same time into carbon dioxide and anthranil. Digested with alkalies or boiled 
with acids, it decomposes into carbon dioxide and anthranilic acid. See Berichie, 
19, Ref. 66 upon f-methylisatoic acid, 

Acetyl-anthranilic Acid, C,H Re CH, results when acetyl-o-tolui- 
dine is oxidized, when o-amidobenzoic acid and anthranil (see above) are acted 
upon with acetic anhydride, and in the oxidation of methyl ketol and quinaldine 
(see these). It forms flat needles, melts at 180° and is readily decomposed into 
acetic and anthranilic acids. Benzoyl-anthranilic Acid melts at 182°. 

o-Benzam-oxalic Acid, C,H xa ne CO,H? Oxalyl-amido-benzoic acid, 
carbostyrilic acid, kynuric acid, is prepared synthetically by heating anthranilic 
acid with oxalic acid to 130° (Berichte, 17, 401 and Ref. 110); it is als - 
tained from indoxylic acid, from carbostyril, aceto-tetra- hydroquinoline, kya 
and kynurenic acid (see these). It crystallizes from hot water in long needles 
containing one molecule of water (C,H,NO;.H,O), and melts with decomposition 
at 200°. In a dessicator, more rapidly at 70-80°, it loses water and evolves car- 
bon dioxide at 100°. When digested with alkalies it is decomposed into anthra- 
nilic and oxalic acids. Its ethyl ester, from the ester of indoxanthinic acid 
(Berichte, 15, 778), melts at 180°. 

Similar compounds, ¢, g., benzamoxalic acid, are prepared, too, from meta- 
amidobenzoic acid, by means of oxalic and malonic acids (Berichte, 18, 214; 
see also Berichte, 19, Ref. 252). 

Meta-amidobenzoic Acid (1, 3), from m- -nitrobenzoic acid, consists of aggre- 
gations of needles, dissolves readily in hot water and melts at 173-174°. It reacts 
acid, forming salts with acids and bases. The ethyl ester, obtained by reducing 
m-nitrobenzoic ester, is a thick oil. When in aqueous solution nitrous acid con- 
verts it into ordinary oxy-benzoic acid. Cyanogen chloride acts on it to form 


750 ORGANIC CHEMISTRY. 


m-cyanamido-benzoic acid, C,H CTH or This yields uramido-benzoic acid, 


CHK NiHtCO.NH, with hydrochloric acid (p. 392). The latter is also pro- 
duced by fusing together meta-amido-benzoic acid and urea, or by mixing the 
hydrochloric acid salt with potassium cyanate. It contains one molecule of water, 
and forms small needles. When heated it becomes urea-dibenzoic acid, CO(NH. 
C,H,.CO,H), (Berichte, 15, 2122). 

Para-amidobenzoic Acid, from para-nitrobenzoic acid, or from para-toluidine, 
crystallizes in needles, is rather easily soluble in water, and melts at 186-187°. 
Nitrous acid converts it into para-oxybenzoic acid. 

The amido-benzoic acids, just like the anilines (p. 653), are changed, through 


the diazo-compounds, into Hydrazine-benzoic Acids, C,H NHN, Of 
these the ortho-body (from anthranilic acid), is the one which, when exposed to a 


temperature of 230°, forms the zzmer anhydride, C,H NH NH> (Berichee, 14, 
478). . : 
Dinitro-para-amidobenzoic Acid, CoH4(NOq)2< Co, 44> Chrysanisic 
2 
Acid, results when dinitro-anisic and dinitro-ethyl para-oxybenzoic acids are 
digested with aqueous ammonia. The group O.CH, is supplanted by NH, 
(P- 593) — 2 


0.CH NH 
CoH, (NO,),€ C0, 4. NH. oe CoHA(NO.).€ Co, i + CH,.OH. 
Dinitroanisic Acid, ! Chrysanisic Acid. 


Chrysanisic acid forms light, golden-yellow leaflets or needles, melts at 259° 
and sublimes. 

Diamidobenzoic Acids, C,H,(NH,),.CO,H. Four of the six possible 
isomerides are known. The elimination of CO, by one of them gives rise to para- 
phenylene diamine, two others yield ortho-, andthe third meta-phenylene diamine. 
These acids conduct themselves towards the diazo-benzene-sulphonic acids, just 
the same as the corresponding phenylene- diamines (Berichée, 15, 2197). 

Triamido-benzoic Acid, C,H,(NH,),.CO,H (1, 3, 4, 5—CO, in 1), has 
been obtained from dinitro-para-amidobenzoic acid. It yields (1, 2, 3)-triamido- 
benzene upon distillation (p. 625). For the isomeric acid (1, 3, 5, 6) see Berichte, 
15, 2200. 





sc) AZO-BENZOIC ACIDS. 


€ action of sodium amalgam upon the mononitro-benzoic acids produces 
(same as from the nitrobenzenes) azoxy-, azo- and hydrazo-benzoic acids 


(p. 640) :— 


CO,H CO,H cO,H 
C,H, nN. | CH. {Ny 2 C,H, { it 
| SO : 
NZ N NH 
CoH CO,H CeHid Con CoH. 1 Co,H 
Azoxy-benzoic Acids. . Azo-benzoic Acids. Hydrazo-benzoic Acids. 


m-Azobenzoic Acid, C,,H,)N,O, + %H,O, azo-benzene-m-dicarboxylic acid, 
is precipitated by hydrochloric acid as a yellow, amorphous powder, and dissolves 
with difficulty in water, alcohol and ether. When distilled it sustains decomposi- 
tion. It is a dibasic acid, and yields crystalline yellow salts and ethers, Azoben- 


0 EE 


AZO-BENZOIC ACIDS. 751 


zene is formed by the distillation of the copper salt; the calcium salt yields azo- 
diphenylene, C,,H,N,. Para-azo-benzoic acid is a red, amorphous powder. 

An azobenzene-mono-carboxylic acid, CgH;.N,.C,H,.CO,H, has been obtained 
from amido-azobenzene by replacing its amido-group by cyanogen, etc. (Lerichie, 
1g, 3022). 

i EE Acid, C,,H,)N.O; (1, 3), is formed when the alcoholic solu- 
tion of meta-nitrobenzoic acid is boiled with potassium hydroxide. Hydrochloric 
acid precipitates it in yellowish masses. : 

m-Hydrazo-benzoic Acid, C,,H,,N,O, (1, 3), is obtained when ferrous sul- 
phate is added to the boiling sodium hydroxide solution of m-azobenzoic acid. 
Hydrochloric acid precipitates the acid in yellow flakes from the filtered solution. 
It is not very soluble in hot alcohol. The aqueous solution of its salts absorbs 
oxygen, and changes to azobenzoic acid. When boiled with hydrochloric acid it 
is converted into the isomeric diamido-diphenyl-dicarboxylic acid (diamidodiphenic 
acid), derived from diphenyl :— 


C.H / CO,H / CO,H 
& 4NNE\, ields PN\NH 
+ SNCOOL 6.9 CO 


this resembles the formation of benzidine from hydrazo-benzene (p. 650). The 
latter acid is converted, by distillation with baryta, into benzidine and carbon 
dioxide. Two additional isomeric acids are produced by reducing m-azo- and 
azoxybenzoic acids with stannous chloride (Berichte, 23, 913). 





Diazo-compounds. The aromatic amido-acids, analogous to the anilines, form 
diazo- and diazo-amido-compounds (p. 629) :— 


\N=N.NO, o*'4\ N = N—NH.C,H,.CO,H. 
Diazo-benzoic Acid Nitrate. Diazo-amidobenzoic Acid. 


The diazo-compounds are produced by the action of nitrous acid upon salts of the 
amido-acids in aqueous or alcoholic solution, and sustain transpositions perfectly 
similar to those of other diazo-compounds. The addition of nitrous acid to the 
alcoholic solution of the free amido-acids causes the separation of the diazo-amido 
acids, which dissolve with difficulty. These are produced, too, on mixing solu- 
tions of the nitrates of the diazo-acids with amido-acids, When boiled with id 
acids they decompose into substituted acids and amido-acids, which continu : 


solved as salts :— 
/ CO,H ee 
CoH N..NH.C,H,.CO,H + 2HBr = 
CO,H NH 
KBr asl CHA Co, fr HBr + N,. ¢ 
The sulphates of the diazobenzoic acids, when boiled with hydrochloric, hydro- 
bromic and hydrofluoric acids, are similarly converted into their corresponding 
halogen benzoic acids. Hydriodic acid reacts at the ordinary temperatures 
(Berichte, 18, 960). 
m-Diazobenzoic Acid Nitrate, C,H;N,O,.NO,, from (1, 3)-amidobenzoic acid, 
is soluble with difficulty in cold water, and separates in colorless prisms which 
explode with violence. Caustic potash precipitates a yellow and very unstable mass 
from the aqueous solution. This is probably the free acid. Boiling water changes 


C,H 


” 


752 | ORGANIC CHEMISTRY. 


it to m-oxybenzoic acid. Bromine precipitates the serbromide, C,H;N,0,Br,, 
as an oil, from the aqueous solutions; it solidifies in yellow prisms. It yields 
metabrombenzoic acid when digested with alcohol. Aqueous ammonia converts 
the perbromide into the diazoimide, C,H;N,O,N (p. 640), which crystallizes 
from alcohol and ether in white leaflets. It is an acid, and forms salts with 
bases. | 

Diazo-m-amidobenzoic Acid, C,,H,,N,QO,4, is precipitated as an orange-red 
crystalline powder when nitrous acid is led into the alcoholic solution of meta- ° 
amidobenzoic acid. It is almost insoluble in water, alcohol and ether. It is a 
feeble, dibasic acid; its salts are very unstable in aqueous solution. When 
heated with the haloid acids it yields the corresponding halogen benzoic acids 
(see above). : 

Ortho- and para-amido-benzoic acids yield corresponding diazo- and diazo- 
amido.compounds. 





‘Cyanbenzoic Acids, CHS ae 


These are formed on boiling the HCl-diazo-benzoic acids with potassium cyanide 
and copper sulphate in aqueous solution (p. 633) (Berichte, 18, 1496). 0-Cyan- 


benzoic Acid rearranges itself in its formation to phthalimide, han N H 
(Berichte, 19, 2283). . : 
m-Cyanbenzoic Acid is readily soluble in ether, alcohol and hot water. It isa 
white microcrystalline powder, melting at 217°, and subliming with partial decom. 
position. It forms isophthalic acid on boiling with the alkalies (Bexichte, 20, 524). 
p-Cyanbenzoic Acid consists of microscopic needles, melting at 214°. It yields 
dicyanbenzophenone by the distillation of its calcium salt (Berichte, 20, 521). 

Sulpho-benzoic Acids, CHE Con 

On heating benzoic acid for some time with fuming sulphuric acid, or by con- 
ducting the vapors of SO, into the acid, we obtain as chief product Metasulpho- 
benzoic Acid, and in smaller amount Parasulphobenzoic Acid. 

The three isomerides can be obtained by oxidizing the three toluene sulphonic 
acids with an alkaline solution of potassium permanganate (p. 665). The sz/- 
phamides or sulphamin-benzoic acids, C, HY ne ae , are similarly obtained from 
the toluene sulphamines, C,H ,(CH,).SO,.NH, (by potassium permanganate or 
i. ferricyanide Berichte, 21, 242). The ortho-derivative eliminates water 
a 


asses readily into its inner anhydride—denzoic-sulphinide, C,H ne >NH 
(Berichte, 20, 1596; 22, 754, Ref. 662, 822). ogi, 
o-Sulphobenzoic Acid dissolves readily in water, crystallizes in large tablets and 


melts at 250°. Its amide-anhydride—denzoic-sulphinide, CoH 50, >NH (see 
2 


above), dissolves in cold water with difficulty, and crystallizes from hot water or 
alcohol in delicate needles, melting at 224°. It possesses an exceedingly sweet 
taste (I part = 200 parts cane sugar), hence has been called Saccharin. It has 
been employed as a2 substitute for sugar in the case of diabetic patients (Tech. 
Preparation, Berichie, 19, Ref. 375 and 471; 21, Ref. 100). When the sulphi- 
nide is evaporated to dryness with hydrochloric acid it changes to the ammonium 
salt of sulphobenzoic acid. Commercial saccharin contains 43-48 per cent. of 
sulphinide and 50 per cent. of para-sulphamine benzoic acid (Berichée, 22, Ref. 
$22). In aqueous solution the sulphinide has a somewhat acid character being 


ee 


HOMOLOGUES OF BENZOIC ACID. 753 


able to form imide salts, C,H XK won SNMe, which are different from the salts of 
2 


sulphamin-benzoic acid, CH gs prod ‘ 
as 


The alkyl iodides convert the sulphinide salts into ethers (Berichze, 21, Ref. 
100). For the methyl saccharin from /-toluidine sulphonic acid, consult Berichée, 
22, Ref. 719). 





HOMOLOGUES OF BENZOIC ACID. 
Acids, C,H,O,. 


1. Toluic Acids, CHC CofE Methyl-benzoic Acids. 
2 


The three toluic acids are produced when the three xylenes are 
boiled for some time with dilute nitric acid (p. 571), and also by 
the action of sodium and carbon dioxide, or chlorearbonic esters, 
upon brom- and iodo-toluene. The easiest course to pursue con- 
sists in converting the three toluidines into tolunitriles, then saponi- 


fying the latter with the alkalies or sulphuric acid (of 75 per cent.) 
(see Berichte, 19, 756). 


’ Orthotoluic Acid (1, 2) results upon heating phthalide with phosphorus and 
hydriodic acid (Berichte, 20, Ref. 378). It crystallizes from hot water in long 
needles, melting at 102.5°. It is very volatile with steam. The calcium salt, 
(C,H,0O,),Ca + 2H,0, and the daritum salt, (C,H,O,),Ba + 2H,0, are readily 
soluble in water, and crystallize in delicate needles. (hromic acid decomposes 
it, yielding carbon dioxide; potassium permanganate forms phthalic acid. 

Metatoluic Acid (1, 3) is obtained by oxidizing pure xylene with dilute nitric 
acid (p. 573) (pure metaxylene is only oxidized at 130-150°). The most satisfac- 
tory course for its preparation consists in oxidizing m-xylene sulphamide with 
potassium permanganate, and then decomposing the sulphamide that results with 
hydrochloric acid (Berichte, 14, 2349). It is more soluble in water than its two 
isomerides, and crystallizes in minute needles, melting at 110° and boiling at 263°. 
It is easily volatilized with aqueous vapor. Chromic acid oxidizes it with ease to 
isophthalic acid. Its calcium salt, (C,H,O,),Ca + 3H,O, is very soluble in 
water. 

Paratoluic Acid (1, 4) is obtained by boiling paraxylene or cymene for 
several days with dilute nitric acid. It crystallizes from alcohol or hot wat ' 
needles, melting at 180°; it boils at 275° (corrected). It is very volatile with 
steam. Nitric acid or chromic acid oxidizes it to terephthalic acid. 


2. Phenyl-acetic Acid, C,H;.CH,.CO,H, Alphatoluic Acid, 
is obtained: from benzyl cyanide, C,H,;.CH,.CN, when» boiled 
with alkalies; from mandelic acid, CH;.CH(OH).CO,H, by heat- 
ing with hydriodic acid; from vulpic acid by boiling with baryta ; 
and from brombenzene and monochloracetic ester by means of 
sodium. 


To prepare it benzaldehyde is first changed to phenyl-chloracetic acid, C,H,. 
CHCI.CO,H (see mandelic acid) and the latter then reduced by zinc dust, in am- 
moniacal solution (Berichte, 14, 240). A better procedure consists in boiling 


63 


754 : ORGANIC CHEMISTRY. 


benzyl chloride with potassium cyanide, then saponifying the latter with caustic 
potash, or with moderately dilute sulphuric acid (Berichte, 19, 1950), which is 
a simpler method. The ethyl ester can be directly obtained from the cyanide by 
conducting hydrochloric acid gas into its alcoholic solution (Berichte, 20, 592). 


Phenyl-acetic acid crystallizes in shining leaflets, resembling 
those of benzoic acid; it melts at 76.5°, and boils without decom- 
position at 262°. Benzoic acid is formed when it is oxidized with 
chromic acid. The methyl ester, C;H,O,.CHs3, boils at 220°; the 
ethyl ester at 226°. 


The CH,,-group of phenylacetic esters, C,H,.CH,.CO,R, cannot be replaced by 
alkyls (distinction from benzyl cyanide, p. 734) (Berichze, 21, 1306). 

Phosphorus pentachloride converts the acid into phenyl acetic chloride, C,H,. 
CH,.COCI, which boils at 102° under a pressure of 17 mm. It forms desoxyben- 
zoin with benzene and aluminium chloride (Berichte, 20, 1389). Phenylacetic 
anhydride, (C,H,.CH,CO),O, is produced by the action of the chloride upon 
silver phenylacetate. It melts at 72°. 

If the acid be acted upon by chlorine or bromine in the cold the halogens will 
enter the benzene nucleus and in the para-position; if heat be applied the side- 
chain will be substituted. The latter mono-halogen derivatives are also produced 
from mandelic acid, C,H,.CH(OH).CO,H, if it be heated with hydrochloric or 
hydrobromic acid to 130-140°, and when boiled with alkalies regenerate mandelic 
acid. Phenyl-chloracetic Acid, C,H;.CHCI.CO,H, is also directly prepared 
from CNH-benzaldehyde (see Mandelic Acid), crystallizes in leaflets, and melts at 
78°. Phenyl-bromacetic Acid melts at 83-84°, and when potassium cyanide 
acts upon its ester diphenyl-succinic acid is produced. 

Phenyl-isonitroso-acetic Acid, C,H,.C(N.OH).CO,H, is produced from 
phenyl-glyoxylic acid (p. 762) with hydroxylamine and from isonitrosobenzyl 
cyanide, CgH,.C(N.OH).CN; it melts at 128°. The ethyl ester, melting at 113°, 
has been obtained from nitrophenyl-isonitroso- acetic ester (Berichte, 16, 519). 

Phenyl-amido-acetic Acid, C,H;.CH(NH,).CO,H, results from phenyl- 
isonitroso-acetic acid by reduction with tin and hydrochloric acid; from phenyl- 
bromacetic acid with ammonia, and from CNH-benzaldehyde, C,H,.CH(OH). 
CN, by ammonia and saponification. It consists of pearly leaflets, melting at 
256°. It decomposes, when distilled, into carbon dioxide and benzylamine. 





* 


Nitrophenyl-acetic Acids, C,H,(NO,).CH,.CO,H. 

The para-nitro acid, with a small amount of the ortho-nitro acid, is produced on 
dissolving phenyl-acetic acid in cold, fuming nitric acid. These acids can be 
separated by means of their barium salts. The three nitro-acids may be obtained 
synthetically from the three nitrobenzyl cyanides, C,H,(NO,).CH,.CN (p. 735). 

o-Nitrophenyl-acetic Acid crystallizes from hot water in needles, melts at 
141° (137°), and by oxidation yields o-nitrobenzoic acid. m-Nitrophenyl-acetic 
Acid melts at 120°. -Nitrophenyl-acetic Acid dissolves with difficulty in 
water, and melts at 152°. Further nitration of ortho- and para-nitrophenyl-acetic 
acid produces 0f-Dinitrophenyl-acetic Acid (I, 2, 4), melting at 160°, and 
decomposing into carbon dioxide and of-dinitro-toluene. Its methy/ ester melts at 
82°, and the ethyl ester at 35°. These dissolve in alcoholic alkalies, forming deep- 
- red colored salts, ¢. g., C,H,(NO,),.CHNa.CO,R, the metal of which can be 
replaced by other radicals (Berichie, 21, 1307, 2475). Diazobenzene chloride 


HOMOLOGUES OF BENZOIC ACID. 755 


produces an azo- or hydrazone derivative. Its potassium salt, C,H,(NO,),.C(N. 
NNa.C,H;).CO,R, is deep blue in color, and is capable of entering a remarkable 
transposition, leading to the formation of a pyrazole derivative (Berichte, 22, 


320; 23, 1574). 


Adah actecas: A — C,H,(NH,).CH,.CO,H. 


These can be obtained by reducing the nitro-acids. The ortho- 
compound and other ortho-amido-acids can, by the exit of water, 
form amide-anhydrides. This is analogous to the formation of lac- 
tones (p. 351) from oxy-acids. The oxygen may be taken from 
the hydroxyl or from the CO-group of carboxyl ; in the first instance 
so-called /actams (inner amides) are produced, in the latter the 
Zactimes (inner imides) :— 


CoH, ¢ CHLC0.08 victas CoH uid CO + H,0, 


o-Amidophenyl-acetic Acid. A Lactam, Oxindol. 
/CO.CO.OH .. SCO US 
CoH.< NH, yields CoHae N yZoOR + H,0O. 
o-Amidophenyl-glyoxylic Acid. A Lactime, Isatin. 


This anhydride formation sometimes occurs spontaneously in the 
separation of the free acids from their salts (or in the reduction of 
the nitro-compounds). 

As yet, dut one anhydride (lactam or lactime) has been obtained 
from each acid ; the other form cannot necessarily be designated the 
unstable or pseudo form; however, the two forms may probably be 
tautomeric (p. 54). These anhydrides do yield two entirely dif- 
ferent series of alkyl derivatives, depending upon whether the hy- 
drogen of the NH-group in the /actam ethers, or the H of hydroxyl 
in the /actime ethers, is replaced by alkyl, e. g. :— 

C oH. NaH.) ' CO and C oye oe O.CH,. 
Lactam Ether, Methyl Oxindol. Lactime Ether, Methyl Isatin. 

The ethers of the lactams (in which the alkyl is attached to nitro- 
gen) are very stable, whereas the lactimes are decomposed by 
heating with hydrochloric acid. It is possible to prepare b 
varieties of ethers with many of the anhydrides. This would indicate 
that the two anhydride forms are identical (see Carbostyril and 
Berichte, 18, 1528; 20, 2009). 

The acids, with 2 and 3 carbon atoms in the side-chain, condense in this way; 
the former yield indol-, the latter quinoline-derivatives :— 


oH, .CH,.CO.OH .. /CH,.CH 
C,H, «\.NH, yields C A4< NHCO 2S 
o-Amidophenyl-propionic Acid. A Lactam, Hydrocarbostyril. 
. CH:CH 
/CH:CH.CO.OH .. 8 
NH yields CH,C | 
: 3 N: C.OH. 
o-Amidophenyl-acrylic Acid. A Lactime, Carbostyril. 


C,H 


756 ae ORGANIC CHEMISTRY. 


- The indol-bodies contain a chain of 4 C-atoms (2 of which belong to the ben- 
zene nucleus), closed by 1 N-atom (a chain of 5 members)—analogous to the 
pyrrol compounds (p. 538); they may also be compared to the y-lactones and the 
furfurane compounds. In the quinoline derivatives we have a chain of 5 C-atoms, 
the same as in the d-lactones. A ring of 3 C-atoms linked by N has only been 
confirmed in the case of anthranil (p. 749); it is, however, analogously very un- 
stable, as in the B-lactones (p. 353). : 

The ortho-amido-derivatives of the aldehydes and ketones, in which the CO- 
group represents the second or third member of the side-chain, are capable, too, 
of condensing and producing compounds belonging to the indol- and quinoline- 
groups. Thus, from o-amidophenyl-acetaldehyde we get indol (p. 721); from 
o-amidophenyl-acetone, methyl ketol (p. 730); and from o-amidobenzyl-acetone, 
hydromethyl-quinoline (p. 730). Yet, chains (with 6 and more C-atoms and I 
N-atom) having 7 or more members, could not be produced (Berichie, 13, 122; 
14, 481; 20, 377). 


o-Amidophenyl-acetic Acid passes immediately into its 
lactam, oxindol, when it is produced (by reduction of the ortho- 
nitro-acid). When oxindol is heated to 150° with baryta water, 
water is absorbed and the barium amidophenyl-acetate produced. 
Acids liberate oxindol from it (Berichte, 16, 1704). 


Acetyl-o-amido phenyl-acetic Acid, C,H,(NH.CO.CH,).CH,.CO,H, is 
obtained by dissolving acetyl oxindol in dilute sodium hydroxide ; it melts at 142°, 
and when heated with alkalies or acids decomposes into oxindol and acetic acid. 

m-Amidophenyl Acetic Acid, from the nitro-acid, crystallizes from hot 
water in leaflets, and melts at 149°. Z-Amidophenyl-acetic Acid, from the 
nitro-acid, consists of pearly leaflets, and melts at 200°. 

When dinitrophenyl-acetic acid (p. 754) is reduced with tin and hydrochloric 
acid, Diamido-phenyl-acetic Acid results, and this immediately passes into 
p-amido-oxindol, C,H,(NH,)NO. Partial reduction of the dinitro-acid with am- 
monium sulphide yields 4-amido-o-nitro-phenyl-acetic acid, CgsH,(NH,)(NO,). 
CH,.CO,H. ‘This treated with amyl nitrite and alcohol yields o-Nitrophenyl- 
isonitroso-acetic Acid, C,H,(NO,).C(N.OH).CO,H, and o-nitrobenzaldoxime 
(p. 720). Isomeric -Amido-m-nitrophenyl-acetic Acid, from f-amidophenyl 
acetic acid, yields m-nitrobenzaldoxime with the same reagents. An isomeric 
Pseudophenyl-acetic Acid, C,H,O,, seems to have been prepared by the 
action of diazo-acetic ester upon benzene (p. 207). Homologous acids have been 
formed in the same way (Berichte, 18, 2377). 


~ 





Acids, CsA O;. 


1. Dimethylbenzoic Acids, C,H,(CH;),.CO,H. Four of the six 
possible acids with this formula are known. 


Mesitylenic Acid has the symmetrical structure (1, 3, 5), and is obtained by 
gradually oxidizing mesitylene with dilute nitric acid. It crystallizes from alcohol 
in large prisms, from water in needles; it melts at 166° and sublimes very readily. 
The barium salt, (C,H,O,),Ba, is very soluble in water and consists of large, 
shining prisms.. The e¢hy/ ester, CgH,(C,H,;)Og, solidifies at 0° and boils at 
241°. Distilled with excess of lime, mesitylenic acid yields isoxylene. Nitric 
acid oxidizes it further to uvitic and trimesic acids. 


HYDROCINNAMIC ACID. 757 


_ The oxidation of pseudocumene (p. 574) with dilute nitric acid produces 
xylic acid, C,H,(CH,),.CO,H(1, 2, 4—CO,H in 1), and so called para-xylic 
acid (1, 3, 4); both distil with aqueous vapor and can be separated by means of 
their calcium salts. Xylic acid has also been obtained from bromisoxylene by the 
action of sodium and carbon dioxide. From alcohol it crystallizes in long prisms, 
dissolves with difficulty in water, melts at 126° and sublimes readily. Its calcium 
salt, (C,H,O,),Ca + 2H,0, forms thick prisms and is more easily soluble in 
water than the salt of paraxylic acid. Isoxylene results when it is distilled with 
lime. Nitric acid oxidizes it to xylidic acid, C,H,(CH,).(CO,H),; chromic acid 
decomposes it into carbon dioxide. 

Paraxylic acid crystallizes from alcohol in concentrically grouped needles and 
melts at 163°. Its calcium salt contains three and one-half molecules of water and 
consists of needles. Distilled with lime it yields ortho-xylene; both methyl groups, 
therefore, occur in the ortho-place. Oxidation converts it into xylidic acid. ; 


2. Tolyl-acetic Acids, CoH. Ge co. Alpha-xylic Acids. The 
2° 


three isomeric acids have been obtained from the three xylene bromides, C,H, 
(CH,).CH,.Br, by means of the cyanides (Berichte, 15, 1744). The ortho-acid 
melts at 89°; the meta at 61°, and the fara at 91°. The latter acid has also been 
obtained from tolylglyoxylic acid by reduction with hydriodic acid and phospho- 
rus. It melts at 72° (Berichte, 20, 2051). 

3. LEthyl-benzoic Acids, CHK CR The para-acid (1, 4) may be ob- 
tained by oxidizing para-diethyl benzene with nitric acid, and from para-brom- 
ethyl benzene, C,H, Br.C,H,, by the action of sodium and carbon dioxide. It 
crystallizes in leaflets from hot water, melts at 112° and sublimes readily. Oxida- 
tion converts it into terephthalic acid. The ortho-acid is formed by reducing 
acetophenone carbonic acid with hydriodic acid. It melts at 62°. 

(4) The phenylpropionic acids, C,H ,.C,H,.CO,H, are hydrocinnamic acid and 
hydroatropic acid :— 


(2) Hydrocinnamic Acid, C,H;.CH,.CH,.CO,H, #-Phenyl- 
propionic Acid, is obtained: by the action of sodium amalgam 
upon cinnamic acid (phenylacrylic acid), or upon heating the latter 
with hydriodic acid (Berichte, 13, 1680); when potassium cyanide 
acts upon a-chlorethylbenzene, C,H;.CH,.CH,Cl (p. 586); from 
benzyl aceto-acetic ester and benzyl malonic ester, also from ben- 
zylic acetic ester (p. 740); and in the decay of albuminoid sub- 
stances. It is very soluble in hot water and alcohol, crystallizes in 
needles, melts at 47° and distils without decomposition at 280°. 
Chromic acid oxidizes it to benzoic acid. 


Haloid Hydrocinnamic Acids, of the formula C,H,.CHX.CH,.CO,H, are 
obtained from cinnamic acid, C,H,.CH:CH.CO,H, by the addition of the 
haloid acids (p. 223) and by the action of these upon (-phenyl-hydracrylic acid, 
C,H,.CH(OH).CH,.CO,H. On heating or boiling with water the free acids 
decompose (as B-oxyacids are produced at first, p. 346) into the haloid acid and 
cinnamic acid; when neutralizéd with alkaline carbonates they split up, even in 
the cold, into a halogen acid, carbon dioxide and styrolene, C,H,.CH:CH,. 
$-Chlor-hydro-cinnamic acid, C,H,.CHCIL.CH,.CO,H, melts at 126°; the 
brom-acid at 137°, the iodo-acid at 120°. 

a8-Dibromhydrocinnamic Acid, C,H,.CHBr.CHBr.CO,H, Cinnamic 
Bromide, is formed by the addition of bromine to cinnamic acid (dissolved in 


~ ee 
. 


758 ORGANIC CHEMISTRY. 


CS,) (Aunalen, 195, 140). It crystallizes-from alcohol in leaflets, melts at 201°, 
and decomposes. When digested with a soda solution it is decomposed into 
a-bromstyrolene, C,H,.CH:CBrH, carbon dioxide and hydrobromic acid; when 
boiled with water phenyl a-brom-lactic acid is also produced. a$-Dichlorhydro- 
cinnamic Acid deports itself similarly, and melts at 163° (Berichze, 14, 1867). 

a- and 8-Monobrom-cinnamic acids are produced when dibromhydro-cinnamic 
acid is treated with alcoholic potassium hydroxide (see this). 





Phenylamido-propionic Acids. 

Phenyl-a-amido-propionic Acid, C,H,.CH,.CH(NH,).CO,H, Phenylala- 
nine, is produced from phenyl-acetaldehyde with prussic acid and ammonia (Az- 
nalen, 219, 186). It is soluble with difficulty in both cold water and hot alcohol. 
It crystallizes in leaflets or prisms. It does not part with ammonia when boiled with 
caustic potash or concentrated hydrochloric acid. It readily combines to form 
salts with bases and acids. When slowly heated it sublimes without decomposi- 
tion; quickly heated phenyl ethylamine and a lactimide are produced. It also 
occurs in the sprouts (along with asparagine) of Lupinus luteus, and is formed in 
the decay of albumen (Berichze, 16, 1711). 

The nitration of phenyl-alanine yields the jara-nitro-compound, which by 
reduction becomes #-Amidophenyl-alanine, C,H,(NH,).CH,.CH(NH,).CO,H. 
The latter is also obtained in the reduction of dinitro-cinnamic acid, C,H,(NO,). 
CH:C(NO,).CO,H (Berichte, 16, 852), and when acted upon by one equivalent 
of nitrous acid forms tyrosine (Annalen, 219, 170). 

Phenyl-$-amidopropionic Acid, C,H,.CH(NH,).CH,.CO,H, is obtained on 
treating B-bromhydro-cinnamic acid with aqueous ammonia; it is easily soluble 
in water and alcohol, melts at 121°, and when boiled with acids decomposes into 
NH, and cinnamic acid. It does not combine with Bases, and with difficulty with 
acids (Berichte, 17, 1498). 





The Halogen-hydrocinnamic Acids, C,H,.X.CH,.CH,.CO,H, containing 
the substitutions in the benzene nucleus, are obtained from the corresponding halo- 
gen cinnamic acids on heating them with hydriodic acid and phosphorus (Berichie, 
15, 2301; 16, 2040). _ 

Nitrohydrocinnamic Acids, C,H,(NO,).CH,.CH,.CO,H. 

The nitration of hydrocinnamic acid produces the Jara and ortho acids, which 
can be separated by crystallization from water. o-Nitrohydrocinnamic Acid is 
more easily obtained from the dinitrohydrocinnamic acid (see below). It forms 
small yellow crystals, and melts at 113°. 

m-Nitrohydrocinnamic Acid results from /-amido-m-nitrohydrocinnamic 
acid (see below) by the elimination of the amido-group, and melts at 118°. 
p-Nitrohydrocinnamic Acid melts at 163°, and is oxidized to f-nitrobenzoic 
acid by a chromic acid mixture. 





Amido-hydrocinnamic Acids, C,H,(NH,).CH,.CH,.CO,H. 

o-Amido-hydrocinnamic Acid. When this acid is formed by the reduction 
of o-nitrocinnamic acid with tin and hydrochloric acid it at once changes to its 
lactam, Hydrocarbostyril, C,H,NO (p. 755). The latter is intimately related 
to quinoline, C,H.,N, dissolves readily in alcohol and ether, crystallizes in prisms 
melts at 160°, and distils undecomposed. 


HYDRO-ATROPIC ACID. 759 


While the lactime of o-amido-hydrocinnamic acid is unstable, its ethers exist, 
as do those of the lactam (hydrocarbostyril) (p. 755):— 


CH,—+CH, //CHy—CH, 
C,H a / and CoHyC ‘ 
N(C,H;,).CO N = C.(0.C,H,) 
Hydrocarbostyril Ether. Lactime Ether. 


The former is produced from hydrocarbostyril by means of ethyl iodide and 
alcoholic potassium hydroxide; it is very stable; the latter, formed in the reduc- 
tion of o-nitrohydrocinnamic ether, is saponified on heating with hydrochloric acid 
(Berichie, 15, 2103). 

m-Amidohydrocinnamic Acid, prepared by reducing the m-nitro-acid with 
tin and hydrochloric acid, melts at 85°. ~-Amido-hydrocinnamic Acid melts 
at 131°. Energetic nitration of hydrocinnamic acid produces Zo-dinitro-hydro- 
cinnamic acid, C,H,(NO,),.C,H,.CO,H (1, 2, 4), which melts at 126°, Reduc- 
tion with ammonium sulphide affords p-amido-o-nitrocinnamic acid, melting at 
139°. By the elimination of the NH,-group we get o-nitrohydrocinnamic acid. 
The reduction of the dinitro-acid with tin and hydrochloric acid brings about con- 
densation of the diamido-acid at once to -amido-hydrocarbostyril, C,H,(NH,). 
NO (p. 756), melting at 211° (Berichte, 15, 842, 2291). 

The p-Amido-m-nitrohydrocinnamic Acid, C,H,(NH,)(NO,).C,H,.CO, 
H, is formed in the nitration of aceto-g-amidohydrocinnamic acid, melts at 
145°, and by the elimination of the amido-group yields m-nitrohydrocinnamic 
acid. 


(4) Hydro-atropic Acid, CH CB Gas a-Phenyl-pro- 
2 


pionic Acid, is obtained from atropic acid, C,;H,O, = C,H,. 
C(CH,).CO,H, by the action of sodium amalgam, and from aceto- 
phenone, C,H;.CO.CH;, when acted upon with hydrocyanic and 
hydriodic acids (Annalen, 250, 135). It is an oil, boiling at 265°, 
and is volatile in aqueous vapor. Potassium permanganate oxidizes 
it to atrolactinic acid (p. 775) by changing tertiary hydrogen to 
hydroxyl. 


Bromhydro-atropic Acids :— 


CH, 


< coin (8) C,H,.cH¢ CBr 


a) C,H,.CBr : 
(a) CoH, \.CO,H 
Both isomerides result from the addition of HBr to atropic acid, C,H,O,. The 
a-acid, obtained from atrolactinic acid, C)H,,O,, by means of hydrobromic acid, 
melts at 93°, and reverts to atrolactinic acid on boiling with a soda solution. The 
$-acid also melts at 93°, and when boiled with alkaline carbonates yields tropic 
acid, C,H, ,O,, together with atropic acid and styrolene. The chlorhydro-atropic 
acids deport themselves similarly (Anmmalen, 209, 21). 

p- and o- Nitrohydro-atropic Actds are obtained by nitrating hydro-atropic acid 
in the cold. The fara acid melts at 88°, and by reduction yields J-amido-hydro- 
atropic acid, which by diazotizing passes into the f-oxy-acid (phloretinic acid). 
The ortho-nitro-acid yields an amido acid which immediately, by loss of water, 


i i : CH(CH,)\, ‘ 
passes into its lactam, atroxindol, C,H A 8 SCO (p. 7 Berichte, 
18, Ref. 230). : iter AS. ts Sd (p- 755) ( 


760 ORGANIC CHEMISTRY. 


Acids, C\)H,,0,. 

(1) Durylic Acid, C,H,(CH,),.CO.H, obtained by the oxidation of durene, 
crystallizes in hard prisms, and melts at 115°. The two hydrogen atoms in it 
occupy the para position; therefore, when diamido-durylic acid is oxidized its 
quinone, trimethylquinone carboxylic acid, is produced (Berichte, 18, 3496). 

(2) The oxidation of isodurene affords three Isodurylic Acids, the a- melting 
at 215°, the B- at 151°, and y- at 84°. When these split off carbon dioxide the 
corresponding trimethyl benzenes result; from the a we get hemi-mellithene, from 
the 8, mesitylene and from the y, pseudocumene (Berichte, 15, 1855). 


(3) Propyl Benzoic Acids: six isomerides. 


Cumic Acid, CHC EE W: Z-isopropyl benzoic acid (contain- 
ing the isopropyl group), is produced by the oxidation of cuminic 
alcohol and aldehyde with dilute nitric acid, or by the action of 
potassium hydroxide (p. 709). It has been synthetically prepared 
from f-bromcumene, C,H,Br.C;H, (with isopropyl, p. 575), by the 
action of sodium and carbon dioxide (Berichte, 15, 1903). It is 
furthermore produced by the oxidation of cymene (p. 577) in the 
animal organism ; a transposition of normal propyl occurs in this 
case. 


It is obtained from cuminol (Roman caraway oil) by fusion with caustic potash, 
or what is better, by the oxidation with an alkaline potassium permanganate solu- 
tion (Berichte, 11, 1790). { ; 


Cumic acid is very soluble in water and alcohol, crystallizes in 
needles or leaflets, melts at 116°, and. boils about 290°. It yields 
cumene (isopropyl benzene) when distilled with lime. Chromic 
acid oxidizes it to terephthalic acid and potassium permanganate 
converts it into oxypropyl-benzoic acid, C,H,(C,;H,.OH).CO,H, 
and acetobenzoic acid (p. 760). 


Normal Cumic Acid, C,H,(C,H,).CO,H, f-normal propylbenzoic acid 
(with normal propyl), is obtained by oxidizing propylisopropyl benzene and dinor- 
mal propyl benzene with dilute nitric acid (Berichte, 16, 417); also synthetically 
from f-brompropyl benzene, C,H,Br.C,H, (with normal propyl), by the action 
of CO, and Na. It is volatile with aqueous vapor, crystallizes in shining needles 
or leaflets, and melts at 140°. o0-Mormal Propyl-benzoic Acid (1, 2), is produced 
when phthalyl propionic acid is reduced with hydriodic acid. It melts at 58°. 

(4) Tetramethylbenzene Carboxylic Acid, C,H(CH,),.CO,H, Durene 
Carboxylic Acid, results upon treating durene with phosgene in the presence of 
aluminium chloride. It melts at 179°, volatilizes with steam, and if heated to 
200°, together with concentrated hydrochloric acid, breaks down into carbon 
dioxide and durene. Its cyanide is formed upon distilling the acid with lead sul- 
phocyanide. It melts at 77° (Berichte, 22, 1223). 

Pentamethyl Benzoic Acid, C,(CH,),.CO,H, is formed from pentamethyl- 
benzene by the action of phosgene and AICl,. It melts at 210°. If heated with 
lime or hydrochloric acid it breaks down into pentamethyl benzene and carbon 
dioxide. Its cyanide, C,(CH,),.CN, is produced in the same manner as that of 
the preceding acid. It cannot be saponified by acid or alkalies, but decomposes 
into 4mmonia, carbon dioxide and pentamethyl benzene (Berichée, 22, 1221). 


KETONIC ACIDS. 761 


Aldehyde Acids. 

Phenyl Formyl Acetic Acid, C,H,.CH(CHO).CO,H, belongs to this class. 
Its esters are obtained similarly to the ketonic esters (see below) by the action of 
sodium ethylate upon pheny] acetic esters, C,H,;.CH,.CO,R, and formic esters, 
CHO.OR. It is an oily liquid, boiling at 144-145° under a pressure of 16 mm. 
Ferric chloride imparts a blue-violet coloration to its alcoholic solution. The free 
acid is very unstable. The ester, acting as a $-keton-compound, condenses with 
phenylhydrazine to diphenylpyrazolon (Berichie, 20, 2933). 





KETONIC ACIDS. 


The acids of this class in the benzene series are perfectly analo- 
gous to those of the paraffin series. A rather remarkable method 
for their formation is that of the union of benzoic esters with fatty 
acid esters, alcohol being eliminated, and also the union of aceto- 
phenone, C,H;.CO.CH;, with carbonic acid esters and esters of 
oxalic acid. The reaction is similar to that occurring in the forma- 
tion of ketones (p. 726). It follows by the action of dry or alco- 
holic sodium ethylate upon a mixture of the two components 
(Claisen, Berichte, 20, 655, 2178), or by the action of metallic 
sodium (Wislicenus and Piutti, Berichte, 20, 589, 537, 2930) :— 

C,H,-CO.OR + CH,.CO,R = C,H,.CO.CH,.CO,R + ROH, 


Acetic Acid Ester of Benzoyl 
Ester. Acetic Acid. 


C,H,.CO.CH, + RO.CO,R = C,H,.CO.CH,.CO,R + ROH, 
—— Acid 
ster. 


C,H,.CO.CH, ++ RO.CO.CO,R = C,H,.CO.CH,.CO.CO,R + ROH. 


Benzoyl Pyroracemic 
Acid. 


Phenyloxalacetic ester (Berichte, 20, 592) is similarly obtained from phenyl- 
acetic ester and oxalic ester :— 


C,H,.CH, + RO.CO.CO,R = C,H,.CH.CO.CO,R + ROH. 
| | 
co,R cO,R 


Phenyl pyroracemic acid, C,H,.CH,.CO.CO,H, is again obtained from this 
by the ketone decomposition (upon boiling with dilute sulphuric acid). 

Nascent hydrogen converts all the ketonic acids into oxyacids. 

I. a-Ketonic Acids. ; 

These like those of the fatty series are produced (1) by the action of hydrochloric 
acid upon the cyanides of the acid radicals ; (2) by the action of chloroxalic esters 
upon the benzenes in the presence of AICI, (Berichte, 20, 2048) :— 


C,H, + Cl.CO.CO,.C,H,, = C,H,.CO.CO,.C,H,, + HCl; 
(3) by the oxidation of acetyl benzenes (containing a methyl group in addition to 


the acetyl group) with potassium permanganate or potassium ferricyanide (Be- 
richte, 20, 2213; 23, Ref. 641) :— 


ACH : /CH 
CoH co.cH, yields CoHs< Co.Lo,H. 


~ 


64 





762 ORGANIC CHEMISTRY. 


1. Benzoyl Formic Acid, C,H,.CO.CO,H, Phenylglyoxylic Acid, is obtained 
_ in the action of fuming hydrochloric acid at ordinary temperatures upon benzoyl 

cyanide, C,H,;.CO.CN, and by oxidizing acetophenone with potassium ferri- 
cyanide (Berichte, 20, 389), as well as by oxidizing benzoyl carbinol, styrolene 
alcohol (p. 712) and mandelic acid with dilute nitric acid or permanganate. Its 
ethyl ester is formed when ethyl chloroxalic ester acts upon mercury diphenyl, or 
benzene in the presence of AlCl,. The acid is separated from its salts in the form 
of an oil, which slowly solidifies on standing over sulphuric acid. It is very 
soluble in water, melts at 65-66°, and when distilled decomposes into CO and 
benzoic acid, to a less degree into CO, and benzaldehyde. When mixed with 
benzene containing thiophene and sulphuric acid, it is colored deep red, after- 
ward blue-violet;all its derivatives, and also, isatin, react similarly. Its ethy/ 
ester boils at 25 2°, 

Being a ketonic acid it (its esters) unites with sodium bisulphite. It combines 
with CNH, forming oxycyanides, C,H,.C(OH)(CN).CO,H, from which phenyl 
tartronic acid is derived. Sodium amalgam converts it into mandelic acid, and 
hydriodic acid and phosphorus at 160° into alphatoluic acid. Hydroxylamine 
converts it into phenylisonitroso-acetic acid (p. 754). Phenylhydrazine forms a 
hydrazone with it (Aerichze, 23, 1575). 

o-Nitrobenzoylformic Acid, C,H,(NO,).CO.CO,H, is formed from o0-nitro- 
benzoyl cyanide, by means of potassium cyanide, etc. It crystallizes with one 
molecule of water, and melts at 47°. It forms two isomeric hydrazones (Berichze, 
23, 2080). When anhydrous it melts with decomposition at 122°. Ferrous 
sulphate and sodium hydroxide reduce it to— 


o-Amido-pherylglyoxylic Acid, C,H,(NH,).CO.CO,H, 
Isatinic Acid. It is a white powder, obtained from its lead salt by 
hydrogen sulphide. Digestion of its solution converts it at once 
into its lactime—isatin, CsH;NO, (p. 755). 


foo: CO 
The lactam of isatinic acid, C, ed Aw ee (p. 755), is unstable; the aceto- 


derivative, aceto-pseudo-isatin (see this), oe isstable. It dissolves in alkalies, 
forming salts of Aceto-isatinic Acid, CH NHCOCH,’ from which the 
latter may be separated by dilute acids. The acid dissolves with difficulty in cold 
water, crystallizes from alcohol in needles, and melts at 160°. Boiling hydro- 
chloric acid decomposes it with separation of isatin. When in an acetic acid 
solution it is reduced to aceto-o-amido mandelic acid by sodium amalgam (p. 474). 

p-Dimethylamido-phenylglyoxylic Acid, (CH,),.N.C,H,.CO.CO,H, is 
produced from dimethyl aniline and chloroxalic ester (p. 601). It melts at 187°. 

2. ~-Toluyl-formic Acid, C,H,O, = C,H,(CH,;).CO.CO,H, Tolylgly- 
oxylic Acid, is obtained from toluene, chloroxalic ester and AICI, (BerichZe, 20, 
2048), as well as by oxidizing Z-methyl-tolyl ketone with potassium ferricyanide 
(Berichte, 20, 1763). It does not volatilize with steam. It crystallizes from an 
ethereal solution and melts about 96°. Its phenylhydrazine derivative melts at 
144°. Potassium permanganate oxidizes it to Z-toluic and terephthalic acids. It 
yields f-tolyl-oxyacetic and / tolyl-acetic acids upon reduction (p. 757). 

3. Phenylpyroracemic Acid, C,H,O, = C,H,;.CH,.CO.CO,H, results 
from the union of phenyl-acetic estér and oxalic ester by the elimination of carbon 
dioxide from the phenyl-oxalacetic acid produced at first. It is identical with 
phenylglycidic acid, from benzoylimido-cinnamic acid (Berichte, 17, 1616) and 
phenyl-6-bromlactic acid. It dissolves with much difficulty in water, crystallizes 


BENZOYL ACETIC ACID. 763 


in brilliant leaflets, and melts at 154°. Ferric chloride imparts an intense green 
color to its solution. Its Aheny/hydrazone melts at 161°. Being an a-diketone, it 
yields a quinoxaline with o-toluylene diamine (BerichZe, 20, 2465). 

4. Xylyl Glyoxylic Acids, C,,H,,O, = C,H,(CH;),.CO.CO,H, result upon 
oxidizing xylylmethyl ketones (Berichie, 19, 230; 20, 1766). 


8-Ketonic Acids. 

In addition to the general reactions given upon p. 761, this class 
of acids may also be prepared by the action of the benzaldehydes 
upon diazoacetic esters (p. 374) (Berichte, 18, 2371) :— 


C,H,.COH + CHN,.CO,R = C,H,.CO.CH,.CO,R + N,. 


_The f-ketonic-acids form pyrazole compounds with phenylhydra- 
zine (p. 339): eee . 
1. Benzoyl Acetic Acid, C,H;.CO.CH,.CO,H. Its ethyl ester 
was first prepared by dissolving phenyl-propiolic ester in sulphuric 
acid and then diluting with water (p. 726) (Berichte, 16, 2128) :— 


C,H;.C:C.CO,R + H,O = C,H,.CO.CH,.CO,R. 


It is also formed when benzaldehyde is heated with diazo-acetic 
ester, and by the action of sulphuric acid and water upon a-brom- 
cinnamic ester (Berichte, 19, 1392). It is most conveniently made 
by the action of dry sodium ethylate or sodium upon ethyl benzoate 
and acetic ester (Berichte, 20, 653, 2179). 

Small quantities of the ester are produced when esters of carbonic 
acid act upon acetophenone. Benzoylacetic ester is an oil with an 
odor resembling that of aceto-acetic ester. It boils at 265-270° 
with slight decomposition. The /vee acid is obtained by saponifying 
the ester at the ordinary temperature with potassium hydroxide. It 
dissolves with difficulty in water, very readily in alcohol and ether, 
and crystallizes in needles. ‘When rapidly heated, these melt at 
103-104°, decomposing into carbon dioxide and acetophenone. 
Boiling acids produce the same decomposition. Ferric chloride 
imparts a deep violet color to its aqueous solution. 


Benzoyl-acetic ester unites with aniline, forming $-phenylamido-phenylacrylic 
ester, which yields a-phenyl-y-oxyquinoline by condensation (Berichée, 21, 521). 

Diazobenzene chloride converts benzoyl acetic ester into the phenylhydrazone 
of benzoyl-glyoxylic ester, C,H;.CO.C(N,H.C,H;).CO,.C,H; (p. 652) (Berichie, 
21, 2120). 

The CH,-group of benzoyl-acetic ester can be replaced by alkyls and radicals. 

Methylbenzoyl-acetic Ester, C,H;.CO.CH(CH,).CO,R, when treated with 
nitrous acid eliminates the CO, group (p. 338) and forms a-isonitrosopropiophenone, 
C,H;.CO.C(N.OH).CH, (Berichte, 21, 2119). 

Allyl-benzoyl-acetic Acid, C,H;.CO.CH(C,H;).CO,H, is isomeric with 
benzoyl-tetramethylene carboxylic acid (p. 520) and melts at 122-125°. 

p-Nitrobenzoyl-acetic Acid, C,H,(NO,).CO.CH,.CO,H, melts at 135°, 
and is produced in a manner analogous to that of benzoyl acetic acid, 2. ¢., by 
heating g-nitrophenyl propiolic ester, C,H,(NO,).C:C.CO,R, to 35° with sul- 


A 


eo ae 
Re ht f = 


i 


764 ORGANIC CHEMISTRY. 


phuric acid, while o-nitrophenyl propiolic ester is transposed into the isomeric isa- 
togenic ester (Berichte, 17, 326). For additional derivatives see Berichte, 18, 951. 

2. Phenylaceto-acetic Acid, Ci Cg? The ethyl ester of the 
dinitro-acid, C,H,(NO,),.CH(CO.CH,).CO,R, is ‘obtained from sodium aceto- 
acetic ester and of-dinitrobrombenzene. It forms yellow prisms, melting at 94° 
(Berichte, 21, 2470). The ester of the ¢vinitro acid is obtained in a similar 
manner from picryl chloride. It melts at 98° (Berichte, 23,2720). See Berichte, 
22, 990, for the action of tribromdinitrobenzene. 

3. Benzylaceto-acetic Acid, C,H,.CH,.CH¢ Goi; % Its ethyl ester is 
derived from aceto-acetic ester and benzyl chloride (p. 3 37). It boils at 276° and 
by the ketone decomposition yields benzyl acetone (p. 730); by the acid decompo- 
sition it forms phenylpropionic acid (p. 759). 

Of the class of y-ketonic acids may be mentioned :— 

1. Benzoylpropionic Acid, C,H,.CO.CH,.CH,.CO,H, which is obtained from 
benzene and succinic anhydride by means of AICI, :— 


C,H, + C,H,(CO),0 = C,H,.CO.C,H,.CO,H. 


It is also formed by reducing benzoyl acrylic acid with HgNa ; by the elimination of 
carbon dioxide from benzoylisosuccinic acid (p. 765), and from phenacyl.benzoyl- 
acetic ester by the ketone decomposition. It dissolves with difficulty in hot water, 
crystallizes in needles, and melts at 116°. Sodium amalgam reduces it to phenyl- 
y-oxybutyric acid, which, upon the loss of water, becomes phenyl butyrolactone 
(Berichte, 15, 1890) :-— 


C,H,;.CH(OH).C,H,.CO,H yields CoH,.CH.C,Hy. 
| CO + H,0. 
Riser F 


Phosphorus pentasulphide converts the acid into phenyloxythiophene (Ze- 
richte, 19, 553). 
The benzenes condense with other dibasic acid anhydrides; ¢. g., maleic and 
phthalic anhydrides (see benzoyl acrylic acid). 
/ CH,.CO.CH; 


2. Phenyl-levulinic Acid, C,,H,,O, = CeH;.CHX co at 
from phenylacetosuccinic ester. Sodium amalgam converts it into a lactonic acid 
(Berichte, 18, 790). 

‘ ‘ CO.CH 

3. Acetobenzoic Acids, C,H,O, = CHK CoH 


acids,» The ortho form is produced upon heating benzoylaceto-carboxylic acid 
(from phthalyl acetic acid, p. 765) to 100°, or by boiling it with alkalies. It con- 
sists of flat needles, melting at 115°. Hydriodic acid reduces it to o-ethylbenzoic 
acid (p. 754). It unites with hydroxylamine and phenylhydrazine to form pecu- 
liar compounds. Two molecules of water are eliminated (Berichte, 19, 1996). 
Trichlor- and Tribrom-acetophenone-Carboxylic Acid, C,H,(CO.CX,) CO,H, are 
produced by the decomposition of the indene derivatives (Berichte, 21, 2396). 
The fara-acid is prepared by oxidizing oxyisopropylbenzoic acid with a chromic 
acid mixture. It melts at 200°. 


,is derived 


8, acetophenone carboxylic 


4. Propionyl Benzoic Acids, Col coat Propiophenone Carboxylic 
4 2 


Acids. The ortho-form is produced when phthalyl propionic acid is boiled with 
alkalies. It melts at 58°. Hydriodic acid reduces it to o-propylbenzoic acid. 


0 


DIBASIC KETONIC ACIDS. 765 


Diketonic Acids, na 

Benzoyl Glyoxylic Acid, C,H,.CO.CO.CO,H. Its a-hydrazone is derived 
from benzoylacetic ester and diazobenzene chloride (p. 763). 

Benzoyl Pyroracemic Acid, C,H,.CO.CH,.CO.CO,H + H,O, is produced 
from acetophenone and oxalic ester (p. 761). Tt melts ‘at 43°. Ferric chloride 
imparts a blood-red color to it. The free acid melts about 157° with evolution of 
carbon dioxide, and is colored a deep blue by ferric chloride. Phenylhydrazine 
converts the ester into a pyrazole derivative (Berichte, 21, 1131). 

When benzoyl chloride acts upon acetoacetic ester and benzoyl acetic ester it 
produces denzoyl acetoacetic ester, C,H 5-CO.CH.(CO.CH,).CO,R and dibenzoyl- 
acetic ester, (C,H;.CO),.CH.CO,R. - The former decomposes into acetophenone 
and benzoyl acetone (p. 731), while the latter yields acetophenone, benzoic acid 
and dibenzoyl methane, (C,H,;.CO),CH,, melting at 81° and boiling beyond 200°. 

Bromacetophenone (p. 728) a and acetoacetic ester yield Acetophenone (Phenacyl)- 
acetoacetic Ester, C,H COC CH i, CH. CO,R. 


This decomposes. into acetophenone acetone, but by condensation (as a y-dike- 
tone) forms methyl phenyl-furfurane carboxylic acid (p. 527). In the same manner 


benzoyl acetic ester yields Ahenacyl-benzoylacetic ester, C,H, CO. Rosy CH. CO,R, 
which by decomposition forms benzoyl-propionic acid ( (p. 764) and diphenacyl, 
(C,H,.CO.CH,), (p. 731), and by condensation yields diphenyl-furfurane car- 
boxylic acid (p. 524) (Berichte, 21, 3053). 

Quinisatinic Acid, C,H AS apt a o-amido-phenyl mesoxalylic acid. 
It is obtained by oxidizing dioxycarbostyril with ferric chloride. From water it 
crystallizes in yellow prisms. Heated to 120° it becomes a lactime—dquinisatin, 
CH, as 2c OH This is analogous to the formation of isatin from isatinic 


acid (Berichee, 17, 985). 
Diphenacylaceto-acetic Acid, (C,H;.CO.CH,),C.(CO.CH;). CO, H (Be- 
richte, 22, 3225), is a triketonic acid. 





Dibasic Ketonic Acids. 

Benzoyl chloride converts malonic esters into— 

Benzoyl Malonic Ester, C,H,.CO.CH(CO,R), (Berichte, 20, Ref. 381). 
Its 0-zztro-compound (obtained with o- -nitrobenzoyl chloride) yields quinoline de- 
rivatives when reduced (Berichte, 22, 386). 

Benzoyl-isosuccinic Ester, C,H,;.CO.CH,.CH(CO,R), (Berichte, 19, 95), 
is obtained from bromacetophenone and malonic ester. The free acid melts at 
180°, decomposing at the same time into carbon dioxide and benzoyl propionic 


acid (p. 764). 

o-Carbophenyl glyoxylic Acid, C H.C Co, os at is formed by oxidizing 
hydrindene carboxylic acid and also a- -naphthol with potassium permanganate 
(Berichte, 21, 1609). Itis very readily soluble in water, melts at 140°, and de- 
composes into carbon dioxide and phthalic anhydride. Sodium amalgam reduces 
it to an oxy-acid, which immediately changes to its lactonic acid—phthalide car- 
boxylic acid (p. 772): -- 


/CO,H 
H(OH).CO,H 
CHK CO H ee #CoESO + H,0. 


766 | ORGANIC CHEMISTRY.” 


o-Carbobenzoyl Acetic Acid, CHiScoa to Benzoyl aceto-car- 
2 
boxylic acid. This acid is formed when phthaly] acetic acid is dissolved in alka- 
lies. It crystallizes in brilliant needles, melting at 90°, with decomposition into 
carbon dioxide and o-acetobenzoic acid (p. 764). When this acid is dissolved in 
sulphuric acid and precipitated with water it reverts again to phthalyl acetic acid; 
a ketonic acid is transposed into a lactone (p. 352) (Berichte, 17, 2619) :-— 


‘/CO.CH,.CO,H_ .. 4 CH.CO,H 
CHC CoH 2CO2H yields CK co>? +H,0. 


Consult Berichte, 17, 2665; 19, 3144 for different diketone-dicarboxylic acids. 





MONOBASIC OXY-ACIDS. 


The aromatic oxy-acids containing hydroxyl united to the ben- 
zene nucleus, ¢. g., C,H,OH.CO,H, combine the character of 
acids and phenols, hence are designated Phenol acids. Should the 
hydroxyl groups enter the side-chains, we would obtain aromatic 
oxy-acids (alcohol acids), corresponding in all particulars to the 
oxy-fatty acids. 

The phenol-acids are produced :— 

1. From the benzene carboxylic acids by methods analogous to 
those used in the preparation of the phenols from the benzenes: the 
conversion of the amido-acids, by means of nitrous acid, into diazo- 
compounds and then boiling the latter with water; by fusing the 
sulphobenzoic acids with alkalies. The haloid benzene carboxylic 
acids react like the sulpho-acids when subjected to similar treat- 
ment (p. 666) :— 


C,H,Cl.CO,H + KOH = C,H,(OH).CO,H + KCL. 


The homologous phenols become oxy-acids when fused with 
alkalies :— 

CH CO,K 

H;Z) 4 2KOH = C,H, 

- 6 *\oH + 6 *\oK 

whereas they are only oxidized by the ordinary oxidizing agents 

after the hydroxyl hydrogen has been replaced by alkyls or acid 

radicals (p. 686). The oxy-aldehydes that are oxidized with diffi- 

culty are readily changed to oxy-acids upon fusion with the 
alkalies. 

2. The oxy-acids are produced synthetically by the action of 

chlorcarbonic esters or carbon dioxide upon the sodium salts of 


the phenols (p. 739) :— 
C,H,.0Na + CO, =C, 


C 


+ 3H,, 


WH, 70H 
4\. CO, Na’ 


— 


ORTHO-OXYBENZOIC ACID. 767 


At lower temperatures (below 100°) phenol carbonates constitute the chief pro- 
duct. At more elevated temperatures these are re-arranged into their isomeric 
oxy-acids (p. 670). When this occurs the carboxyl-group generally enters the 
ortho-position. The polyhydric phenols are often converted into oxy-acids by 
merely heating them together with ammonium or potassium carbonate (p. 739.) 


3. A specifically synthetic method for the preparation of oxy- 
acids consists in the transposition of phenols by boiling them with 
carbon tetrachloride and caustic potash (Berichte, 10, 2185) :— 


C,H,.0H + CCl, + 5NaOH = C,H + 4NaCl + 3H,0. 
a : 


2 
\co,N 


This reaction is perfectly analogous to that of the formation of 
oxyaldehydes by means of chloroform (p. 723). As a general 
thing the carboxyl-group enters the ortho- or para-position, with 
the formation of two isomeric oxy-acids. 

Their basicity is determined by the number of carboxyl groups 
present, as alkaline carbonates convert them into carboxy] salts. 


Their hydroxyl hydrogen can also be replaced by alkalies, forming daszc salts, 
é. gC, 0 Co Ne: Carbon dioxide, however, will convert the latter into 
neutral salts. The ethers or esters manifest a like deportment, inasmuch as it is 
only the carboxyl esters that are saponified by alkalies (p. 349) :— 


0.CH 0.CH 
ie 3 dy ROM se Cee 


C 
*\co,K 


Hy + CH,.OH. 
\co,.CH, 


The ortho-oxy-acids, unlike the meta- and para-derivatives, volatilize in aqueous 
vapor, are colored violet by ferric chloride, and dissolve in chloroform. The 
meta-oxy-acids are colored reddish brown when heated with concentrated sul- 
phuric acid, with the formation of oxyanthraquinones (Berichée, 18, 2142). They 
are usually more stable than the ortho- and para-acids. Boiling concentrated 
hydrochloric acid decomposes the para-acids into carbon dioxide and phenols. 
Consult Berichte, 18, Ref. 487 for the heat of neutralization of the three oxyben- 
zoic acids. All the oxy-acids decompose into carbon dioxide and phenols when 
distilled with lime (p. 667). 

Alcohol acids (p. 766) are perfectly analogous to the acids of the paraffin series 
in their modes of formation and properties. 





1. Acids, CH,O, = CH. Gy» Oxybenzoic Acids. 

1. Ortho-oxybenzoic Acid, C,H,(OH).CO,H(1, 2),Salicylic 
Acid, occurs in a free condition in the buds of Sp:rea ulmaria, as 
the methyl ester in oil of Gaultheria procumbens (Oil of Winter- 
green) and other varieties of gaultheria, from which it may be 





eee #"ttt‘#t44.eeeeeeeeeeeeeeeeee 


* yt 


768 ORGANIC CHEMISTRY. 


easily obtained by saponification with potassium hydroxide. It is 
prepared artificially : by oxidizing saligenin and salicylic aldehyde ; 
by action of nitrous acid upon anthranilic acid; from the two 
nitro-(1, 3)-brombenzoic acids (p. 748); by fusing orthochlor- 
and brombenzoic acids, orthotoluene sulphonic acid and ortho- 
cresol with alkalies; from phenol with CO,, or with chlorcarbonic 
ester and sodium, or by means of CCl,, and sodium hydroxide (p. 
767). Its production from CO, and sodium phenoxide is especially 
interesting. This reaction is employed for its formation upon a 
large scale. ‘The acid can be made according to two methods :— 

(a) When sodium phenoxide is heated in a current of carbon 
dioxide at 180—220°, the latter is absorbed, half of the phenol dis- 
tils over, and the residue is disodium salicylate—Kolbe :— 


2C,H,.ONa + CO, = CHK CO. Na + C,H;.OH. 

The same reaction occurs when potassium phenoxide is heated to 150° ina 
current of carbon dioxide. At a more elevated temperature, however, there is 
formed with the dipotassium salicylate its isomeride, dipotassium paraoxybenzoate. 
The latter is more abundant in proportion to the increased temperature, until at 
220° it is the sole product. Primary potassium salicylate undergoes a similar 
transposition at 220°; phenol then distils over and dipotassium paraoxybenzoate 
constitutes the residue :— 


OH /OK 
2C HC Co,K = CoH Co, x + Cols OH + CO,. 


The sodium salt also decomposes in this manner, but instead of paroxybenzoic 
acid it yields disodium salicylate. On the other hand, if we expose primary 
sodium paraoxybenzoate, at 280—290°, in a current of CQ,, there results conversely 
(together with phenol) disodium salicylate. This strikingly illustrates the different 
deportment of potassium and sodium on fusion (Jour. pr. Ch. [2], 10, 95; 16, 
Si | 


(4) Sodium phenoxide is saturated under pressure, in closed ves- 
sels, with carbon dioxide, when it is converted into sodium pheno- 
carbonate, C,H;.O.CO,Na (p. 670). By continuing the pressure 
and applying a heat of 120-130°, this salt is changed to sodium 
salicylate, C,H,(OH).CO,Na. In this manner all the phenol is 
converted into salicylic acid (R. Schmitt, Berichte, 18, Ref. 439). 


(c) A third procedure less adapted for the production of salicylic acid, consists 
in heating phenol carbonate (p. 670) at 200°, with caustic soda. Phenol distils 
over and sodium salicylate remains :— 


(C,H,-0),CO + NaOH = C,H,(OH).CO,Na + C,H,.OH. 
Salicylic acid consists of four-sided prisms and crystallizes readily 


from hot water in long needles. It dissolves in 400 parts water at 
“15°, and in 12 parts at 100°; it is very soluble in chloroform. It 





ORTHO-OXYBENZOIC ACID. 769 


melts at 155—156°, and when carefully heated sublimes in needles ; 
when quickly heated (or with water at 220°, more readily with 
hydrochloric acid) it breaks up into carbon dioxide and phenol. 
Its aqueous solution acquires a violet coloration upon the addition 
of ferric chloride. It is a powerful antiseptic, hence its wide appli- 
cation. | 


When salicylic acid is heated with baryta water, the hydrogen atoms of both 
hydroxyls are replaced by barium, and leaflets of the basic salt separate :— 


C,H,7 “92 \Ba + 2H,0. 
ee oe 2th, 


When boiled with lime water the basic calcium salt is precipitated as an insol- 
uble powder. This behavior affords a means of separating salicylic from the other 
two oxybenzoic acids. The halogens react: readily with salicylic acid, yielding 
substitution products. Nitration produces three nitro-salicylic acids. 

PCl, converts salicylic acid into the ch/oride, C,H,Cl.COCI,—an oil, boiling at 
240°. Hot water converts it into orthochlorbenzoic acid. 


PC1,O produces the so-called salicylide, C,H,O, = C,H ote (?), which 


crystallizes in shining leaflets, melting at 195°. Boiling alkalies change it again 
to salicylic acid. 

The esters of salicylic acid appear, according to the common method, by con- 
ducting hydrochloric acid gas into its alcoholic solutions. The methyl ester, 
C,H,(OH).CO,.CHs, is the chief ingredient of wintergreen oil (from Gaultheria 
procumbens). It is an agreeably-smelling liquid, which boils at 224° (corrected) ; 
its sp. gr. = 1.197 at 0°. It dissolves in alkalies, forming unstable phenol salts. 
Ferric chloride gives it a violet coloration. The e/hy/ ester, C§H,(OH)CO,.C,H,, 
boils at 223°. 

When the methyl ester is digested with an alcoholic solution of potassium 
hydroxide and methyl iodide at 120° (p. 670), we get the dimethyl ester, 
CHS eae , which is an oil boiling at 245°. Boiled with potassium 
hydroxide, it is “saponified, yielding methyl alcohol and methyl salicylic acid, 
C,H K ae ag which forms large plates, melting at 98°. It is readily soluble in 

2 


hot water and alcohol. It decomposes into carbon dioxide and anisol, C,H,.0O. 
CH,, when heated to 200°. 

We can produce salicylic-diethyl ester, boiling at 259°, and ethylsalicylic acid 
in the same manner. The latter melts at 19.5°, and at 300° decomposes into 
carbon dioxide, and ethyl phenol, C,H,.0.C,H;. 

Acetyl chloride converts salicylic acid into aceto-salicylic acid, C,H,(O.C,H,O). 
CO,H, which crystallizes in delicate needles, and melts at 218°. 

The phenol salicylic esters are the sa/o/s, used as antiseptics. They are pro- 
duced when POCI, or PCI, acts upon a mixture of salicylic acid and various 
phenols. Or phosgene may be allowed to act upon a mixture of the sodium salts. 
In this way a great variety of different salols has been obtained (Berichte, 21, Ref. 
554; 22, Ref. 309). 

Salicylic Phenol Ester, C,H,(OH).CO,.C,H,, Sa/o/, consists of white crys- 
tals, melting at 43°. When sodium salol, C,H,(ONa).CO,.C,H, (from salol and 
sodium), is heated to 280°-300°, it changes to the isomeric sodium salt of pheny/- 
salicylic acid, C5H,(O.C,H;).CO,H, which melts at 113°, and is not colored by 


770 ORGANIC CHEMISTRY. 


ferric chloride (Berichte, 21, 502; 23, Ref. 342). It changes to diphenylene 
ketonoxide, C.H,¢ RoC. (Xanthone), by the elimination of water (by 
means of sulphuric acid, or upon heating with PCIl,). 

2. Meta-oxybenzoic Acid, CoH. 60.8 (1, 3), is produced: by acting 


with nitrous acid upon ordinary (1, 3)-amidobenzoic acid; by fusing (1, 3)-chlor-, 
brom-, iodo-, and sulpho-benzoic acids and metacresol with potassium hydroxide. 
It also results from metacyanphenol. It usually crystallizes in wart-like masses con- 
sisting of microscopic leaflets, dissolves in 260 parts of water at 0°, and readily in 
hot water. It melts at 200°, and sublimes without decomposition, Ferric chloride 
does not color it. It yields carbon dioxide and phenol when heated with 
alkalies. 

The ethyl ester, C,H,(OH).CO,.C,H,, crystallizes in plates, soluble in hot 
water, and melting at 72°. It boils at 282°. The dimethyl ester, C,H,(O.CH,). 
CO,.CH,, is formed when metaoxybenzoic acid is heated with methyl iodide (2 
molecules) and potassium hydroxide (2 molecules) to 140°. Boiling caustic potash 

_ converts this into methyl-metaoxybenzotc acid, C,H,(O.CH,).CO,H. The latter 
is also obtained from the methyl ether of metabromphenol, C,H,Br.0.CH,, with 
sodium and carbon dioxide. It crystallizes in shining scales, is easily soluble in 
water, melts at 107°, and sublimes undecomposed. 


3. Para-oxybenzoic Acid, C,H we ak ty (1> 4); is obtained from parachlor-, 
: \CO; 


brom-, iodo- and sulpho-benzoic acids, and also from many resins, by fusing 
them with potassium hydroxide. It results, too, when para-amidobenzoic acid is 
treated with nitrous acid or phenol with carbon tetrachloride and sodium hydroxide 
(together with salicylic acid). An interesting way of obtaining it consists in heat- 
ing potassium phenoxide in a current of carbon dioxide (p. 768) at 220°. This is 
the best course to pursue in preparing it ( Journal pract. Chemie, 16, 36, Berichte, 
22, Ref. 622). 

Paraoxybenzoic acid crystallizes from water in monoclinic prisms, containing 1 
molecule of H,O. This it loses at 100°. It is somewhat more easily soluble than 
salicylic acid (in 580 parts H,O at 0°), and melts at 210° with partial decomposi- 
tion into carbon dioxide and phenol. Ferric chloride does not color it, but throws 
down a yellow precipitate which dissolves in an excess of the reagent. Its basic 


barium salt, ei -co Ba, is insoluble, and may be employed to separate the 
acid from its meta-isomeride. 
The methyl ester, C,H iK BO, CH.’ consists of large plates, melting at 17°, and 
distilling at 273°. The ethy/ ester melts at 113°, and boils near 297°. 
Methyl-paraoxybenzoic Acid, CH CO and ethyl-paraoxybenzoic acid, 


C,H KOO are produced the same as the corresponding compounds of the 


other two benzoic acids; the second melts at 195°. 


Anisic Acid, called methyl paraoxybenzoic acid, is obtained 
by oxidizing anisol and anethol (p. 724) with nitric acid or a 
chromic acid mixture :— 


- O.CH. 537 7O.CH 
eH CHCh.cH, +20, = CHA COW + C,H,0,; 
* _ Anethol. Anisic Acid, Acetic Acid. 


ANISIC ACID. 771 


or by oxidizing the methyl ether of /-cresol, wae H, It is 
3 


prepared by oxidizing anisol with a chromic acid mixture (Azna/len, 
I4I, 248). 

Anisic acid crystallizes from hot water in long needles, from 
alcohol in rhombic prisms, melts at 185°, sublimes and boils with- 
out decomposition at 280°. Heated with baryta it breaks up into 
carbon dioxide and anisol, C,H;.0.CH;. It yields paraoxybenzoic 
acid when heated with hydrochloric or hydriodic acid (p. 668). 
The salts of anisic acid are very soluble in water and crystallize 
well. The halogens and nitric acid afford substitution products. 
These yield substituted anisols by distillation with baryta. 





Acids, C,H,Q3. 
1. Oxytoluic Acids, C oH(CH).< Co, H? Cresotinic Acids. The ten pos- 


sible isomerides are known (Berichte, 16, 1966). They result from the toluic 
acids, C,H,.CH,.COOH, by the substitution of OH for one atom of hydrogen in | 
the benzene nucleus, and from the cresols, C,H,(CH,).OH, by the introduction of 
CO,H, by means of sodium and carbon dioxide, or by the carbon chloride reaction 
(p. 767). They can also be obtained by the oxidation (fusion with caustic alkali) of 
their aldehydes, C,H,(CH,)(OH).CHO. The latter are made from the cresols by 
means of the chloroform reaction. Those isomerides in which the O7 occupies the 
ortho. place with reference tothe CO,H group (4 isomerides) are, like salicylic acid, 

colored intensely vio/et by ferric chloride, are readily soluble in cold chloroform, and 
are volatilein steam. When ignited with lime the oxytoluic acids split up into carbon 
dioxide, and the corresponding cresols, C,H,(CH,).OH. Some of them, especially 
the ortho-oxyacids, suffer this change when heated with concentrated hydrochloric 
acid to 200°. Symmetrical metaoxy-m-toluic acid, yields, by nitration, a trinitro- 


product, C,(OH)(NO,)3¢ 655 WD melting at 180°; this is identical with the zztro- 


coccic acid obtained from aloes (Berichte, 18, 251). 

2. Oxyphenyl Acetic Acids, C,H Lon ,.CO,H? oxy-alphatoluic acids. 
The /- and m-acids can be obtained from the corresponding amidophenyl acetic 
acids, CgH,(NH,).CH,.CO,H (p. 756), by diazotizing, and also from the oxyben- 
. zyl cyanides, C eH ,(OH). CH, CN (p. 735)- 

o- Oxy, phenyl Acetic Acid has been obtained from isatinic acid (and isatin), (p. 
762). The diazotizing of isatin at first produces oxyphenylglyoxylic acid, C,H, 
(OH).CO.CO,H, which by action of sodium amalgam becomes 0-oxymandelic acid, 
C,H,(OH).CH(OH).CO,H. The latter on boiling with hydriodic acid yields o- 
oxy-phenylacetic acid, melting at 137°. Ferric chloride colors it violet. Being a 


y-oxyacid it forms a Zactone, CHK SH col when distilled. This melts at 49°, 
is 


and boils at 236° (Berichte, 17, 975). : 

m-Oxyphenyl Acetic Acid melts at 129°. p-Oxyphenyl Acetic Acid occurs in 
urine, and arises from the decomposition of albuminous bodies. It crystallizes in 
flat needles, melts at 148°, and is colored dirty-green by ferric chloride: When 
distilled with lime it yields carbon dioxide, and g-cresol, C;H,(CH;).OH, 


ee 
772 ORGANIC CHEMISTRY. 


3. Oxymethylbenzoic Acids, CA ED Oe, Mineral acids precipitate the 
ortho acid from its salts (obtained by boiling phthalide with alkalies) in the form 
of a powder. This melts at 118°, with decomposition into water and phthalide. It 
is a y-oxyacid, hence by the elimination of water can yield a lactone (even by 
boiling with water) :— 


GH OR» = CHEN 
Mett4\ COOH 1 ABER GOTe Tee 
The lactone, C,H,O,, called Phthalide, is prepared by the action of hydriodic 


acid, or zinc and HCl upon phthalic chloride, Cet C cp oO (Berichte, 10, 
1445). It also results from orthoxylylene chloride upon boiling with water and 
lead nitrate ; by the reduction of phthalic anhydride in acetic acid solution with zinc 
dust (Berichte, 17, 2178); by the action of bromine vapor upon orthotoluic acid at 
140°, and most easily by digesting phthalidin, C,H,NO (from phthalimide) with 
caustic soda (erichte,17, 2598). Phthalide resembles the lactones perfectly and 
is the first discovered member of that series. It crystallizes from hot water and 
alcohol, in needles or plates, melts at 73°, and boils at 290° (cor.). It is reduced 
to orthotoluic acid on boiling with hydriodic acid. Potassium permanganate 
oxidizes it to phthalic acid. Sodium amalgam reduces it to hydrophthalide, 





C;H KCHOH) >°- The esters of benzoic acid are similarly reduced (Berich/e, 


II, 239). 
Phthalide yields the base Phthalidin, C,H,NO = CoH Cina? or 


ee | sco aH. when it is heated in an atmosphere of ammonia. Phthalidin 


can also be very readily obtained by reducing phthalimide with tin and hydro- 

chloric acid. It crystallizes from hot water in needles, melting at 150° and dis- 

tilling at 337°. ; 
Dialkylphthalides, ¢.g,C,H ke 5220, have been obtained by the ac- 
“CO 

tion of zinc and alkyl iodides upon phthalic anhydride (Berichte, 22, Ref. 11). 
The potassium salt of cyan-benzyl-o-carboxylic acid == (cyan-o-toluic acid) is 

formed when phthalide and potassium cyanide are heated to 180° :— 


/CH /CH,CN 


CoH Co 4\ CO,K - 


2>0 + CNK = C,H 


The free acid is a powder that is almost insoluble in water, and melts at 116°, 
without decomposition (Berichte, 19, Ref. 439). 

Other phthalide derivatives worthy of note are phthalide-acetic acid, phenyl- 
phthalide, methylene phthalide, benzylidene phthalide, and the phthalides and 
phthaleins. 


4. Phenylglycollic Acid, Mandelic Acid, C,H;.CH(OH). 
CO,H, was first obtained by heating amygdalin (p. 717) with hy- 
drochloric acid, and is synthetically formed from benzaldehyde by 
the action of prussic acid and hydrochloric acid, and the transfor- 
mation of the oxycyanide first produced :— 


C,H,.CH(OH).CN + 2H,O = C,H,.CH(OH).CO,H + NH,. 





PHENYLGLYCOLLIC ACID. 773 


It can also be obtained from benzoylformic acid (p. 762), by 
reduction with sodium amalgam, and from phenylchloracetic acid 
(p. 754) by boiling it with alkalies, as well as by the action of 
‘alkalies upon dibromacetophenone, C,H;.CO.CHBr,, or phenyl-. 
glyoxal (p. 730). : 

Preparation.—Boil the oxycyanides either with concentrated hydrochloric acid 
or heat them with sulphuric acid, which has been diluted with one-half volume of 
water. Or the oxycyanide can be changed to phenylchloracetic acid by heating 
it to 140° with concentrated hydrochloric acid ( Berichte, 14, 239). The oxycyanide, 
C,H, CH(OH).CN, is obtained by digesting benzaldehyde for some time with 20 
per cent. prussic acid (p. 347), or by gradually adding concentrated hydrochloric 
acid (1 molecule), with constant stirring, to a cooled mixture of benzaldehyde with 
ether and pulverized CNK (1 molecule).—Berichze, 14, 239 and 1965. The oxy- 
cyanide is a yellow oil with an odor resembling that of prussic acid and oil of 
bitter almonds. It solidifies at —10°, and decomposes when heated. 


The natural mandelic acid, obtained from amygdalin, is optically 
active, and, indeed, lzvo-rotatory. It forms brilliant crystals, 
melting at 132.8°. Synthetic-mandelic acid, called paramandelic 
acid, is optically inactive; it crystallizes in rhombic plates or 
prisms, and melts at 118°. It is more soluble in water than the 
levo-acid (100 parts water at 20° dissolve 15.9 parts of the former 
and 8.6 parts of the latter). Both acids manifest like chemical 
deportment (like the tartaric acids, etc.). Dilute nitric acid con- 
verts them into benzoyl-formic acid, while by more powerful oxi- 
dation, they yield benzoic acid. When heated with hydriodic acid 
they form phenyl-acetic acid, with hydrobromic and hydrochloric 
acid chlorphenyl or brompheny] acetic acids. 


Inactive or para-mandelic acid, like racemic acid, consists of dextro- and /evo- 
mandelic acids (p. 64). Fermentation with Penicillium glaucum destroys the 
levo and there remains the dextro-acid, which, so far as physical properties are 
concerned, resembles the so-called natural levo-acid perfectly, only excepting the 
fact that the former rotates the plane equally as much to the right. Lzevo- 
mandelic acid, however, is formed from the para-acid through the influence of a 
schizomycetes (Vibrio?) (Berichte, 17, 2723). The direct splitting up of para- 
mandelic acid into the dextro- and lzvo-acids can be brought about by the crystal- 
lization of the cinchonine salt. The mixing together of the dextro- and lzvo-acids 
(molecular quantities) results in the formation of inactive paramandelic acid. 
When the dextro- or leevo-acid is heated in a tube to 160° it is converted into the 
inactive mandelic acid. 

Nitro-mandelic Acids. 

o-Nitro-mandelic Acid, C,H,(NO,).CH(OH).CO,H, is produced (analogous 
to mandelic acid) by dissolving o-nitro-acetophenone-dibromide, C,H,(NO,).CO. 
CHBr,, in caustic potash. It melts at 140°. When reduced with tin and hydro- 
chloric acid it yields o-amido-mandelic acid, z. ¢., dioxinol (see below) (Berichée, 
20, 2203). 

m-Nitro-mandelic Acid is obtained from m-nitrobenzaldehyde. 


Amido-mandelic Acids. 
o-Amido-mandelic Acid, C,H, CH(OH).CO,H 


4\. NH, , Hydrindic Acid. Its 





a 


774 ORGANIC CHEMISTRY. 


sodium salt is formed from isatin by the action of sodium amalgam, and separates 
from the concentrated solution in brilliant crystals, C,H,NaNO, + H,O. This 
is not stable in a free condition, but immediately passes into its lactam, dioxindol, 
by the splitting-off of water (p. 755) :— 


CH.OH.CO,H CH(OH 
ae cig oH, * 
\NH, bie SG |< Ne 
A more stable compound than the preceding is Aceto-o-amidomandelic 


Acid, fe 5 dca ta This is obtained from aceto-isatinic acid (p. 762) 


C CO + H,O. 


by the action of NaHg, and from aceto-dioxindol by its solution in baryta water. 
It is very soluble in water, crystallizes in needles, and melts at 142°. The action 
of hydriodic acid or sodium amalgam causes it to break up into acetic acid and 
oxindol, the anhydride of o-amido-phenyl acetic acid (p. 756). 





3. Acids, C,H,,03. 


1. Oxyethylbenzoic Acid, C,H,( CH(OH).CH 


CO.H 3 (ortho), is formed from 
acetophenone-carboxylic acid (p. 764) when treated with sodium amalgam. It 
yields a lactone which solidifies below 0° (Berichte, 10, 2205). 


2. Oxymesitylenic Acid, C,H,(CH,),¢ Co, zy (CO,H:OH = 1 : 2), is ob- 
. 2 


tained by fusing mesitylene sulphonic acid with caustic alkali, and when nitrous 
acid acts upon amidomesitylenic acid. It melts at 179°, and being an oxyacid is 
colored a deep blue by ferric chloride. 


3. Oxyphenylpropionic Acids, CHC C.H,CO,H° There are six isomerides. 


o-Hydro-coumaric Acid, Melilotic Acid, CHS CH..CO.H (1, 2), 
2° 2° 2 


occurs free and in combination with coumarin in the yellow melilot (Melilotus 
officinalts), and is produced by the action of sodium amalgam upon coumaric acid 
and coumarin (see this) :— 


C,H,O, + H,O + H, = C,H,,03. 
Coumarin, 


It crystallizes in long needles, dissolves easily in hot water, and melts at 81°. 
Ferric chloride imparts a bluish color to the solution. When distilled it passes 


O 
into the d-/actone, C,H,O, = C,H. a ite Hydrocoumarin, melting at 
\C,H,.CO” 
25°, and boiling at 272°. When boiled with water it regenerates the acid. Meli- 
lotic acid decomposes when fused with alkali into salicylic acid and acetic acid ; 
hence it is a benzene derivative of the ortho-series. Zthyl Melilotic Acid, C,H, 
(O.C,H,).C,H,.CO,H, is produced by ethylating the acid and when sodium 
amalgam acts upon ethyl coumaric and ethyl coumarinic acids; it melts at 80°. 


Z : ‘ : /AOH ; : 
m-Hydro-coumaric Acid, CeHC CH,.CH,.CO,H (1, 3), is obtained from 
meta-coumaric acid by means of sodium amalgam; it melts at 111°. 
é . : : / OH 
f-Hydro-coumaric Acid, CoH CH,.CH,.CO,H 
sodium amalgam acts upon para-coumaric acid, or when nitrous acid acts on 


(1, 4), results when 


TYROSINE. 775 


p-amidohydrocinnamic acid (p. 758), and in the decay of tyrosine. It is very 
soluble in hot water, forms small crystals, and melts at 128° (Berichte, 17, Ref. 


433). 
One of the amido-derivatives of s-hydro-coumaric acid is 


P H 
Tyrosine, C,H,,NO; = CH. CH, CH(NH,).CO,H (3, '4)) 


Oxyphenyl-a-amidopropionic Acid, Oxyphenyl-alanine. It occurs 
in the liver, the spleen, the pancreas, and in stale cheese (tupds), 
and is formed from animal substances, (albumen, horn, hair) on 
boiling them with hydrochloric or sulphuric acid; by fusion with 
alkalies or by putrefaction (together with leucine, aspartic acid, 
etc.). It may be prepared synthetically from /-amido-phenyl- 
alanine (from phenylacetaldehyde, p. 758) by the action of 1 mole- 
cule of potassium nitrite upon the hydrochloric acid salt. It is 
soluble in 150 parts boiling water, and crystallizes in delicate, silky 
needles ; it dissolves with difficulty in alcohol, and is insoluble in 
ether. 


Mercuric nitrate produces a yellow precipitate, which becomes dark red in color 
if it be boiled with fuming nitric acid to which considerable water has been added 
(delicate reaction). Being an amido-acid, tyrosine unites with acids and bases, 
forming salts. If it be heated to 270° it decomposes into carbon dioxide and oxy- 
phenylethylamine, C,H,(OH).CH,.CH,.NH,. When fused with caustic potash it 
yields paraoxybenzoic acid, ammonia and acetic acid. Putrefaction causes the 
formation of hydroparacoumaric acid, and nitrous acid converts the tyrosine into 
peer eeea ee acid, C,H,(OH).CH,.CH(OH).CO,H (Annalen, 219, 
226). 


Phloretic Acid, CHK CH.CO,H (1, 4), oxyphenyl-a-propionic acid, is 
formed together with phloroglucin when phloretine is digested with potassium 
hydroxide (p. 695). It crystallizes in long prisms, is very soluble in hot water, 
and melts at 128-130°. Ferric chloride colors its solution green. Baryta decom- 
poses it into carbon dioxide and ethyl phenol; fusion with potassium hydroxide 
produces paraoxybenzoic and acetic acids, The oxidation of methyl phloretic 
acid yields anisic acid. Phloretic acid, like the cresols, cannot be directly oxid- 
ized (p. 686). 

4. Phenyloxypropionic Acids, C,H;.C,H,(OH).CO,H. There are four 
isomerides :— 


/CH /CH,.0H 
1. CoHs.COOH) 6G 4 2. CoHs.CHY 6G 44 
a-Phenyl-lactic Acid, a-Phenyl-hydracrylic Acid, 
Atrolactinic Acid. Tropic Acid. 
3. C,H,.CH,.CH(OH).CO,H 4. C,H,.CH(OH).CH,.CO,H. 
B-Phenyl-lactic Acid. f-Phesythydracrylic Acid, 


(1) The so-called Atrolactinic Acid is obtained from a-bromhydro-atropic acid 
(p. 759), when the latter is boiled with a soda solution, and by oxidizing hydro- 
atropic acid with potassium permanganate. It is prepared synthetically from 
acetophenone, C,H,.CO.CH,, by means of prussic acid and sulphuric acid or 
dilute hydrochloric acid, and by boiling the cyanide with concentrated hydrochloric 
acid we get 3-Chlorhydro-atropic Acid (p. 759) (Berichte, 14, 1352 and 1980). 


776 ORGANIC CHEMISTRY. 


It dissolves very readily in water, crystallizes with one-half molecule of water in 
needles or plates, and at 80—-85° loses its water of crystallization. While yet con- 
taining water it melts at 91°; when anhydrous at 93°. It remains unaltered when 
heated with baryta water, but when boiled with concentrated hydrochloric acid, it 
decomposes into water and atropic acid. 

(2) Tropic Acid is obtained by digesting the alkaloids, atropine and belladonna, 
with baryta water. It is formed artificially, by boiling 6-chlorhydro-atropic acid 
(p. 759), with a solution of potassium carbonate (Anmalen, 209, 25). The acid 
dissolves with more difficulty in water; crystallizes in needles or plates, and melts 
at 117°. It is inactive, but can be resolved into a /evo- and dextro-form by the 
crystallization of its quinine salt. The dextro-variety crystallizes in bright vitreous 
prisms and leaflets; it melts at 128°. The levo-form melts about 123° ( Berichie, 
22, 2590). It decomposes into water and atropic acid when boiled with baryta 
water. 

(3) 6-Phenyl-lactic Acid, C,H,.CH,.CH.(OH).CO;H, Benzyl-glycollic acid, 
is derived from phenylacetaldehyde (p. 721), with prussic acid and hydrochloric 
acid, and from benzyl-tartronic acid upon heating it to 180°. The acid crystallizes 
from water in large prisms, melts at 97°, and when heated to 130° with dilute sul- 
phuric acid decomposes into phenylacetaldehyde and formic acid. Boiling water 
does not alter it. 

(4) 8-Phenyl-hydracrylic Acid, C,H,.CH(OH).CH,.CO,H, commonly called 
phenyl-lactic acid, results on boiling B-brom-hydro-cinnamic acid (p. 757) with 
water, or by the addition of hypochlorous acid to cinnamic acid :— 


C,H,.CH:CH.CO,H + CIOH = C,H,.CH(OH).CHCLCO,H, 


and then reducing the resulting chlor-acid with sodium amalgam. The acid is 

very soluble in cold water, and melts at 94°. When heated with dilute sulphuric 

acid it decomposes (like the $-oxy-acids) at 100° into water and cinnamic acid 

(together with a little styrolene) (Berichte, 13, 304). When digested with the 

haloid acids it forms phenyl-3-haloid-propionic acids (p. 758). 
Pheny]-halogen-lactic acids (p. 359) :-— 


C,H,.CH(OH).CHCI.CO,H and C,H,.CHBr.CH(OH).CO,H. 


Phenyl-a-chlorlactic acid. Phenyl-8-brom-lactic acid. 


The first of these is produced by the action of chlorine in alkaline solution 
upon phenyl-acrylic acid (cinnamic acid) (see above, and also Anna/en, 219, 184). 
It crystallizes with one molecule of water, which escapes in the dessicator. When 
it contains water it melts at 79°, when anhydrous at 104°. Phenyl-a-bromlactic 
Acid is produced on boiling cinnamic dibromide (p. 757) with water. It crystal- 
lizes in leaflets, containing 1H,O, melts at 121°, loses water of crystallization, and 
then melts at 125°. When boiled with alkalies both acids yield phenylacetalde- 
hyde (p. 721), together with 8-phenylglyceric acid (see Annalen, 219, 180). 

Phenyl-$-brom-lactic Acid (see above) is produced when hydrobromic acid 
acts upon $-phenylglyceric acid (p. 782). It has not been further described (Ze- 
richte, 16, 2820). 

Nitro-phenyl-lactic Acids, C,H,(NO,).CH(OH).CH,.CO,H. 

_ The three isomerides (ortho, meta and para) are obtained from the three nitro- 
cinnamic acids by the addition of hydrogen bromide, and by the action of the al- 
kalies, when their B-Zactones (p. 353)—in the cold—are also produced, C,H,(NO,). 


ay CH, , 
CH CO (Berichte, 16, 2209, 17, 595). 
od: es 
The ortho nitro-acid results further by the condensation of o-nitro-benzaldehyde 
with acetaldehyde by means of a little bartya water, and by oxidizing the aldehyde 


PHENYL-OXYACRYLIC ACIDS. vii 


first produced with silver oxide (Berichte, 16, 2206). It melts at 126°, and when 
heated to 190° with dilute sulphuric acid yields o0-nitro-cinnamic acid. Its §-lac- 
tone melts at 124°, and decomposes on boiling with water into carbon dioxide and 
o-nitrostyrolene; it yields oxydihydrocarbostyril when reduced (Serich/e, 17, 
2011). 

Tie meta-nitro-acid melts at 105°; its 3-lactone at 98°. The para-nitro-acid, 
obtained by oxidizing f-nitro-cinnamic aldehyde with argentic oxide, melts at 
132°, and its lactone at 92°. When the three nitro acids are heated with alco- 
holic zinc chloride, we do not get their lactones, but their esters (Berich/e, 17, 


1659). 





Two phenyl-oxyacrylic acids, or oxy-cinnamic acids, have been prepared 
by the action of alcoholic potash upon phenylchlor- and brom-lactic acids (Be- 
richte, 16, 2815) :— 

C,H;.CH:C(OH).CO,H and C,H,.C(OH):CH.CO,H. 
Phenyl-a-oxyacrylic Acid. Phenyl-8-oxyacrylic Acid. 
One, at least, of these acids represents Phenylglycidic acid, C,H ,.CH.CH.CO,H 
(Berichte, 20, 2465). 
O 

The nitrophenyl-glycidic acids (p. 456), obtained by saponifying the nitro- 

phenylchlor-lactic acids with alcoholic potash, have been studied more fully :— 


C,H,.(NO,).CH(OH)  C,H,(NO,).CH.Cl C,H,(NO,).CH 
| 
CHCl and CH.OH yield 
| | 
CO,H CO,H CO,H 
Nitrophenyl-a-chlorlactic Nitrophenyl-8 chlorlactic Nitrophenyl-glycidic 
Acid. Acid. Acid, 


Para-nitrophenylglycidic acid melts at 280° with decomposition. It unites with 
hydrochloric acid to f-nitrophenyl- chlorlactic acid, which, like the a-acid, melts 
at 167-168°. Alcoholic potash again changes it to glycidic acid. Sulphuric acid 
and water convert glycidic acid into f-nitrophenyl-glyceric acid. 

Ortho-nitropheny] glycidic acid, from o-nitrocinnamic acid (Berich/e, 13, 2262), 
contains one molecule of water and melts at 94°. When anhydrous, it melts at 
108°, It combines with hydrochloric acid to o-nitrophenyl-8-chlorlactic acid, 
melting at 126°. Alcoholic potash regenerates glycidic acid ( Berichte, 19, 2649). 
Anthranil and anthroxanaldehyde result when o-nitroglycidic acid is boiled with 
water. 





Acids, C, 5H 03. . 

1. Phenyl-y-oxybutyric Acid, C,H;.CH(OH).CH,.CH,.CO,H, is precipitated 
in the cold, from its salts, by hydrochloric acid. It melts at 75°, with decomposi- 
tion into water and its lactone—phenyl-butyrolactone, C,,H,,O,. The latter 
is obtained from phenyl-brombutyric acid (from isophenylcrotonic acid) with a 
soda solution. It melts at 37°, and boils at 306° (Annalen, 216, 103). 

2. Propyloxybenzoic Acids, C.Hy(OH) = ih Six of the twenty possible 
isomerides, having this formula (normal propyl and isopropyl), are known. 

3. Oxyisopropylbenzoic Acid, C,H one ns oxycumic acid, is ob- 


tained from cumic acid (p. 760), by the hydroxylation of the isopropyl group. 
O55 





778 ORGANIC CHEMISTRY. 


This is effected by the oxidation with potassium permanganate (p. 346). It crys- 
tallizes from hot water in thin prisms, and melts at 156°. Its sulpho-acid is simi- 
larly formed from paracymene and paraisocymene-sulphonic acid (p. 522) with 
potassium permanganate. When boiled with hydrochloric acid it parts with water,and 
becomes Propenylbenzoic Acid, CHS cea which melts at 161°. 
2 

Similarly, nitrocumic acid yields Nitro-oxypropylbenzoic Acid, and Nitro- 
propenylbenzoic Acid, and by the reduction of the latter, the amido acids. 
Amido-oxypropylbenzoic acid yields the czazonic compounds (Berichte, 16, 2577, 
17, 1303), which are analogous in constitution to the ethenyl-amido-phenols (p. 683). 
With nitrous acid amido-oxypropenyl benzoic acid affords methyl-cinnolinecar- 
boxylic acid (Berichte, 17, 724). 





MONOBASIC DIOXYACIDS. 


1. Dioxybenzoic Acids, C,H,O, = C,H;.(OH),.CO,H. These 
are also termed the carboxylic acids of the corresponding dioxy- 
benzenes, C,H,(OH), (Resorcinol, pyrocatechin, hydroquinone), 
since they can be obtained from the latter by the direct introduc- 
tion of carboxyl (on heating with ammonium carbonate or potas- 
sium carbonate, p. 767), or by the oxidation of the corresponding 
aldehydes, C,H;(OH),.CHO (p. 723). Three of the six possible 
isomerides are derived from resorcinol (1, 3), two from pyrocate- 
chin (1, 2), and one from hydroquinone (1, 4). Conversely, by the 
elimination of carbon dioxide from the acids we regenerate the 
dioxybenzenes. 


(1) Symmetrical Dioxbenzoic Acid (1, 3, 5), a-resorcylic acid, corresponding 
to orcinol, is obtained from a-disulphobenzoic acid (p. 692) on fusion with potas- 
sium hydroxide. It crystallizes with 1144H,O, melts at 233°, and by the exit of 
carbon dioxide yields resorcinol. Ferric chloride does not color it. When dis- 
tilled or heated with sulphuric acid to 130° it yields anthrachrysone, a derivative 
of anthracene. Its dimethyl ether, C,H,(O.CH;),.CO,H, is produced on oxid- 
izing dimethylorcin, and melts at 176°. 

(2) B-Resorcylic Acid (1, 2, 4 — CO,H in 1) is obtained on heating resor- 
cinol with potassium carbonate (Berichte, 18,1985), also on fusing #-disulpho- 
benzoic acid and #-resorcylaldehyde (also umbelliferon) with caustic potash. It 
dissolves with difficulty in cold water, crystallizes with 114, 2% and 3 molecules 
of water in fine needles, melting in the anhydrous state at 213°, and decomposing 
into CO, and resorcin. Ferric chloride colors ita dark red. Peomol is a derivative 
of #-resorcylic acid (Berichte, 19, 1777). 

(3) y-Resorcylic Acid (1, 2,6 — CO,H in 1) is formed together with /- 
resorcylic acid from resorcinol, by means of ammonium carbonate (erich/e, 13, 
2380) ; it decomposes about 150° into CO, and resorcinol, and is colored a blue- 
violet by ferric chloride. On warming it reduces alkaline copper and silver solu- 
tions. 

(4) Hydroquinone Carboxylic Acid (1, 4,CO,H), Oxysalicylic Acid, was 
first prepared from gentisin, hence called gentisinic acid. It is obtained from 
brom-, f-iodo-, and amido-salicylic acids; also from hydroquinone by means of a 
potassium dicarbonate solution, and by fusing gentisinic aldehyde (from hydroqui- 
none with potassium hydroxide (Berichte, 14, 1988). It melts at 200°,-and at 


PROTOCATECHUIC ACID. 779 


215° breaks up into carbon dioxide and hydroquinone. Ferric chloride colors it 
a deep blue. On warming it reduces alkaline copper and ammoniacal silver solu- 
tions. When oxidized it yields a yellow-colored acid, which is decolorized by 
reducing agents, and is in all probability quinone carboxylic acid, C,H,(O,). 
CO,H 

( 5) Pyrocatechin-ortho-carboxylic Acid (1, 2, 3 — CO, in1) is obtained 
from m-iodo-salicylic acid by fusion with KOH, and from pyrocatechin on heating 
with ammonium carbonate to 140° (together with protocatechuicacid). It crystal- 
lizes in small needles (with 2H,O), is colored an intense blue by ferric chloride, 
melts at 204°, and decomposes further into carbon dioxide and pyrocatechin 
(Annalen, 220, 117). 


(6) Protocatechuic Acid, C,H; 1 Ore (1, 3, 4— CO,H in 
2 


1), Pyrocatechin-para-carboxylic acid, is obtained from many ben- 
zene tri-derivatives (e.g., brom- and iodo-para-oxybenzoic acids, 
bromanisic acid, para- and meta-cresolsulphonic acid, eugenol, 
catechin), as well as from various resins (benzoin, asafoetida, myrrh) 
on fusion with potassium hydroxide (and usually together with 
some paraoxybenzoic acid); furthermore, on heating hydroquinone 
with ammonium carbonate (together with pyrocatechin ortho- 
carboxylic acid) and by the action of bromine upon quinic acid. 
It is most easily prepared from kino by adding the latter to fused 
caustic soda (Annalen, 177, 188). It crystallizes with one mole- 
cule of water in shining needles or leaflets, and dissolves readily in 
hot water, alcohol and ether. At roo® it loses its water of crystalli- 
zation, melts at 199°, and decomposes further into carbon dioxide 
and pyrocatechin. Ferric chloride colors the solution green ; after 
the addition of a very dilute soda solution it becomes blue, later 
red (all derivatives containing the protocatechuic residue, (OH),C— 
Berichte, 14, 958, react similarly). Ferrous salts color its salt solu- 
tions violet. It reduces an ammoniacal silver solution, but not an 
alkaline copper solution. 


Diprotocatechuic Acid, C,,H,,O,, is a tannic acid, which results on boiling the 
preceding with aqueous arsenic acid. It is very similar to common tannic acid, 
but is colored green by ferric oxide. 

The dimethyl- and diethyl-protocatechuic acids are obtained by heating with 
potassium hydroxide and methyl or ethyl iodide. 

Dimethyl-protocatechuic Acid, C,H, { (OCH s)s, also results from dimethyl- 
protocatechuic aldehyde (p. 725), methyl creosol (p. 693) and methyl eugenol, on 
oxidation with potassium permanganate. It is the so-called veratric acid, 
C,H,,0,, which occurs together with veratrin a the alkaloids) in the sabadilla 
seeds (from Veratrum Sabadilla). Wt crystallizes from hot water in needles, 
melting at 179.5°. Heated to 150° with hydrochloric acid, it splits off a methyl 
group and yields the two monomethyl compounds. When digested with 
lime or baryta it decomposes into carbon dioxide and dimethyl-pyrocatechin- 

. 690). 

Fret pipetoeabieals acid melts at 149°. 











780 - ORGANIC CHEMISTRY. 


Monomethyl-protocatechuic Acids, CSH,O,:— 


(CO,H (1) CO,H (1) 
(1) cai | O.CH, (3) and = (2) cat, | OF (3). 
OH (4) O.CH, (4) 


The first body is vanillic acid, obtained by the energetic oxidation of its alde- 
hyde, vanillin (and from coniferine, p. 725), also from aceteugenol, acetferulic 
acid, and from aceto-homovanillic acid when oxidized with potassium permanga- 
nate (p. 781). It crystallizes from hot water in shining needles, melts at 211°, 
and can be sublimed. When it is heated to 150° with hydrochloric acid it decom- 
poses into methyl chloride and protocatechuic acid; distilled with lime it yields 
guaiacol. When methylated it is converted into dimethyl-protocatechuic acid, 
from which it is again regained by a partial demethylation. 

Isomeric monomethyl-protocatechuic acid (Formula 2),—Isovanillic Acid,— 
was first obtained from hemipinic acid, and is prepared together with vanillic acid 
by methylating protocatechuic acid, or by demethylating dimethyl-protocatechuic 
acid, and by oxidizing hesperitinic acid. It melts at 250°. 

Coniferyl alcohol (p. 725), eugenol and ferulic acid, stand in close relation to 
vanillic acid; they contain unsaturated side-chains, and, therefore, are treated in 
connection with the cinnamic acid derivatives. Meconine, opianic acid and hemi- 
pinic acid bear close genetic relation. 

The methylene ether of protocatechuic acid is 


Piperonylic Acid, C,H,O, = C,H, (o> 7 oe): .CO,H, Methylene-proto-cate- 


chuic acid, which is formed upon oxidizing its aldehyde, piperonal (p. 725), and 
safrol_ with potassium permanganate. It is prepared synthetically by heating 
protocatechuic acid with methylene iodide and potassium hydroxide, and can be 
decomposed conversely into protocatechuic acid and carbon on heating with hydro- 
chloric acid. It sublimes in fine needles, melting at 228°, and is soluble with dif- 
ficulty in hot water. Heated to 210° with water it breaks up into pyrocatechin, 
carbon dioxide and carbon. 

Ethylene-protocatechuic acid is a perfect analogue of piperonylic acid. It is 
prepared by means of ethylene bromide, and melts at 133°. 

Ether derivatives of protocatechuic acid and the trivalent phenol, phloroglucin 
(p. 695), are:—Luteolin, Maclurin, and Catechin. The first, C,,H,.O,, 
occurs in Reseda /uteo/a and crystallizes in yellow needles. Ferric chloride colors 
it green. When fused with potassium hydroxide it is resolved into protocatechuic 
acid and phloroglucin :— 


Croll; sO, + 33H,0 = 2G. H 0, +.C,H,(0H),. 


The second and third bodies are generally included among the tannic acids. 
They also are decomposed into protocatechuic acid and phloroglucin on fusion 
with potassium hydroxide. 





2. Acids, C,H, O,. 

(2) Dioxyphenyl-acetic Acids, C,H,;(OH),.CH,.CO,H- 

I. Homoprotocatechuic Acid and Homovanillic Acid, its monomethy] 
ether, have their side-groups occupying the same positions as those of protocate- 
chuic and vanillinic acids :— 

CTE. COu ia tt) CH,.CO,H (1) 
C,H, 1OH (3) and C,H, jock, (3). 
OH (4) OH (4) 


DIOXYTOLUIC ACIDS. 781 


The latter is produced, er with vanillic acid, by the careful oxidation of acet- 
eugenol, C,H,(C,H;) {5 O. ct. ,0” and the saponification of the acetyl deriva- 


tive produced at first. It melts at. 143°, and when heated with hydrochloric acid 
to 180° yields homo-protocatechuic acid, melting at 127°, and methyl chloride. 
Homopyrocatechin is produced when it is heated with lime. 


2. Symmetrical Dioxyphenyl-acetic Acid (1, 3, 5). 


The triethyl ester, obtained from the dicarboxylic acid derived from this acid, is 
produced by the condensation of acetone dicarboxylic ester (p. 566). It melts at 
98° and yields dioxyphenyl-acetic acid upon saponification (two molecules of car- 
bon dioxide are eliminated at the same time). The acid is soluble in water, alco- 
hol and ether. It crystallizes with one molecule of water and melts at 54°. It 
resembles orcin in its reactions, and yields the latter when its silver salt is heated 
(Berichte, 19, 1449). 





(6) Dioxytoluic Acids, C,H, (OH). 66" ey 

There are five isomerides. Of these orsellic or lecanoric acid, C,,H,,0, + 
H,O, is found in different mosses of the varieties Roccella and Lecanora. It can 
be extracted from the same by means of ether or milk of lime. Its crystals are 
almost perfectly insoluble in water, melt at 153°, and are colored red by ferric 
chloride. Boiling with lime changes it to orsellinic acid, C,H,O,. The latter 
consists of easily soluble prisms, and is colored violet by ferric chloride. It melts 
at 176°, and decomposes into carbon dioxide and orcin, C,H,(CH,)(OH), (p. 692). 

Erythrin, Cy 9Ho201 ou. Acid), is an ether-like derivative of orsel- 
linic acid and erythrite, C 4H,(OH), (p. 474). It occurs in the lichen Roccella 
Jusciformis, which is applied i in the manufacture of archil (p. 693) and is extracted 
from it by means of milk of lime. Erythrin crystallizes with 14% molecules of 
H,0 and is soluble with difficultly in hot water. Exposure to the air causes it to 
assume a red color. When it is boiled with water or baryta-water it breaks up 
into orsellinic acid and picroerythrin :— 


C, 5H, 20), 3 H,0 — C,H,0, = x C, 2H, 6O7- 


Picro-erythrin, C,,H,,0, + H,O, forms crystals, which dissolve readily in 
alcohol and ether, and on further boiling with baryta water yield STHaNe, orcin 
and carbon dioxide :— 


C,,H,,0, + H,O = C,H,,0, + C,H,O, + CO,. 
The structure of the preceding compounds is as follows :— 


C,H,(CH 
Orsellinic hey i *< 6 H,(CHs) ise CO, H 
Orsellic Acid, 
Diorsellinic Acid. 
C,H,(OH) 
(OW), a a 
O OH C,H,(CH,).CO,H 
\C,H, (CH) of OH 
CO,H. NG Fen) < 
Picroerythrin. \co,H 


Erythro-orsellinic Ether. Erythrin, 
Erythro-diorsellinic Ether. 


782 ORGANIC CHEMISTRY. 


3. Acids, C,H,,O.4. 

Hydro-umbellic Acid, C,H,(OH),.CH,.CH,.CO,H (1, 2, 4 — CH, in 1). 
The position of its side-chains is the same as in f-resorcylic acid (p. 778). It is 
obtained from umbellic acid, C,H,O,, and umbelliferon, C,H,O, (see this), by 
the action of sodium amalgam. Above I10° it decomposes, water separating, and 
melts at 120°. Ferric chloride colors it green. It reduces alkaline copper and 
silver solutions. It yields resorcinol on fusion with KOH. 


Hydrocaffeic Acid, C,H,,0,. 


CH,.CH,.CO,H(1 _ (CH,.CH,.CO,H CH,.CH,.CO,H 
C,H, OH (3) C,H, O.CH, C,H, OH 
OH (4) OH O.CH, 
Hydrocaffeic Acid. : Hydroferulic Acid. Isohydroferulic Acid. 


The hydrocaffeic acid, with the same arrangement of side-chains as in proto- 
catechuic acid, is obtained from caffeic acid by the action of sodium amalgam; 
is colored the same by ferric chloride, etc., as the protocatechuic acid (779), and 
reduces both alkaline copper and silver solutions. Hydroferulic and Isohydro- 
ferulic Acids are its monomethyl ethers. They correspond to vanillic and iso- 
vanillic acids. Sodium amalgam converts ferulic and isoferulic acids into the 
above hydro-acids. The former melts at 90°, the latter at 147°. 

Everninic Acid, C,H,,O,, is produced, together with orsellinic acid, on boil- 
ing evernic acid, C,,H,g0, (from Lvernia Prunastri), with baryta. It melts at 
157°, and is colored violet by ferric chloride. 





Dioxy-alcoholic Acids, C,H yO, 


CH,.OH 
C,H,.C(OH) ¢ 602i C,H,.CH(OH).CH(OH).CO,H. 
a-Phenyl Glyceric Acid. B-Phenyl! Glyceric Acid. 


The a-Acid (Atroglyceric Acid) results on boiling dibrom-hydro-atropic acid 
(p. 759) with excess of alkalies, and from benzoyl ecarbinol (p. 712) by means of 
prussic acid and hydrochloric acid (Berichte, 16,1292). It crystallizes from water 
in warty masses, and melts at 146°. 

The B-Acid (Phenylstyceric Acid) is qbtained from af-dibromhydrocin- 
namic ester (p. 757) by first getting the dibenzoyl ester and saponifying it, or by 
boiling phenyl-a-chlorlactic acid and the two phenyloxyacrylic acids (p. 777) with 
water (together with phenylacetaldehyde); also by oxidizing cinnamic acid, 
C,H,.CH:CH.CO,H, with potassium permanganate (p. 460) (Berichte, 21, 920). 
It is a crystalline mass, very soluble in water, and melts at 143°, with decomposi- 
tion into phenylacetaldehyde, carbon dioxide and water. p- and 0-NVitro-phenyl 
glyceric acids have been obtained from nitrophenyl-glycidic acids (p. 777). 





MONOBASIC TRIOXYACIDS. 


Trioxybenzoic Acids, C,H,O;. Three of the six possible isome- 
rides are known :— 

1. Gallic Acid, C,H,(OH),.CO,H (1, 3, 4, 5—-CO,H in 1), 
occurs free in gall nuts, in tea, in the fruit of Cesa/pinia coriaria 
(Divi-divi), in mangoes, and in various other plants. When com- 
bined, and then chiefly as a glucoside, it occurs in some tannic 


GALLIC ACID, 783 


acids. It is obtained from the ordinary tannic acid (tannin) by 
boiling it with dilute acids. It is prepared artificially on heating 
di-iodo-salicylic acid to 130° with potassium carbonate, and from 
brom-dioxy-benzoic acid, brom-proto-catechuic and veratric acids 
(p. 779) when fused with potassium hydroxide. 7 


Gallic acid arises, like pyrogallol carboxylic acid (below), from the adjacent 
trioxybenzene (pyrogallol). Since the carboxyl in the latter occupies the ortho- 
position referred to a hydroxyl, and since but 2 pyrogallol acids are possible, gallic 
acid would then be the second isomeride (Berichte, 17, 1090). 


Gallic acid crystallizes in fine, silky needles, containing one 
molecule of water. It dissolves in three parts of boiling, and 130 
parts of water at 12°, and readily in alcohol and ether. It has a 
faintly acid, astringent taste. It melts and decomposes near 220°, 
into carbon dioxide, and pyrogallol, C,H,(OH);. It reduces both 
gold and silver salts (hence its application in photography). Ferric 
chloride throws down a blackish-blue precipitate in its solutions. 

Although gallic acid is monobasic, it can, by virtue of its being 
a trivalent phenol, combine also to salts with four equivalents of 
metal. The solutions of the alkali salts absorb oxygen when exposed 
to the air, and, in consequence, become brown in color. 


Gallic acid forms a triacetate, C,H,(O.C,H,O),.CO,H, with acetyl chloride. 
This crystallizes from alcohol in needles. The ethy/ ester, C,H,(OH),.CO,.C,H;. 
crystallizes with 24%4 molecules, of H,O and is soluble in water. When anhydrous 
it melts at 150°, and sublimes. 77rzethyl-gallate, C,H,(O.C,H,),.CO,H, from 
gallic acid, melts at 112°, and forms an easily soluble barium salt. 

Rufigallic Acid, C,,H,O,, a derivative of anthracene (see this) is obtained by 
heating gallic acid with four parts of sulphuric acid to 140°. 

Oxidizing agents, such as arsenic acid, silver oxide, iodine and water, convert 
gallic into LV/agtc Acid, C,,H,O,. The latter occurs in the bezoar stones (an in- 
testinal calculus of the Persian goat). It is obtained from this source by boiling 
with potassium hydroxide, and precipitating with hydrochloric acid. Ellagic acid 
separates out in the form of a powder containing 1 molecule of water of crystalliza- 
tion. It is insoluble in water. 

2. Pyrogallol-carboxylic Acid, C,H,(OH),CO,H (1, 2, 3, 4—CO, in 1), is 
isomeric with gallic acid, and is prepared by heating pyrogallol with ammonium 
carbonate. It dissolves with more difficulty in water, crystallizes in shining 
needles containing 4%H,O, and sublimes without decomposition in a current of 
carbon dioxide. Ferric chloride colors it violet and greenish-brown; it also re- 
duces alkaline copper and silver solutions. 7Z7tethyl-pyrogallol-carboxylic Acid, 
C,H,(O.C,H;),.-CO,H, crystallizes in long shining needles, and melts at 105°. It 
also results in the oxidation of triethyldaphnetic acid (vide this). It yields triethyl 
pyrogallol by the elimination of carbon dioxide (p. 695). 

3. Phloroglucin Carboxylic Acid, C,H,(OH),.CO,H (1, 2, 4,6—CO,H in 
1), may be obtained by heating phloroglucin with potassium bicarbonate. It crys- 
tallizes with one molecule of water, is very unstable and decomposes even at 100°, 
also when boiled with water, into carbon dioxide and phloroglucin. 

4. Oxy-hydroquinone Carboxylic Acid, C,H,(OH),.CO,H(1, 2, 4,CO,H), 
is not known in a free condition. Its triethyl-ether acid, C,H,(O.C,H,),.CO,H, 
has been obtained from zesculetin. It melts at 134°, splits off carbon dioxide and 
becomes triethyl-oxyhydroquinone (p. 696). 


784 ! ORGANIC CHEMISTRY. 


TANNIC ACIDS. 


The tannins or tannic acids are substances widely disseminated 
in the vegetable kingdom. They are soluble in water, possess an 
acid, astringent taste, are colored dark blue or green (ink) by fer- 
ric salts, precipitate gelatine and enter into combination (leather) 
with animal hides (gelatine). Hence they are employed in the 
manufacture of leather, and for the preparation of ink. They are 
precipitated from their aqueous solutions by neutral acetate of 
lead. 

Some tannic acids appear to be glucosides of gallic acid, 7. ¢., 
ethereal compounds of the same with various sugars. They decom- 
pose into gallic acid and grape sugar upon boiling with dilute acids. 
Others contain phloroglucin, C,H,(OH),, instead of grape sugar. 
Common tannic acid, tannin, appears to be, at least in a pure state, 
not a glucoside but a digallic acid. 

When the tannic acids are fused with potassium hydroxide they 
yield mostly protocatechuic acid and phloroglucin. 

Tannic Acid, Tannin, C,,H,O, -+ 2H,O, Digallic Acid, 
occurs in large quantity (upwards of 50 per cent.), in gall nuts 
(pathological concretions upon the different oak species, Quercus 
infectoria, produced by the sting of insects); in sumach (hus 
coriaria), in tea and in other plants. It is prepared artificially by 
oxidizing gallic acid with silver nitrate, by heating it with phos- 
phorus oxychloride to 130°, or by boiling with dilute arsenic 
acid. Conversely, it passes, on boiling with dilute acids or alka- 
lies, into gallic acid (without the appearance of sugar) :— 


C,H, ,0, + H,O = 2C,H,0,. 


Pure tannin must, therefore, be considered a digallic acid (Berichie, 
17, 1478). 


Tannin is best obtained from gall-nuts. The latter are finely divided and ex- 
tracted with ether and alcohol. The solution separates into two layers, the lower 
of which is aqueous and contains tannin chiefly, and this is obtained by evapora- 
tion. 


Pure tannic acid is a colorless, shining, amorphous mass, very 
soluble in water, slightly in alcohol, and almost insoluble in ether. 
Many salts (e. g., sodium chloride) precipitate it from its aqueous 
solutions, and it can also be removed from the latter with ether. 
It reacts acid and is colored dark-blue by ferric chloride; gelatine 
precipitates it. Quantitative methods of estimating tannin are 
based on this behavior. 


'» The acid generally forms salts with two equivalents of metal; these are obtained 
pure with difficulty. Acetic anhydride converts the acid into a penta-acetale, 


QUINIC ACID. 785 


C,,0,(C,H,0),0,. Heated to 210° it decomposes with formation of pyrogallol, 


° GallyL-gallic Acid, C,,H,)O,, a keto-tannic acid, forms an oxime and phenyl- 
hydrazone, see Berichte, 22, Ref. 754; 23, Ref. 24. 

The other tannic acids found in plants have been but little investigated: we 
may mention :— 

Kino.tannin, which constitutes the chief ingredient of kino, the dried juice of 
Pterocarpus erinaceus and Coccoloba uvifera. Its solution is colored green by 
ferric salts. It yields phloroglucin on fusion with potassium hydroxide. 

Catechu- Tannin occurs in catechin, the extract of Mimosa Catechu. Ferric 
salts color it a dirty-green (p. 779). Catechin or Caterhinic Acid, C.,H)0, + 
5H,0, is also present in catechu. It crystallizes in shining needles. 

Moringa-Tannin, C,;H,O, + H,O, Maclurin, is found in yellow wood 
(Morus tinctoria) from which it may be extracted (along with morin) with hot 
water. When the solution cools morin separates out; maclurin is precipitated 
from the concentrated liquid by hydrochloric acid, in the form of a yellow crys- 
talline powder, soluble in water and alcohol. Ferric salts impart a greenish-black 
color to its solutions. When fused with caustic potash it yields protocatechuic 
acid and phloroglucin. 

Morin, C,,H,O, + 2H,O, decomposes into phloroglucin and resorcin. Nitric 
acid oxidizes it to 3-resorcylic acid. 
The Zannin of Coffee, CyoH,,0;,, occurs in coffee beans and Paraguay tea. 
Gelatine does not precipitate its solutions. Ferric chloride gives them a green 
color. It decomposes into caffeic acid (see this) and sugar, when boiled with 
potassium hydroxide. Protocatechuic acid is produced when it is fused with potas- 

sium hydroxide. 

The Zannin of Oak is found in the bark (together with gallic acid, ellagic acid, 
quercite). It has the formula C,,H,,O,), and is a red powder, not very soluble in 
cold water, but more readily in acetic ether. Ferric chloride colors its solution 
dark blue. Boiling, dilute sulphuric acid converts it into the so-called oak-red 
(phlobaphene), C,,H,,O,,. 

The Zannin found in the quinine barks is combined with the quinia-alkaloids. 
It closely resembles ordinary tannic acid, but is colored green by ferric salts. 
When boiled with dilute acids-it breaks up into sugar and guzna-red, an amor- 
phous brown substance, yielding protocatechuic acid and acetic acid on fusion with 
potassium hydroxide. 





Quinic Acid is very probably derived from hexahydrobenzene, C,H,(H,) 
(p. 567), and must be considered tetraoxyhexahydrobenzene carboxylic acid, 
C,H(H,)(OH),.CO,H. It is a polyhydric phenol carboxylic acid. It is converted 
into normal benzene derivatives in various reactions. Quercite is intimately 
related to it (p. 697). 


Quinic Acid, C,H,,0,, is present in the cinchona barks, in 
coffee beans, in bilberry and many other plants. It is obtained as 
a secondary product in the preparation of quinine, by extracting 
the quinia bark with dilute sulphuric acid, and precipitating the 
alkaloids with milk of lime. When the filtered solution is evapo- 
rated the calcium salt of the acid separates out. 


The acid consists of rhombic prisms, and dissolves very easily in water, but with 
difficulty in strong alcohol. The aqueous solution is levo-rotatory. It melts at 
66 


a 


786 ORGANIC CHEMISTRY. 


162°, and upon further heating decomposes into hydroquinone, pyrocatechin, ben- _ 
zoic acid, phenol and other products. Oxidizing agents (MnO, and sulphuric acid) | 
convert it into formic acid, carbon dioxide and quinone. Ferments decompose it 
into propionic acid, acetic acid and formic acid. It is a monobasic acid and 
furnishes easily soluble salts. The calcium salt, (C,H,,0,),Ca + 10H,0O, 
crystallizes in rhombic leaflets, which effloresce on exposure to the air. 

Quinic acid is reduced by hydriodic acid to benzoic acid :— 


C,H,(OH),.CO,H + 2HI.— C,H,.CO,H + 4H,0 + I,. 
Phosphoric chloride converts it into chlor-benzoic chloride :— 
C,H,(OH),.CO,H + PCI; = C,H,Cl.COCl] + PO,H; + 3HCl + H,0O. 


Acetic anhydride will convert its ethyl ester into tetracetyl- ethyl ester, C,H,(O. 
C,H,0),CO,.C,H,, which yields large crystals, melting at 135°. 





DIBASIC ACIDS. 


Acids, -G.H,0, <> Gia nats. There are three isomerides. 
2 

1. Phthalic Acid, C,;H,O, is the ortho-dicarboxylic acid of 
benzene, and was first obtained by oxidizing naphthalene and 
chlorinated naphthalenes with nitric acid. It also results on oxidizing 
ortho-xylene and ortho-toluic acid with potassium permanganate, 
alizarin and purpurin with nitric acid, or with manganese dioxide 
and sulphuric acid ; and in slight amount in the oxidation of ben- 
zene and benzoic acid. It is very difficult to get it by using chromic 
acid as an oxidizing agent, since the latter is very apt to burn it at 
once to carbon dioxide (p. 738). It can be synthetically obtained 
from o-nitrobenzoic acid by converting the latter into o-cyanbenzoic 
acid and then boiling this with alkalies (p. 752). 


Preparation.—Boil naphthalene tetrachloride, C,)H,Cl,, with ro parts of 
nitric acid (sp. gr. 1.45) until perfect solution is reached. Naphthalene tetra- 
chloride is obtained by adding a mixture of naphthalene (2 parts) and potassium 
chlorate (1 part) to crude hydrochloric acid (11 parts) (Berichée, 11, 735). 


Phthalic acid crystallizes in short prisms or in leaflets, which 
dissolve readily in hot water, alcohol and ether. It melts above 
200°, decomposes at 140° into phthalic anhydride (melting at 128°) 
and water. When heated with an excess of calcium hydroxide it 
yields benzene and 2CO,. Only 1CO, is split off and calcium ben- 
zoate produced (p. 741) if its lime salt be heated to 330—-350° with 
1 molecule of Ca(OH),. Barium chloride added to aqueous 
ammonium phthalate precipitates barium phthalate, C,H,O,Ba, 
which is very sparingly soluble in water. 


PHTHALIC ANHYDRIDE. 787 


PCI, converts phthalic acid, or phthalic anhydride at 170°, into phthaly! chlo- 


ride, C,H,(CO.Cl),. In accord with all its transpositions this appears to have 
the sceihcie: C,H KO #0. Zinc and hydrochloric acid convert it into 


phthalide (p. 772), aiphthalyl, cog Hc 4, 1500, and hydrodi- 
phthalyl (Berichte, 21, Ref. 1 39), and with benzene and AICI,, or with mercury 
diphenyl it yields C,H Kon! “oHs)2~0, phthalophenone, and with zinc ethyl, 


agra scent C,H <i 22> 0 is sehen erat The latter does not com- 


melting at 178° (Berichte, 19, Ref. 303; 20, Ref. ey With fideo tactee 
C(N.OH) 

és No 
*\co A " 
melting at 230°, as is obtained from phthalic anhydride (Berichte, 16, 1781). 
Phthalyl chloride is a liquid boiling at 268°, and reverts to phthalic acid when 
boiled with water. The esters derived from phthalic chloride differ from those 


derived from phthalic acid { Berichte, 16,860). Sodium amalgam converts phthalyl 
chloride (unlike other transformations) into phthalyl alcohol (p. 712). 


phthalyl chloride yields the same phthalyl-hydroxamic acid, C,H, 





Phthalic Anhydride, Gatto (see p. 402), is obtained 


by distilling phthalic acid or digesting it with acetyl chloride. It 
erystallizes in long, prismatic needles, melting at 128°, and boiling 
at 284°. It yields phthalyl-hydroxamic acid with hydroxylamine, 
and phthalylphenyl-hydrazone with phenylhydrazine. Zinc dust 
and glacial acetic acid convert it into phthalide (p. 772). 


Phthalic anhydride. readily condenses with unsaturated side-chains as a CO- 
group is present to take part in the reaction (p. 716). Thus, phthalyl acetic acid 
is formed on boiling the anhydride with acetic anhydride and sodium acetate, and 

Co ee 
ethine diphthalyl, Sie oe oe (Berichte, 18, 3115), 


when succinic anhydride and sodium acetate are used. It reacts in like manner 
with malonic ester and aceto-acetic ester (Berichte, 19, Ref. 832). It condenses 
with phthalide to diphthalyl (see this). Phthalic anhydride also condenses with 
the benzenes forming benzoylbenzoic acid and phenylphthalides, With the 
phenols it yields the important phthalein dyes (see these). 


Phthalimide, C,H ce or C,H KO >O ty Shlain oo 


By heating phthalic anhydride or chloride in ammonia gas, or by heating 
ammonium phthalate ; 

By heating phthalic acid with ammonium or potassium sulphocyanide (p. 732) 
(Berichte, 19, 1398) ; 

By the molecular rearrangement of the isomeric o-cyanbenzoic acid (p. 752) 

(Berichte, 19, 2283). 
Phthalimide crystallizes in six-sided prisms, which melt at 238°, and sublime. 
It forms fotassium phthalimide, C,H ,(CO),NK, by the action of alcoholic potash. 


ee 


788 ORGANIC CHEMISTRY. 


Salts of the heavy metals can be obtained from it by double decomposition. The 
metal in these salts can be replaced by various radicals (Berichte, 23, 994). Tin 
and hydrochloric acid reduce phthalimide to— 


Phthalimidine, C,H ea ao. which can also be made by a rearrange- 


ment of o-cyanbenzyl alcohol, C,H,(CN).CH,.OH (Berichte, 22, Ref. 9; 23, 


2479). 
Hydrophthalic Acids. 


Phthalic acid can take up two, four and six hydrogen atoms, forming di-, tetra-, 
and hexahydrophthalic acids. These must be considered as derivatives of hexa- 
methylene, and the partially reduced benzene nuclei, C,H, and C,H,. A. 
Baeyer’s theory (Aunalen, 258, 145; Berichte, 23, Ref. 577), based on the spatial 
configurations of van’t Hoff as to the union of the C-atoms, is best explained by the 
scheme of Kekulé, and allows for seven dihydrophthalic acids (enantiomorphous 
forms not included): one geometrical and six structural isomerides. But one of 
the seven forms is known. It also supposes the existence of six tetrahydrophthalic 
acids (four structural isomerides and two geometrical isomerides—the four first 
are known), and two geometrically isomeric hexahydrophthalic acids. The latter 
isomerism is due to the different positions occupied by the carboxyls relatively to 
the plane of the hexamethylene ring, and corresponds to that of maleic and fumaric 
acid (Annalen, 258, 176); hence the isomerides are termed maleinoid and fuma- 
roid (or cts and trams) forms. Baeyer indicates the structure of the di- and tetra- 
hydro-acids by representing the double unions with A (see p. 568). The partially 
hydrided phthalic acids behave the same as the unsaturated acids of the paraffin 
series. They unite quite readily with bromine and are oxidized with ease by potas- 
sium permanganate. 

Dihydrophthalic Acid, C,H,(H,)(CO,H), (1, 2), results from the action of 
sodium amalgam upon a cold solution of phthalic acid. The acid melts at 215°, 
combines readily with Br, and two molecules-of hydrobromic acid, and is at once 
decomposed by potassium permanganate (Berichte, 23, Ref. 578). 

Tetrahydrophthalic Acids, C,H4(H,)(CO,H),. Four of the six possible iso- 
merides are known. 

The A,-acid is produced by the solution of its anhydride in hot water. It crys- 
tallizes in leaflets containing one molecule of water. They effloresce quite rapidly. 
The acid is very similar to pyrocinchonic acid (dimethyl maleic acid, p. 430), and 
readily changes to its anhydride, C,H,O,. The latter can also be obtained 
by the distillation of hydropyromellitic acid. It crystallizes from ether in leaflets. 
It melts at 74°, and is readily volatilized. Boiling potash converts the A,-acid into 
the A,-acid (Berichte, 23, Ref. 579; Annalen, 258, 161). 

A,- and A,-Tetrahydrophthalic Acids are formed by reducing phthalic acid with 
sodium amalgam or by boiling dihydrophthalic acid. The first melts at 215-218°, 
and yields an anhydride, melting at 140°. The second acid yields the A,-acid 
when heated to 220° or if boiled with water. The A,-acid melts at 174°. 

Hexahydrophthalic Acid, C,H, .(CO,H),, exists in a fumaroid and maleinoid 
form. The first dissolves with difficulty and melts at 215°. It forms an anhydride 
- with acetyl chloride, melting at 140°. The maléinoid form is more soluble in 
water and melts at 192°, forming an anhydride, melting at 32°. (For its analogy 
with fumaric and maleic acids, see Aunalen, 258, 176.) 


2. Isophthalic Acid, BEd con (1, 3), is obtained: by 


oxidizing isoxylene and isotoluic acid with a chromic acid mixture ; 
by fusing potassium m-sulphobenzoate, m-brombenzoate and ben- 


TEREPHTHALIC ACID. 789 

e 
zoate with potassium formate (terephthalic acid is also formed in 
the last two cases); by the action of the ester of chlorcarbonic acid 
and sodium amalgam upon m-dibrombenzene; from m-dicyanben- 
zene (p. 735) and m-cyanbenzoic acid (p. 752); also by heating 
hydro-pyromellitic and hydro-prehnitic acid (p. 798), and by oxi- 
dizing colophony with nitric acid. Isophthalic acid crystallizes 
from hot water in fine, long needles. The most convenient method 
for its production consists in converting m-xylylene bromide into 
the diethyl ether and then oxidizing the latter (Berichte, 21, 47). 
It is soluble in 460 parts boiling, and 7800 parts cold water. It 

melts above 300°, and sublimes in needles. 


The barium salt, C,H,O,Ba + 3H,O, crystallizes in fine needles, and is 
very soluble in water; therefore, it is not precipitated by barium chloride from a 
solution of ammonium isophthalate (distinction between phthalic and terephthalic 
acids). 

The Dimethyl-isophthalate, C,H,(CO,.CH,),, crystallizes from alcohol in 
needles, and melts at 65°. The dzethy/ ester is liquid, solidifies below 0°, and boils 
at 285°. 

Isophthalyl Chloride, C,H,O,Cl,, is formed upon heating isophthalic acid 
with PCI, to 200°. Its formula is C,H,(COCI),. It melts at 41° and boils at 
276°. ‘There is only one tetrahydro-acid derived from the hydroisophthalic acids. 


3. Terephthalic Acid, C,H,(CO,H), (1, 4), was first obtained 
by oxidizing turpentine oil. It results in oxidizing paraxylene, 
paratoluic acid and all di-derivatives of benzene having two carbon 
chains belonging to the para-series (e. g., cymene and cumene) 
with chromic acid. The oxidation of crude xylene affords tere- 
phthalic (15 per cent.) and isophthalic (85 per cent.) acids, which 
are separated by means of their barium salts. Terephthalic acid is 
produced, too, when /-dicyanbenzene, C,H,(CN), (p. 735), and 
p-cyanbenzoic acid are boiled with alkalies as well as from 
p-dibrombenzene, by the action of chlorcarbonic acid and sodium. 
The best course to pursue in forming terephthalic acid is to oxidize 
caraway oil (a mixture of cymene and cuminol) with chromic acid, 
or it may be prepared from /-toluidine by changing this into the 
nitrile, C,H,(CH;).CN, etc. (Berichte, 22, 2178). 

Terephthalic acid is a powder, which is almost perfectly insoluble 
in water, alcohol and ether, and is, therefore, precipitated from its 
salts by acids. It sublimes without previous fusion when it is 
heated. Sometimes terephthalic acid is obtained with properties 
slightly different from the regular acid (insolic acid). The cause 
of this seems to be due to an admixture of acetophenone-carboxylic 
acid. 

The calcium salt, C,H,O,Ca + 3H,O, and barium salt, C,H,O,Ba + 4H,0, 
are very sparingly soluble in water. The methy/ ester, C,H,(CH,),O,, melts at 
140°; the ethyl ester, at 44°. 

Terephthalyl Chloride, C,H,(COCI1),, is formed when terephthalic acid is 


790 ORGANIC CHEMISTRY. 


bd 
heated with PCl,. It melts at 78° and boils at 259°. It forms terephthalophe- 
none with benzene and AICI. 

Nitroterephthalic Acid is produced when terephthalic acid is boiled with con- 
centrated nitric acid. It melts at 259°. Reduction converts it into amidotere- 
phthalic acid, C,H,(NH,).(CO,H),, which can be further changed to cyantere- 
phthalic Acid, C,H,(CN) (CO,H), (Berichie, 19, 1634). 

Hydroterephthalic Acids. 


Ten hydroterephthalic acids are possible according to Baeyer’s theory: five 
dihydro-, three tetra-hydro, and two hexahydro acids ; three of these are geomet- 
rical isomerides (Annalen, 259, 1 and 149; Berichte, 23, Ref. 569,577). The 
unsaturated hydrophthalic acids contain only double (no para) linkages. In de- 
portment they are perfectly analogous to the unsaturated acids of the paraffin 
series, particularly muconic acid and the two hydro-muconic acids (Berichie; 23, 
Ref. 231). Ferricyanide of potassium oxidizes most of the hydro-acids to 
terephthalic acid. They are completely destroyed by potassium permanganate. 
With bromine the A,, ,- and A,, ,-dihydro-acids yield only dibromides, whereas 
the acids A,, ,- and A,, ,;- yield tetrabromides. The first product in the oxidation 
of terephthalic acid is A,, ,-dihydro-terephthalic acid. A ava addition very prob- 
ably occurs in this instance, which finds explanation, according to Baeyer, in the 
analogous deportment of muconic acid (Annalen, 208, 148; 256, 1). 

The ten isomerides have all been prepared and differ in their constitution 
(Baeyer, Berichte, 23, Ref. 570). : 





2. Acids, CgH,O,. (1) Methylphthalic Acids, C,H ,(CH,) { atte 

Uvitic Acid, Mesidic Acid (1, 3, 5), is obtained by oxidizing mesitylene, 
C,H,(CH,),, with dilute nitric acid (mesitylenic acid is produced at the same 
time, p. 756). It is formed synthetically by boiling pyroracemic acid with baryta 
water (p. 566). It crystallizes from hot water in needles, melting at 287°. 
Chromic acid oxidizes it to trimesic acid (p. 797); distilled with lime it at first 
yields metatoluic acid, then toluene (p. 741). 

The synthesis of uvitic acid from pyroracemic acid is due to the condensation 
of three molecules of pyroracemic acid, with one molecule of acetaldehyde. In 
this reaction a portion of the pyroracemic acid is decomposed. If a mixture of 
pyroracemic acid and higher fatty aldehydes be used homologous alkylisophthalic 
acids, C,H,(R)(CO,H),, will result. Thus propyl aldehyde produces ethyliso- 
_ phthalic acid, C,H,(C,H,;)(CO,H),, isobutyric aldehyde yields isopropyl isophthalic 
acid, etc. (Doebner, Berichte, 23, 2377). 

Xylidic Acid, C,H,(CH,).(CO,H),, is obtained by oxidizing pseudocumene, 
C,H,(CH,), (1, 3, 4), xylic acid and so-called paraxylic acid with dilute nitric 
acid; hence its structure is (1, 3, 4—CH, in 3) (p. 756). Potassium permanga- 
nate oxidizes it to trimellitic acid. It separates from boiling water in flocculent 
masses; melts at 282° and sublimes. 





(2) Homophthalic Acids, Osi an 

Phenylaceto-carboxylic Acid, Isouvitic Acid, is the ortho-compound. It 
may be obtained by fusing gamboge with caustic potash (Aerich/e, 19, 1654), 
and by saponifying cyan-o-toluic acid (from phthalide and potassium cyanide, 
p. 772). It crystallizes from hot water in stout prisms, melting at 175°, with the 


PHENYL-SUCCINIC ACID. 791 


elimination of water. Its anhydride, C,H,O,, obtained by digesting the acid 
with acetyl chloride, melts at 141°. 

Homophthalimide, C,H,NO,, is produced when the ammonium salt is 
-heated. It crystallizes in minute needles, melting at 233° and distilling without 
decomposition. When it is heated with phosphorus oxychloride it yields dichlor- 
isoquinoline, C,H,NCIl,, which becomes isoquinoline when further heated with 
hydriodic acid (Berichte, 19, 2354) :-— 


CHa CO SECC CH:CH 
CoH | CoH | CoH | r° 
CO. NH CCl: N CH:N 
Homophthalimide. Dichlorisoquinoline. Isoquinoline. 


Homophthalimide is directly converted into isoquinoline when it is heated with 
zinc dust; the reaction is analogous to the production of pyrrol from succinimide 
(Berichte, 21, 2299). 

The hydrogen atoms of the CH,-groups are replaced by two alkyls when 
homophthalimide is heated with caustic potash and alkyl iodides. JM/ono-alkyl 
derivatives of homophthalimide are also produced when o-cyanbenzyl cyanide, 


C,H hoot ene (homophthalonitrile), is alkylized and further re-arranged 


(Berichte, 20, 2499). 

The fara-compound, homoterephthalic acid, C,H,(CO,H).CH,.CO,H, has 
been obtained from g-cyanbenzyl cyanide, C,H,.(CN).CH,.CN, and melts at 
228° (Berichte, 22, 3216). 

(3) Phenyl Malonic Acid, C,H,.CH(CO,H),. The ethyl ester of dinitro- 
phenylmalonic acid may be obtained from sodium malonic ester and bromdinitro- 
benzene. It forms yellow prisms, melting at 51°. It dissolves in the alkalies 
forming dark-red colored salts (Berichte, 21, 2740). Dinitrobromphenylmalonic 
ester ( Berichte, 21, 2034) is formed by the action of tribromdinitrobenzene upon 
malonic ester. 





(3) Acids, C,,H,,0,. 
Dimethyl Phthalic Acids, C,H,(CH,),(CO,H),. Two isomeric acids, 
called cumidic acids, have been obtained by the oxidation of durene and durylic 


acids (p. 760) (Berichte, 19, 2508). 
: : ; : CH,.CH,.CO,H : 
o-Hydrocinnamic Carboxylic Acid, CoH Colin Sore te 2 


formed by oxidizing tetrahydro-$-naphthylamine with potassium permanganate. 
It melts at 165° (Berichte, 23, 1562; 21, 1120). 

Phenylene Diacetic Acids, C,H CH COME The para- and ortho- 
acids have been obtained from the xylylene cyanides (p- 735). The first melts at 
244°, and the second at 150°. 

C,H,.CH.CO,H 
Phenyl-Succinic Acid, » results from a-chlorstyrene, 
CH,.CO,H 

C,H,.C,H,Cl, by means of potassium cyanide; by the decomposition of pheny]l- 
acetsuccinic ester, by means of alkalies; from phenyl-ethane-tri-carboxy-succinic 
acid (p. 797), and from the so-called hydro-cornicularic acid, C,H, ,O,. It crys- 
tallizes from hot water in warty masses, melts at 167° (162°) and (like succinic 
acid) yields an anhydride, C,,H,O,, melting at 54°. 

Phenylmalic and phenylmaleic acids (Berichte, 23, Ref. 573) are produced 
when bromine, etc., acts upon phenylsuccinic acid. 

. B-Phenylisosuccinic Acid, C,H;.CH,.CH(CO,H),, Benzyl Malonic Acid, 


792 ORGANIC CHEMISTRY. 


formed from sodium malonic ester, CH(Na)(CO,R),, and benzyl chloride is very 
readily soluble in water, melts at 117°, and at 180° decomposes into carbon diox- 
ide and hydrocinnamic acid, C,H,.CH,.CH,.CO,H. 

The ester of dibenzyl malonic acid, (C,H,.CH,),C.(CO,H), (Berichie, 20,: 
Ref. 380), is produced simultaneously with benzyl-malonic ester by the entrance of 
a second benzyl group. . 

The action of o- and g-nitrobenzyl chloride upon malonic ester produces the 
corresponding nitrobenzyl- and bi-nitrobenzyl-malonic esters (Berichte, 20, 434). 

4. Benzylsuccinic Acid, C,H,.CH,.C,H,(CO,H), = C,,H,,.0x4. results 
from ethan-tricarboxylic ester (p. 471), or ethan-tetracarboxylic ester (p. 481), by 
the action of benzyl chloride, etc. (Berichte, 17, 449), as well as by the reduction 
of phenylitaconic acid (Berichte, 23, Ref. 237). It melts at 161° and forms an 
anhydride, melting at 102°. 

Symmetrical benzyl-alkyl-succinic acids, capable of existing in two alloisomeric 
forms, are similarly produced (Berichée, 23, 1942). 





OXYDICARBOXYLIC ACIDS AND OXYALDEHYDIC ACIDS. 


The oxyphthalic acids,C,H,O, = C,H,(OH).(CO,H),, can be obtained from 
the phthalic acids by the introduction of the OH-group by means of the amido- 
or sulpho-derivatives. . They are also formed from the oxy-monocarboxylic acids, 
C,H,(OH).CO,H, by heating their alkali salts in a current of carbon dioxide, or 
by means of the CCl, reaction (p. 767). Their ether acids, e.g.,C,H,(O.CH,) 
(CO,H),, result by the oxidation of the ether acids of the oxytoluic acids, C,H, 
(O.CH,) Cries (p. 771), and by the same treatment of the oxyaldehydic acids, 

2 


C,H,(0.CH,) CC0.H (the latter are obtained from the oxymonocarboxylic 
acids, C,H,(OH).CO,H, by means of the CCl,H reaction, and by further intro- 
duction of methyl); when the phenol ethers are heated with hydrochloric acid the 
free oxydicarboxylic acids result. Hence, the six possible Oxyphthalic Acids, 
C,H,(OH).(CO,H),, can be obtained by these reactions (Berichze, 16, 1966). 

Oxyterephthalic Acid, C,H,(OH)(CO,H),, has. been obtained from nitro- 
terephthalic acid. It is a powder that dissolves with great difficulty. Sodium 
amalgam converts itinto Tetrahydro-oxyterephthalic Acid, C,H,(OH)(CO,H),, 
or C,H,(O)(CO,H),, which at 118° (or readily when heated with water) decom- 
poses into carbon dioxide and Hexahydro-ketobenzoic Acid, CO,H.C 
H eH" CO. 2>CH,. The latter isa syrup. It forms an oxime with hydroxyla- 
mine and a hydrazone with phenylhydrazine, Acids transform the latter into a 
carbazol derivative (Aerichte, 22, 2179). 

C,H,.C(OH).CO,H C,8,.CH.CO.H 

Phenyl-malic Acids, | and | he 

; CH,.CO,H CH(OH).CO,H 
first may be obtained from phenylsuccinic acid by the action of bromine and 
water. It melts at 187°. The second acid is derived from phenyl-formy! acetic 
ester (p. 761) by the action of CNH, etc. It melts at 150—160° (Berichée, 23, 
Ref. 572). . OH ; 

Oxyuvitic Acid,C,H,O, = C,H,(CH,) (COOH),? #§ # homologue of the 
oxybenzenedicarboxylic acids, and is produced by the action of chloroform, chloral 
or trichloracetic ester upon sodium aceto-acetic ester (Ammadlen, 222, 258). It 
crystallizes from hot water in fine needles, and melts with decomposition at 
about 290°. 


DIOXY-CARBOXYLIC ACIDS. 793 


The y-oxybenzene dicarboxylic acids at once eliminate water and become Jac- 


tonic acids. In this class may be included :— / CH-CO,H 
Phthalid-carboxylic Acid, C,H,O, = C,H, No  - Thisis produced 
\CO / 


by reducing phenyl-glyoxyl-o-carboxylic acid (p. 765) with sodium amalgam (Ze- 
richte, 18, 381). It is quite soluble in water, crystallizes in leaflets, melts at 149°, 
and beyond 180° decomposes into carbon dioxide and phthalide. 
/ CH-CH,-CO,H 
Phthalid-acetic Acid, C,,H,0, = C,H, \o . Derived from 
m CO 7 


benzoyl aceto-carboxylic acid (p. 765) by the action of sodium amalgam. It is 
very soluble in hot water and alcohol. It crystallizes with one molecule of water 
in delicate needles, melting at 151°. 

Phenyl-paraconic Acid, C,,H,,0,, and Phenyl-itamalic Acid, 


C,,H,,0;: 
C,H,.CH.CH(CO,H).CH, /CO,H 
ah C.8, CHORES CH CO.H 


Phenyl-paraconic Acid. Phenyl-itamalic Acid. 





The lactone acid of phenyl-itamalic acid is obtained by heating benzaldehyde 
with sodium succinate and acetic anhydride. It crystallizes from hot water in 
shining needles, and melts at 99°; when perfectly anhydrous at 109°. When 
it is boiled with alkalies it yields the salts of phenyl-itamalic acid. The latter, 
when in a free condition, immediately reverts to- phenyl-paraconic acid. This, 
upon distillation, breaks down into carbon dioxide, phenylbutyrolactone (p. 777) 
and phenylisocrotonic acid. A further product is a-naphthol. 

Three ch/orparaconic acids are similarly produced from sodium succinate and the 
three chlorbenzaldehydes. They yield three chlorinated a-naphthols (Berich/e, 21, 
Ref. 733). Pyrotartaric acid and benzaldehyde (p. 462) yield a- and 8-methy/- 
phenyl paraconic acid, C,,H,,O,, from which methyl-a-naphthol may be produced 
by distillation (Berichte, 23, Ref. 96). Sodium, or sodium ethylate, acting upon 
phenyl-paraconic ester, produces pheny/-ttaconic acid, C,H ,.CH:CH(CO,H)CH,. 
CO,H (Berichte, 23, Ref. 236), by a reaction peculiar to lactonic acids. 





DIOXY-CARBOXYLIC ACIDS. 


Dioxyphthalic Acids, C,H,(OH),(CO,H),. Eleven isomerides. 

1. There are four possible dioxy-acids of ortho-phthalic acid. The most re- 
markable of these is dioxy-phthalic acid (1, 2, 4, 5—the hydroxyls in 4 and 5). It 
has not yet been isolated, because it readily loses carbon dioxide and passes into 
protocatechuic acid (2, 4, 5—CO,H in 2). The following compounds are among 
its derivatives ; they have been prepared from narcotin: hemipinic acid, C\yH,)O,, 
opianic acid, CH yO;, noropianic acid, CsH,O;, meconinic acid, C,)H,,0,, and 
meconine, CyyH, O, :— 

(O.CH,), (4, 5) CHO (O.CH,), 
C,H, <CO,H (2) C,H, <~CO,H C,H, < CO,H 


2 


CO,H = (1) (OH), CHO 
Hemipinic Acid. Noropianic Acid. Opianic Acid. 
--((0.CH). 
C,H 1 OG 
CH, x 


Meconine. 


794 ORGANIC CHEMISTRY. — 


Hemipinic Acid, C,,H,,O,. This should be regarded as a carboxy] derivative 
of dimethyl protocatechuic acid, since it decomposes, when heated with hydro- 
chloric acid, into protocatechuic acid, carbon dioxide and methy] chloride :— 


C,oH,,0, + 2HCl = C,H,0O, + CO, + 2CH,Cl. 


It is formed together with opianic acid and meconine by oxidizing narcotin with 
dilute nitric acid. In an anhydrous state it melts at 182°, and yields an anhydride, 
melting at 167°. Hence, the CO,H groups occupy the ortho-position. 

Metahemipinic Acid, isomeric with hemipinic acid, is.formed by the oxida- 
tion of papaverine (Berichte, 21, Ref. 787; 22, Ref. 195). 

Noropianic Acid, C,H,O,, dioxyaldehyde carboxylic acid, aldehydo-proto- 
catechuic acid (see above), is obtained from opianic acid by the elimination of the 
two methyl groups upon heating with hydriodic acid’ (isovanillin is simultaneously 
formed by the removal of one methyl group and carbon dioxide). It is rather 
readily soluble in water, melts when anhydrous at 171°, and is colored bluish-green 
by ferric chloride. 

Opianic Acid, C,,H,,0O,, the dimethyl ether of the preceding compound, is 
an aldehyde-dimethy]-protocatechuic acid, because when it is heated with hydro- 
chloric acid it yields protocatechuic aldehyde, carbon dioxide and two molecules 
of methyl chloride. It is converted into dimethyl-protocatechuic aldehyde 
when heated with soda-lime. It crystallizes from hot water in fine prisms, 
melting at 150°. It is oxidized to hemipinic acid. Opianic acid unites with 
phenylhydrazine with the elimination of two molecules of water (Zerichée, 19, 
763). Consult Berichte, 2¥, 2518, for its combinations with diphenylhydrazine, 
hydrazobenzene, etc. When opianic acid combines with hydroxylamine, two 
molecules of water escape, and hemipinimide ( Berichée, 19, 2278, 2913) is formed. 
Consult Berichte, 19, 2299; 20, 875 for azo-opianic acid derived from nitro-opianic 
acid. 

Meconine, C,,H,,0,, results when sodium amalgam acts upon opianic acid and 
the solution is precipitated by acids. At first the sodium salt of Meconinic Acid, 
C,,H,,0;, is produced. The latter is a y-oxyacid, and at once parts with water, 
passing into its lactone anhydride—meconine (see Phthalide, p. 772). Meconine 
occurs already formed in opium, and is obtained on boiling narcotine with water. 
It yields shining crystals, melting at 102°, and dissolving with difficulty in water. 
It dissolves in the alkalies, yielding salts of meconinic acid. In the same manner 
that phthalimide yields phthalide (p. 788), hemipinimide furnishes -meconine, 
and not meconine (Berichte, 20, 833). : 

2. The most interesting of the four possible dioxy-acids derived from tere- 
phthalic acid is— 

p-Dioxy-terephthalic Acid, C,H,(OH),(CO,H), (1, 4-2, 5), containing 
the hydroxyl groups in opposite para-positions. It is isomeric or tautomeric with 
hypothetical diketo-tetrahydro-benzene dicarboyxlic acid :— 


ZC(OH)—CH—~ got ee: Be 
7 HEO,CY Gls S C(Oi) Oat HOO, cq — co 76 COM. 
p-Dioxyterephthalic Acid, Diketo-tetrahydro-benzene 
Dicarboxylic Acid. 





Free dioxyterephthalic acid may be obtained by boiling its ester with sodium 
hydroxide. It crystallizes from alcohol in yellow leaflets, containing two mole- 
cules of water. Ferric chloride imparts a deep blue coloration to its solution. 
When rapidly distilled it decomposes into two molecules of carbon dioxide and 
hydroquinone. Sodium amalgam reduces it to succino-succinic acid (Berich/e, 22, 
2168). Its diethyl ester, C§H,O,(C,H;),, may be prepared by withdrawing two 
hydrogen atoms from succino-succinic ester (C,H,O,(C,H;),), by means of bro- 


Oe ee 





DIOXY-CARBOXYLIC ACIDS. 795 


mine or PCI, (Berich/e, 22, 2107), or by the action of sodium ethylate upon di- 
bromacetoacetic ester (Aznalen 219, 78). It crystallizes in two distinct forms, 
at the-ordinary temperature in yellowish green prisms or plates, at higher tempera- 
tures in colorless leaflets. It also sublimes in the latter form. It melts at 133°. 
In most of its reactions the ester conducts itself like a hydroxyl-derivative. It 
does not combine with hydroxylamine or phenylhydrazine, and with sodium and 
alkyl iodides yields dialkyl esters. It, however, does not react with phenylcyanate 
(p. 613) (Berichte, 23, 259), and shows some analogies with succino-succinic 
ester. Hence, it is considered a quinone- or diketo-derivative—corrresponding to 
the tautomeric formula given above. The different physical modifications of the 
ester and analogous compounds, according to Hantzsch, correspond to the two 
desmotropic conditions (p. 54)—the colored variety agreeing with the quinone 
formula, while the colorless ¢orresponds to the hydroxyl formula (Serichée, 22, 
1294). However, the color cannot be regarded as a certain criterion for the dis- 
tinction of the ketone from the hydroxyl form. Even chemical reactions do not 
prove that desmotropic forms can be accepted (Nef, Berichte, 23, Ref. 585; 
Goldschmidt, Berichte, 23, Ref. 260). 

Dioxyterephthalic ester, by reduction (boiling with zinc and hydrochloric acid 
in alcoholic solution), is again changed to succino-succinic ester (Berichte, 19, 
432; 22, 2169). A dihydroxamic acid is formed with hydroxylamine hydro- 
chloride; ¢etrahydrodioxy-terephthalic acid, C,H,(H,)(OH),(CO,H),, is pro- 
duced at the same time, and decomposes at 180° with carbonization (erich/e, 
22, 1280). 

Succino-succinic Acid, C,H,O,, may be represented by either of the follow- 
ing formulas :— 


- 


HCO,.CH.CO.CH, HCO,.C = C(OH)— CH, 
| or : 
CH,.CO.CH.CO,H CH,—C(OH) — C.CO;H 
p-Diketo-hexahydro-benzene Dioxy-dihydro-terephthalic Acid, 


Dicarboxylic Acid. 


The first is derived from hexahydrobenzene, the second from A, ,-dihydrotere- 
phthalic acid (Berichte, 22, 2107 and 2169). The diethyl ester is produced by 
the condensation of two molecules of succinic ester through the agency of sodium 
or sodium ethylate upon succinic ester or bromacetoacetic ester (p. 333) (Berichte, 
21, 1464; 22, 1282). It crystallizes in bright green triclinic prisms or colorless 
needles, melting at 126-127°. It is insoluble in’ water, dissolves with difficulty in 
ether, very readily in alcohol; its solution shows a bright blue fluorescence. 
Ferric chloride imparts a cherry red color to it. The digethyl ester, C,H,O, 
(CH,),., from methyl succinic ester, melts at 152°. The esters dissolve in alkalies 
(not ammonia) with a yellow color. They yield metallic derivatives by the 
replacement of two hydrogen atoms (Berichte, 19, 428). 

With hydroxylamine (in alkaline or acid solution) succino-succinic ester does . 
not react directly like a diketone, but, splitting off CO,R and four hydrogen 
atoms, yields quinone-dioxime carboxylic ester (C,H,(N.OH),.CO,R), forming 
yellow needles, melting at 174° ( Berichte, 22, 1283). The ester appears to form 
a normal hydrazone with phenylhydrazine (Berichte, 19, 429). It does not react 
with phenylcyanate (Berichte, 23, 258). PCl, converts the ester into dichlor- 
hydroterephthalic acid, C,H ,Cl,(CO,H), (Berichte, 21, 468). 

If succino-succinic ester be saponified by dilute alkalies, with exclusion of air, 
it yields free : 

Succino-succinic Acid, CSH,0O, = C,H,O,(CO,H), (see above). This may 
be more readily obtained by boiling dioxyterephthalic ester with sodium hydroxide 
and reducing the product with sodium amalgam (Berichte, 22, 2168). It is a 


796 : ORGANIC CHEMISTRY. 


yellow pulverulent precipitate, which dissolves with difficulty. Air oxidizes it in 
solution to dioxyterephthalic acid. Water gradually decomposes it into carbon 
dioxide and succinylo-propionic acid, C,H,O,.CO,H. The acid breaks- down 
into two molecules of carbon dioxide and diketohexamethylene upon the applica- 
tion of heat. ) 

Chlorine converts succino-succinic ester and dioxyterephthalic ester into /-di- 
chlorquinone-dicarboxylic ester, CC1,0,(CO,.C,H,),. This consists of greenish 
yellow crystals, melting at 195°. Bromine produces the analogous dibrom- 
derivative (Berichte, 21, 1761). Zinc dust and glacial acetic acid yield 

Dichlorhydroquinone-dicarboxylic Ester, C,Cl,H,O,(CO,R),, crystal- 
lizing in two different forms—coloriess needles and yellow-green plates, corre- 
sponding to the desmotropic forms (see above) (Berichte, 20, 2796) :— 


R.CO,.C — CCl = C(OH) R.CO,.CH — CCl — CO 
| | | 
C(OH) — CCl = bco,r CO — CCl = CH.CO,R. 


However, the existence of a chemical difference has not been proven (Berichée, 
23, 260). Dibromhydroquinone-dicarboxylic Ester, C,Br,H,O,(CO,R), 
(Berichte, 21, 1759), shows a like deportment. 

Dioxy-quinone-dicarboxylic Ester, C,H,(OH),(CO,R), = C,H,O,R,, 
may be prepared by shaking dichlorhydroquinone-dicarboxylic ester with sodium 
hydroxide, and by the action of nitrous acid upon dioxy-terephthalic ester (Berichée, 
19, 2385). It melts at 151°, and crystallizes in pale yellow leaflets and intense 
greenish yellow prisms. The latter form is:probably diquinoyl-dihydrobenzene 
dicarboxylic ester, C,H,(O,)(O,)(CO,R), (Berichte, 20,1307). It reacts acid, 
and forms salts with two equivalents of the metals. It does not form a dioxime 
with hydroxylamine, but an oxyammonium salt, and with phenylhydrazine a 
phenylhydrazine salt (Berichte, 22, 1290). Furthermore, it does not react with 
phenylcyanate (Berichte, 23, 265). Boiling hydrochloric acid decomposes the 
ester into carbon dioxide and dioxy-quinone (p. 702). By the absorption of two 
atoms of hydrogen (by reduction with sulphurous acid) the ester becomes 

Tetroxy-terephthalic Ester, C,(OH),(CO,R,), or Dioxy-quinone-dihydro- 
carboxylic Ester, C,H,(O,)(OH),(CO,R),. It crystallizes in golden yellow 
leaflets and melts at 178° (Berichée, 20, 2798). Its alkaline solution oxidizes on 
exposure to the air (giving up two hydrogen atoms) to dioxy-quinone-dicarboxylic 
ester, hence, it yields the same products with hydroxylamine and phenylhydrazine 
(Berichte, 22, 1291). It forms a tetracarbanilido-derivative (Berichte, 23, 267) 
with four molecules of phenylcyanate. 





The following is a trioxy-dicarboxylic acid :— 

Gallocarboxylic Acid, C,H(OH),(CO,H), = C,H,O,. It may be prepared 
from pyrogallol by heating it to 180° with ammonium carbonate. Pyrogallo-car- 
boxylic acid is formed at the same time. It dissolves in water with difficulty, 
crystallizes in needles, and melts at 270° with decomposition. 





TRIOXY-TRICARBOXYLIC ACIDS. 197 


TRIBASIC ACIDS. 


Benzene Tricarboxylic Acids, CsH;(CO,H);, 3 isomerides. 


1. Trimesic Acid, C,H,O, (1, 3, 5), is formed when mesity- 
lenic and uvitic acids are oxidized with a chromic acid mixture 
(mesitylene is at once burnt up); by heating mellitic acid with 
glycerol (together with tetracarboxylic acids), or hydro- and iso- 
hydromellitic acid with sulphuric acid. The synthetic methods for 
its production are: heating benzene trisulphonic acid with potassium 
cyanide and saponifying the resulting cyanide (p. 660); by poly- 
merizing propiolic acid (p. 565); and by the action of sodium upon 
a mixture of acetic and formic esters (p. 566). It crystallizes in 
short prisms, which dissolve readily in hot water and alcohol. It 
melts about 300°, and sublimes near 240°. Heated with lime it 
decomposes into 3CO, and benzene. Its triethyl ester melts at 


122°. 


2. Trimellitic Acid, C,H,(CO,H), (1, 2,4). This is obtained (together 
with isophthalic acid) by heating hydropyro-mellitic acid with sulphuric acid, or 
upon oxidizing xylidic acid with potassium permanganate. It is prepared most 
readily (along with isophthalic acid) by oxidizing colophony with nitric acid 
(Annalen, 172, 97), is very soluble in water, and separates in warty masses. It 
melts at 216°, decomposing into water and the anhydride, C,H,(CO,H)(CO),0. 
The latter melts at 158°. 

3. Hemimellitic Acid, C,H,(CO,H), (1, 2, 3). This is formed on heating 
hydromellophanic acid (below) with sulphuric acid. It forms needles, which are 
sparingly soluble in water, melts at 185°, and decomposes into phthalic anhydride 
and benzoic acid. 

Phenyl-ethenyl-tricarboxylic Acid, C,H,.CH(CO,H).CH(CO,H), (vide 
p. 471), is obtained from phenylchloracetic ester, C, H;.CHCI1.CO,R, by the action 
of sodium malonic ester, CHNa(CO,R),. It is a crystalline mass, easily soluble 
in water, and at 191° decomposes into carbon dioxide and phenyl succinic acid 
(p. 791) (Berichte, 23, Ref. 573). 





TRIOXY-TRICARBOXYLIC ACIDS. 


Phloroglucin-tricarboxylic Acid, C,H,O, = C,(OH),(CO,H), or C,H, 
O, (CO,H), (p. 695), belongs to this class. Its ¢rte‘hy/ ester may be formed by the 
condensation of malonic ester upon heating its sodium compound to 120—145° 
(p. 566), or by the action of zinc alkyl. The ester, C)H,(C,H,),Oog, crystallizes 
from alcohol in yellow needles. These melt at 104°, It dissolves in ether with 
a greenish fluorescence. It deports itself quite like succino-succinic ester, dissolves 
unchanged in alkalies, and is colored a cherry-red by ferric chloride. Acetic 
anhydride converts it into a triacetyl derivative, and with hydroxylamine it yields 
a trioxime, C,H,(N.OH),(CO,R), (Berichte, 21, 1766), with phenyl cyanate it 
forms a tricarbamido-derivative (Berichte, 23, 270). Fused with alkalies it forms 
phloroglucin. 


798 ORGANIC CHEMISTRY. 


TETRABASIC ACIDS. 


Benzene Tetracarboxylic Acids, C,H,(CO,H),. There are three isomerides. 

I. Pyromellitic Acid, C,,H,O, (1, 2, 4, 5). Its anhydride is produced 
when mellitic acid is distilled, or better, when the sodium salt is subjected to the 
same treatment with sulphuric acid (114 parts) :— 


C,(CO,H)¢ = C,H,(CO,H), + 2CO, and 
C,H,(CO,H), = C,H,(CO),0, + 2H,0. 


The acid results when the anhydride is boiled with water. It is also produced 
by oxidizing durene and durylic acid with potassium permanganate. 

Pyromellitic acid is very similar to phthalic acid. It crystallizes in prisms, 
containing 2H,O, and dissolves readily in hot water and alcohol, At 100° it 
loses its water of crystallization, melts at 264°, and decomposes into water and the 
dianhydride, C, ,H,0, = C,H, cee? ) 2, Which sublimes in long needles, 
and melts at 286°. The ethyl ester, C,H,(CO,.C,H;),4, melts at 53°. 

Hydro- and iso-hydro-pyro-mellitic acids, C,,H,,0, = C,H,(H,)(CO,H),, 
are obtained by the continued action of sodium amalgam upon the aqueous solu- 
tion of the ammonium salt, The first results as a gummy mass upon evaporating 
the ethereal solution; it is very soluble in water. The second crystallizes with 
2H,O, loses the same about 120°, melts near 200°, and decomposes into water, 
carbon dioxide and A,-tetrahydrophthalic anhydride (p. 788) (Avmaden, 258, 205). 
When heated with sulphuric acid both evolve CO, and SO, and form trimellitic 
and isophthalic acids. 

By replacing the two p hydrogen atoms in pyromellitic ester by O, (by eiidiciig 
the diamido-compound with nitric acid) Sovgnmas Ig, 516) we obtain 

Quinone Tetracarboxylic Ester, C,(O,)(CO,.C,H;),, crystallizing in 
quinone-yellow needles, melting at 148°—1 Ga?! Tt odorless, but sublimes quite 
readily. Zinc reduces it in glacial acetic acid solution to 

Hydroquinone Tetracarboxylic Ester, C,(OH),(CO,.C,H;), or C,H, 
(O,)(CO,.C,H,),, crystallizing in bright yellow needles, melting at 126-1 28° 
(Berichte, 22, Ref. 289). Its solutions exhibit a beautiful blue fluorescence. It 
dissolves with a yellowish red color in caustic soda. Nitric acid readily reoxidizes 
it to the quinone-acid. In its entire deportment it shows great analogy to dioxy- 
terephthalic ester (p. 794). In alcoholic solution it is reduced by zine dust and 
hydrochloric acid to 

Quinone-tetrahydro-tetracarboxylic Ester, C,H,(O,)(CO,.C,H,), or 

CHR—CHR, 

p- een pve iy lean -tetracatbexylic Ester, cof CO 
[R = CO,.C,H,]. \CHR—CHR” 

It crystallizes from alcohol in co/ordess needles or prisms, contains water of crys- 
tallization, softens at 110°, and then melts at 142-144°. Its deportment is per- 
fectly analogous to that of succino-succinic ester. Ferric chloride imparts a 
cherry-red color to its alcoholic solution. Bromine changes it again to hydro- 
quinone tetracarboxylic ester. 

2. Prehnitic Acid, C,,H,O,, (1, 2, 3, 4) results (together with mellophanic acid 
and trimesic acid) upon heating hydro- and isohydro-mellitic acid (p. 800) with 
sulphuric acid, also by oxidizing prehnitol (p. 576) with potassium permanganate 
( Berichte, 2i, ’907). It is very soluble in water, and crystallizes in warty masses 
containing 2H,O, and melting at 238° with the formation of an anhydride. Its 
salts crystallize with difficulty. 

Sodium amalgam acting upon the ammonium salt solution, produces Aydro- 








HEXABASIC ACIDS. 799 


prehnitic acid, C,>H,,O,,° an amorphous, very soluble mass, which yields 
prehnitic acid and isophthalic acid when it is heated with sulphuric acid. 

3. Mellophanic Acid, C,H,(CO,H), (1, 2, 3, 5), is formed together with 
prehnitic acid from hydro- "and isohydromellitic acid, and also by the oxidation of 
isodurene (Berichte, 17, 2517). It is also very soluble in cold water and crystal- 
lizes in small prisms. It melts at 240° with decomposition into water, and an 
anhydride melting at 238°. 

Benzene Pentacarboxylic Acid, C,H(CO,H);, is produced by oxidizing 
penta-methylbenzene with permanganate. -It is an amorphous powder containing 
six molecules of water. 





HEXABASIC ACIDS. 


Mellitic Acid, C,,H,O,, = C,(CO,H),. This occurs in meZ/ite 
or honey-stone, which is found in some lignite beds. Honey-stone 
is an aluminium salt of mellitic acid, C,,Al,0,, + 18H,O, and affords 
large quadratic pyramids of a bright yellow color. 


In preparing the acid, honeystone is boiled with ammonium carbonate, ammo- 
nium hydroxide added, and the separated aluminium hydroxide filtered off. The 
ammonium salt, C,,(NH,4),0,, + 9H,0, crystallizes from the filtrate in large 
rhombic prisms, which effloresce in the air. The free acid is obtained by con- 
ducting chlorine into the aqueous solution of the ammonium salt (erich/e, 10, 
560). 


An interesting formation of mellitic acid is that whereby pure 
carbon (graphite, charcoal, etc.) is oxidized with an alkaline solu-. 
tion of potassium permanganate. Another is when the carbon is 
applied as positive electrode in electrolysis (Berichte, 16, 1209 ; 17, 
Ref. 701). 

Mellitic acid crystallizes in fine, silky needles, readily soluble in 
water and alcohol. It is very stable, and is not decomposed by 
acids, by chlorine or bromine, even upon boiling. When heated it ~ 
melts and decomposes into water, carbon dioxide and pyromellitic 
anhydride. It yields benzene when distilled with lime. 


Mellitic acid forms salts with six equivalents of metal. The calcium and barium, 
C,,Ba,0,, + 3H,0, salts are insoluble in water. The methyl ester, C, 
(CO,.CH,)g, crystallizes i in leaflets, melting at 187°; the e¢hy/ ester melts at 73°. 
Phosphorus pentachloride produces chloranhydrides. 

The known amides of mellitic acid are Paramide and Luchroic Acid ; they ap- 
pear in the dry distillation of the ammonium salt. 

Paramide or Mellimide, C,,H,N,O0, = C, (co>NDs: is a white, amor- 
phous powder, insoluble in water and alcohol. Heated to 200° with water, it is 
converted into the tertiary ammonium salt of mellitic acid. The alkalies con- 
vert paramide into euchroic acid. 


Euchroic Acid, C,,H,N,O, =C, (co >NH ) { oe one crystallizes in large 


800 ORGANIC CHEMISTRY. 


prisms, and is sparingly soluble in water. Heated with water to 200° it yields 
mellitic acid. Nascent hydrogen changes euchroic acid to euchrone, a dark blue 
precipitate, which reverts to colorless jeuchroic acid upon exposure. Euchrone 
dissolves with a dark red color in alkalies. 

Sodium amalgam acting on ammonium mellitate produces Hydromellitic Acid, 
C,,H,(H,)O,,.. This is very soluble in water and alcohol, sparingly in ether, 
and is indistinctly crystalline. It melts with decomposition. It is hexabasic, its 
calcium salt being more soluble in cold than in hot water. If the acid be heated to 
180° with concentrated hydrochloric acid, or if it be preserved, it is transformed 
into the isomeric /sohydromellitic Acid, C,,H,,0 9, crystallizing in large, six- 
sided prisms. Hydrochloric acid precipitates it from its aqueous solution. 

When more highly heated with sulphuric acid, both acids yield prehnitic acid, 
mellophanic acid and trimesic acid :— 


A C,H,(CO,H), = C,H,(CO,H), + 3H, + 2CO,, 
an 


C,H,(CO,H), = C,H,(CO,H), + 3H, + 3CO,. 





UNSATURATED COMPOUNDS. 


The benzene derivatives previously studied contain saturated 
side-chains, having carbon present in them. Perfectly analogous 
compounds exist, in which unsaturated side-chains are present :— 


C,H,.CH:CH,. C,H,.CH:CH.CO,H. 
Phenyl-ethylene, ‘ Phenyl-acrylic Acid, 
Styrolene, Cinnamic Acid, 
C,H,.CH,.CH:CH, C,H,.CH,.CH:CH.CO,H 
Phenyl-allyl. ; Phenyl: rotons Acid. 
CH, LC C.H,.C—=C.CO.H, ete. 
Phenyl-acetylene. ~ Phenyl-propiolic Acid. 


Hydrogen converts them into the corresponding saturated com- 
pounds. 


Hydrocarbons. 


Phenyl Ethylene, C,H, = C;H;.CH:CH,, Styrolene, Vinyl- 
benzene, occurs in storax (808) (1-5 per cent.), from which it is 
obtained upon distillation with water. It is prepared by the action 
of zinc dust and glacial acetic acid upon phenylacetylene. Sodium 
and methyl alcohol will produce the same result (two hydrogen 
atoms are added) (Berichte, 21, 1184); by heating cinnamic acid 
with lime or with water to 200°; by the action of alcoholic potash 
-upon brom-ethyl benzene, and by the condensation of acetylene, 
C,H,, upon application of heat. It is best obtained from #-brom- 
hydro-cinnamic acid (p. 757), which is immediately decomposed 
by a soda solution into styrolene, carbon dioxide and hydrobromic 
acid (Berichte 15, 1983). It is a mobile, strongly refracting liquid, 


’ 


NITRO-STYROLENES. So1 


with an agreeable odor. Pure styrolene is optically inactive and 
boils at 144-145°; its sp. gr. = 0.925 at o°. 


Hydriodic acid converts styrolene into ethyl benzene, C,H,.C,H,; chromic 
acid or nitric acid oxidizes it to benzoic acid. 

Being an unsaturated compound, styrolene can directly take up two halogen 
atoms, forming af-derivatives of ethylbenzene. It condenses with phenol, on 
boiling with sulphuric acid, to oxy-diphenyl ethane, C,H ,.C,H,.C,H,.OH (Be- 
richte, 23, 3145). 

Two series of mono-substitution products result when the hydrogen of the side- 
chain of styrolene suffers replacement :— 


C,H,.CH:CHBr and C,H,.CBr:CH,. 


a-Brom-styrolene. B-Brom-styrolene. 


The a-products are derived (along with phenylacetaldehyde) from the phenyl- 
a-chlor (brom-) lactic acid (p.776), upon heating with water. They are oils having 
a hyacinth-like odor, boil undecomposed, and are far less reactive than the /-pro- 
ducts (similar to the halogen propylenes). a-Chlor-styrolene, C,H ,.CH:CHCl, 
is obtained from a-dichlor-ethyl-benzene (p. 586), and boils at 199°. a-Brom- 
styrolene is formed from dibrom-hydrocinnamic acid (p. 757), by boiling with 
water or digesting with a soda solution. It melts at 7° and boils at 220°. When 
it is heated with water it yields phenyl-acetaldehyde, C,H,.CH,.CHO. 

The {-products result on heating styrolene chloride (-bromide), C,H,.C,H, 
Cl,, alone, with lime or with alcoholic potash. They do not distil undecom- 
posed, and possess a penetrating odor, causing tears. They yield acetophenone, 
C,H,.CO.CH, (Berichte, 14, 323), when they are heated with water (to 180°) 
or with sulphuric acid, $-Chlor-styrolene, C,H,.CCIl:CH,, also results from 


$-dichlorethyl benzene (p. 586), when it is digested with alcoholic potash. 


{£-Brom-styrolene yields phenyl acetylene with alcoholic potash at 120°; sodium 
and carbon dioxide convert it into phenyl-propiolic acid. 

NVitro-styrolenes. 

a-Nitro-styrolene, C,H,.CH:CH(NO,), phenylnitro-ethylene, is obtained by 
boiling styrolene with fuming nitric acid, by heating benzaldehyde to 190° with 
nitromethane, CH,(NO,), and ZnCl, to 190° (Berichte, 17, Ref. 527), and by the 
action of fuming nitric acid upon phenyl-isocrotonic acid (Berichte, 17, 413), as 
well as by the action of NO, upon cinnamic acid, when the dinitro-compound, 
C,H,.C,H,(NO,),.CO,H, formed at first, decomposes (Berichte, 18, 2438). It 
possesses a peculiar odor, provoking tears, is readily volatilized in aqueous vapor, 
and yields yellow needles, melting at 58°. Dilute nitric acid decomposes it into 
benzaldehyde, carbon monoxide and hydroxylamine. : 

The nitro-styrolenes, C,H,(NO,).CH:CH, (0-, m- and f), containing the 
nitro-group in the benzene nucleus, result from the nitrophenyl-$-brom-lactic 
acids (from the three nitro-cinnamic acids, p. 764), by the action of a soda solu- 
tion in the cold, or upon boiling the #-lactones obtained from the phenyl-brom- 
lactic acids with water (Berichte, 16, 2213, 17, 595). Orthonitro-styrolene 
melts at 13°, has a peculiar odor, and is colored blue by sulphuric acid. Meta- 
nitro-styrolene melts at —5°, para-nitro-styrolene at 29°; both have an odor 
like that of cinnamic aldehyde. 


o-Nitro-chlor-styrolene, C,H,(NO,).CH:CHCI, is produced in the prepa-.* 


ration of o-nitro-phenyl-chlor-lactic acid and melts at 59° (Berichte, 17, 1070). 
Dinitro-styrolene, C,H,(NO,).CH:CH(NO,), results from /-a-dinitro-cin- 
namic acid (p. 811), by the splitting off of CO, ; it consists of yellow leaflets, melt- 
ing at 199°. Whenit is heated to 100° with sulphuric acid. it is broken up into 
p nitrobenzaldehyde, carbon monoxide and hydroxylamine (Berichte, 17, Ref. 528). 
66 


802 ORGANIC CHEMISTRY. 


Amido-styrolenes. 

o-Amido-chlor-styrolene, C,H,(NH,).CH:CHCI, is obtained by reducing 
o-nitro-chlor-styrolene (see above) with tin and hydrochloric acid; it consists 
of white prisms. Heated to 170° with sodium alcoholate it yields indol, C,H,N. 

f-Amido-styrolene, C,H,(NH,).CH:CH,, is produced (together with s- 
amido-cinnamic acid) in the reduction of /-nitro-cinnamic ester; it melts about 


81°, 





Phenyl Acetylene, C,H;.C : CH, acetenyl benzene, is produced 
when f-brom-styrolene and acetophenone chloride, C,H;.CCl. 
CH,, are heated to 130° with alcoholic potash; also from phenyl- 
propiolic acid (p. 814), on heating it with water to 120°, or upon 
distilling the barium salt :— 


C,H CiC.00.0 = C)H, .C!CH + CO,. 


 Itis a pleasant-smelling liquid, boiling at 139-140°. It forms 

metallic compounds, like acetylene, with ammoniacal silver and 
copper solutions: (C,H;),Cu,, is bright yellow, (CsH;).Ag, -+ Ag,O 
is white. The sodium compound, C,H;Na, inflames in the air, and 
with carbon dioxide it yields propiolic acid. When phenyl-acety- 
lene is dissolved in sulphuric acid and diluted with water, it yields 
aceto-phenone (see p. 726). 


o-Nitrophenyl Acetylene, C,H ute Thisis produced on boiling nitro- 
phenylpropiolic acid with water. It forms needles, melting at 81-82°, and yields 
metallic compounds with Cu and Ag. 

p-Nitrophenyl Acetylene, C,H,(NO,).C:CH, from /-nitro-phenylpropiolic 
acid, melts at 152°. 

o-Amidophenyl Acetylene, C,H,(NH,)C :CH, is produced in the reduction 
of o-nitrophenyl-acetylene with zinc dust and ammonia, or with ferrous sulphate 
and potassium hydroxide, and in the decomposition of o-amido-phenylpropioli¢ 
acid. It is an oil with an odor resembling that of the indigo vat. Sulphuric acid 
and water convert it into o-amido-acetophenone. 

Phenyl-diacetylene, C,H;.C:C.C:C.C,H,. This arises on shaking the cop- 
per derivative of phenyl acetylene in the air (with some ammonia) or more readily 
by the action of alkaline potassium ferricyanide (Berichte, 15, 57). It crystallizes 
from alcohol in long needles, melting at 97°, combines with eight atoms of bro- 
mine and does not form metallic derivatives. J¢ 7s the parent hydrocarbon of 
indigo-blue. Its o-dinitro-derivative, C,H KONDO i CH 4 obtained from 
o-nitro-phenyl acetylene copper, by means of alkaline potassium ferricyanide and 
melting at 212°, yields isomeric ditsatogene, C,,H,N,O,, with sulphuric acid. 
Ammonium sulphide at once converts this into indigo-blue, C,,H,,N,O, 
(Berichte, 15, 53). 

Phenyl Allylene, C,H,.C:C.CH,, has been obtained from phenylbrom- 
propylene, C,H,.C,H,?Pr (from a-methylcinnamic acid, p. 814). It is a liquid 
with a disagreeable odor. It boils at 185° (Berich/e, 21, 276). 

* 


PHENYL ACETYLENE. 803 


Phenols. /C,H 

I. Vinyl Phenols, CoH On 3, The methyl ethers of the o- and £-com- 
pounds, the vinyl anisols, C,H,(C,H,;).0.CH, have been obtained from the cor- 
responding oxycinnamic acids. o-Vinyl anisol boils about 198°, the 4-compound 
at 205°. : C.H 

2. Allyl Phenols, CoH Oy 5. Chavicol, the para-derivative, occurs in 
- the oil obtained from the leaves of Chavica Betle. It is a colorless oil with pecu- 
liar odor and boils at 237°. It is not colored by ferric chloride. Its specific 
gravity is 1.035 at 20°. Its alkyl ethers are produced by heating it with 
caustic alkali and alkyl iodides. Methyl Chavicol, C,H,(C,H,)O.CHs, boils at 
226°; its specific gravity is 0.986 at 22°. Zthyl Chavicol boils at 232° (Berichte, 
22, 2739). 3 

a ae asi Phenols, C,H,(C,H;).OH, containing the propenyl group— 
CH:CH.CH,. Avo, the para-compound, may be obtained from its methyl ether, 
anethol, by heating it together with caustic alkali to 200-230°. It consists of 
brilliant leaflets, melting at 92°. It decomposes upon distillation. Its methyl 
ether, C,H,(C, H;).0.CHg, anethol, occurs in ethereal oils, from which it separates 
in the cold in the form of white, shining scales, melting at 21° and boiling at 232°. 
Anethol has been synthetically prepared from g-methoxyphenyl crotonic acid 
(Berichte, 10, 1604). This would prove the group, C,H;, to be propenyl. A 
rather remarkable formation of anethol is that resulting from the molecular re- 
arrangement of methyl chavicol (see above), when the latter is heated with alcoholic 
potash. In this change the allyl group is transposed to the propenyl group. A// 
allyl benzene derivatives sustain similar transformations into propenyl compounds 
(Berichte, 23, 859); safrol is converted into isosafrol, methyl eugenol into methyl 
isoeugenol, apiol into isapiol etc., etc. The propenyl derivatives are distinguished 
from the allyl compounds by higher specific gravities, higher boiling points and 
greater refractive power (Berichte, 22, 2747; 23, 862). 

Chromic acid oxidizes anethol to anisic and acetic acids; less intense oxidation 
produces anisic aldehyde. 

4. Allyl Dioxybenzenes, C,H,(C,H,;)(OH),. There are six possible iso- 
merides; the (1, 3, 4)-compound is known in its ethers :— 


C,H; (1) 
C,H, t C,H; ts 
C,H, + O.CH, (3) C,H, + OH (3 C,H, Ov (3) 
OH (4) O.CH, (4) CH, 
Eugenol. Chavibetol. o*% (4) 
Safrol. 


Eugenol, C,,H,,0, (Eugenic Acid), occurs in clove oil (from Caryophyllus 
aromaticus), in all-spice (from Myrtus pimenta). On shaking oil of cloves with 
alcoholic potassium hydroxide it solidifies to the potassium salt of eugenol; this 

‘is then pressed, washed with alcohol, and decomposed with an acid: It is an 
aromatic oil, that boils at 247°, and is colored blue by ferric chloride. Potassium 
permanganate oxidizes it to homovanillin, vanillin and vanillinic acid. It breaks 
down into acetic acid and protocatechuic acid, C,H,(CO,H)(OH), (1, 3, 4), 
when fused with potassium hydroxide (p. 779). 

Methyl Eugenol, C,H,(C,H,)(O.CH,)., is formed when eugenol is heated 
together with caustic potash and methyl iodide. It is a liquid, boiling at 237—239°. 
Chromic acid oxidizes it to dimethyl protocatechuic acid. The compound, C,H, 
(C,H,)(O.CH,)., the chief constituent of the oz/ of asarum, appears to be identi- 
cal with methyl eugenol (Berichte, 22, 3472). wf 

Chavibetol, C,H,(C,H;)(OH)(O.CHs) (1, 3, 4) (see above), occurs with 
chavicol in oil of betel (Berichte, 23, 859), and is isomeric with eugenol. 


804 ' ORGANIC CHEMISTRY. 


O 
Safrol, C,,H,,O, = C,H,(C,H;) ( eu, ) (see above), is the methylene 
O 


ether of allyl dioxybenzene. It is present in the oil of Sassafras officinalis and 
Llicium religiosum, hence called Shikimol. When the oil is chilled it separates 
as a white crystalline mass, melting at + 8°. Potassium permanganate oxidizes it 
to piperonal and piperonylic acid (Berichte, 21, 474; 23, 864). 

5. Isoeugenol, ethyl isochavibetol and isosafrol are derivatives of— 

Propenyl Dioxybenzene, C,H,(C,H,)(OH), (containing the propenyl 
group—CH:CH.CH,), isomeric with allyl dioxybenzene. These can be formed 
by the rearrangement of corresponding allyl derivatives upon heating the latter 
with alcoholic potash. 

Isoeugenol, C,H,(C,H,)(O.CH,).OH, is formed when homoferulic acid is 
distilled with lime. It is an oil boiling at 260° (Berichte, 23, 860). 


O 

Isosafrol, C,H,(C,H;) ( yeu); is obtained from safrol by heating it 
O 

with sodium, or more readily by boiling it with alcoholic soda (Berichte, 23, 1160). 

It is an oil boiling at 246-248°. Chromic acid oxidizes it chiefly to piperonal 

(artificial Ae/iotropine). Sodium and alcohol reduce it to dihydrosafrol and 

m-propyl phenol. 

6. Asarone, C,,H,,O, = C,H,(C,H;)(O.CH,),, is a derivative of propeny/ 
trioxybenzene. It is the solid component of the oil from Asarum europeum, 
whereas the liquid portion consists of methyl eugenol and terpenes (erichie, 21, 
615, 1057; 22, 3172). Asarone forms monoclinic prisms, melting at 61° (67°), 
and boils at 295°. Potassium permanganate oxidizes it to tri-methoxybenzoic 
acid, C,H,(O.CH,),.CO,H, which yields carbon dioxide and the tri-methyl ether 
of oxyhydroquinone upon distillation with lime (Berichte, 23, 2294). 

7. Apiol, C,,H,,O, = C,H(C,H,)(O,:CH,)(O.CH,),, is a derivative of allyl 
tetroxybenzene, C,H(C,H,)(OH),—its methylene dimethyl ester. It occurs in 
parsley seeds and is volatile in a current of steam. It crystallizes in long needles, 
with a slight parsley odor. It melts at 30°, and boils at 294°. It dissolves with 
a blood-red color in oil of vitriol. Potassium permanganate oxidizes it to apiol 
aldehyde and apiolic acid, C,H(O,:CH,)(O.CH,),.CO,H, melting at 175° (Be- 
richte, 21, 1624). When heated with dilute sulphuric acid to 140° apiolic acid 
breaks down into carbon dioxide and afione, the methylene dimethyl ether of 
apionol, 2. ¢., of tetroxybenzene (Berichie, 23, 2293). 

Boiling alcoholic potash converts apiol into its isomeric propenyl-derivative— 
Lsapiol (p. 803). The latter forms leaflets, melts at 56°, and boils at 304°. Potas- 
sium permanganate or potassium bichromate and sulphuric acid convert it into 
apiol aldehyde (Berichte, 23, 2293). 





Alcohols and Aldehydes. 

Styryl Alcohol, C,H,,O = C,H,.CH:CH.CH,.OH (Styrene, Cinnamyl Alco- 
hol), is obtained by saponifying styracine, its cinnamic ester, with potassium 
hydroxide.. It crystallizes in shining needles, is sparingly soluble in water, pos- 
sesses a hyacinth-like odor, melts at 33°, and distils at 250°. When carefully 
oxidized it becomes cinnamic acid, but in case the oxidation is energetic, benzoic 
acid is the product. In the presence of platinum sponge it oxidizes in the air to 
cinnamic aldehyde. It yields cinnamic ether (Cy) H,),O0—a mobile oil—when it 
is digested with boric anhydride. 


BENZYLIDENE ACETONE. 805 


Cinnamic Aldehyde, C,H,O, is the chief ingredient of the 
essential oil of,cinnamon and cassia (from Persea Cinnamonum and 
Persea Cassia). It is obtained by the oxidation of cinnamic alco- 
hol, by dry distillation’ of a mixture of calcium cinnamate and for- 
mate, and by saturating a mixture of benzaldehyde and acetalde- 
hyde with hydrochloric ae; or by the action of caustic soda 


(pp. 716, 806) :— 
C,H;.COH + CH,.COH = C,H,.CH:CH.CHO + H,0O. 


Sodium ethylate is preferable to aqueous or alcoholic sodium 
hydroxide for condensation purposes (Berichte, 20, 657). 


To obtain the aldehyde from cinnamon oil, shake the latter with a solution of 
primary sodium su] phite, wash the crystals which separate with alcohol, and decom- 
pose them with dilute sulphuric acid (Berichte, 17, 2109). Cinnamic aldehyde 
is obtained synthetically by allowing a mixture of benzaldehyde (10 parts), acet- 
aldehyde (15 parts), water (900 parts),and Io per cent. ordinary sodium hydroxide 
to stand and then extracting with ether (Berichte, 17, 2117). 


Cinnamic aldehyde is a colorless, aromatic oil, which sinks in 
water and boils at 247°; it distils readily in aqueous vapor. When 
exposed to the air it oxidizes to cinnamic acid, and in other 
respects shows all the properties of the aldehydes. 


Dry ammonia converts it into the crystalline base Hydro- cinnamide, 
(CyH,),N, (p. 715) (Berichte, 17, 2110). 

Its phenylhydrazone, C,H,.CH:CH.CH(N,H.C, H,), melts at 168°, 

Nitrocinnamic Aldehydes, C,H,(NO,).CH: :CH.CHO. Ortho. and para- 
derivatives are produced by the nitration of cinnamic aldehyde when added toa 
cold mixture of sulphuric acid (500 gr.) and nitre (20 gr). They can be separated 
by means of sodium bisulphite (Berichte, 18, 2335). The three isomerides can be 
synthesized by the condensation of the nitrobenzaldehydes with acetaldehyde, in- 
duced by caustic soda. By using dilute alkali nitrophenyl-lactic aldehydes are 
the first products; heated with acetic anhydride they become nitrocinnamic alde- 
hydes. 

The ortho acid crystallizes from hot water in long needles, melting at 270° 
(Preparation, Berichée, 18, 2335). The meta acid melts at 116°, the Jara at 142°. 
See Berichte, 20, 193, for ‘the cumaric aldehydes. 





Ketones. 


Benzylidene Acetone, C,H;.CH:CH.CO.CH;, Benzal Ace- 
tone, Cinnamyl-methyl ketone, is obtained on distilling calcium 
cinnamate and acetate. It is very easily procured by the condensa- 
tion of benzaldehyde with acetone (p. 716) on shaking with dilute 
sodium hydroxide (Aznalen, 223, 139) :— 


C,H,.CHO + CH,.CO.CH, = C,H,.CH:CH.CO.CH, + H,0. 





ryt 


806 ORGANIC CHEMISTRY. 


It separates as a thick oil which solidifies after distillation. It has 
a peculiar odor, crystallizes in brilliant quadratic plates, melts at 
41-42°, and boils near 262°. It dissolves in sulphuric acid with 
an orange-red color, and combines with sodium bisulphite. 

Phenylhydrazine converts it into a hydrazone, C,H;.CH:CH. 
C(HN..C,H;).CH;; the rearrangement of this compound gives rise 
to diphenylmethylpyrazoline (Berichte, 21, 1097). Boiling sodium 
hypochlorite converts. benzalacetone into cinnamic acid. Chloro- 
form is eliminated at the same time. 


The nitration of benzalacetone with sulphuric acid and nitric acid in the cold 
produces the ortho- and para-nitro-derivatives; these can be separated by means 
of alcohol (Berichte, 16, 1954). : 

o-Nitrobenzal Acetone, C,H,(NO,).CH:CH.CO.CHs, forms warty crystals, 
melting at 59°. The action of alcoholic potash, hydrochloric acid, and then 
sodium hydroxide produces indigo (see below). a-Methyl-quinoline results from 
it by reduction with stannous chloride and hydrochloric acid (p. 755 and p. 721) :— 


/CH:CH.CO.CH, CH:CH 
CH —— 


ft 
NH ee bcu, 
a-Methy! Quinoline. 


p-Nitrobenzal Acetone, melts at 254° (Berichte, 16, 1970). 


7 C1 iCHCHN g : 
Dibenzylidene Acetone, C.H..CH:CH so (Cinnamone), is produced by 


the condensation of benzylidene acetone (see above) with benzaldehyde, caused 
by the action of sodium hydroxide in alcoholic solution. It crystallizes in bright 
yellow needles, and melts at 112°. 

Benzylidene Acetophenone, C,H,.CH:CH.CO.C,H,, is formed when 
benzaldehyde and acetophenone are allowed to stand together with sodium ethylate 
(Berichte, 20,657). It crystallizes in prisms or plates, melting at 58° and distilling 
about 346°. 


Acids. 


In addition to the general methods for preparing aromatic acids 
(p. 739) and for the conversion of saturated into unsaturated acids 
(p- 234), we can also prepare the unsaturated aromatic acids syn- 
thetically, by the following methods :— 

(1) By the condensation of aromatic aldehydes with the fatty acids 
(p. 716), effected by heating with the chlorides of the acids, ¢. g., 
CH;.COCI (Bertagnini), or with the free acids in the presence of 
zinc chloride or hydrochloric acid (Schiff) :— 


-C,H,.CHO + CH,.CO,H = C,H,.CH:CH.CO,H + H,0; 
Benzaldehyde. Acetic Acid. Cinnamic Acid, 
Phenylacrylic Acid. 


or, better, with a mixture of the sodium salts and the anhydrides of 
the fatty acids (Perkin). 


BENZYLIDENE ACETONE. 807 


In the last case the reaction occurs between the aldehyde and the sodium salt 
(Berichte, 14, 2110: Annalen, 227, 48; compare Berichte, 19, Ref. 346), when, 
by the aldol condensation, we obtain a -oxyacid :— 


C.H..CHO + CH,.CO,Na = C,H,.CH(OH).CH,.CO,Na 
ie * : , . B-Pheny Bata : 


which is then deprived of water by the acid anhydride :— 
C,H,.CH(OH),CH,.CO,H = C,H,.CH:CH.CO,H + H,0. 


All aromatic aldehydes (aldehyde phenols, aldehydic acids), react similarly 
with the homologous fatty acids and with many other compounds (p. 716). Thus, 
phenyl-crotonic acid, C,H,.C,H,.CO,H, is produced from benzaldehyde by 
means of the sodium salt and the anhydride of propionic acid, and the coumaric 
acids, C,H,(OH).C,H,.CO,H, etc., from the oxybenzaldehydes, C,H ,(OH). 
CHO, with acetic acid. With the higher fatty acids the condensation occurs in 
such a manner that the two hydrogen atoms are withdrawn from the carbon atom 
in union with carboxyl (Ammalen, 204, 187, and 208, 121) :— 


7 ome 
C,H,.CHO + CH,.CH,.CO,H = CoH s-CHCY 60 44 + H,O. 
Propionic Acid. Phenyl-meth-acrylic Acid. 


Similarly, phenyl-paraconic acid (p. 793), and (by withdrawal of CO,) phenyl- 
isocrotonic acid (p. 813) are obtained from benzaldehyde with sodium succinate 
and acetic anhydride. Benzalmalonic acid, C,H,.CH:C(CO,H),, and !cinnamic 
acid are formed from benzaldehyde and malonic acid. Glacial acetic acid may 
be employed instead of acetic anhydride (Berichte, 16, 1436, 2516). 

(2) By condensation of benzaldehydes with fatty acid esters, by means of sodium 
ethylate or metallic sodium; esters of the unsaturated acids are produced (Claisen) 
(p. 716) ( Berichte, 23, 976) :— 


C,H,.CHO + CH,.CO.0.C,H, = C,H,.CH:CH.CO,.C,H, + H,0. 





1. Phenyl Acrylic Acids, C,H,.C,H,.CO,H. 
According to the structural theory, there are two possible isomerides, with this 
formula :— 
Cr. 


(1) C,H,.CH:CH.CO,H and (2) Cnet oF 
B-Phenylacrylic Acid. a-Phenylacrylic Acid. 


The first belongs to cinnamic acid; the second to atropic acid (p. 813). Cinna- 
mic acid, in accordance with the stereochemical representations, can occur in two 
stereochemical forms (similar to crotonic acid (p. 238) and fumaric and maleic 
acids (p. 425) :— 
CH.C,H, C,H,.CH 
(t) Il (2) | 
CH.CO,H CH.CO,H. 


The first is the plane-symmetric arrangement ; the second, the axially-symmetric 
or preferable configuration (p. 52). Wislicenus gives cinnamic acid the first 
formula, The} formation of the acid by! the reduction of phenyl-propiolic acid 


808 ; ORGANIC CHEMISTRY. 


argues in favor of this view (Berichte, 22, 1181). However, there is the opposing 
fact that the recently discovered zsocinnamic acid (p. 812), which must be given 
the axially-symmetric formula (2) is less stable than ordinary cinnamic acid and 
is readily converted into it. Furthermore, these stereochemical ideas have been 
proved insufficient by the discovery of a third $-phenylacrylic acid—a@//o-cinnamic 
acid (p. 813). 





Cinnamic Acid, C,H,O, = C,H;.CH:CH.CO,H, f-Phenyl- 
acrylic acid (Acidum cinnamylicum), occurs in Peru and Tolu 
balsams (p. 742), in storax and in some benzoin resins. It results 
in the oxidation of its aldehyde or its alcohol, by the condensation 
of benzaldehyde with sodium acetate, by the decomposition of 
benzal malonic acid, and by the reduction of phenylpropiolic acid 
with zinc dust and glacial acetic acid (Berichte, 22, 1181). 


Cinnamic acid is obtained either synthetically from benzaldehyde, or from 
storax (Styrax officinalis)—the pressed-out, thick sap of the bark of Ligautdambar 
orientale, This contains, besides a resin, some free cinnamic acid and styrolene, 
C,H,, but chiefly s¢yracine (cinnamic cinnamate and phenyl-propylic cinnamate 
p. 711). The styrolene is distilled off upon boiling with water. ‘The residue is 
boiled with a soda solution, in order to remove the cinnamic acid; cold alcohol 
will extract the resin from what remains and only styracine is left. To obtain the 
cinnamic acid, storax is boiled for some time with sodium hydroxide, when the 
cinnamyl alcohol which is formed will distil over. Hydrochloric acid precipitates 
cinnamic acid from the solution. It is purified by distillation or crystallization 
from benzine (comp. Aznalen, 188, 194). - 

To get the acid from benzaldehyde, a mixture of the latter (3 parts) with 
sodium acetate (3 parts) and acetic anhydride (10 parts), is boiled for several 
hours, water is then added and the acid dissolved in soda (Berichte, 10, 68). A 
more convenient procedure consists in heating benzalchloride, C,H,;.CHCI, (1 part) 

with sodium or potassium acetate (2 parts) to 200°. 


Cinnamic acid crystallizes from hot water in fine needles, from 
alcohol in thick prisms, is odorless, melts at 133°, and when quickly 
heated distils near 300° with almost no decomposition. It is 
soluble in 3500 parts of water of 17°, and readily in hot water. 


The cinnamates are similar to the benzoates; ferric chloride produces a yellow 
precipitate in their solutions. In chemical character cinnamic acid closely resem- 
bles the acids of the acrylic acid series. Fusion with caustic potash decomposes it 
into benzoic and acetic acids (p. 236) :— 


C,H,.CH:CH.CO,H + 2KOH = C,H,.CO,K + CH,.CO,K + H,. 


Nitric acid and chromic acid oxidize it to benzaldehyde and benzoic acid. When 
heated with water to 180—200°, or with lime, it breaks up into CO, and styrolene. 
The acid of distyrene, C,,H,,O,, and distyrolene are produced on heating with 
sulphuric acid. : 

The ethyl ester of cinnamic acid, C,H,O,(C,H,), is a liquid, boiling at 271°. 
It readily combines with bromine (dissolved in CS,) to form the dibromide, 


CINNAMIC ACID. 809 


C,H,Br,O,.C,H;, melting at 69°. Like the esters of other unsaturated acids it 
combines with sodmalonic ester and sodacetoacetie ester (Berichte, 20, Ref, 258, 
504). The methyl ester melts at 33.5°, and boils at 263°. Cinnamein, contained 
in Tolu and Peru balsams,/consists of benzylic benzoate and cinnamate. It is 
obtained artificially by heating sodium cinnamate with benzylic chloride. It pos- 
sesses an aromatic odor, crystallizes from alcohol in small, shining prisms, melting 
at 39°, and boiling about 320°. 

Siyracine, present in storax, is the cinnamic ester of cinnamyl alcohol, C,H,. 
CO.0.C,H, (p. 808). It is best obtained from storax, by digesting the latter at 
30° with dilute sodium hydroxide, until the residue (styracine) | becomes colorless. 
It crystallizes from hot alcohol in fine needles, melting at 44°, and decomposes 
when distilled. 

As cinnamic acid is unsaturated it is capable of taking two additional affinities. 
Hydrogen converts it into hydrocinnamic acid; chlorine produces dichlor-, brom- 
ine dibrom-hydrocinnamic acid (cinnamic dibromide), and hydrobromic and 
hydriodic acids convert it into 6-brom- and iodo-hydro. ieee acids (p. @), 
Hypochlorous acid changes it to phenyl-a-chlor-lactic acid (p. 776) 





The halogen cinnamic acids (0-, m-,and f-), having the substitutions in the ben- 
zene nucleus, are obtained from the three diazocinnamic acids, C,H, (N, X). 
CPOs, when they are digested with the haloid acids, and in this way all nine 
chlor-, brom., and iodo-cinnamic mares C,H,X.C,H,.CO,H, have been prepared 
(Ber ichte, 15, 2301, 16, 2040). 





Two possible isomerides can exist for each monohalogen cinnamic acid or 
phenylhaloid acrylic acid, with the substituting group in the side-chain :-— 


C,H,.CH:CCLCO,H and C,H,.CCl:CH.CO,H. 


a-Chigkcingainie Acid. B- EP hict-claanieis Acid. . 


However, three (or four) isomeric chlor- and brom-cinnamic acids are known. 
We therefore have relations to deal with similar to those observed with fumaric 
and maleic acids (p. 425) Apparently, the a- and $-acids possess the same 
structural formula (1), and the so-called f-acid bears the same relation to the 
a-acid that maleic bears to fumaric acid. Following the suggestion of Michael 
we designate the §-chlor- and brom-acids, the allo-a-haloid cinnamic acids, and the 
two recently discovered chlor- and brom-cinnamic acids (y and d) are termed p- 
and allo-f-acid (Berichte, 20, 550; 22, Ref. 741). Erlenmeyer regards B-brom- 
cinnamic acid as corresponding to isocinnamic acid, as the latter is produced by 
the reduction of the former (Berichte, 23, 3130). Until these relations are more 
fully determined the old designations a, (3, etc., will be continued. 

Two chlorcinnamic acids are obtained from a$-dichlorhydrocinnamic acid 
by the action of alcoholic potash (Berichée, 15, 788). 

a-Chlor-cinnamic Acid is produced synthetically in the condensation of ben- 
zaldehyde and sodium chloracetate, when heated to 110°, with acetic anhydride 
(Berichte, 15, 1945) :— 


C,H,.CHO + CH,CLCO,Na = C,H,.CH:CCl.CO,Na + H,O; 
and from phenyl-a-chlorlactic acid (p. 776) by the withdrawal of water on heating 
68 


810 ORGANIC CHEMISTRY. 


with acetic anhydride (Berichte, 16, 854). It melts at 137°; its alkali salts are 
very readily soluble in water. 

B-Chlor-cinnamic Acid melts at 111°; upon distillation it suffers a very slight 
transposition into the a-acid. 

y-and-d Chlor-cinnamic Acids ((-and allo--acid) are produced by the addi- 
tion of hydrogen chloride to phenyl-propiolic acid (p. 814). The first melts at 
132°; the second at 142° (Berichte, 22, Ref. 741). 

The brom-cinnamic acids are prepared like the chlor-cinnamic acids, by 
boiling the a@$-dibrom-hydro.cinnamic acid with alcoholic potassium hydroxide. 
They can be separated by means of their ammonium salts, or by the fractional 
precipitation of the salt mixture (Annalen, 154, 146). 

a-Brom-cinnamic Acid, the ammonium salt of which dissolves with difficulty, 
and is first precipitated, crystallizes from hot water in fine needles, melting at 131°, 
and then sublimes. Its ethyl ester boils at 290°. Concentrated sulphuric acid 
converts it into benzoyl acetic ester (Berichie, 19, 1392). 

$-Brom-cinnamic Acid crystallizes from hot water in shining leaflets, melting 
at 121°. Its alkali salts are deliquescent. It changesto the a-acid if heated with 
hydriodic acid, and if distilled or heated for some time to 150-180°. It sustains 
a like transposition if converted into its ethers by alcohol and hydrochloric acid; 
the ester of the a-acid is then formed. Consult Berichte, 20, 551, 1386, upon the 
methyl and ethyl esters of a-and $-brom-cinnamic acids. Both acids yield phenyl- 
propiolic acid when boiled with alcoholic potassium hydroxide. 

y-Brom-cinnamic Acid, C,TI,.CBr:CH.CO,H(?) (see above), is produced by 
the addition of hydrobromic acid to phenyl-propiolic acid, C,H,.C:C.CO,H 
(Berichte, 19, 1936). A fourth acid is produced simultaneously ; it is very similar 
to a-brom-cinnamic acid (Aerichze, 20,553). It dissolves with difficulty in cold 
alcohol, and crystallizes in needles, melting at 158.5° (153.5°). 

The addition of two bromine atoms to phenyl-propiolic acid‘ produces two a/3- 
dibrom-cinnamic acids, C,H,.CBr:CBr.CO,H, called a- and B-. The a- melts at 
139°, and the B- at 100°. The first passes readily into the second (Anna/en, 247, 


139). 





Nitro-cinnamic Acids, C,H ,(NO,).CH:CH.CO,H. 

The introduction of cinnamic acid into nitric acid of specific gravity 1.5 leads to 
the formation of the ortho- (60 per cent.), and para-nitro acids, of which the former 
is the more easily soluble in hot alcohol. To separate them cover the acid mixture 
with 8-10 parts of absolute alcohol, and conduct hydrochloric acid gas rapidly into 
the liquid, until complete solution ensues. On cooling the para-ether separates. 
The mother liquor is evaporated, and the ortho-ether recrystallized from ether 
(Annalen, 212,122, 150). The esters are saponified with sodium carbonate, or 
by heating with a mixture of 10 parts sulphuric acid, water and glacial acetic acid 
(equal parts), to 100°, or with water and sulphuric acid (Annalen, 221, 265). 

The three isomeric acids can be prepared from the corresponding nitro-benzal- 
dehydes by means of sodium acetate, etc. 


o-Nitro-cinnamic Acid is insoluble in water, crystallizes from 
alcohol in needles, melting at 240°, and sublimes with partial de- 
composition. It colors concentrated sulphuric acid dark blue upon 
warming. Chromic acid oxidizes it to nitro-benzoic acid, and 
potassium permanganate converts it into o-nitrobenzaldehyde 
(p. 719). Bromine unites with it with difficulty, yielding the a- 


AMIDO-CINNAMIC ACID. 811 


bromide, C,H,(NO,).CHBr.CHBr.CO,H, melting at 180°, and 
forming o-nitrophenylpropiolic acid (p. 815), and then isatin when 
digested with sodium hydroxide. Indol results upon heating it 
with sodium hydroxide and zinc dust. 


The ethy/ ester of o-nitrocinnamic acid is very soluble in cold alcohol, crystal- 
lizes in needles or prisms, and melts at 44°. It yields carbostyril (p. $12), if 
digested with aqueous ammonium sulphide, and oxy-carbostyril if the solution be 
alcoholic. Tin and hydrochloric acid reduce it to o-amido-cinnamic ester (see 
below), and zinc dust and hydrochloric acid to hydrocarbostyril (p. 810). The ester 
readily unites with bromine, yielding the dibromide, C,H,(NO,).CHBr.CHBr. 
CO,.C,H;, melting at (110°) 71° (Annalen, 212, 130), and serving for the 
preparation of o-nitrophenylpropiolic acid (p, 815). 

m-Nitro-cinnamic Acid has been obtained from m-nitrobenzaldehyde, and 
consists of bright, yellow needles, melting at 197°. Oxidation changes it to 
m-nitrobenzoic acid; its ethyl ether melts at 79°. 

p-Nitro-cinnamic Acid (see above) crystallizes from alcohol in shining 
prisms, and melts at 286°. Chromic acid oxidizes it to f-nitrobenzoic acid, while 
sulphuric and nitric acid convert it into g-nitrobenzaldehyde (p. 720). _ Its ethy/ 
ester is almost insoluble in cold alcohol and ether, forms fine needles, and melts at 
138°. 

pa-Dinitro-cinnamic Acid, C,H,(NO,).CH:C(NO,).CO,H, is obtained from 
p-nitrocinnamic acid by the action of sulphuric and nitric acids at —10°. It is 
very unstable, and at 0° decomposes into carbon dioxide and dinitrostyrolene 
(p. 801). Its ethyl ester, from f-nitrocinnamic ester, melts at 110°, and upon 
reduction yields Z-amidophenyl alanine (p. 758). -Nitrocinnamic acid deports 
itself very much like the A-acid (Berichte, 18, Ref. 554). 





Amitdo-cinnamtic Actds. 


a Amido-cinnamic Acid, C,H,.CH:C(NH,).CO,H, obtained from benzoyl- 
amido-cinnamic acid ( Berichte, 17, 1620), is very similar to phenyl-alanine (p. 758), 
decomposes at 240° with formation of phenyl vinyl-amine, C,H,.CH:CH(NH),, 
and by reduction yields phenyl-alanine. 


The amido-cinnamic acids, C,H,(NH,).C,H,.CO,H, with the 
substitutions in the benzene nucleus, can be obtained from the three 
nitro-cinnamic acids by reduction with tin and hydrochloric acid. 
There is greater advantage in reducing them with iron sulphate in 
alkaline solution (p. 592). 


To prepare the o-amido-acid add an excess of ammonia and the ammoniacal 
solution of o-nitrocinnamic acid (5 grs.) to the boiling solution of green vitriol 
(50 grs.), continue boiling on a sand-bath and let the brownish-black precipitate 
of ferroso-ferric oxide subside. The solution should smell of ammonia, and be 
perfectly clear, and pure yellow in color, and if this be not the case add ammonia 
and apply heat. Concentrated hydrochloric acid is gradually added to the filtered 
solution of the ammonium salt of the amido-acid, as long as the yellow acid is 
precipitated (erichte, 15, 2294). For the reduction by means of ferrous sulphate 
and baryta water, see Anna/en, 221, 226. 


812 ; ORGANIC CHEMISTRY. 


o-Amido-cinnamic Acid separates in fine yellow needles, 
when hydrochloric acid is added to solutions of its salts. It melts 
at 158-159°, evolving gas. It is readily soluble in hot water, in 
alcohol and ether ; the solutions exhibit a greenish- blue fluorescence. 
It yields ortho-coumaric acid when diazotized and boiled with 
water. The splitting-off of water causes it’to pass into its lactime— 
the so-called carbostyril (a-oxyquinoline)—(p. 755) :— 


CH:CH 
So OUCH COONS 5 Sey ges 
POPANE, ‘\n:COH)* . 


a-Oxyquinoline. 


This anhydride formation ensues on protracted boiling with hydrochloric acid, 
more rapidly on heating to 130° with hydrochloric acid, 6r upon heating the 
acetyl derivative of the o-amido-acid. When the acid is heated alone (unlike the 
o-amido-hydro-cinnamic acid, p. 757), it does not yield an anhydride (similar to 
ortho-coumaric acid). 


The ethyl ester was first obtained by reducing o-nitro-cinnamic ester with tin 
and hydrochloric acid in alcoholic solution (Berich/e, 15, 1422); a simpler method 
consists in conducting hydrochloric acid gas into the alcoholic solution of the free 
amido acid, evaporating and precipitating the aqueous solution with sodium acetate, 
when the ether will separate in fine yellow needles, melting at 77°. Its solutions 
show an intensely yellowish-green fluorescence. If digested at 90° with alcoholic 
ZnCl, it will yield ethyl-oxy-quinoline (see above); and oxy-quinoline if oor 
rated with hydrochloric acid. 

Ethyl Amido-cinnamic Acid, C oS Net Ci.” 0 oH is obtained when 
ethyl iodide and potassium hydroxide act upon o- amido- cinnamic acid. It melts 
at 125°, and forms a witroso-body which, by reduction and the splitting-off of 
HO, yields an isindazole compound (p. 841). 

The diazo-derivative of the amido-acid unites with sodium sulphite and forms 
o-Hydrazine-cinnamic Acid, C oH NE fin, alt. which on application of 
heat yields Indazole, C,H,N, (p. 841). 

m- and ~-Amido-cinnamic Acids, fone 4-(NH,).C,H,.CO,H, are similarly 
formed from m- and /-nitrocinnamic acids by reduction with green vitriol and 
ammonia (Berichte, 15, 2299); the first melts at 181°, the second at 176°. The 
halogen cinnamic acids (p. 809) result upon boiling the diazo- -compounds with the 
haloid acids; and when water is employed #- and f-coumaric acids result. 

2. Isocinnamic Acid, C,H,.CH:CH.CO,H (p. 807), is found in the acid 
mixture—truxillic, cinnamic and benzoic—that results upon decomposing cocaine 
(for the preparation of ecgonine). It is distinguished from the associated acids 
by greater fusibility and solubility (Berichée, 23, 141, 512). Itis not present in 
the cinnamic acid obtained synthetically from oil of bitter almonds. It has been 
artificially prepared from $-bromcinnamic acid by replacing its bromine (2erichie, 
23, 3131). 

It is so aatas from the aqueous solution of its salts in the form of an oil, dis- 
solves very easily in the common solvents, crystallizes from petroleum ether in 
brilliant crystals, melting at 45-47°, and when absolutely pure at 57°. It boils at 
265°, changing at the same time to ordinary cinnamic acid, boiling at 300°. 

It is also transformed into the latter by solution in sulphuric acid, or by boiling 
with iodine and carbon disulphide. A determination of its molecular weight by 


AMIDO-CINNAMIC ACID. 813 


the method of Raoult leads to the simple molecular formula. The isocinnamic 
acid derivatives, the salts excepted, are mainly identical with those of ordinary cin- — 
namic acid. 

3. Allo-cinnamic Acid, C,H,;.CH:CH.CO,H, occurs with the iso-acid in 
the acid mixture in which the latter is present. “It is not as soluble in ligroine 
and melts at 68°. Its salts differ from those of the other two cinnamic acids. 
Potassium permanganate oxidizes the allo- and iso-cinnamic acids to benzalde- 
hyde. Direct sunlight converts iso- and allo-cinnamic acids into ordinary cin- 
namic acid (Berichte, 23, 2510). 

4. In addition to the three monomolecular cinnamic acids there are sbwieed 
(probably four)— 

Dicinnamic Acids, (C,H,O,),, or Truxillic Acids. They probably originate 
from tetramethylene, C,H,, and correspond to the formulas :— 


C,H,.CH — CH.CO,H C,H,.CH — CH.CO,H 
and | : 
C,H,.CH — CH.CO,H HO,C.CH — CH.C,H,; 
Their differences are based upon stereochemical isomerisms (Berichte, 23, 


2516 

5. Pair Acid, C,H,O,, a-Phenylacrylic Acid, results from atropine, 
tropic acid and atrolactinic acid (p. 775) when they are heated with concentrated 
hydrochloric acid or with bartya water (Anna/en, 195, 147). It crystallizes from 
hot water in monoclinic plates, is sparingly soluble in cold water, easily in ether, 
carbon disulphide and benzene; melts at 106°, and distils with aqueous vapor. 
Chromic acid oxidizes it to benzoic acid ; sodium amalgam converts it into hydro- 
atropic acid, and hydrochloric and hydrobromic acids change it to a- and 6-halogen 
hydro atropic acids (p. 759). 

Atropic acid sustains the same relation to cinnamic acid as hydro-atropic to 
hydro-cinnamic acid or methyl] acrylic acid to ordinary crotonic acid (p. 238) :— 


C,H,.CH:CH.CO,H C,H,.CH,.CH,.CO,H 
Cinnamic Acid, Hydrocinnamic Acid. 
@CH, CFs 
C,H sco? H C,H CH CO, I. 
Atropic Acid. Hydroatropic Acid: 


Like all unsaturated acids when fused with caustic alkali, it splits at the point 
of double union, and yields formic and a-toluic acids, C,H;.CH,.CO,H, whereas 
cinnamic acid decomposes into benzoic and acetic acids. 

Protracted fusion, or heating with water or hydrochloric acid (in small quantity, 
even upon recrystallization), converts atropic acid into two polymeric zsatropic 
acids (C,H ,O,), (melting at 237° and 206°) which are very sparingly soluble, 
and no longer capable of yielding additive products. 





2. Acids, C, »H; 904. 

Phenyl-iso-crotonic Acid, C,H,.CH:CH,CH,.CO,H, is produced on heating 
benzaldehyde with sodium isosuccinate. Phenyl-paraconic acid (p. 793) is pro- 
duced at first, but this then parts with carbon dioxide. The acid melts at 86°, and 
when boiled yields water and a-naphthol. It unites with hydrogen bromide, forming 
phenyl-y-brombutyric acid, which yields pheny]-butyro-lactone (p. 777) with a soda 
solution. Boiling dilute sulphuric (1 part : 2 parts water) converts it directly into 
phenylbutyrolactone (p. 352). 


814 ORGANIC CHEMISTRY. 


Phenyl-methacrylic Acid, C,H CH:CZ ke, , is obtained from benzalde- 
ae \ CO, 
2 


hyde and sodium propionate, as well as by the action of sodium upon propionic 
benzyl ester (Berichte 20, 617), It crystallizes from water in long needles, that 
melt at 78°, and boil at 288°. Sodium amalgam converts it into phenylisobutyric 
acid: Bromine in the presence of alkali converts the amide of the latter into 
phenylisopropylamine, C,H;.CH,.CH(CH,).NH, (p. 160) (Berichte, 20, 618). 


Methyl Atropic Acid, CHS CEC uw is obtained from phenyl-acetic 
2 


acid, C,H,.CH,.CO,H, and acetaldehyde. It melts at 135°. 


Methyl Cinnamic Acids, C HC CH (CH.CO;H. The three isomerides, o-, 


m- and g-, have been prepared from the corresponding toluic aldehydes by means 
of sodium acetate. The ortho melts at 169°, the para at 197° ( Berichte, 23, 1029, 
1033) and the me¢a at 107° (Berichte, 20, 1215). 

Propenyl Benzoic Acid, CjH KOoHe 


2 
benzoic acid (p. 777). . Boiling hydrochloric acid converts it (analogous to atropic 
acid) into a polymeric acid. 


2, is obtained from oxyisopropyl 





3. Phenyl-angelic Acid, C,,H,,0, = C,H,.CH: CCB E bp ‘from benzaldehyde 


and normal butyric acid, yields Phenyl-valeric Acid, C,H,.CH,.CH(C,H,). 
CO,H, with sodium amalgam, It melts at 104°. The ortho-nitro product of this 
is reduced to an ortho-amido-acid, which parts with water and yields the anhy- 
peu CILC.H, 
dride, ethyl-hydrocarbostyril, C,,H,,NO =C,H, | ° which can 
\NH.CO 
be easily changed into @-ethyl-quinoline, C,H,(C,H,)N (analogous to the for- 
mation of quinoline from ortho-amido-hydrocinnamic acid, p. 758). 
p-Cumenyl-Acrylic Acid, C,,H,,O, = C,H,.C,H,.CH:CH.CO,H (with iso- 
propyl), may be obtained from cumic aldehyde and sodium acetate. It melts at 
158°. Nitration produces f-nitrocinnamic acid and o-nitrocumenyl-acrylic acid 
(melting at 156°). Cumin indigo (di-isopropyl indigo) can be obtained from the 
latter (this is analogous to the rearrangement of o-nitro-cinnamic acid). 0-Amido- 
cumenyl-acrylic acid, obtained by reduction, condenses to cumostyril (isopropyl- 
carbostyril ) (p. 812), ’and cumoquinoline. In addition to o-nitro-cumenyl-acrylic 
acid, o-nitro-p-propylcinnamic acid, C,H,.C,H;(NO,)CH:CH.CO,H (with the 
normal propyl group), is also formed by a molecular rearrangement. Its amido- 
derivative is #-propylcarbostyril (Berichte, 19, 255; 20, 2771). 





We have an example of a doubly unsaturated acid in 

Phenyl-propiolic Acid, C,H,O, = C,H;.C:C.CO,H (p. 244). 
It is obtained by boiling a- and #-brom-cinnamic acids with alco- 
holic potash, by acting upon sodium phenyl-acetylene, C,H;.C: CNa, 
with carbon dioxide, and when the latter and sodium act upon /- 
brom-styrolene. It is prepared by boiling the dibromide of ethyl 
cinnamate (p. 809), with alcoholic potash (3 molecules). It crys- 


AMIDO-PHENYL PROPIOLIC ACID. 81 5 


tallizes from hot water or carbon disulphide in long, shining 
needles, melting at 136—137° and subliming; under water it melts 
at 80°. When heated to 100° with water it decomposes into carbon 
dioxide and phenyl acetylene. It combines with 2 and 4Br, and 
yields hydrocinnamic acid with sodium amalgam. Zinc dust and 
glacial acetic acid, or sodium and methyl alcohol, convert it into 
cinnamic acid. When its ethyl ester is dissolved in sulphuric acid 
and diluted with water we get benzoyl acetic ester (p. 763). 


Nitro-pheny] propiolic acids, C,H,(NO,).C:C.CO,H. 

o-Nitro-phenyl Propiolic Acid is obtained when aqueous soda acts upon the 
dibromide of o-nitro-cinnamic acid. An easier method consists in mixing the di- 
bromide of the o-nitro-cinnamic acid ester (p. 811) with alcoholic potash (3 mole- 
cules) (Amnalen, 212,140). It occurs in commerce in the form of a 25 per cent. 
paste. ‘To purify this it is first converted into the ethyl ester. The acid crystal- 
lizes from hot water or alcohol, in needles, or shining leaflets, and decomposes at 
156°. When boiled with water it decomposes into carbon dioxide and o0-nitro- 
phenyl acetylene (p. 802). When boiled with alkalies it yields isatin :— 


/C:C.CO,H __ 


co 
NO, = C,H, ¢ \ SC.OH Un Goes 


IN NG 


It dissolves in concentrated sulphuric acid, with conversion into the isomeric 
isatogenic acid, which at once forms carbon dioxide and isatin. ‘ 

If digested with alkaline reducing agents (grape sugar and potas- 
sium hydroxide, ferrous sulphate, hydrogen sulphide, potassium 
xanthate) z¢ readily changes to indigo blue (Baeyer, 1880) :— 


C,H 


2C,H,NO, + 2H, = C,,H,,N,0, + 2CO, + 2H,0. 


Therefore nitrophenyl propiolic acid may serve as a substitute for 
natural indigo, especially in calico printing. 


The e¢hy/ ester of the acid is obtained by rapidly conducting hydrochloric acid gas 
into the mixture of the acid and Io parts absolute alcohol, until solution ensues. 
It is very soluble in ether and separates in large crystals, melting at 60-61°. It 
is saponified on heating a mixture of sulphuric acid, water and glacial acetic acid 
(equal parts) to 100°. (p. 810) When it is dissolved in sulphuric acid it changes to 
the isomeric isatogenic ester. Ammonium sulphide reduces it to the indoxylic 
ester. 

p-Nitrophenyl Propiolic Acid is formed from the Z-nitro cinnamic ester, after the 
same manner as the ortho-acid (Amnalen 212, 139, 150). It crystallizes from 
hot alcohol in needles, and melts at 198° (181°) with decomposition. When 
boiled with water it breaks up into carbon dioxide and ‘g-nitrophenyl acetylene. It 
yields f-nitroacetophenone (p. 728), if digested at 100° with sulphuric acid. 

The ethyl ester crystallizes from alcohol in needles; melting at 126°. When 
digested with sulphuric acid at 35° it forms -nitrobenzoyl acetic acid (p. 763). 


o Amido-phenyl Propiolic Acid is obtained by reducing 
nitrophenyl propiolic acid with ferrous sulphate and ammonia 
(Berichte, 16, 679). It separates as a yellow, crystalline powder, 





816 ORGANIC CHEMISTRY. 


melting at 128-130°, with decomposition into carbon dioxide and 
amidophenyl acetylene (p. 802). When boiled with water it yields 
amido-acetophenone (p. 728). 


y-Chlorcarbostyril results when the acid is boiled with hydrochloric acid, and 
y-oxycarbostyril upon heating it with sulphuric acid. Here there occurs a closed, 
ringed-shaped union of atoms (Berichte, 15, 2147) :— 


"e 
+ HCY C,H C.OH + H,0. 
ee 4 
y-Chlorcarbostyril. 


Sodium nitrite converts the hydrochloride into the diazo-chloride, which at 70° 
yields cinnoline-oxy-carboxylic acid (see this). 

Homologous Acids with two double unions :-— 

Cinnamenyl Acrylic Acid, C,,H,,O, = C,H;.CH:CH.CH:CH.CO,H, Cin- 


namenyl Methacrylic Acid, Cy,H,.0, = CoH, .CH:CH.CH:CC 664, etc., have 


been produced by the condensation of cinnamyl aldehyde with acetic acid, pro- 
pionic acid, etc. (p. 806). 

Ketonice Acids (p. 761). 

Cinnamyl Formic Acid, C,H;.CH:CH.CO.CO,H. This is the only unsat- 
urated a-ketonic acid known. It is obtained, like benzoyl formic acid, from cin- 
namic chloride, with potassium cyanide, etc.; and by the condensation of ben- 
zaldehyde and pyroracemic acid, CH,.CO.CO,H, by means of hydrochloric acid 
gas (p. 716). It is a gummy mass and is gradually decomposed into its compo- 
nents by the alkalies, even in the cold. 

The ortho nitro derivative is similarly formed from o0-nitrobenzaldehyde, melts 
at 135°, and is changed by alkalies, even in the cold, with elimination of oxalic 
acid, into indigo (Berichte, 15, 2863) :— 


2C,H,(NO,).C,H,.CO.CO,H +.2H,0 = 
(C,H,:C,ONH), + 2C,0,H, + 2H,0. 
Indigo, 


Unsaturated $-efonic acids are produced by the condensation 
of benzenes with maleic anhydride, etc., by means of AICI, (see 
benzoyl propionic acid) (just as phthalic anhydride condenses with 
fatty acids and benzenes p. 787) :— : 


C,H, + C,H,(CO),0 — C,H,.CO.C,H,.CO,H. 


Benzoyl Acrylic Acid, C,H,.CO.CH:CH.CO,H, from benzene and maleic 
anhydride, crystallizes with water in shining leaflets, melting at 64°, but at 97° 
when anhydrous (Berichte, 15, 889). It yields benzoyl propionic acid by reduc- 
tion (p. 764). 

Benzoyl Crotonic Acid, C,H,.CO.C,H,.CO,H, from benzene and citraconic 
anhydride, melts at 113°. /CO.CH 

Benzal-Aceto-acetic Acid, Alia eeueed sah , 


by the condensation of benzaldehyde and aceto-acetic ester by means of HCl or 
ZnCl,. Sometimes it solidifies in crystalline form, and melts at 60°; it boils near 
296°. It condenses with phenylhydrazine to diphenylmethylpyrazole, Benzalde- 


Its ethyl ester is formed 


AMIDO-PHENYL PROPIOLIC ACID. 817 


hyde condenses with ethyl and diethyl aceto-acetic esters, acting at the time upon 
the methyl group (Azna/en, 218, 181). . 
3-Benzal-levulinic Acid, CuHy CHLCC car eet up is produced by the con- 
gs 


densation of benzaldehyde and lzevulinic acid in acid solution, and melts at 125°. 
It parts with water upon distillation and forms aceto a naphthol, C,H,:C,H,(OH). 
(CO.CH,), just as a-naphthol is produced from phenyl-isocrotonic acid (p. 813). 
When benzaldehyde and levulinic acid condense in alkaline solution the pro- 
duct is :— 
6-Benzal-levulinic Acid, C,H,CH:CH.CO.C,H,.CO,H, melting at 120° 
( Berichte, 23, Ref. 576). 





Oxy-acids and coumarins. 

The unsaturated oxy-acids, or phenol acids, containing hydroxyl 
in the benzene nucleus can be obtained from the unsaturated amido- 
acids (the amido-cinnamic acids) by boiling the diazo-derivatives 
with water :— 


/NH /OH 
CEs Cen con CeHa< CH:CH.CO,H. 
Amido-cinnamic Acid. Oxy-cinnamic Acid, 


They are synthetically prepared from the oxybenzaldehydes, C,H, 

(OH).CHO, by heating them with the sodium salts of the fatty 

acids (p. 806). The  acidyl derivatives of the oxy-acids are first 
produced :— : 


ie 4+ CH,.CO,Na + (C,H,0),0 = 
O 
/OLH,0 


H 
° “\CH:CH.CO,Na 


H,7 
6 *\ cH 


Cc + C,H,0, + H,0. 


These yield the acids when saponified with alkalies. Those isome- 
rides, belonging to the ortho-series, can here, by exit of water, 
yield inner anhydrides (d-lactones), called coumarins :— 


aH 0 ers : 
SH S| = C,H CO + C,H,0.OH. 
e “NCHCH CON.) Nee 
Aceto-o-coumaric Acid, Coumarin, 


Such coumarins are produced (1) by the condensation of: phenols 
and aceto-acetic esters when they are heated with sulphuric acid 
(v. Pechmann, Berichte, 16, 2126) :— 


. 


C,H OH 4+ co” ; = ‘CO -LC,H,.0H 
oF \CH;.CO,C.H, 2" Seren) cH Shake et 


Resorcinol especially is very reactive, forming (-methyl umbelliferon. Orcin 


818 ORGANIC CHEMISTRY. 


yields dimethyl umbelliferon, and pyrogallol yields methyl daphnetin, etc. (Be- 
richte, 17, 2129, 2187). Citric acid (Berichte, 17, 931) reacts like aceto-acetic 
ester. Resorcinol and phloroglucin also yield di- and tri-coumarins (Berichte, 20, 


1329). 


2. The condensation of the phenols with malic acid when heated 
with sulphuric acid or ZnCl, (it is very probable the malic acid 
first yields malonic aldehyde, CHO.CH,.CO,H) (v. Pechmann, 
Berichte, 17, 929, 1646) :— 


Ono 
C,H,(OH) + CHO.CH,.CO,H = CHK op 4 2H,0. 


Coumarin. 


Resorcinol yields umbelliferon (oxycoumarin, p. 821), while daphnetin is 
obtained from pyrogallol (p. 823). Hydroquinone, orcin, phloroglucin and 
B-naphthol react similarly. 

3. Dicoumarins are produced by the condensation of salicylic aldehyde and 
succinic acid (p. 807); with pyrotartaric acid the product is coumarin propionic 
acid (Berichte, 23, Ref. 97). 


The coumarins correspond to the 6-lactones of the paraffin series, 
_ derived from the 6-oxy-acids (p. 353). They are distinguished 
from them by their much greater stability. Boiling water does not 
affect them; they dissolve unaltered in the alkalies (carbon dioxide 
again separates them) and are converted into salts of the o-oxy- 
acids by protracted heating with concentrated alkalies. Similarly, 
the oxy-acids are not converted into the corresponding coumarins 
either by boiling with water, or by heating them. ‘This change 
only occurs upon distilling their aceto-compounds, or through the 
action of hydrobromic acid (Berichte, 18, Ref. 28). 


(1) Oxycinnamiic Acids, CH ecw ton Coumaric Acids. 


Meta-coumaric Acid (1, 3), from m-amido-cinnamic acid and from m-oxy- 
benzaldehyde (p. 817), crystallizes from hot water in white prisms, and melts at 
191°. Sodium amalgam converts it into hydro-#z-coumaric acid (p. 774). 

Para-coumaric Acid (1, 4) is obtained from Z-amido-cinnamic acid, and from 
p-oxybenzaldehyde, also on boiling the extract of aloes with sulphuric acid. 
Preparation, Berichte, 20, 2528. It crystallizes from hot water in needles, and 
melts at 206°. Sodium amalgam converts it into hydropara-coumaric acid ; 
fused with KOH it yields Z-oxybenzoic acid and acetic acid. It is identical with 
naringinic acid from the glucoside naringine (Berichte, 20, 296). 


Ortho-coumaric Acid (1, 2) occurs in Mellotus officinalss, 
together with o-hydro-coumaric acid. Nitrous acid converts o-amido- 
cinnamic acid into coumaric acid; its acetyl derivative is obtained 
from salicylic aldehyde and sodium acetate. It is most readily 
prepared by boiling coumarin for some time with concentrated 


COUMARIN. . 819 


potassium hydroxide, or better, with sodium ethylate (Berichie, 18, 
Ref. 28; 23, 1714). 

Ortho-coumaric acid is very easily soluble in hot water and in 
alcohol, and melts with decomposition at 208°. Sodium amalgam 
converts it into melilotic acid, and fusion with potassium hydroxide 
into salicylic and acetic acids. Its alkali salt solutions are yellow 
colored and show a green fluorescence. <Aceto-coumaric acid (see 
above) melts at 146°, and is split into acetic acid and coumarin on 
the application of heat. The free coumaric acid heated alone does 
not yield coumarin, but only when treated with acetic chloride or 
anhydride. 


In addition to the above ortho-coumaric acid (8) we have also a-coumaric 
. AIS ; O eet ag 
acid or the so-called Coumarinic Acid, C,H 4\.C,H,.CO,H’ which is known 


only in its salts and ethers, and when set free at once yields water, and its 
anhydride—coumarin. Its relations to common coumaric acid are perfectly simi- 
lar to those of maleic to fumaric acid; the latter, according to Wislicenus, is 
axtally-symmetric, whereas coumarinic acid, only known in its anhydride, is A/ane- 
symmetric i— 


HO.C,H,.CH CH.C,H,.0H 
| | 
CH.CO,H bH.CO,H 
Ordinary Coumaric Acid. Coumarinic Acid. 


These assumptions do not accord with the behavior of nitrocoumaric ester, which 
rather points to the idea of Michael, that coumarinic acid is a dioxylactone 
( Berichte, 22,1714). The basic salts of the acid, e. g., C,H ,(ONa).C, H,.CO,Na, © 
are obtained on boiling coumarin with dilute alkalies, and differ from the salts of 
ordinary coumaric acid, which are prepared by strongly heating coumarin with 
alkalies (see above). From the former acids precipitate coumarin, from the latter, 
coumaric acid. If coumarin be boiled with caustic potash (2 molecules) and 
methyl iodide (2 molecules), in alcoholic solution, we obtain a dimethyl ether, 
which, on saponification, yields Methylcoumarinic Acid, C,H ,(O.CH,).C,H,. 
CO,H, melting at 90°; greater heat (150°) produces a dimethyl ether which when 
saponified, yields Methylcoumaric Acid, melting at 182°. The latter acid is 
more readily obtained by boiling coumaric acid with caustic potash (1 molecule), 
methyl iodide and alcohol. It is, moreover, directly prepared from methyl sali- 
cylic aldehyde, C,H,(O.CH,).CHO (p. 817), by means of sodium acetate, etc. 
Strong heat, boiling with hydrochloric acid and even sunlight, converts methyl 
coumarinic acid into stable methyl coumaric acid. Sodium amalgam converts both 
acids into methyl-melilotic acid; and also yields the same addition product with 
bromine. Potassium permanganate oxidizes both to methyl salicylic acid. Ethyl 
coumarinic and Ethyl coumaric Acid, C,H,(O.C,H;).C,H,.CO,H, manifest 
the same deportment; the former melting at 102°, the latter at 132° (Amnalen, 
216, 139). 


Coumarin, CHO, 2 GHZ Bae S00), the 3-lactone of 
2 2 , 


coumarinic acid, occurs in Asferula odorata, in the Tonka beans 
(from Dipterix odorata), and in Metilotus officinalis. It is artifici- 
ally prepared by heating salicylic aldehyde with sodium acetate and 


520 ORGANIC CHEMISTRY. 


acetic anhydride. At first we get aceto-coumaric acid, which de- 
composes further into acetic acid and coumarin (p. 818). It is 
soluble in hot water, readily in alcohol and ether, crystallizes in 
shining prisms, possesses the odor of the Asferuda, melts at 67°, 
and distils at 290°. When warmed it dissolves in alkalies with a 
yellow color; on boiling coumarinic and coumaric acids result 
(see above). Potassium permanganate destroys it (like the homo- 
logous phenols). Sodium amalgam changes it to melilotic acid 


(p. 774)- 


Bromine converts it into a dibromide, C,H, Br,O,, melting at 105°. Coumari- 
lic acid is produced when coumarin dibromide or brom-coumarin is boiled with 
alcoholic potash (p. 825). 

o-Nitro-coumarin, C,H,;(NO,)O,, from o nitrosalicylic aldehyde, melts at 
I91°, and cannot be directly rearranged into carbostyril (Berichte, 22, 1705). 
o-Nitro-carbostyril is produced by heating the amide of o-nitro coumarinic acid with 
hydrochloric acid. 

When salicylic aldehyde acts upon the higher fatty acids we derive homologous 
alkyl coumarins (p. 807) Propionyl-coumarin, C,,H,O,, a-methyl coumarin, 
from propionic acid, melts at 90°, and boils at 292°. {-Methyl coumarin (p. 818), 
from phenol and acetoacetic ester, melts at 125°. Butyryl-Coumarin, C,,H,,0,, 
a-ethyl coumarin, from butyric acid, and salicylaldehyde melts at 71°, and boils at 
299°. 

‘ /O0.CH / O0.CH 
The alkyl-ether acids, CeH4¢ CH.cit.co,H, CoH CH:c{CH, ).CO, Hete., 
Meshylosyphcayt Acrylic Methyloxyphenyl Prcionic 
cid. Acid. 


derived from the alkyl-oxy-benzaldehydes. (methyl salicylic aldehyde, methy] 
anisaldehyde), yield esters. of unsaturated phenols (just as styrolene arises from 
cinnamic acid) by the action of hydrochloric acid and a soda solution, when carbon 
dioxide is eliminated, e. ¢.:— 


/O0.CH, / 0.CH, 
eeney Chen. | ee SAN Pa CH CH. ete. 
Vinylanisol. Propenylanisol. — 
The latter i is the anzethol (p. 803) found in anise oil. 





Dioxyacids. 


The dioxyphenyl acrylic acids are caffeic acid and its methyl esters: /erw/ic and 
tsoferulic acids, and umbellic acid, whose anhydride is umbelliferon. ‘The first 
acids are intimately related to protocatechuic acid and its ethers, and to vanillic 
and iso-vanillic acids, since they have the side groups in the same position 


(p. 780) :-— 


CH:CH.CO,H (1) CH:CH.CO,H CH:CH.CO,H 
C,H |oH (3) C,H foct, ras .{ oH 
OH (4) OH O.CH, 
Caffeic Acid. Ferulic Acid. Isoferulic Acid. 


In umbellic acid the side-chains occupy the same position as in £-resorcylic 
acid (p. 778); one hydroxyl group is in the ortho-place referred to the side-chain 


* 


COUMARIN. 821 


containing carbon, hence the acid can yield an inner anhydride (umbelliferon), 
just as o-coumaric acid forms coumarin :-— 


CH:CH.CO,H (1) C,H,.cO 
C,H,{OH | (2 Gs OF 
OH (4 OH 
Umbellic Acid. Umbelliferon. 


Caffeic Acid, C,H,O,, is obtained when the tannin of coffee (p. 785) is boiled 
with potassium hydroxide. It is prepared artificially from proto-catechuic aldehyde 
if the latter be heated with acetic anhydride and sodium acetate, and then the 
resulting diacetate saponified. It crystallizes in yellow prisms, and is very readily 
soluble in hot water and alcohol. The aqueous solution reduces silver solutions 
upon application of heat, but not alkaline cupric solutions. Ferric chloride causes 
a green coloration, which becomes dark red by the addition of soda. When fused 
with potassium hydroxide, caffeic acid decomposes into _protocatechuic acid and 
acetic acid. Pyrocatechin results when it is exposed to dryedistillation. “Sodium 
amalgam converts it into hydrocaffeic acid (p. 782). . 

Ferulic Acid, C,)H,,O,, is the methyl-phenol ether of caffeic acid and corre- 
sponds to vanillin. It is found in asafcetida, from which it may be obtained by 
precipitation with lead acetate and by the subsequent decomposition of the lead 
salt with sulphuric acid. It has been synthetically prepared from vanillin when 
heated with sodium acetate, etc.; also from m-methoxy-cinnamic ester (from 
m-nitrobenzaldehyde) (Berich/e, 18, Ref. 682). It is very soluble in hot water, 
crystallizes in shining needles or prisms, and melts at 169°. Ferric chloride im- 
parts a yellowish-brown coloration to its aqueous solution. When fused vie 
potassium hydroxide, it forms protocatechuic acid and acetic acid. Potassiu 
permanganate oxidizes the acetate to aceto-vanillin. Ferulaldehyde, the aldehyde 
of ferulic acid, has been obtained from glycovanillin (Berichte, 18, 3482). 

Isoferulic Acid, Hesperetinic Acid, C,,H,,O, (see above), was first obtained 
from the glucoside hesperidine, and is prepared by partially methylating caffeic 
acid (together with a little ferulic acid). It melts at 228°, and if fused with potas- 
sium hydroxide decomposes into protocatechuic acid and acetic acids. The oxida- 
tion of its acetate produces isovanillic acid; sodium amalgam yields isohydro- 
ferulic acid (p. 782). 

By the introduction of more methyl] into ferulic and. isoferulic acids, as well as 
caffeic acid, there results dimethyl caffeic acid, C,H,(O.CH,),.C,H,.CO,H, 
melting at 181°; this is oxidized by potassium permanganate to dimethyl proto- 
catechuic acid. Methylene Caffetc Acid, CoH, (9 SCH,)-CH,.CO,H, is ob- 
tained synthetically from piperonal (p. 726) by means of sodium acetate, etc. 

Umbellic Acid, C,H,0O, = C,H,(OH),.C,H,.CO,H (see above), is ob- 
tained by digesting umbelliferon with caustic potash, and then precipitating with 
acids. It is a yellow powder, decomposing about 240°. Its anhydride, corre- 
sponding to coumarin, is— ; 

Umbelliferon, C,H,O,, Oxycoumarin. It is*“found in the bark of Daphne 
mezereum, and is obtained by distilling different resins, such as galbanum and 
asafoetida. It is obtained synthetically from (-resorcyl aldehyde, C,H,(OH),. 
CHO, by means of sodium acetate, etc.; and also by the condensation of resor- 
cinol with malic acid (p. 818). It consists of fine needles, sparingly soluble in 
hot water and ether, melts at 224°, and sublimes undecomposed. When heated 
it has an odor resembling that of coumarin. It dissolves with a beautiful blue 
fluorescence, in concentrated sulphuric acid. It dissolves in cold alkaline hydrox- 
ides unaltered, but when heated umbellic acid is produced. Sodium amalgam 
converts it into hydro-umbellic acid (p. 782). Fusion with caustic alkali affords 
B-resorcylic acid and resorcinol. 


822 ORGANIC CHEMISTRY. 


When umbelliferon is treated with methyl iodide and caustic alkali it conducts 
itself like coumarin (p. 819). The products of the reaction are a-Dimethyl- 
umbellic Acid, and the more stable $-Dimethyl-umbellic Acid, C,H. 
(0.CH;),.C,H, CO, H; these correspond toe methyl coumarinic and methy! 
coumaric acids (Berichte, 16, 2115; 19,1777). Oxycoumarilic acid is formed 
in like manner from the dibromide by the action of alcoholic potash. 


The so-called 6-Methyl-umbelliferon, C,H,(OH). \C(CH,);CH 76 Bes 


been prepared synthetically by the condensation of resorcinol with aceto acetic 
esters (p. 818). It melts at 185°, and when fused with caustic potash yields 
resacetophenone, C,H,(OH),.CO.CH, (p. 729) and resorcinol (Berichée, 16, 
2120). The introduction of methyl! produces dimethyl] 8-methyl umbellic acid, 
C,H,(O.CH,),.C(CH, ):;CH.CO,H, which potassium permanganate oxidizes tu 
dimethyl-8-resorcylic acid (p. 778). 





As a representative of the doubly unsaturated dioxyacid class we may mention 
Piperic Acid, C,,H,,0, = C,H, (0 CH,).CH:CH.CH:CH.CO,1. Zis side- 


chains are arranged like those in protocatechuic acid.- Its potassium salt is pro- 
duced when the alkaloid piperine is boiled with alcoholic potassium hydroxide. 
It consists of shining prisms. The free acid is almost insoluble in water, and crys- 
tallizes from alcohol in long needles, melting at 217°. Its salts with 1 equivalent 
of, base are very sparingly soluble. It combines with four atoms of bromine. It 
is oxidized to piperonal when digested with potassium permanganate; at 0° the 
side-chain is eliminated as racemic acid (Berichte, 23, 2372). When fused with 
potassium hydroxide it breaks down into acetic, oxalic and protocatechuic acids. 
Chromic acid destroys it completely. Sodium amalgam converts it into two iso- 
meric hydropiperic acids, C,,H,,O,,a@ and @. The a-acid melts at 78°, and 
when digested with sodium hydroxide is converted into the (-acid, melting at 
131°. ‘The a-acid yields a dibromide with bromine; the 6-acid when acted upon 
with sodium amalgam passes into the so-called piperhydronic acid, C,,H,,0,, 
melting at 96°. 





JE sculetin and Daphnetin are anhydrides (d-lactones) of unsaturated trioxy- 
acids, and may also be designated dioxy-coumarins :— 


/CH:CH.CO (1) /CH:CH.CO (1) 

Oo, ARS RE ot fe, Pes 5 arose) 

\(OH), (4,5 \(OH), ac 4). 
Fscul etin. Daphne 


The three hydroxyls in zesculetin have the same position as in oxyhydroquinone, 
C,H,(OH), (1, 3, 4), and in daphnetin they are in the same relation as in pyro- 
gallol. Their corresponding acids are only known as tri-ethyl-ether acids :—_ 


/CH:CH.CO,H (1) /CH:CH.CO,H (1) 
oHa< (O.C,Hy)s (2 4 5) Talia\ (0.G,H, ls (2, 3 4)- 


Triethyl-zscufetinic acid. Triethyl Ganaetic acid. 


Cc 


ZEsculetin, C,H,O,, is present in the bark of the horse chestnut, partly free 
and partly as the glucoside escudin, from which it is prepared by decomposition 
with acids or ferments. It crystallizes with a molecule of water in fine needles or 


PHTHALYL ACETIC ACID, 823 


leaflets, and dissolves with a yellow color in the alkalies. It reduces silver and 
alkaline copper solutions and receives a green color from ferric chloride. 

Ethyl iodide and caustic alkali convert it (analogous to the deportment of um- 
belliferon and coumarin) into two isomeric triethyl-zesculetinic acids (see 
above), which are oxidized by MnO,K into a ¢riethoxybenzoic acid, C,H, 
(O.C,H,),-CO,H, which parts with carbon dioxide and becomes triethoxyhydro- 
quinone, C,H,(O.C,H;), (Berichte, 20, 1119). 

Daphnetin, C,H ,O, (see above), is obtained by the decomposition of the glu- 
coside dafhnin. It is prepared synthetically by the condensation of pyrogallol 
with malic acid through the action of sulphuric acid (p. 818). It crystallizes in 
yellow needles or prisms, melting at 255°. It reduces silver and alkaline copper 
solutions, even in the cold, and receives a green color from ferric chloride. Ethyl 
iodide and caustic alkali convert it into triethyl daphnetic acid, C,H, 
(O.C,H,),.C,H,.CO,H, from which we obtain Triethyl-pyrogallol-carboxylic 
Acid (p. 782)— Berichte, 17, 1089—by means of potassium permanganate. 





Unsaturated disasic acids. Under this head may be classed 

(1) Benzal-malonic Acid, C,H,.CH:C(CO,H),. This is produced in the 
condensation of benzaldehyde and malonic acid on digesting with glacial acetic acid 
(p. 716). It crystallizes from hot water in shining prisms, melting at 196°, with 
decomposition into carbon dioxide, and cinnamic acid. When it is boiled with 
water it splits into benzaldehyde and malonic acid; its salts, however, are stable. 
Sodium amalgam converts it into benzyl-malonic acid (p. 791). Its diethyl ester, 
C,H,;.CH:C(CO,.C,H;),, is derived from benzaldehyde and malonic ester by 
means of HCl or ZnCl,. It boils with slight decomposition about 310° (Anuna- 
len, 218, 121). 

The three s7trobenzalmalonic acids, C,H,(NO,).CH:C(CO,H),, have been 
prepared by the condensation of the nitrobenzaldehydes with malonic acid. The 
ortho-acid yields (:carbostyril carboxylic acid (Berichte, 21, Ref. 253) upon re- 
duction with ferrous sulphate. 

(2) Phenyl-maleic Acid, C,H,.C,H(CO,H),, from phenylmalic acid 
(p. 792), forms very soluble prisms. It passes into its anhydride at temperatures 
below 100°, The anhydride melts at 119° (Berichte, 23,Ref. 573). 


(3) Cinnamyl Carboxylic Acids, CoH. cHtcH Co.p, The ortho-acid 
:CH.CO,H. 


(1, 2), is produced when phthalidacetic acid is digested with alkalies and by 
carefully oxidizing $-naphthol with potassium permanganate (Aerichie, 22, Ref. 
654). More energetic oxidation produces carbophenyl glyoxylic acid (p. 765). 
It melts at 174°, and reverts again to phthalidacetic acid. 

The fara-acid is obtained from terephthal-aldehydic acid and sodium acetate. 
It is an insoluble, infusible powder. Nitration converts it into an ortho-nitro acid, 
which yields indigo-dicarboxylic acid (this is analogous to o-nitro-cinnamic acid) 
(Berichte, 19, 948). 

The following are anhydrides (lactones) of oxydicarboxylic acids :— 

5 C= CH.CO,H 

(1) Phthglyl Acetic Acid, C,,HO, = C,H,~ Oo , is 
formed by condensation of phthalic anhydride with sodium acetate (analogous to 
the reaction of Perkin) (p. 806) (Berichfe, 17, 2521) :— - 


C = CH.CO,H 
CoO N 2 
CHC Co >° + CH,.CO,H = CHK Oo yo 


. 


4+ H,O. 


— 824 ORGANIC CHEMISTRY. 


It is insoluble in water, soluble with difficulty in alcohol, and melts with decom- 
position about 243°. Salts of benzoylaceto-carboxylic acid (p. 765) are obtained 
by dissolving it in alkalies. When it is heated with water to 200° it breaks down 
into carbon dioxide and aceto-phenone-carboxylic acid (p. 764). When heated 
C2 CH.COH 
with ammonia it forms Phthalimide Acetic Acid, CHK NNH 
\co% 

(p. 787); the ethylamines react analogously (Berichte, 19, 2368). Phthalyl- 
acetic acid decomposes by distillation into carbon dioxide and methylene phthalide, 


C,H oie . This derivative has an odor strongly resembling that of 
CO 
phthalide. It forms vitreous rhombs, melting at 58-60° (Berichte, 17, 2522). 


Phthalic anhydride forms similar compounds with propionic acid, succinic acid, 
etc. (Berichte, 14, 919). 


may so Me Ge / C | 
Ethine diphthalyl, CHA yo pete GH (Berichte, 17, 
CO CO 
Gate TALC 


2770), and Lthidene phihalide, C5H aa yo , very similar to methy- 
CO 
lene phthalide (Berichte, 19, 838), result upon condensation with succinic acid. 
Phthalic anhydride and phenylacetic acid, C,H;.CH,.CO,H, condense to 
Benaylidene Phthalide (Berichte, 18, 3470), which can be transposed into 
isomeric /sobenzal-phthalide (Berichte, 20, 2363) :— 


C=CH . CH = CCH, 
Cue oN” yields GB ee 7 ; 
\co” CO.0 
Benzylidene Phthalide. Isobenzalphthalide. 


Ammonia converts the latter into /sobenzal-phthalimidine, that can be changed to 
Phenyt-isoguinoline (Berichte, 18, 3478; 19, 830): 


CH = C.C,H CH as CCH, 
AG per and Fd [as 
\co — NH \cH =N 
Isobenzal-phthalamidine. Phenyl-isoquinoline. 
O —— CO 


(2) Coumarin-Carboxylic Acid, C,H,@ l , is produced by 
Ch = Cow 

condensing salicylic aldehyde and malonic acid upon heating them with glacial 
acetic acid. It melts at 187°, and about 290° breaks down into carbon dioxide 
and coumarin (Berichte, 19, Ref. 350). 





Derivatives of Benzene containing closed Side-chains. 

The parent substances of the compounds included in this series 
are benzene furfurane (coumarone), benzothiophene (thionaphthene), 
and denzopyrrol (indol) :— | 


CH I CH 
CoH you CUZ... SCH Cu.~° SCH 
O S 


Coumarone. Benzothiophene. Indol. 


BENZOFURFURANE OR COUMARONE GROUP. 82 5 


They contain, in addition to the benzene nucleus, a closed chain 
of five members (as in furfurane, thiophene and pyrrol, p. 521) ; 
two of the C-atoms belong to the benzene nucleus. 





1. BENZOFURFURANE or COUMARONE GROUP. 


The coumarone compounds are produced :— 
(1) By the action of alcoholic potash upon coumarin dibromides 
or a-brom-coumarins (Fittig, Annalen, 126, 170) :— 


ocr Pic 
H,O= C8 C.CO,H + HBr. 
hoe bat 2 6 ‘Uo gH + r 
Other coumarins react similarly. Thus, umbelliferon yields oxycoumarilic acid 
(Berichte, 19, 1783), and zesculetin and daphnetin give dioxycoumarilic acids 
(Berichte, 17, 1075). The coumarones are produced by the elimination of the 
carboxyl group from the coumarilic acids. 


C,H 


(2) By the action of chloraceto-acetic esters upon the sodium salts 
of the phenols; @-methyl coumarilic esters result (Hantzsch, Be- 
richte, 19, 1291 3 1298) :— 


os 
CO.CH, ra : 

C,H,.0.Na + | =c me SC.CO,R + NaCl + H,O. 
CHCLCO,R 


deck Coumarilic Ester. 


Thus, dimethyl coumarilic acid is derived in this way from para-cresol, and the 
two naphthols yield two naphthofurfuranes (erichée, 19, 1301). Resorcin and 
hydroquinone afford benzo-difurfurane, and pyrogallol a benzo-trifurfurane deriva- 
tive (Berichte, 19, 2930; 20, 1332). 

(3) By heating o-aldehydo-phenoxy-acetic acid (from salicylaldehyde and chlor- 
acetic acid) with sodium acetate (Berichée, 17, aoe 


C,H, ZCHO 


4\.0.CH,.CO,H = Se Hae 


Ncu + co, + H,0. 


ER 


CHy 
Coumarone, C,H,O = C,H Lip SCH, is formed by distilling coumarilic 


acid with lime. It is present in Sal tar (Berichte, 23, 78). It is an oil that sinks 
in water, and boils at 169°. Concentrated acids convert it into a resin. With bro- 
mine it yields a dibromide, melting at 88°. 


C(CHs) 
{b-Methyl Coumarone, C,H,O = C,H es : "SCH, from (-methyl cou- 


marilic acid, is an oil, boiling at 189°. "Dusk! coumarone, C,H,(CH,) 
7 o(CHs) 


Sees ae 
69 


SCH, from dimethyl coumarilic acid, boils at 210°. 


826 ORGANIC CHEMISTRY. 


CHL 
a-Coumarilic Acid, C,H,O, =C,H,¢. -SC.CO,H, a-coumarone car- 
9 6-3 6 4\. O ug 2 


boxylic acid, is obtained from coumarin dibromide or a-brom-coumarin. It crys- 
tallizes from hot water in delicate needles, melting at 190° and distils at 310°. It 
breaks down into salicylic and acetic acids, when fused with caustic potash. It 
does not combine with bromine or hydrobromic acid. Sodium amalgam converts 
it into Aydrocoumarilic acid, C,H,O,, melting at 116°, and distilling, with de- 
composition, at 300°. ; 
B-Methyl Coumarilic Acid, C,H,(CH,)O,. Its e¢hy/ ester is produced on 
heating sodium phenoxide with aceto-acetic ester (see above), It melts at 51°, 
and boils at 290°. ‘The free acid crystallizes from hot water in needles, melting at 
189°, and then subliming. If it be rapidly heated it decomposes into carbon di- 
oxide and 6-methyl coumarone. 
H,) 


C.(CH,)— 
Dimethyl Coumarilic Acid, C,H,(CH,)@ ‘SC.CO,H, has been pre- 
g**3 3)\ 0 2 Pp 


ig 
pared from sodium para-cresol with chlor-acet-acetic ester, and from dimethyl cou- 
marin bromide. It melts at 224°, and at higher temperatures decox poses into 
carbon dioxide and dimethyl coumarone. 





2. BENZO-THIOPHENE GROUP. 


CH K 
CH, bears the same relation to thiophene as 
S . 
benzofurfurane to furfurane (p. 824). It also bears the same relation to naphtha- 
lene that thiophene bears to benzene (the group CH=CH of a benzene nucleus 
is replaced by a sulphur atom in it), hence it is also known as Thionaphthene. 
The only known derivative of this series is a-Oxybenzothiophene, or Oxy- 
thionaphthene, C,H,(OH)(C,H,S), corresponding to a-naphthol. It is pro- 
duced by the condensation of thiophenaldehyde and succinic acid (Berichte, 19, 
1618). It sublimes in long needles, and melts at 72°. It resembles a-naphthol in 
its reactions. 


Benzo-thiophene, CHL 





3. BENZOPYRROL OR INDOL GROUP. 


This embraces a series of bodies which can be regarded as deriva- 
tives of the simplest of them all—of zudo/, C;H,N. They were 
first derived from indigo-blue, and bear an intimate relation to the 
latter. The most important members are :— 


: /CH\. /C(OH)\ 
CHinn CH CHA Ny’ SCH 
Indol. Indoxyl. 
/CH,\ /CH(OH)\, /COV, 
CoHaC yf >©O CoH NW” CO CoH y DCOH. 


Oxindol. Dioxindol, Isatin. » 


INDOL. 827 


The last three bodies, so far as concerns their synthetic methods 
of formation, are amido-anhydrides of ortho-amido-acids of ben- 
zene (p. 755). Oxindol is the lactam of o-amido-phenyl-acetic 
acid (p. 755), dioxindol the lactam of o-amido-mandelic acid (p. 
772), while isatin represents the lactime of o-amido-benzoyl-formic 
acid (p. 762). On the other hand, these three bodies can be con- 
verted into each other, and have been obtained from isatin. By 
complete reduction they may be transformed into indol. All indol- 
derivatives contain a closed chain, comprising four carbon atoms 
(two of which belong to the benzene nucleus) and one nitrogen 
atom (p. 824) analogous to that in pyrrol, hence, indol may be 
called benzene-pyrrol. In accord with this indol and especially the 
more stable methyl indols exhibit the reactions of pyrrol (Berichte, 
19, 2988, 3028). By the rupture of the pyrrol ring (in oxidations, 
etc.), the indol compounds are changed to ortho-amido-acids of 
benzene. 

Our knowledge of the indol derivatives and their kinship to 
indigo rests mainly upon the researches of Baeyer (Berichte, 13, 
2254, 16, 2188). | 

Indol, C,H,N, was first obtained in the distillation of oxindol, 
and is a product of the reduction of indigo-blue with zinc dust. It 
is also produced by heating o-nitro-cinnamic acid with caustic pot- 
ash and iron filings. From a theoretical standpoint, the following 
methods of. formation are especially interesting: the reduction of 
o-nitrophenyl-acetaldehyde (p. 721) with zinc dust and ammonia, 
and the action of sodium alcoholate upon o-amido-chlorstyrolene 


(p. 802) :-— 


/CH:CHCl __ /CHY 
CHiCnn, | = Coa yy CH + HC. 


This method represents indol as the anhydride of o-amidophenyl- 
vinyl alcohol, C,H,(NH,)CH:CH(OH). 


Indol may be obtained by various other methods; thus, by conducting the 
vapors of the mono- and di-alkyl anilines and ortho-toludines through a tube 
heated to redness (Berichte, 10, 1262); by distilling nitro-propenylbenzoic acid 
(p. 814) with lime, or phenyl glycocoll with calcium formate; and in the pancreatic 
fermentation of albuminates, or (together with skatole) in the fusion of the latter 
with potassium hydroxide, but is best obtained by the first procedure (Zerichie, 8, 
336). A more convenient procedure is to distil a-indol-carboxylic acid (skatole) 
with lime (Berichte, 22, 1976). Another noteworthy formation is that from the 
quinoline derivatives, ¢. g., the fusion of carbostyril with potassium hydroxide, or 
when tetrahydro-quinoline is conducted through a red-hot tube. 


Indol crystallizes from water in shining leaflets, melting at 52° 
and boiling about 245° with partial decomposition. It is readily 
volatilized in aqueous vapor. Its vapor density (under diminished 
pressure) corresponds to the formula C,H,N. It possesses a pecu- 


828 ORGANIC CHEMISTRY. 

liar odor, resembling that of naphthylamine. A pine splinter moist- 
ened with hydrochloric acid and dipped into its alcoholic solution 
acquires a cherry-red color. Indol possesses but very feeble basic 
properties (similar to pyrrol), and is scarcely dissolved by dilute hy- 
drochloric acid. Hot acids resinify it very readily. 


On adding sodium nitrite toa solution of indol in acetic acid (90%) the latter 
assumes a deep red color owing to the formation of JVitroso-indol, C,H,N(NO) 
yellow crystals, melting at 172° (Berichte, 23, 2299). 

B-Aceto-indol, nB-Diaceto-indol (Berichte, 22, 1977), and n-Aceto-indol (Be- 
richte, 23, 1359, 2296) are all produced upon heating indol (and a-indol-carboxylic 
acid) to 180° with acetic anhydride. 


Alkyl Indols. 


These are derived by replacing the hydrogen of indol by alkyls. Their isomer- 
ides can be readily deduced from the following scheme :— 








H 
C 4 
yee 
HC} 0C_CH ge Nesey 
1 | 
at C bg nib 2 a 
VCA\4 NAN a! 
H N a 
H betes ae 


It corresponds to that given to pyrrol. The benzene hydrogen atoms are 
marked by the numbers 1 to 4. The substitution products derived from the 
 pyrrol nucleus can exist in three isomeric forms; they are designated, as with the 
pyrrol derivatives, 2-, a- and 3B :— 


_CH:CH CHOGH /E(CHs) :CH 
CoHyc ba CoH * CoHa 
N.CH, \NH NH 
n-Methyl Indol. a-Methy] Indol. B-Methyl Indol. 


E. Fischer terms the derivatives of the pyrrol nucleus Py-(1, 2, 3)-derivatives, 
those of the benzene nucleus B-(1, 2, 3, 4)-derivatives (Annalen, 236, 121; 
Berichte, 19, Ref. 829). 

The alkyl indols may be synthesized :-— 


(1) By the production of closed rings from o-amido-compounds (p. 827) : 
o-amidobenzylmethyl ketone forms a-methyl indol (p. 729); o-amidochlorstyro- 


lene, C,H Pm pid sd § yields z-methyl indol; while a-phenyl indol is obtained 
orpets.. 


from o-nitrodesoxybenzoin, C,H Knee tS: 

(2) By heating the anilines with compounds, containing the group—CO,CHC1. 
For example, aniline and chloraldehyde form indol; with chloracetone, CH,.CO. 
CH,Cl, the product is a-methyl indol, and with 6-bromlevulinic acid, CH,.CO. 
CHBr.CH,.CO,H, a@-dimethyl indol is the product. The alkyl anilines and 
toluidines (Berichte, 21, 3360) react in a similar manner. 

The reaction does not always pursue the same course; thus, aniline and brom- 
acetophenone, heated together, yield a-phenyl indol and not the 6-product. This 
is very probably due to the fact that the first product is C, H,.C(N.C,H,).CH, Br 


INDOL. 829 


o 
(Berichte, 21, 1076). Similarly, 2-methyl-a-phenyl indol is formed from brom- 
acetophenone (Berichte, 21, 2595). 
(3) Upon heating together phenylglycocolls and calcium formate. In this way, 
phenylglycocoll, C,H;.NH.CH,.CO,H, yields indol and tolyl glycocoll, toluindol 
( Berichte, 23, Ret, 654) :— 


CH,.C, H,.NH.CH,.CO,IT + CHO.OH = 
NH 

CH, C,H Cy CH + CO, + 2H,0. 
4. A noteworthy and excellent method for the production of the alkyl indols 
consists in condensing the phenylhydrazones of the aldehydes, ketones and ketonic 
acids (p. 656) by heating them with hydrochloric acid or zinc chloride (E. Fischer, 
Berichte, 19, 1563; 22, Ref. 14). The compounds of 6-methyl-phenylhydrazine 
behave similarly (p. 657). Thus, propylidene phenylhydrazone yields $-methyl 


indol :-— /CH, 
C,H,.NH.N:CH.CH,.CH, = ARGS 4+ NH,. 
NH 
Propylidene-phenyl-hydrazone. B-Methy]l Indol. 


Phenylacetaldehyde, C,H;.CH,.CHO, in like manner yields 6-phenyl indol. 
a-Methy]l indol is prepared from acetone-phenylhydrazone :— 


. w<GE /CH\ 
C,H NILN:CC Gy? = CoH. yy SCC, + NHy. 
Acetone-phenyl-hydrazone. a-Methyl Indol. 


na-Dimethyl indol is derived from acetone-methyl-phenyl-hydrazone :— 


CH———C.CH, 
CoH rs + NH. 
N(CH,) 


CH, 
C,H.N(CH,)N:C€ - 
CH; : 
na—Dimethy! Indol. 
The first products from phenylhydrazine and the a- and y-ketonic acids (better 
their esters) are the zndol carboxylic acids (and their esters); these lose carbon 
dioxide and pass into indols :-— 


af CHL a ACH\ 
CoH, NHLNCC €G3 Cy, = CoH yy »C-CO-C Hs + NHy. 
Phenylhydrazone-pyroracemic Ester, | a-Indol-carboxylic Ester. 


The (-alkylhydrazine derivatives react very easily with pyroracemic acid, 
upon warming them with dilute hydrochloric acid, sulphuric or phosphoric acid ; 
the products are # alkyl-indol-carboxylic acids’ When the phenylhydrazine de- 
rivatives of the -ketonic acids, ¢. g., aceto-acetic ester, are heated with zinc 
chloride they are principally converted into pyrazole compounds (p. 656). On 
the other hand, compounds of acetoacetic ester and #-alkylhydrazines (which 
cannot form pyrazole compounds) yield indol derivatives with zinc chloride :— 


CH,.CO,.C,H, SOP aah 


ttl: — 
CoHy-N(CH,).NICC = CoH Nou, 4 NH, 


3 
Methylphenyl-hydrazone- Wi CH 


< 3 
Acetoacetic Ester, na-Dimethyl Indol 
Carboxylic Ester. . 


830 ORGANIC CHEMISTRY. 


See Annalen, 239, 223 for the indols from tolyl and naphthyl hydrazones. 

Nearly all the alkyl indols possess the feecal odor of indol. The odor of the 
u-methyl indols is similar to that of methyl aniline. The phenyl indols and indol 
carboxylic acids are non-volatile and odorless. ‘They are more stable toward acids 
than indol, dissolve in concentrated hydrochloric acid, and are reprecipitated unal- 
tered by water. Picric acid unites with all of them, forming compounds, crystalliz- 
ing in red needles (distinction from the pyrrols, Berichte, 21, 3299). Most of the 
indol derivatives give the pine-shaving reaction, the exceptions being the indol 
carboxylic acids and the a(-dialkyl indols (Berichte, 21, 3300). It is only the 
B-alkyl- and a-dialkylindols that yield simple nitroso-compounds with nitrous acid 
(Berichte, 23, 2299). 

The methyl indols, like pyrrol, combine with aldehydes, acid anhydrides and © 
diazo-compounds (Aerichte, 20, Ref. 429; 21, Ref. 18). Red dye-stuffs, resem- 
bling fuchsine and called rosindols (Berichte, 20, 815), are produced by heating 
m-, a- and 3-methyl indol with benzene*chloride and zinc chloride. 

Interesting transformations are those of methyl indols and indol into quinoline 
derivatives (similar to formation of pyridine compounds from pyrrol, p. 541). In 
this change a methylene group pushes itself into the pyrrol ring, and the resulting 
pyridine ring is then further methylated. The conversion ensues upon heating the 
compounds with chloroform and sodium alcoholate (Berichze, 21, 1940), or with 
alkyl iodides (Berichte, 20, 2199). In this manner a- and -methy] indol as 
well as indol together with methyl iodide at 130° yield trimethyl-dihydroquino- 
line :— 

C,H ,N(CH,) + 3CH,I = C,H, N(CH,), + 3HI (Berichte, 23, 2629; 22, 1979). 
n-Acetyl- and (-acetyl-a-methyl indol are produced upon boiling a-methyl 
indol with acetic anhydride, while a-acetyl-3-methyl indol is obtained by like 


treatment from 6-methylindol. Boiling hydrochloric acid causes the elimination 
of the acetyl groups (Berichée, 21, 1936). 





a-Methyl Indol, C,H,N(CH,), may be obtained by heating #-methyl-indol 
carboxylic acid tor200°. It is an oil, boiling at 239°. #-Ethyl Indol, C,H,N. 
C,H, (boiling at 247°), is prepared the same as the preceding compound. Sodium 
hypobromite oxidizes both compounds, forming methyl and ethyl pseudo-isatin. 
2z-Phenyl Indol, C,H,N(C,H,), from -phenyl-indol-carboxylic acid, is a heavy 
oil. It imparts an intense, bluish-violet color to a pine shaving (Berichte, 17, 568). 
a-Methyl Indol, C,H,(CH,)NH, Methyl Ketol, arises in the anhydride- 
formation of o-amido-benzyl-methyl ketone (p. 729), and is very easily prepared 
~~» by heating acetone phenylhydrazone with ziric chloride to 180° (see above), It 
crystallizes from ligroine in colorless needles or leaflets, melting at 59°. Its odor 
is like that of indol, and its reactions are similar. Oxidation with MnO,K (by 
rupture of the pyrrol ring at the point of the double binding) converts it into 
aceto-o-amido-benzoic acid (p. 749). .a-Indol carboxylic acid is formed when it is 
fused with caustic potash. 
a-Phenyl Indol, C,H,(C,H,;)NH, may be formed from acetophenone phenyl- 
hydrazone (p. 728) by fusion with zinc chloride, from o-nitro-desoxybenzoin 
(p. 828) by reduction, by the action of aniline upon brom-acetophenone, and from 
phenylacetaldehyde-phenylhydrazone by the molecular rearrangement of the 
#-phenyl-indol, which first forms. It crystallizes from alcohol in colorless leaflets 
and melts at 187° 
B-Methyl Indol, C,H,(CH,)NH, Ska/ole, occurs in human feces (with a 
little indol). It may, be obtained, together with indol, from reduced indigo (p. 
$27), by the putrefaction of albuminoids, or (with indol) in the fusion of the same 


OXINDOL. 831 


with potassium hydroxide. See Berichte, 18, Ref. 80, for the isolation of indol. 
In the putrefaction skatole carboxylic acid, C,H,N.CO,H, first results; this 
melts at 161°, and decomposes into carbon dioxide and skatole. It was first syn- 
thesized by distilling nitrocumic acid with zinc dust. It can be prepared without 
difficulty by heating propidene-phenylhydrazone with zinc chloride (p. 829). It 
crystallizes from ligroine in leaflets, melting at 95°, and boils at 265°. It hasa 
penetrating fecal odor. For the reaction with a pine shaving, see Azna/en, 236, 
140. . 

B-Phenyl Indol, C,H,(C,H,)NH, may be prepared by heating phenyl-ace- 
taldehyde-phenylhydrazone, C,H,;.CH,.CH:N,H.C,H,, with alcoholic hydro- 
chloric acid (isomeric a-phenylindol is furmed by fusion with zinc chloride). It 
forms white leaflets, melting at 89° (Berichte, 21, 1811). Various methyl-phenyl 
indols sustain analogous transpositions (Berichte, 22, Ref. 672). 


Indol Carboxylic Acids. 


These are produced (p. 829) when indol and alkyl indols are heated with sodium 
and carbon dioxide (similar to the pyrrol carboxylic acids, Berichte, 21, 1925); 
further by fusing the alkyl indols with caustic alkali. Ordinary oxidizing agents 
do not attack them (erichle, 21, 1929, 1937). Heated alone or with lime they 
break down into carbon dioxide and indols. 

a-Indol Carboxylic Acid, C,H,N.CO,H, from pyroracemic-phenyl hydrazone. 
and from a-methyl indol, crystallizes from hot water in delicate needles, melting at 
200°, and decomposing into carbon dioxide and indol. It yields zmzde anhydride, 
C\,H,)N,O, (Berichte, 22, 2503) if heated with acetic anhydride. -AZethyl- and 
n-Ethyl-a-indol-carboxylic acid, C,H,;N(CH,)CO.H, are produced from pyro- 
succinnic acid with methyl and ethyl hydrazine (p. 829). They break down when 
fused into carbon dioxide and methy]- and ethyl-indol. 

$-Methyl-a-Indol Carboxylic Acid, C,H,(CH,)N.CO, H, skatole carboxylic 
acid, results from the decay of albuminates. It crystallizes in leaflets, melting 
at 165°, and decomposing into carbon dioxide and skatole. Another product, 
formed at the time, is Skatole Acetic Acid, C,H;(CH,)N.CH,.CO,H, melting at 
130° (Berichte, 22, Ref. 701). 

$-Indol Carboxylic Acid, C,H,N.CO,H, is produced when skatole is fused 
with caustic potash, and upon heating indol with sodium in a current of carbon 
dioxide at 230—300° (together with a little of the a-acid). It crystallizes from hot 
water in leaflets and melts with decomposition at 218°. Being a f-acid it cannot 
yield an imide anhydride (Berichte, 23, 2296). ma-Dimethyl--indol carboxylic 
acid, C,H,(CH,)N(CH,):CO,H, from methyl-phenylhydrazone-acetoacetic ester 
(p. 829), melts at 200°, and decomposes into carbon dioxide and ma-dimethy] 
indol. 





’ 


Oxindol, C,H,NO = C,H NE OO the lactam of o-amido-phenyl acetic 
acid (p. 755), was first obtained by the reduction of dioxindol with tin and hydro- 
chloric acid, or with sodium amalgam in acid solution. It is also produced in the 
reduction of aceto-o-amido-mandelic acid (p. 774) with hydrochloric acid. It 
crystallizes from hot water in colorless needles, and melts at 120°. It oxidizes to 
dioxindol when exposed in a moist condition; by protracted boiling it will reduce 
an ammoniacal silver solution. It has both basic and weak acid properties, forms 
a stable hydrochloride, and dissolves in alkalies. If heated to 150° with baryta 


water it is converted into o-amido-phenyl-acetic acid (p. 756). CH,.CO 
Oxindol boiled with acetic anhydride yields Aceto-oxindol, C,H < ee ae 
N.CO.CH, 


which crystallizes in long needles, and melts at 126°. It dissolves to aceto-o- 


832 ORGANIC CHEMISTRY. 


amido-phenyl acetic acid in sodium hydroxide (p. 756). The action of nitrous 
acid upon the aqueous solution of oxindol causes a transposition and isatoxime 
results (p. 837); this was formerly taken for z¢roso-oxindo/; the latter passes, by 
reduction with tin and hydrochloric acid, into the so-called Amido-oxindol, 


CH(NH,) 
CHC co (2). Ferric chloride oxidizes this to isatin. 

SS aa 
An isomeride of the last compound is H,N.C,H sweet DOO, p-Amido- 
oxindol, which is produced by the reduction of dinitrophenyl-acetic acid (p. 754). 
Isatoxime also results from it when it is acted upon by nitrous acid and boiled with 


aqueous vapor. If it be heated with baryta water or with concentrated hydro- 
chloric acid to 150° the ethyl group will not be split off (compare p. 755) (Berichte, 
16, 1705). 





Indoxyl and pseudo-indoxyl are isomeric with oxindol. The second is only 
stable in its derivatives; the two forms are therefore probably tautomeric :— 


/AC(OH)\ of GQ 
ea om) NcH and CH Nyy >CHy 
Indoxyl. Pseudoindoxyl. 

Indoxyl, C,H,NO, results in the elimination of carbon dioxide from indoxylic 
acid (see below). This is best effected by boiling with water. It is an oil not 
volatile in aqueous vapor, and is rather easily soluble in water, showing yellow 
fluorescence. It is very unstable, and in aqueous or slightly acid solution is readily 
resinified. It dissolves with a red color in concentrated hydrochloric acid. It is 
oxidized to indigo blue when its alkaline solution (best ammoniacal) is exposed to 
the air. Ferric chloride and hydrochloric acid effect the conversion more quickly :— 


2C,H,NO + 20 =C,,H,,N,0, + 2H,0. 


When indoxyl is digested with potassium pyrosulphate, S,O0,K, (compare p. 
670), we get potassium indoxylsulphate, C,H,N.O.SO,K, which crystallizes from 
hot alcohol in shining leaflets. This is found in the urine of herbivorous animals 
(Urine indican), generally after the ingestion of indol.. When digested with acids 
the salt decomposes into sulphuric acid and indoxyl, which forms indigo blue by 
the addition of a little ferric chloride (an excess of ferric chloride destroys the 
indigo). We proceed similarly in the detection of indoxylsulphuric acid in urine. 

The presence of the imide group in indoxyl is proven by the formation of a 
nitrosamine and a phenyl-diazo compound ( Berichée, 16, 2190); the existence of 
a phenol-like hydroxyl is inferred from the production of indoxylsulphuric acid 
and of ethyl-indoxyl (see below). 

OH) 


Indoxylic Acid, C,H,NO, = Ce SC.CO,H, corresponding to 


indoxyl, is produced from its ethyl ester by fusion with caustic soda at 180° (Be- 
richte, 17,976). Acids precipitate it from its salts in the form of a white crys- 
talline precipitate. It melts at 123°, with decomposition into carbon dioxide and 
indoxyl. Like the latter, it is oxidized to indigo blue. Its ethyl ester is obtained 
by reducing o-nitrophenyl propiolic ester with ammonium sulphide, or isatogenic 
ester with zinc and hydrochloric acid and from indoxanthic ester (p. 833). It 
crystallizes in thick prisms, and melts at 120°. When digested with sulphuric acid 
it affords a quantitative yield of indigo-sulphonic acid. It possesses a phenol 


INDOXANTHIC ESTER. 833 


character, dissolves in alkalies and is again precipitated by carbon dioxide. Ethyl 
iodide converts the phenol salts into Ethyl Ethoxy-indoxylic Ester, C,H, 


Pooks H;) x 
Ethoxy-indoxylic Acid. The latter consists of brilliant needles, melting at 
160°. It yields indoxyl when digested with hydrochloric acid (just as in the case 
of ethyl indoxyl), and this gives indigo blue with ferric chloride. 

If fused it separates into carbon dioxide and ethoxy-indoxyl, C,H, 
C(0.C,H;) 
“i SCH. The latter is an oil, volatile in steam, and having an odor 

Nauaaienet 


like that of indol, which it resembles in other respects. Nitrous acid converts it 
into a nitrosamine (Berichte, 15, 781). 
Pseudo-indoxyl (see above) is known only in its derivatives. Its zsonztroso- 


compound, C,H Rea dit .OH), formerly considered nitroso-indoxyl, is pro- 


C.CO,.C,H,, which by saponification with baryta water, forms 


duced by the action of nitrous acid upon ethoxyindoxylic acid. A transposition 
occurs here. It is identical with pseudo-isatoxime (p. 837). 
The derivatives of pseudo-indoxyl— 


OOS /CO \c.c/CH 

CoHa< wo /CCH.CoHs and CoH na OC Co.n, 
are similarly obtained from indoxyl or indoxylic acid by condensation with benzal- 
dehyde and pyroracemic acid. They are called the z#dogenides of the latter 
compound, and are perfectly similar to pseudo-isatin ethoxime (p. 937). The 
- divalent group, CHK NHC =, is termed indogen ( Berichte, 16, 2197). 


The condensation of isatin with benzenes produces perfectly analogous indogen- 
CON co 

en NE A 

Indirubin, C,,H,,N,O,, is of this class. It is isomeric with indigo-blue, 
and appears in nearly all the indigo syntheses, and in its entire character is very 
similar to this substance. It is produced by effecting the condensation of indoxyl 
(pseudo-indoxyl) with isatin (pseudo-isatin) by means of a dilute soda solution 
( Berichte, 17, 976), and therefore, may be called an indogenide of pseudo- 


isatin :— 


ides. In this case the isatin changes to pseudo-isatin, C,H 


ca: 7 OO Ncw, 3: cor SS 


‘NH 7 \C, Hy 
Pseudo-indoxyl. Pseudo-isatin, 
SCO NR Kr SOL 
CHK wi DC = cca, NE + HO. 
Indirubin. 


In the same manner indoxyl may be oxidized (by the union of two pseudo- 
indoxyl groups with separation of water) to indigo-blue, which, therefore, is to be 
considered a di-indogen (Berichte, 16, 2204). 





Indoxanthic Ester, C,,H,,NO, = CoH Nit >C(OH).CO,.C,Hy results 


from the oxidation of indoxylic ester with ferric chloride or chromic acid. It 
yields a nitrosamine with nitrous acid (Berichte, 15, 774). Further oxidation pro- 


7° 


834 ORGANIC CHEMISTRY. 


duces anthranil oxalylic ester, CoH NHPCO.CO,R (p. 749)—this is analogous 
to the formation of aceto-anthranilic acid (p. 830) from methyl ketol. Indoxanthic 
ester reverts to indoxylic ester when reduced. 
SPE CO2 CoH s 
Isatogenic Ester, C,,H,NO,=C,H, /\ (?), is obtained by 
N—O 


a transposition of the isomeric o-nitrophenyl propiolic ester when it dissolves in 
concentrated sulphuric acid (p. 815). It crystallizes in yellow needles, melting at 
115°. Various reducing agents convert it into indoxylic ester, but with ferrous 
sulphate we get indoxanthic ester. In the solution of free o-nitrophenyl acetic 
acid in sulphuric acid, the free Isatogenic Acid, C,H,.NO,.CO,H, is very pro- 
bably produced; it cannot, however, be isolated. Isatin, C;H,NO,, exists in the 
solution diluted with water. 

Di-isatogen, C,,H,N,O,, isomeric with the preceding, is similarly formed 
by dissolving o-dinitrophenyl-diacetylene (p. 802) in sulphuric acid (by the union 
of two isatogen groups, C,H,:(C,NO,). It crystallizes in red needles and by re- 
duction yields zxdigo-blue -— ; 


C,,H,N,0, + 3H, = C,H,N,0, + 2H,0. 


On adding sulphate of iron to the solution of isatogenic ester, di-isatogen or 
o-nitropheny! propioli¢ acid in sulphuric acid, the solution becomes blue in color 
and Indoin, C,,H,,N,O, (?), separates. This is very similar to indigo-blue. 
It is also formed by adding o-nitrophenyl propiolic acid to the solution of indoxyl 
or indoxylic acid in sulphuric acid. 





a is the lactam of o-amido- 
mandelic acid, not capable of existing in a free condition, or hydrindic acid (p. 773). 
It is more readily obtained by boiling isatin with zinc dust, water and a slight 
quantity of hydrochloric acid. It is rather easily soluble in water and alcohol, 
crystallizes in colorless prisms, melting at 180° and decomposing about 195° with 
formation of aniline. It oxidizes readily in aqueous solution to zsatid and Zsatin. 
It forms salts with bases and acids; it combines with two equivalents of the 
former. Nitrous acid converts it into the nitroso-compound, C,H,(NO)NO,, 
melting at 300° and subliming in white needles. Di-oxindol heated with acetic 


anhydride to 140° yields aceto-oxindol C,H KNCocHy> , melting at 127°, 


Di-oxindol, C,H,NO, = AY ig 


and dissolving in baryta water with the formation of aceto-o-amido-mandelic acid 


(p- 774)- 





Isatin, C,H;NO,, is the lactime of o-amido-phenyl-glyoxylic acid 
or itsatinic acid (p. 762), whose lactam, the hypothetical Aseudo- 
isatin, is known only in its derivatives :— 


Ci Ky pCO CB Gna 
Isatin. 1 Pseudo-isatin. 


Isatin was first obtained by the oxidation of indigo. It is also 
prepared from oxindol by transposition into the so-called amido- 


ISATIN. 835 


oxindol (p. 831) and then oxidizing the latter with ferric chloride. 
It arises in a similar manner from indoxyl. Its ready formation 
from o-nitro-phenyl-propiolic acid by boiling with alkalies (p. 815), 
and by the decomposition of isatogenic acid (p. 834), is worthy of 
remark. It is also obtained from a-oxyquinoline (carbostyril) in its 
oxidation with potassium permanganate. 


The easiest method of preparing isatin consists in oxidizing indigo with nitric 
acid (Berichte, 17,976). To purify it, dissolve it in potassium hydroxide, add 
hydrochloric acid as long as a black precipitate is formed, and then treat the filtrate 
with hydrochloric acid. 


Isatin crystallizes in yellowish-red monoclinic prisms, melting 
at 201°, and subliming partially undecomposed. It dissolves in 
_ water and alcohol with a reddish-brown color. It dissolves in caustic 
alkalies (equivalent quantities), forming salts, ¢. g., CsH,NKO,. The 
solution, violet at first, soon becomes yellow, with the production of 
isatinates; digestion with excess of alkali causes the immediate 
transformation. Acids liberate the readily soluble isatinic acid from 
its salts; and on standing, more quickly upon the application of 
heat, this changes to isatin, at the same time assuming a yellowish- 
red color. Isatin also possesses a ketone-like character; it unites 
with alkaline bisulphites to crystalline compounds, with hydroxyla- 
mine to isatoxime (p. 837), and with phenyl- hydrazine hydrochloride 
to a yellow compound, melting at 210°, which may be employed i in 
detecting isatin (Berichte, 17, 577): 


Isatin unites with phenylisocyanate, forming carbanilido-isatin. It affords a dark 
blue solution with benzene containing thiophene and sulphuric acid (p. 530). Water 
precipitates a blue dye, zzdophenin, C,,H,NOS = (C,H,NO, + C,H,S— H,O) 
( Berichte, 18, 2638). 

Two molecules of phenol, toluene or dimethyl-aniline and isatin are condensed 
by concentrated sulphuric acid to colorless compounds, derivatives of pseudo-isatin, 
C,H NH CO (Berichte, 18, 2639). 

Isatoic acid is formed when isatin is oxidized with chromic acid i in glacial acetic 
acid solution (p. 749). 

Isatin yields nitrosalicylic acid when oxidized with nitric anid; and aniline 
when fused with potassium hydroxide. When reduced (boiling with zinc dust, 
etc.), it first becomes dioxindol (a derivative of pseudo-isatin) ; with ammonium 
sulphide we get an intermediate product—isatid, C,,H,,N,O,. This is a color-_ 
less powder, readily re-oxidizing to isatin. 

In a solution of potassium-isatin, or in one of ammonia containing isatin, — 
silver nitrate precipitates sé/ver isatin, C,H,AgNO,,ared compound. Chlorine 
and bromine (in glacial acetic acid) convert isatin into substitution products, 
which conduct themselves just like isatin, and if dissolved in alkalies yield sub- 
stituted isatinic acids. Nitration in the cold produces nitroisatin, C,H,(NO,) 
NO,—red needles, melting at 230°. 

If ammonia should act upon isatin suspended in ether, there will result Imesa—. 
tin, C,H, NO(NH), forming dark yellow crystals, and when digested with alka- 
lies or ‘acids, decomposing again into isatin and NH,. Tolyl-methylimesatin, 


836 ORGANIC CHEMISTRY. 


C,H,(CH,)NO(N.C,H,,), is an analogous compound. It contains the residue of 
para toluidine, C,H,(CH;)N =, in place of the NH-group. It is obtained by 
heating f-toluidine with dichloracetic acid (by condensation) (Beriche, 16, 2261). 
Concentrated hydrochloric acid decomposes it (like imesatin) into toluidine and 
p-Methylisatin, C,H,(CH,)NO, = C,H,(CH,).C,NO,H. The latter re- 
sembles isatin; with PCI, it affords -Methylisatin chloride, C,H ,(CH,)NOCI, 
which (in the same manner as isatin chloride, etc.), may be converted into di- 
methyl indigo-blue, C,,H,(CH,).N.,O, (methylated in the benzene nucleus), 


; FCO, 
Isatin Chloride, CoH. N/ 
isatin with PCI, (in benzene solution). It crystallizes in brown 
needles and dissolves with a blue color in ether, alcohol and glacial 
acetic acid. Hydriodic acid or zine dust acting onits glacial acetic 
acid solution produces éudigo-blue :— 


fOr LOLLCO. . 
2H yc + 2H, = CHC” ne CoH, + 2HCl. 


CCl, is produced by digesting 


We can also obtain from the substituted isatins (brom-, nitro-, 
methyl-isatin) substitution products of indigo blue, dibrom-, di- 
nitro, and dimethyl-indigo-blue (Berichte, 12, 456). 


Ether derivatives of isatin and pseudo-isatin :— 


CO 
CHK ‘C(0.CH,) CHK OG 
N 7 N(CH,) 
Methyl-isatin. Methyl-pseudo-isatin. 


The alky/ isatins result from the action of alkyl iodides upon silver-isatin, and 
are blood-red colored crystalline bodies. Methyl-isatin, C,H,NO,(CH,), melts 
at 102°. Ethyl dibrom-isatin, C,H,Br,NO,(C,H,), at 88°, They-are saponi- 
fied by alkalies, and yield salts of isatin and isatinic acid. Acids separate isatin 
from these. Ammonium sulphide with air contact converts them at once into 
indigo blue (Berichte, 15, 2093). 

When isatin is boiled with acetic anhydride a transposition occurs and we ob- 
tain Becto=pseude-isatin, C,H <N(CO.CH,)>" crystallizing in yellow 
needles, and melting at 141°. When digested with water or acids it splits into 
acetic acid and isatin. It dissolves in alkalies, forming salts of aceto-isatinic acid, 
Cc.H.~% CO.CO,H 

6 "4\.NH(CO.CH;) 
acetic acid. 

Ethylpseudoisatin (see above) is obtained by the reduction and subsequent 
oxidation of ethoxypseudo-isatin-ethoxime (see below). It crystallizes in large, 
blood-red crystals, melting at 95°. It dissolves, immediately in alkalies with a yellow 
color, forming salts of ethyl isatinic acid, C,H, si NHC US from which acids at 
once separate ethylpseudo-isatin (Berich/e, 16, 2193). The latter is also obtained 
from ethyl indol (p. 830), by oxidation with a hypobromite (Berichte, 17, 566). 
Methyl-pseudoisatin, formed in the same way, consists of red needles, melting 
at 134°. 


(p. 762), which decompose on warming into isatinates and 


TE ae oe RN ea = ere ae 


INDIGO. 837 


Isonitroso-derivatives of Isatin and Pseudoisatin :— 





/C(N.OH)\, JCO 
CoH yt pCO CoH wy >C(N-O8). 
Isatoxime, Pseudo-isatoxime. 


Isatoxime, C,H,N,O, (Isatin-oxime), was first obtained by the action of 
nitrous acid upon oxindol (p. 831), and was, therefore, formerly considered nitroso- 
oxindol. It is also prepared (analogous to the formation of the acetoximes, 
from isatin and hydroxylamine; or from para-amido-oxindol (P- 832), by action 
of nitrous acid, and boiling with alcohol (Berichte, 16, 518). It crystallizes 
from alcohol in yellow needles, and melts at 202°, with decomposition. It 
dissolves with a yellow color in the alkalies. When reduced with tin and hydro- 
chloric acid it yields so-called amido-oxindol (p. 832). By the successive action 
of ethyl iodide upon the silver salt ws obtain a mono-, and a diethyl derivative 
from which isatin (Berichte, 16, 1706) is formed by reduction and subsequent _ 
oxidation. 

Pseudo-isatoxime (see above) is prepared (by transposition) by the action of 
nitrous acid upon ethyl indoxylic acid.: It was formerly considered nitroso-in- 
doxyl (p. 833). It crystallizes from alcohol in shining yellow needles, and de- 
composes at about 200°. It does not give the nitroso reaction. It dissolves in 
alkalies and is separated again by carbon dioxide (Berichte, 15, 782). Ethyl 
iodide and sodium ethylate convert it into :— 


CO.C(N.O.C,H,) CO.C(N.O.C,H,) 

CH pete ee: — 
\nit ‘“ NC,H, 

Pseudoisatin-ethoxime. Ethoxypseudoisatin-ethoxime. 


This first yields isatin by reduction and oxidation (as does isatoxime and its two 

ethers, loc. cit.). The same treatment applied to ethoxy-pseudo-isatin-ethoxime 
CO.CO 

yields ethylpseudoisatin, CHK f (see above). The reduction of ethyl- 
N(C,H;) . 

pseudo-isatin-ethoxime with ammonium sulphide produces diethyl indigo, in which 

the two ethyl groups are united to nitrogen (Berichte, 16, 2201) :— 


CO.CO CO.C====C.CO 
aC Ee Open \ SC, H, + 2H,0. 
>» N(C,H; ‘ N(C,H,)(C,H,)N~ 





Z C. —CHO : 
Anthroxan Aldehyde, C,H,NO, = C,H,< | JO (with an atomic 
NN 


grouping similar to that of isatogenic ester), is isomeric with isatin, and is formed 
when o-nitrophenyl glycidic acid (p. 777) is boiled with water (together with 
anthranil) (Berich/e, 16, 2226). Silver oxide converts it into anthroxanic acid, 
C,H,NO.CO,H. 





INDIGO-BLUE. 


Indigo-blue or Indigotin. This commercially important 
chromogen is found in ordinary indigo and possesses the molecular 
formula, C,,H,)N,O,, which is in accord with its vapor density. 
The innumerable synthetic methods for its production, already 


838 ORGANIC CHEMISTRY. 


mentioned, were discovered by A. von Baeyer. The most important 
of these are:fthe reduction of isatin chloride (p. 836) first with 
phosphorus (1870), then with zinc dust or HI (1879) :2the trans- 
formation of o-nitrophenyl propiolic acid (p. 815) by digestion 
with alkalies and reducing agents (1880) ;4 the condensation of 
o-nitrobenzaldehyde with acetone in alkaline solution (pp. 719 and 
730), acetaldehyde and pyroracemic acid (p. 815) (1882) ;yand the 
conversion of a-dibrom-o-nitro-acetophenone (p. 728) by boiling 
with alkalies (1882) (Berichte, 17, 963). 


Recently several very simple syntheses of indigo-blue have appeared :— 

1. Fusion of bromacetanilide, C,H;.NH.CO.CH,Br, with caustic potash, and 

. oxidation of the aqueous solution of the product by air. The indoxyl or pseudo- 

indoxyl formed at first is then oxidized to indigo blue (Flimm, Berichte, 23, 57). 
2. Indigo can also be formed by fusing phenylglycocoll, C,H,.NH.CH,.CO,H, 

with potassium hydroxide, etc., as well as from anthranilic acid (Heumann, Ze- 

richte, 23, 3043, 3431; Biedermann, Berichte, 23, 3289). 


According to A. von Baeyer’s investigations the constitution of 
indigo blue is very probably expressed by the formula’:— 


/L0—C=C—CO. 
| H,. 
meet Ne 


This accounts best for its entire deportment and all its transforma- 


tions. 

According to this formula indigo-blue contains two indol groups, ane ag 
in combination with each other. That the union is through the carbon atoms fol- 
lows from the synthesis of indigo-blue from o-dinitro-diphenyl-diacetylene (p. 802) 
and, therefore, diphenyl-diacetylene, C,H,;.C:C.C:C.C,H,, may be looked 
upon as the parent hydrocarbon of indigo-blue. This we infer also from the 
formation of indigo-blue from the indoxyl and isatogenic derivatives, which is 
analogous to that of the indogenides (p. 833). As arguments forthe existence of 


the group, GHCR we have the production of indigo-blue from isatin 


chloride and the isatin ethers (p. 836), as well as from brom-acetophenones (see 
above); from the indoxyl compounds, from indoxanthic ester and di-isatogen 
(p. 834). Another support for this view is the fact that only those derivatives of 
o-nitro-cinnamic acid, C,H,( NO,).CH:CH.CO,H, yield indigo in which the carbon 
atom joined to the benzene nucleus is also in connection with hydroxyl or oxygen; 
thus the o-nitro-phenyl-oxyacrylic acids (p. 777) and not the o-nitro-cinnamic acid 
yield indigo. The condensation products of o-nitrobenzaldehyde behave similarly ; 
o-nitrophenyl lactic methyl ketone, C,H,(NO,).CH(OH).CH,.CO.CH,, yields 
indigo, but o-nitro-cinnamyl-methyl ketone (p. 806) oes not. With the latter 
bodies (in the formation of indigo-blue) there occurs a splitting-off of the excessive 
carbon atoms of the side-chains in the form of formic acid, acetic acid, etc. 

Finally, the presence of 2 NH groups in indigo-blue is rendered very probable 
by the formation of di-ethyl indigo from ethyl pseudo-isatoxime (p. 837). 

In the production of indigo-blue from indoxyl derivatives there occurs, in all 
probability, a conversion of indoxyl into pseudo-indoxyl and pseudo-isatin, and 





INDIGO-BLUE. | 839 


this leads us to regard indigo-blue as a di-indogen, corresponding to the indogen- 
ides of benzaldehydes, etc. (p. 833). The absorption of two hydrogen atoms 
reduces indigo-blue to indigo-white, C,,H,,N,O,, which has the character of a 
phenol. In this reaction the doubly united carbon atoms are at first saturated and 
then the indogen group is changed to the indoxyl group :— > 
Peete mamas smi: 
CH CH 
Ae! ONE ee 
yields 
©(OH):C—C:(HO)C, 
CoH, eee Bin, ee poole 
NH HN 


Indigo-white. 





Indigo-blue constitutes the principal ingredient of commercial 
Indigo, derived from different /udigofere and from woad (J/sazs 
tinctorta). It occurs in these plants as a glucoside, called zudican, 
which parts with its variety of glucose and becomes indigo-blue, 
when boiled with dilute acids, or if acted upon with a ferment (if 
the various portions of the plant be covered with water and exposed 
to the action of the air). The indigo-blue separates in the form of 
a powder. 


Commercial indigo is a mixture of several substances, of which the indigo- 
blue is alone valuable. Boiling acetic acid extracts iwdigo gluten from it; and 
dilute potassium hydroxide takes out zzdigo-brown, which is precipitated as a 
brown mass by sulphuric acid. The residue finally yields to boiling alcohol the 
indigo-red,a red powder which dissolves in alcohol and ether with this color. 
The residual mass is almost pure indigo-blue. 


Indigo-blue can be obtained from commercial indigo by sub- 
limation, but it nearly all decomposes by the operation. ~ It is ad- 
visable to first reduce indigo to soluble indigo-white, which can 
then be oxidized to indigo-blue by the exposure of the alkaline 
solution to the air. 


Grape sugar is the best reducing agent for indigo. The latter, in a finely di- 
vided state, is mixed with an equal weight of grape sugar, and upon this are 
poured 14 parfs concentrated caustic soda and hot alcohol or water (150 parts), 
and the whole allowed to stand in a closed flask filled with the same liquid for 
some hours. The clear yellow solution is next poured into dilute hydrochloric 
acid and shaken with air (Ammalen, 195, 305). 


Indigo-blue or indigotin is a dark-blue powder with a reddish 
glimmer; it becomes metallic and copper-like under pressure. It 
sublimes in copper-red, metallic, shining prisms. It is insoluble in 
water, alcohol and ether, in alkalies and dilute acids, and is odor- 


840 ORGANIC CHEMISTRY. 


less and tasteless. It dissolves in hot aniline with a blue, in molten 
paraffin with a purple-red color, and can be crystallized from these 
solvents. It crystallizes from hot oil of turpentine in beautiful 
blue plates, At 300° it is converted into a dark-red vapor. If 
boiled with potassium hydroxide and manganese peroxide, it yields 
anthranilic acid (p. 748); aniline results on distilling with potas- 
sium hydroxide. See Berichte, 18, 1426, for the absorption spec- 
trum of indigo and its derivatives. 


We will yet mention some of the substituted indigotins, which are quite similar 
to indigotin and have been prepared synthetically. ' 

Dichlor, brom-, nitro-indigoes result from the substituted isatins (p. 836), and 
from brom o-nitroacetophenones (p. 838). <A dichlor-indigo has been prepared 
from o-nitro--chlorbenzaldehyde (Berichte, 18, Ref. 8). Tetrachlor-indigo is 
obtained from o-nitro-dichlor-benzaldehyde (Berichte, 18, Ref. 470). Dimethyl . 
indigoes result from nitro-7-toluic aldehyde (p. 721) and g-methyl-isatin (p. 836). 
Diethyl indigo (its imide groups contain ethyl) is obtained from ethyl-pseudo. isa- 
tin-ethoxime (p. 837). Di-isopropyl indigo, cumin indigo, is derived from 
o-nitro-cumenyl propioli¢ acid (Berichte, 19, 261). Indigo-dicarboxylic acid, 
C,,H,N,O,(CO,H),, may be prepared from nitro-phenylpropiolic acid. It dis- 
solves in alkalies with a bluish green color (Berichte, 18, 950). 

The isomerides of indgotin are indigo-red, present in commercial indigo, 
indirubin, the indogenide of pseudoisatin (p. 833), indigo-purpurin, formed 
together with indigotin from isatin chloride (p. 836) and indin. The latter is 
obtained by the action of alcoholic potassium hydroxide upon isatid (p. 835), or by 
boiling dioxindol with glycerol. Di-isatogen, C,,H,N,O,, and indoin (p. 834) 
bear a close relation to indigotin. 


Indigo White, C,,H,.N.O,., is obtained by the reduction of 
indigo-blue (see above). It can be precipitated from its alkaline 
solution by hydrochloric acid (air being excluded) as a white crys- 
talline powder, soluble in alcohol, ether and the alkalies, with a 
yellowish color. It rapidly re-oxidizes to indigo-blue by exposure 
to the air. It yields di-indol when heated with baryta-water and 
zinc dust. 


When indigo-blue is dissolved in concentrated sulphuric acid (8-15 parts) and 
digested for some time, we get indigotin monosulphonic acid, CyH,N,O,.SO,H 
(phoenicin sulphuric acid), and izdigotin disulphonic acid, C,,H,N,0,(SO;,H), 
(ccerulin sulphuric acid). Water precipitates the former from its solution as a 
blue powder, soluble in pure water and alcohol, but not in dilute acids. Its salts 
with the bases possess a purple-red color and dissolve with a blue color in water. 
_ The*disulphonic acid is obtained when indigo is digested with strong, fuming 
sulphuric acid. It can be absorbed from its aqueous solution by clean wool and 
again removed from the latter by ammonium carbonate, Its alkali salts, ¢. 2., 
C,,H,N,O,(SO,K),, are sparingly soluble in salt solutions, and are thrown out 
from their solution in the form of dark-blue precipitates by alkaline carbonates and 
acetates. They constitute m commerce what is known as indigo-carmine. When 
the indigotin sulphonic acids are reduced, they yield, just as does indigo-blue, the 
indigo-white sulphonic acids. 

Goods (wool) are dyed in two ways with indigo: the wool is immersed in the 


BENZO-AZOLE COMPOUNDS. 841 


aqueous solution of indigotin sulphonic acid (Saxony-blue dyeing), or the indigo- 
blue is changed by fermentation to indigo-white (indigo-vat), the cloth saturated 
with the latter and exposed to the air, when indigo-blue forms and sets itself upon 
the fibre. In printing, a mixture of 0-nitrophenyl propiolic acid and an alkaline 
reducing agent (potassium xanthate, etc.) are sometimes substituted for the indigo. 
Steaming causes the formation of indigo-blue. 





4. BENZO-AZOLE COMPOUNDS. 


The benzoazoles or benzodiazoles attach themselves to indol or benzopyrrol 
(p. 826). They contain a “ five-membered ring” with two nitrogen atoms (p. 551). 
Like the azole derivatives they occur as a- or (1, 2)-diazoles (with two adjacent 
n-atoms) and as {- or (1, 3)-diazoles. The first are known in two forms, izda- 
zoles and tsindazoles (benzopyrazoles). The (-benzodiazoles contain (in addition 
to the benzene ring) the ring of glyoxaline (p. 551); hence they may be termed 
Benzoglyoxalines (Annalen, 227, 303; Berichte, 18, Ref. 223) :— 


CH CH NH 
CHW | SNH CH? we Cee ee 
Diget 22 aun oat 
a-Benzodiazole, Benzopyrazole, B-Benzodiazole, 

Indazole. Isindazole. Benzoglyoxaline. 


(1) Indazole, C,H,N,, is formed by heating o-hydrazine-cinnamic acid, 
CH / CH:CH.CO,H 
6°" 4\. NH.NH, 
water in colorless needles, melting at 146°, and boiling at 270°. It is soluble in 
dilute acids. Its salts are very unstable. It yields ~-ethyl indazole, C,H;N, 
(C,H;), when it is heated with rh ony 
3 
a-Methyl Indazole, CHK | \NH , is derived from o-hydrazine-aceto- 
N/ 


’ when acetic acid is eliminated. It crystallizes from hot — 


phenone, GHA NH NEL It melts at 113° and boils at 280°. 


OCH CO,H 
a-Indazole Acetic Acid, bk aig | \nuH , Tesults from the oxidation 
N 


of o-hydrocinnamic acid, in alkaline solution, on exposure to the air. It crystal- 
lizes from hot water in yellow needles, melting at 168-170°, decomposing at the 
same time into carbon dioxide and a-methy] indazole. 





“ 


(2) Zsindazole or Benzo-pyrazole compounds (see above) were formerly con- 
sidered to be quinazole derivatives (they contain a side-chain of six members). 
Isindazole, C,H,N,, the parent substance, is only known in its derivatives. 


Pes oe 


é ; 
n-Ethyl-isindazole Acetic Acid, Ghee. SN . is formed when 
N(CH)” 


842 _ ORGANIC CHEMISTRY. 

; ; : . : CH:CH.CO,H 

the aqueous solution of ethyl hydra -cinnamic acid, C.H e eer 
q yl hydrazine-cinnamic acid, C, 4\ N(C,H,).NH, , 


is shaken with air. It melts at 131°, and at 162° breaks down into carbon dioxide 
and ethyl-methyl isindazole. 
CH, 


n-Ethyl-methyl Isindazole, C,H 





(3) Benzo-glyoxaline compounds (see above), condensation products of the 
o-phenylene diamines, have been described with the latter, and there designated as 
anhydrobases or aldehydines (p. 627). yon. 

Benzo-glyoxaline, C,H,N, = C,H, CH, is ordinarily known as 
phenylene methenyl amidine (p. 628). se a 

(4) We may yet add to the benzo-diazoles (or imidazoles) the demz0-oxazoles 
and denzo-thiazoles. These not only contain the benzene-ring but also those of 
oxazole and thiazole (pp. 554, 555) :— 


O S 
GH CH. and CH. SCH. 
ANF ERE S 2 
Benzo-oxazole ; Benzthiazole, 
Methenylamidophenol. Methenylamidothiophenol. 


They have been obtained as condensation products of o-amidophenol and 
o-amidothiophenol, hence are usually treated with these (p. 679). 





DERIVATIVES WITH TWO OR MORE BENZENE NUCLEI. 


Although in general very stable the benzenes yet possess to a 
high degree the power, by exit of hydrogen, of combining with 
each other in part directly, and partly by the assistance of other 
carbon atoms. The hydrocarbons derived in this manner yield 
numerous derivatives. 

They may be classified as follows: (1) those with directly com- 
bined benzene nuclei, aphenyl derivatives; (2) those in which the 
benzene nuclei are joined by 1 carbon atom, a@- and “riphenyl 
methane derivatives ; (3) those with benzene nuclei linked together 
by two or more carbon atoms, azbenzy/ derivatives; (4) those with 
condensed benzene nuclei, zaphthalene and anthracene derivatives. 

1. Derivatives of directly combined benzene nuclei. 


DIPHENYL, 843 


DIPHENYL GROUP.* 


* (1) Diphenyl, C,,Hy = C,H;.C,H;, results from the action of 
sodium upon the solution of brom-benzene in ether or benzene: 
2C,H;Br + Na, = C,,Hy + 2NaBr. It is also produced in slight 
amount when benzoic acid is distilled with lime (together with 
traces of benzene). It is present in that portion of coal-tar which 
boils about 240-260°. : 


Preparation,—Conduct benzene vapors through an iron tube heated to redness. 
The tube is filled with fragments of pumice stone. The yield of the diphenyl is 
about 50 per cent. of the benzene taken (Berichte, 10, 1602). It may be obtained 
from aniline by converting the latter into diazobenzene sulphate and decomposing 
the latter with copper or zinc dust (p. 634) (Berichte, 23, 1226). 


Diphenyl crystallizes from alcohol and ‘ether in large, colorless 
leaflets, melting at 71°, and boiling at 254°. If dissolved in glacial 
acetic acid and oxidized with chromic anhydride it yields benzoic 
acid. 


Metallic sodium reduces diphenyl, dissolved in amyl alcohol, to e¢ra-hydro- 
diphenyl, C,,H,,, boiling at 245°. The latter readily forms a dibromide which 
alcoholic potash converts into dihydro-diphenyl, C,,H,., boiling at 248° (Be- 
richte, 21, 846). 

The halogens, nitric acid and sulphuric acid convert diphenyl into mono- and ai- 
substitution products. In the first, ¢.g., C,,H,Br, C,,H,(NO,), C,,.H,SO,H, the 
substitution groups occupy the para-position, referred to the point of union of the 
two benzene nuclei. When these are oxidized with chromic acid we obtain para- 
derivatives of benzoic acid, the other~ benzene nucleus being destroyed. The 
di-derivatives, ¢. g., C,H, Br,, occur in two isomeric modifications. The di-para- 
derivatives predominate; in these the two side-chains have the para-position 
referred to the point of union. Chromic acid oxidizes them to two para-derivatives 
of benzoic acid; thus from brom-nitro-diphenyl we get para-brom and para-nitro- 
benzoic acid. 

The energetic chlorination of diphenyl and its derivatives (p. 580), produces 
perchlor-diphenyl, CyCl,,; brilliant plates or prisms, melting above 280°, and 
boiling at about 440°. Like perchlor-benzene, it is very stable, and does not un- 
dergo any further decomposition. 

The nitration of diphenyl in the cold, or when dissolved in glacial acetic acid, 
yields two nitro diphenyls, C,,H,(NO,); the para-compound is not soluble in 
alcohol, melts at 113°, boils at 340°, and when oxidized with chromic acid be- 
comes para-nitro-benzoic acid. The other nitro-diphenyl (very probably ortho) 
forms plates, melting at 37° and boiling at 320°. 

Fuming nitric acid produces a- and -dinitro-diphenyl, C,,H,(NO,),; the 
former (dipara) is very sparingly soluble in hot alcohol, and melts at 233°, and 
by reduction yields diphenylin. The dimeta-compound, from dinitro-benzidine, 
melts at 197°. 

(2) Phenyl Tolyls, C,H;.C,H,.CH,, Methyl Diphenyls. The para-compound, 
like diphenyl, results from the action of sodium upon a mixture of brombenzene 





* Consult Annalen, 207, 363, for a tabulation of these diphenyl derivatives. 


ee ORGANIC CHEMISTRY. 


and f-bromtoluene. A liquid boiling at 265°, and solidifying below 0°. Its 
sp. gr. is 1.015. Chromic acid oxidizes it to p diphenyl carboxylic acid and tere- 
phthalic acid. 

(3) Ditolyls, CH;.C,H,.C,H,CH,, dimethyl diphenyls. The di-para-com- 
pound is produced by the action of sodium upon g-bromtoluene, It melts at 121° 
and distils without decomposition. It yields Af-diphenyl dicarboxylic acid (p. 850) 
when oxidized. mm-Ditolyl has been obtained from o-tolidine by the substitution 
of the two NH,-groups. It is an oil boiling at 289° (Berichfe, 21, 1096). 





Amido-derivatives. 


Amido-diphenyls, C,H,.C,H,.NH,. The ortho compound, from o-nitrodi- 
phenyl, melts at 45°. The para compound, xenylamine, crystallizes from hot water 
in colorless leaflets, melts at 49° and boils at 322°. 


: 1. Diamido-diphenyl, C,,H;,(NH,),. (1) (di-para), Benzidine 
(4,4) is obtained: by the reduction of Zf-dinitrodiphenyl ; and by 
the action of sodium upon para-brom-aniline. It is technically pre- 
pared from azobenzene by the action of tin and hydrochloric acid 
upon its alcoholic solution (Annalen, 207, 330); the hydrazo- 
benzene formed at first rearranges itself to benzidine (p. 649) (com- 
pare Berichte, 23, 3265). Inthe cold the latter is the chief product. 
Diphenylin is also formed on the application of heat :— 


C,H,.NH—NH.C,H, yields H,N.C,H,—C,H,.NH,. 


Benzidine dissolves easily in hot water and alcohol, crystallizes 
in silvery leaflets melting at 122°, and subliming with partial de- 
composition. It forms salts with two equivalents of acid; the 


sulphate 
C,,H,(NH,),.SO,H,, 


is almost wholly insoluble in water. --It oxidizes to quinone if 
boiled with manganese dioxide and dilute sulphuric acid. | 


Consult Berichte, 23, Ref. 644, for the compounds of benzidine with aldehydes. 

oo-Dinitrobenzidine, C,,H,(NO,),(NH,).(NH,:NO, = 4:3), * (is formed on 
nitrating diacetobenzidine. Red crystals, melting at 220°. When the two NH,- 
groups are substituted it forms mm-dinitrodipheny]) (p. 843). SnCl, reduces it to 
oo-diamidobenzidine. 

The nitration of benzidine in concentrated sulphuric acid gives rise to m-Di- 
nitrobenzidine, C,,H,(NO,),(NH,).(NH,:NO, = 4. 2), crystallizing in yellow 
leaflets, melting at 214° (Berichte, 23, 795). When reduced it yields mm-dt- 
amido-benzidine (leaflets melting at 165°), which loses NH, and forms diamido- 
carbazol, C,,H,(NH,),.:NH (p. 847) (Berichte, 23, 3252). 

When benzidine is heated with concentrated sulphuric acid (2 parts) to 210° 
(Berichte, 22, 2464) it becomes o0-Benzidine-disulphonic Acid, C,,H,(NH,), 
(SO,H),(NH,:SO,H = 4:3); its diazo-derivatives are feeble dye-stufts. 





* The terms o- and m#- with the benzidine derivatives refer to the amido-groups ; 
in the case of diphenyl to the points of union (p. 843) (Berichie, 23, 3268). 


BENZIDINE DYES. 845 


mm-Benzidine Disulphonic Acid (NH,:SO,H = 4:2) is prepared by the 
reduction of an alkaline solution of m-nitro-benzene sulphonic acid and its further 
transposition (Berichte, 22, Ref. 785). It does not yield dye-substances; they 
may be obtained from the diamido-diphenylene oxide (H,N.C,H,).O, prepared by 
fusing it with caustic potash. Benzidine Sulphone, C,,H,(NH,),SOg,, is pre- 
pared by heating benzidine sulphate with fuming sulphuric acid (Berichte 21, 
Ref. 873; 22, 2467). 

pp-Oxyamido-diphenyl, H,N.C,H,.C,H,.OH, is formed by replacing the 
NH,-group of benzidine by hydroxyl. It yields a yellow color with salicylic acid 
and a reddish violet with 1-naphthol-4-sulphonic acid. 

2. mm-Diamido-diphenyl, H,N.C,H,.C,H,.NH,(C,:NH, = 1:3), is 
formed when eliminating the two NH,-groups from oo-dinitrobenzidine (see above). 

3. op-Diamido-diphenyl, Diphenylin, is obtained, together with benzidine, 
by the rearrangement of hydrobenzene or by the reduction of azobenzene with tin 
and hydrochloric acid. It crystallizes in needles, melting at 45° and boils at 232°. 
See Berichte, 22, 3011, for its derivatives. 

2. Diamido-phenyl-tolyl, H,N.C,H,.C,H,(CH,).NH,(CH,:NH, = 4: 3), 
o-Methyl Benzidine, is formed upon reducing a mixture of nitrobenzene and 0-nitro- 
toluene in alkaline solution. It melts at 115° and yields substantive dyestuffs 
(Berichte, 23, 3222). , : 


3. Diamido-ditolyls, Tolidines, H,N.C,H;(CH;).C,H; 
(CH;).NH,. They are produced, like benzidine, by the alkaline 
reduction of the three nitrotoluenes and further rearrangement of 
the resulting hydrazotoluenes. In doing this the two benzene 
rings, in o- and m-tolidine (from o- and m-nitrotoluene) unite at the _ 
para-points, with reference to the amido-groups; in the case of — 
p-tolidine (from f-nitrotoluene) they combine at the ortho-positions. 
The first two contain the 2NH,-groups in para-positions relative to 
the diphenyl union, hence yield substantive azo-dyes (see below) 
(see Berichte, 21, 3145). The substituted azobenzenes (Berichte, 
23, 3265) deport themselves similarly. 


o- Tolidine, from o-nitrotoluene (see above), crystallizes in leaflets with mother- 
of-pearl lustre, and melting at 128° (Berichte, 21, 746, 1065). It is largely used 
in the manufacture of substantive azo-dyes. See Berichte, 21, Ref. 874; 22, 
2473 for the sulpho-acids of o0-tolidine. 

m-Tolidine, from m-nitrotoluene (Berichte, 22, 838), separates from its salts as 
an oil, which gradually solidifies and melts at 109°. 

p-Tolidine, from p-azotoluene (Berichte, 17, 472), forms delicate leaflets, melt- 
ing at 103°. 

Ditolylin, H,N.C,H,.C,H,.NH, (corresponding to diphenylin, see above), 
is formed together with o0-tolidine (see above), and does not yield substantive dyes 
(Berichte, 23, 3253). 

Analogous diamidodiphenyls have been prepared from nitroxylenes (Berichie, 
21, 3147). 





- Benzidine Dyes. 


By diazotizing benzidine (action of sodium nitrite (2 molecules) 
and hydrochloric acid upon its salts, p. 629) we produce the salts 


of tetrazo- or bis-diazodiphenyl, ¢. g., Ca N,Cl (p- 639); 
7 \N,Cl 


846 ORGANIC CHEMISTRY. 


these combine with amines and phenols (amine sulpho-acids, phenol 
sulpho-acids, oxycarboxylic acids, etc.) forming disazo-or tetrazo- 
. compounds (pp. 645-652). These azo dyes possess the remark- 
able property of fixing themselves in the form of alkali salts upon 
unmordanted plant fibres (P. Griess, 1879; Berichte, 22, 2459). 
They are called substantive dyes (cotton dyes), and are largely em- 
ployed in dyeing. Dipheny]l tetrazochloride and salicylic acid yield 
a yellow dye, whose sodium salt, C,,H,[N,.C,H;(OH).CO,Na], is 
_chrysamine or flavophenine (the first benzidine dye applied tech- 
nically) (Berichte, 22, 2459). Diphenyl-tetrazo-chloride and 
a-naphthylamine sulphonic acid (naphtionic acid) (2 molecules) 
form a red dye; its sodium salt is the technically important Congo 
red (Bottger, 1884) :— 


/ Nx Gols(NH,).SO,Na 
Hye , Congo Red. 
N,-C,)9H;(NH,).SO,Na 
All the substantive dyestuffs, similar to benzidine, yield diamido-diphenyls and 
analogous bodies, containing the two diamido-groups in the para position with 
reference to the diphenyl union, e¢. g., orthotolidine (p. 845), diamidostilbene, 
H,N.C,H,.CH:CH.C,H,.NH, (Berichte, 21, Ref. 383), dimethyl oxybenzidine 
(p. 848); further, thiotoluidines (p. 684), thiobenzidine, etc. (Berichte, 20, Ref. 
272). It may be said that as a rule those substituted benzidines (nitro and sulpho- 
benzidines, tolidines, etc.) having the substitution in the meta-position (relative to the 
amido-group) yield ixzactive, or feeble substantive azo dyes. Diamido-diphenylene 
oxide, benzidine sulphone (p. 845) and diamido carbazol (p. 847) constitute 
exceptions. They contain a third ring-shaped chain ( BerichZe, 23, 3252, 3268). 
The o-tolidine derivatives are also important from a practical standpoint. Thus, 
o-tolidinetetrazochloride and a- and $-naphthylamine sulphonic acids yield two 
benzopurpurines, that form blue-tinted red; a-naphthol-sulphonic acid forms the 
red-tinted blue dye—azob/ue, C,,H,(CH;),[N..C,)H;.(O0H ).SO,Na], (Berichée, 
19, Ref. 422). Dimethoxyl-benzidine (dianisidine) (p. 836) and a-naphtholsul- 
phonic acid form the blue denzazurine, stable on exposure to the light. More 
recent dyes are sulphon-azurine, from benzidine sulphone (p. 845) (Berichte, 22, 
2499), and various dyestuffs from diamido diphenylene oxide (p. 846) (Berichte, 
23, Ref. 442). 
For the preparation of these dye-substances add the aqueous solution of the 
tetrazochloride to the aqueous solution of two molecules of the sodium salt of 
the other component :— 


CyH(N,Cl), + 2C,,H,(NH,)SO,Na = 
C,,H,(N,.C,,H,(NH,).SO,NO), + 2HCI. 


Sodium acetate, sodium carbonate or ammonia is added to the solution of the 
sodium salt to combine the hydrochloric acid which is liberated. In all these 
reactions the tetrazochloride first acts upon but one molecule of the amine or 
phenol, forming an immediate product that dissolves with difficulty, as— 


N,Cl ; 
CoN? CI + C,.H6(NH,)SO;Na = _ 
C7 Fe PR tesa A 
12°°8\.N,.C, »9H;(NH,).SO, + NaCl + HCl, = 








OXY-DIPHENYL. | 847 


which immediately, in alkaline solution, attacks the second molecule of the amine 
or phenol. If the intermediate product be allowed to act upon a different amine 
or phenol mixed tetrazodyes (see Berichte, 19, 1697, 1755; 21, Ref. 71) result. 


Diphenyltetrazo-chloride, sulphanilic acid (1 molecule) and phenol (1 molecule) — 


yield a mixed dye of this description :— 
/N,—C,H,.0H . 
Congo yellow = Cullis. Ne _¢ ‘H,(NH,)SO, Na. 





Diphenylimide, Carbazol, C,,H,N, is produced when the vapors of di- 
Tega or Po are conducted through a tube heated to redness :— 


NN se sh “SN H + H,; also nEPR heating thiodiphenylamine (p. 604) 
C,H; 
with "reduced sms nis 20, 233). 

It occurs in that portion of crude anthracene boiling at 320-360°, and is a by- 
product in the manufacture of aniline. Carbazol dissolves in hot alcohol, ether 
and benzene, crystallizes in colorless leaflets, melts at 238° and distils at 351°. 
Its concentrated sulphuric acid solution has a yellow color, and is colored a dark 
green. by oxidizing agents. The nitrogen atom of diphenylimide is inserted in the 
two ortho-positions of the two benzene rings (relatively to the diphenyl union) ; 
with two carbon atoms of each of these nuclei it forms a closed, five-membered 
ring, such as is present in pyrrol and in indol (Berichte, 20, 234). This explains 
the similarity of many reactions of carbazol with those of pyrrol and indol (Be- 
richte, 21, 3299). Thus, it gives the pine shaving reaction, the dark blue colora- 
tion with sulphuric acid and isatin, and forms with nitric acid a compound that crys- 
tallizes in red needles, melting at 186°. Its acetate, C,,H,N.C,H,O, melts at 69°. 
Its nitroso-derivative, C,,H,.N.NO, consists of long, golden yellow needles, melt- 
ing at 82°. A dye, analogous to diphenylamine blue, is produced upon heating 
together carbazol and oxalic acid (Berichte, 20, 1904). ~f-Diamido-carbazol, 
C,,H,(NH,),N, is formed when mm-diamido-benzidine (p. 845) is heated to 180° 
with hydrochloric acid. It forms needles with a silvery lustre. It chars above 
200°. Its tetrazo-compounds form substantive so (Berichte, 23, 3267). See 
Berichte, 22, 2185 for tetra hydro-carbazol, C,,H,,N. Phenyl-naphthyl carba- 
zol, C,,H|,N = ce Ht NH, is perfectly analogous to carbazol. It is found 
in the anthracene an and is prepared artificially from $-phenyl-naphthyl- 
amine, C,,H,.NH.C,H,. It is greenish-yellow in color and melts at 330°. 


Azo-diphenylene, ESN +N »» is produced when the calcium azobenzoates 


(ortho-, meta-, para) are ‘distilled. It sublimes in yellow needles, melting at 
170°. 





We obtain a mono- and a di-sulphonic acid, C,,H,.SO,H, and C,,H,(SO,H),, 
on digesting diphenyl with sulphuric acid. The first is formed with a very little 
sulphuric acid. The disulpho-acid (di-para) crystallizes in deliquescent prisms, 
melting at 72.5°. The oxy-diphenyls are the products on fusion with alkalies. 

Oxy-diphenyl, C,,H,.OH, Diphenylol, is obtained by diazotizing amido- 
diphenyl sulphate. It sublimes in shining leaflets, melting at 165°. It boils at 
305-308°. It dissolves with a beautiful green color in concentrated sulphuric acid. 


848 ORGANIC CHEMISTRY. 


Dioxydiphenyls, Diphenols, C,,H,(OH),. The di-para-compound, C,H,(OH). 
C,H,(OH)(y), is obtained from benzidine by means of the diazo-compound and 
by fusing diphenyl-disulphonic acid with caustic alkali. It consists of shining 
leaflets or needles, melting at 272° and boiling above 360°. f0-Diphenol (0), 
formed on fusing phenol-ortho- and para-sulphonic acids with potassium hydrox- 
ide, and from diphenylin, through the diazo-compound, melts at 161°. Two 
additional diphenols (a and 8) are obtained when phenol is fused with caustic 
potash ; the a-melts at 123° and the f- at 190°. 

Oxydiphenyl-amido-derivatives can be produced by nitrating and reducing the 
oxydiphenyls (Berichte, 21, 3331; 22, 335), or from the oxyazobenzenes by the 
molecular rearrangement of the hydrazo-compounds formed at first (Berichie, 23, 
3256) :— 

C,H,.N:N.C,H,.0.CH, yields H,N.C,H,.C,H,(O.CH;).NH,. 


The arrangement does not occur unless a para position of the benzene nuclei is 
unoccupied (Berichte, 23, 3256). Various diamido diphenol ethers (e. g., di- 
methoxyl-benzidine from nitranisol) form blue dyestuffs, like dexzoazurine (p. 846) 
(Berichte, 21, Ref. 872) with naphthol sulphonic acid. 


Diphenylene Oxide, C,,H,O = \° a results when phenylphosphate is 
Catt 


6144 
distilled with lime, or from calcium phenylate or phenol and lead oxide under 
the same treatment. It crystallizes in leaflets melting at 81° and distilling at 
287°. 


C 
Diphenylene Sulphide, |’ |S, is produced when phenyl sulphide and 
P ase | P phenyl sulp 


H,% 

phenyl disulphide (p. 672) are distilled through an ignited tube. Shining needles 
or leaflets, melting at 97° and distilling at 332°. Chromic acid oxidizes it to di- 
phenylene sulphone, C,,H,:SQ,. 





; Coeroulignone or Cedriret, C,,H,,O,, is a derivative of hexa- 
oxydiphenyl:— 


0.CH O.CH 
C,H, { Se ), C,H, { ‘Oi), a) . ok el 
Coeroulignone. Hydrocoeroulignone. sis Pata arpa 
Coeroulignone separates as a violet powder when crude wood-spirit is purified 
on a large scale by means of potassium chromate. It is further formed on oxidiz- 
ing dimethyl-pyrogallol (p. 695) with potassium chromate or ferric chloride :— 


Coit. ae 
O 


2C,H | (Ora) yield Z 
) CoH, ((0.CH,), 

Coerulignone is insoluble in the ordinary solvents, and is precipitated in fine, 
steel-blue needles, from its phenol solution, by alcohol or ether. It dissolves in 
concentrated sulphuric acid with a beautiful blue color, resembling that of the 
corn-flower. Large quantities of water color the solution red at first. Reducing 
agents (tin and hydrochloric acid) convert coeroulignone into colorless hydro- 
coeroulignone, which changes again to the first by oxidation. Coeroulignone is, 
therefore, a quinone body, deports itself towards hydrocoeroulignone like quinone 
to hydroquinone, and hence may be called a double-nuclei quinone (p. 698). 


PORN eS ee Cee 
“Ee LL Seige ror. So 








DIPHENYL-DICARBOXYLIC ACIDS. 849 


Hydrocoeroulignone, C,,H, ,O,, crystallizes from alcohol and glacial acetic 
acid in colorless leaflets, melting at 190°, and distils with almost no decomposi- 
tion. It is a divalent phenol. When heated with concentrated hydrochloric or 
hydriodic acid it breaks up into methyl chloride and _Hexaoxydiphenyl, 
CioH 1 90g — O CH 

one: 9 { On) s)¢ 4 4HCl = C,,H,(OH), + 4CH,Cl. 
2 
The latter crystallizes from water in silvery leaflets. It dissolves with a beautiful 
bluish-violet color in potassium hydroxide. Acetyl chloride converts it into an 
hexacetate. Dipheny] results when it is heated with zinc dust. 





If potassium diphenyl-mono-sulphonate and disulphonate be distilled with potas- 
sium cyanide the mztri/es, C,yHy.CN and C,,H,(CN),, result; the former melts at 
85°, the latter at 234°. The corresponding diphenyl-carboxylic acids are obtained 
when these are saponified with alcoholic potassium hydroxide or with hydrochloric 
acid. 

Diphenyl-carboxylic Acids, C,,H,,O, = C,H;.C,H,.CO,H. The three pos- 
sible isomerides are known. 

The ortho-acid, o-phenyl-benzoic acid, is produced by fusing diphenylene 
ketone (p. 851) with caustic potash. It dissolves with difficulty in hot water and 
melts at 111°. Diphenylene is reformed when it is distilled with lime. It sustains 
a similar change upon being heated with sulphuric acid to 100° (Berichie, 20, 
847) :— : 

ae hae 8 IRs | C,H, 
= | >Cco ot H,0. 


6H, 6°" 4 


If its sodium salt be heated with POCI,, the product will be diphenylene keton- 
oxide (p. 860). The mefa-acid is formed by oxidizing isodiphenylbenzene and 
melts at 161°. The fara- is formed from diphenyl cyanide and when J-dipheny] 
benzene (p. 852) is oxidized with CrO, and glacial acetic acid or phenyl tolyl 
with nitric acid. It crystallizes from alcohol in bundles of grouped needles, 
melting at 218°. It affords diphenyl] on distillation with lime, and yields tere- 
phthalic acid if oxidized with a chromic acid mixture. 
Diphenyl-dicarboxylic Acids, C,,H, ,0, = C,,H,(CO,H),. 


(1) The ortho-acid, Diphenic eis | (Berichte, 20, 847), is pro- 
gngCO, 

duced when phenanthrene or phenanthraquinone are oxidized with a chromic acid 
mixture; from the latter also by the action of an alcoholic potassium hydroxide solu- 
tion. It is very readily soluble in hot water, alcohol and ether, crystallizes in shining 
needles or leaflets, melting at 229°, and sublimes. Jts barium and calcium salts 
are readily soluble in water. The dimethyl ester melts at 73°; the diethyl ester at 
42°. Chromic acid changes diphenic acid to carbon dioxide. It yields diphenyl 
when distilled with soda-lime; heated with lime it forms diphenylene ke- 
tone. When diphenic acid is digested with acetic anhydride, its anhydride, 
C,,H,(CO),0O, is formed. This melts at 213-217°, and when heated to 120° 
with concentrated sulphuric acid decomposes into carbon dioxide and diphenylene 
ketone carboxylic acid (p. 852) ( Berichte, 21, Ref. 726). 

The nitration of diphenic acid produces two dinitro-diphenic acids, C,,H,(NO,), 
(CO,H),, a and , which are also formed in the oxidation of dinitro phenanthra- 


71 


8 5° ORGANIC CHEMISTRY. 


quinone. The reduction of the a-acid (melting at 253°) with tin and hydrochloric 
acid yields diamido-diphentc acid, C,,H,(NH,),(CO,H),, which may also be 
obtained through the molecular transposition of meta-hydrazo-benzoic acid (p. 751). 
Distilled with baryta-or lime it yields benzidine (together with diamido-fluorene). 
The elimination of the NH, group causes it to change to diphenic acid. We, 
therefore, infer that the latter (and also Phenanthrene, see this) is a diortho-de- 
rivative of diphenyl. 

(2) Isodiphenyl Dicarboxylic Acid, C,H,(CO,H).C,H,(CO,H), zsow?- 
phenic acid (ortho-meta), may be prepared by fusing a-diphenylene-ketone car- 
boxylic acid with caustic potash. It dissolves with difficulty in water and melts at 
216°. Chromic acid oxidizes it to isophthalic acid. It yields diphenylene ketone 
when distilled with lime. 

(3) #p-Diphenyl-dicarboxylic Acid is obtained from diphenyl-dicyanide, 
and by oxidizing ditolyl with chromic acid ina glacial acetic acid solution. It is an 
amorphous white powder, insoluble in alcohol and ether. It decomposes at higher 
temperatures without first fusing. Heated with lime it affords diphenyl. 

(4) of-Diphenyl Dicarboxylic Acid may be obtained from diphenylene by 
replacing its amido-groups with CN and then saponifying. White crystalline 
leaflets, melting at 231° (Berichte, 22, 3019). 





We also have a series of compounds, the diphenylene derivatives, in which 2 
hydrogen atoms of the diphenyl group (both in the ortho-position with reference 
to the point of union of the diphenyl group), are replaced by one carbon atom. 
The following bodies are classed here :— ; 


C,H C,H, €.H... 
c SCR: r CH.OH % "CH.CO,H 

ed: Ca C,H, 

Diphenylene Fluorene Diphenylene 
Methane. Alcohol. Acetic Acid. 


C,H 
|’ “c(OH).cO,H 
Og 


6" 4 
Diphenylene Glycollic Acid. 


Carbazol, diphenylene oxide (p. 847) and diphenylene sulphide, are such di- 
phenylene-diortho-derivatives. Intimately related to the diphenylene derivatives, 


e Ley 
Goes. CHoX 
Ca, 2 or Cn 


they are frequently derived from the latter on heating, by an ortho-condensation of 
the two phenyl groups with the exit of two hydrogen atoms. Diphenic acid, 
phenanthraquinone and anthraquinone are intimately related to them :— 


G,H,.CO,H C,H,.CO CO 
Apatis, airs Chk DC Hy 

C,H,.CO,H C,H,.CO co 

Diphenic Acid. Phenanthraquinone, Anthraquinone. 


. CH 4\ | 
Diphenylene Methane, C,,H,, = d fora Fluorene, occurs in coal 
H 
tar (boiling at 300-305°) and is obtained by conducting diphenylmethane, ~ 
(C,H,),CH,, through an ignited tube, also on heating diphenylene ketone 


FLUORENIC ACID. 851 


with zinc dust, or with hydriodic acid and phosphorus to 160°. (For the detec- 
tion of fluorene in presence of phenanthrene and anthracene see Berichte, 11, 
203 

tp crystallizes from hot alcohol in colorless leaflets with a violet fluorescence, 
melts at 113°, and boils at 295°. It forms a compound with picric acid, which 
crystallizes in "red needles, melting at 80-82°. The chromic acid mixture oxidizes 
it to diphenylene ketone. Fusion with caustic potash produces dioxydiphenyl. 


C,H 
Fluorene Alcohol, % ~CH.OH, results in the action of sodium amalgam 


upon the alcoholic solution “of diphenylene ketone and by heating sodium di- 
phenylene glycollic acid to 120°. It crystallizes from hot water in fine needles, 
from alcohol in six-sided plates, melting at 153°. Chromic acid changes it back 
to diphenylene ketone. Concentrated sulphuric acid or P,O, colors it an intense 
blue, and produces fluorene ether, (C,3H,),O0, melting at 290°. 


Diphenylene Ketone, C,,H,O = d “Yoo, is obtained from diphenic acid, 


H, 

isodiphenic acid or o-phenylbenzoic acid when heated with lime and by oxidizing 
diphenylene-methane with a chromic acid mixture, and by heating anthraquinone 
and phenanthraquinone with caustic lime (Annalen, 196, 45). It is very soluble 
in alcohol and ether, crystallizes in large yellow prisms, melting at 84°, and boil- 
ing at 337°. Being a ketone it unites with hydroxylamine to produce an acetoxime, 
melting at 192°. Potassium permanganate oxidizes it to phthalic acid. It is con- 
verted into o-phenyl benzoic acid, on fusion with potassium hydroxide. 


; > } CoHay ‘ 
Diphenylene Glycollic Acid, | ~ C(OH).CO,H, is produced when 
: C,H 


via 
phenanthraquinone is boiled with sodium hydroxide — 
C,H,—CO | C,H 4\ 
| | + H,O ger POOH) COse; 
C,H,—CO gil, 


in this instance an atomic rearrangement occurs, similar to that observed in the 
transition of benzil to benzilic acid. It crystallizes from hot water in shining 
leaflets, melting at 162°. It dissolves with an indigo blue color in concentrated 
sulphuric acid; this color disappears on the addition of water. Carbon dioxide 
and water split off and fuorene ether results. This is also produced by heating 
the acid above its melting point. Chromic acid oxidizes it to diphenylene ketone. 
If the acid be heated to 120° bi i and P it becomes, 


Diphenylene Acetic Acid, Lo "Sct, CO,H,—Fluorene Carboxylic Acid. 
This is insoluble in water, forms Ae crystals, and melts about 221°, Its 


ethyl ester melts at 165°. When heated above its melting point, more readily 
with soda-lime, it is decomposed into carbon dioxide and diphenylene methane. 





C,H, 
a-Fluorenic Acid, 5 "CH i is formed by the action of sodium amalgam 


es 
CO,H 
upon a-diphenylene-ketone carboxylic acid. Itis almost entirely insoluble in water, 
and melts at 245°. It yields fluorene when distilled with lime. Potassium per- 
manganate reproduces diphenylene-ketone carboxylic acid. 


852 ORGANIC CHEMISTRY. 


C,H 
Diphenylene-ketone Carboxylic Acids,C,,H,O,= | : 00: The a-acid 


OOS 
is produced by the oxidation of fluoranthene with a chromic acid mixture. It 
crystallizes in red needles, melting at 191°. Sodium amalgam converts it into 
fluorenic acid. Isodiphenic acid results when it is fused with potassium hydroxide 
(p. 850), while heating with lime breaks it down into carbon dioxide and diphenylene 
ketone; fluorene is produced if it be distilled with zinc dust. 

The {-acid is formed upon heating silver diphenylene-ketone dicarboxylate. 
Yellow needles that sublime withoutmelting. The y- or ovtho-acid is formed when 
diphenic acid is heated to 110° with concentrated sulphuric acid. It crystallizes 
from alcohol in yellow needles, melting at 223° (Berichte, 20, 846). Fusion with 
caustic potash changes it to diphenic acid. Its oxime melts at 263°; its hydra- 
zone at 205° (Berichte, 22, Ref. 727). Cc 

Diphenylene-ketone Dicarboxylic rate 


ee 


oHay 

aed 
“S(CO,H) es 

quinone is oxidized with potassium permanganate. A sulphur-yellow, crystalline 

powder, which does not melt, but above 270° breaks down into carbon dioxide and 

p-diphenylene-ketone carboxylic acid. It yields diphenyl when distilled with lime. 

Diphenylene-ketone is produced from the silver salt (Berichte, 18, 1751). 


CO, results when retene- 





Diphenyl Benzene, C,,H,, = C,H, eb 4 5, Diphenyl Phenylene, is pro- 
duced when sodium acts on a mixture of dibrombenzene, C,H,Br,(1, 4) .and 
C,H,Br, also on conducting a mixture of diphenyl and benzene through ignited 
tubes. Isodiphenyl benzene also results in the latter case; therefore, both are 
produced in the preparation of diphenyl (Berichze, 11, 1755). 

p-Diphenyl benzene is sparingly soluble in hot alcohol and ether, easily in benzene, 
crystallizes in flat needles, melts at 205°, sublimes readily, and boils at 400°. Chromic 
acid, in glacial acetic acid, oxidizes it to Z-diphenyl carboxylic acid (p. 849), and 
then to terephthalic acid. Isomeric isodiphenyl benzene melts at 85°, and boils 
about 360°. Chromic acid, in glacial acetic acid, oxidizes it to benzoic acid and 
an isomeric #-diphenyl carboxylic acid. 

Triphenyl Benzene, C,H,(C,H,), (1, 3, 5), is formed from acetophenone, 
C,H,.CO.CH,, when heated with P,O,, or by conducting hydrochloric acid gas 
into it, when there occurs a condensation similar to that observed in the formation 
of mesitylene from acetone, CH;.CO.CH, (p. 566). It crystallizes from ether in 
rhombic plates, melting at 169°, and distils above 360°. Chromic acid oxidizes 
it, in acetic acid solution, to benzoic acid ( Berichze, 23, 2533). 





2. Derivatives of benzene nuclei joined by one carbon atom. 


ae 1. DIPHENYL METHANE DERIVATIVES. 


The compounds, having two benzene nuclei joined by one car- 
bon atom, are obtained according to the following methods :— 

1. Zine dust is added'to a mixture of benzyl chloride and ben- 
zene, and heat applied. An energetic reaction ensues, hydrogen 


_ DIPHENYL METHANE DERIVATIVES. 853 


chloride escapes and diphenyl methane results (Zincke, Annalen, 
159, 367):— * : | 
C,H,.CH,.Cl + C,H, = C,H,.CH,.C,H, + HCl. 
Diphenylmethane. 
Benzyl chloride reacts similarly upon toluene, xylene and other 
hydrocarbons :— 


C,H,.CH,Cl + C,H,.CH, = C,H,.CH,.C,H,.CH, + HCl; - 
Pesayt Toluene. 


and upon phenols or their acid esters (Berichte, 14, 261) :— 
C,H,.CH,Cl + C,H,.0OH = C,H,.CH,.C,H,.0H + HCl. 


Aluminium chloride may be employed as a substitute for zinc dust 
(Pp. 569). 


The tertiary anilines (compare p. 601) react similarily to the phenols on the 
application of heat (even without zinc) ; thus from benzyl chloride and dimethyl 
aniline we get the base, C,H,.CH,.C,H,N(CH,),, dimethylamido-diphenylme- 
thane. 


2. The fatty aldehydes are mixed with benzene (toluene, naphtha- 
lene, dipheny!, etc.) and concentrated sulphuric acid then added ; 
water separates and two phenyls replace the aldehyde oxygen ~ 
(Baeyer, Berichte, 6, 221) :— 

2C,H, -+ COH.CH, = Cty? SOHLCH, + H,0. 
Aldehyde. Hipheny) Ethane, 


The acetaldehyde is applied as paraldehyde, and it is necessary to employ 
strongly cooled sulphuric acid. Methylene aldehyde is applied in the form of 
methylal, CH,(O.CH,), (p. 301), or methyl diacetate :— 


2C,H, + CH,(0.CH,), = (C,H;),CH, + 2CH,.OH. 
Methylal. Diphenylmethane. 


The reaction proceeds with special ease on using anhydrous chloral (or with 
mono-and dichlor-aldehyde) and chlorine substitution products result :— 


2C,H, + COH.CCl, = (C,H,), CH.CCl, + H,0. 


Sodium amalgam causes the replacement of the halogens in these derivatives, and 
we get the corresponding hydrocarbons. 


The benzene hydrocarbons react with the aromatic alcohols just 
as they do with the aldehydes :— 


C,H,.CH,.0H + C,H, = C,H,.CH,.C,H, + H,0. 


Triphenyl methane, (C,H;),.CH.C,H,, is similarly formed from benz- 
hydrol, (C,H;),CH.OH. Triphenyl methane derivatives are the 
chief products when benzaldehyde is used. 


854 ORGANIC CHEMISTRY. 


The benzenes also condense with ketones, aldehydic acids and ketonic acids. 
Thus from benzene and glyoxylic acid we obtain diphenylaeetic acid, with pyro- 
racemic acid, a-diphenylpropionic acid. Sometimes we get an aldol condensation 
with the production of oxy-compounds (p. 716); in this way dibrom-atrolactinic 

3 CHBr 
acid, CoH,.C(OH)C Co 

The aldehydes also act upon the phenols, yielding phenol-derivatives of the 
diphenylmethanes; here it is better to substitute SnCl, for sulphuric acid (Be- 
richte, 11, 283). Thus we get diphenol ethane from paraldehyde and phenol :— 


CH,.CHO + 2C,H,.0H — CH,.CH(C,H,.OH), + H,0. 
Ethidene dinaphthyl ether, CH,.CH(O.C,,H,),. and the condensation product, 


CH,.CHY G19 50 (Berichte, 19, 3004, 3318), are produced when acetalde. 
1 . 
hyde acts upon f-naphthol in the presence of glacial acetic acid and a little hy- 
drochloric acid. 

The tertiary anilines react like the phenols (p. 601) and amido-derivatives 
result. Instead of the aldehydes (or their ethers) we can employ their haloids, 
when the reaction will begin on the application of heat. For example, 


from methylene iodide, CH,I,, and dimethyl aniline we obtain the base 
cH, (Gols N(CHs)2 . the same product results with CCl,H and CCl,. Ace- 


2\ C,H,.N(CH,),? B 
tone and zine chloride yield the base, (CH) CC CH NICH)? (Berichte, 21, 


results from benzene and dibrom-pyro-racemic acid. 


Ref. 16). Such bases are also produced as by-products in the manufacture of 
methy] aniline and malachite green. 

Benzaldehyde and the dimethyl anilines condense to amidobenzhydrols when 
heated with concentrated hydrochloric acid, whereas triphenylmethane deriva- 
tives result if zinc chloride, sulphuric acid and oxalic acid be used. Chloral reacts 
similarly with dimethylanilines, accompanied by hydrol condensation (Berichée, 


21, 3299). 





If the hydrocarbons be oxidized with a chromic acid mixture 
they yield £etones, and the group CH, or CHR is converted into CO. 
From dimethyl methane and dimethyl ethane we obtain diphenyl 
ketone :— 


C,H C8 4 eS | 
coy’ } CH and ¢° i? | CH.CH, yield CoH? } CO. 
Should alkyls be present in the benzene nucleus these are oxidized 
to carboxyls :— 


C,H..CH,.C.H,.CH, yields C.H,.CO.C,H,.CO,H. 
Benzyl Toinene. bis houses! Bensoic Acid. 


Such ketones are further produced :— 


1. If benzoic acid or its anhydride be heated with benzenes and P,O; (J/er2). 
A condensation similar to that of the hydrocarbons takes place here :— 


C,H,.CO.OH + C,H, = C,H,.CO.C,H, + H,0. 


enzoic Acid. biphenyl etone. 


DIPHENYL METHANE DERIVATIVES. 855 


2. By the action of benzoyl chloride on benzenes, in the presence of aluminium 
chloride (comp. p. 853) :-— 


C,H,.COCI + C,H,.CH, = C,H,.CO.C,H,.CH, + HCl. 
Bensoy! Chloride, *foltuene. Pheny] tolyl Ketone. 


Phosgene reacts in the same manner, and acid chlorides are the first products 
(comp. p. 739) ?— 
COC], + 2C,H, = C,H,.CO.C,H, + 2HCl. 


3. According to the general method of producing ketones, on heating the cal- 
cium salts with aromatic acids:— __, 


C,H, CO,H + C,H,.CO,H = (C,H,),CO + CO, + H,0, 


Benzoic Acid. Benzoic Acid. Diphenyl Ketone. 
oo = Ae C,H.\ 
C,H;.CO,H + CH Con = cH, (chy 2©O + 02 + HL0 
Benzoic Acid. Toluic Acid. Phenyl-tolyl Ketone. 


On heating with zinc dust or hydriodic acid and amorphous 
phosphorus, the ketones sustain a reduction of the CO group and 
revert to the hydrocarbons, for example, diphenyl ketone yields 
diphenyl methane. Sodium amalgam changes them to secondary 


alcohols :— 
(C,H,),CO ++ H, = (C,H,),CH.OH. 


Pinacones are simultaneously produced through the union of two 
molecules (see benzpinacone). 





The oxy-ketones and ketone phenols are produced from the phenols by the ac- 
tion of benzoyl chloride, by heating with zinc chloride, or more readily with 
aluminium chloride; further by heating benzo-trichloride, C,H,.CCl,, with 
phenols and zine oxide :— 


C,H,.COCI + C,H,.0H = C,H,.CO.C,H,.0H + HCl, 
Benzoyl Phenol, 


C,H,.CCl, + C,H,.OH + ZnO = C,H,.CO.C,H,.0H + ZnCl, + HCl 


The reaction is analogous to the action of chloroform upon phenols in alkaline 
solution, when aldehyde phenols (oxy-aldehydes) are obtained (p. 723). 

Instead of the free phenols it is better to use the benzoyl esters of the phenols 
(e. g., C,H,;.0.C,H,O). The first products are the benzoyl esters of the phenol 
ketones, e. g., C,H,.CO.C,H,.0.C,H,O, which yield the free phenol ketones 
when saponified with alcoholic potassium hydroxide (Berichte, 10, 1969). In the 
use of the free phenols we get, on the contrary (especially with C,H,.CCl,, even 
by gentle digestion), dye substances, which belong to the aurine series, and 
are derived from triphenyl methane. 

When benzoyl chloride and zine chloride act on the divalent phenols (their 
benzoyl esters) ¢. g., resorcin, we obtain their mono- and di-ketones (Berichie, 12, 
661), as— 

C,H,.CO.C,H,(OH), and CH" Co CoH a(OH).. 

Zinc chloride converts salicylic acid, C,H ,(OH).CO,H, and phenol into salicyl- 

phenol, C,H,(OH).CO.C,H,.OH (Berichie, 14, 656). 


Sse ORGANIC CHEMISTRY. 


We can also derive the amido-ketones, e. g., C,H,.CO.C,H,.NH,, by methods 
similar to those employed with the ketones and oxy-ketones :— 


1. By heating benzoic acid with tertiary anilines and P,O, :— 
C,H,.CO.OH + C,H,.N(CH,), = C,H,.CO.C,H,.N(CH;), + H,0, 


whereas, by the action of benzoyl chloride two benzoyl groups enter the benzene 
nucleus (Anznalen, 206, 88); 2. By the action of benzoyl chloride upon primary 
anilines, in which both amide hydrogens are replaced by acid radicals (as in 
phthalanile,C,H,.N(CO),C,H, (p. 611), on heating alone, or with zinc chloride 
or aluminium chloride :— 


C,H,.COC] + C,H,.N(CO.R), = C,H,.CO.C,H,.N(CO.R), + HCl. 


The free amido-ketones are obtained by the saponification of these anilides 
| (Berichte, 14, 1836). 





Furthermore, efonic acids and diketones are produced according to these 
methods. For example, we obtain meta-benzoyl benzoic acid (its chloride) from 
benzoyl chloride and benzoic anhydride, with zine chloride (Berichze, 14, 647) :— 


2C,H,.COC] + (C,H,.CO),0 = 2C,H,.CO.C,H,.COCI + H,O, 
Benzoyl Benzoic Acid. 
and meta benzoyl. benzoic acid together with so-called isophthalphenone (Ze- 
richte, 13, 321; 19,146) from isophthalic chloride and benzene by means of 
AIC], :-— 
JOR (1) PCO GA Peg 2 SS 
CoH co.c1(3) 7 «coc ° A CO.C,H;? 


v-benzoylbenzoic acid is obtained from phthalic anhydride and benzene with 
aluminum chloride. It is further converted.into o-diphenyl phthalide (p. 880). 
The latter can be directly obtained from o-phthalyl chloride and benzene by means 
of AlCl. 


elds C,H and C, 





1 Diphenyl Methane, C,,H,, = C,H;.CH,.C,H;, Benzyl ben- 
zene, is obtained according to the synthetic methods already men- 
tioned : from benzyl chloride and benzene with zinc dust or AIC], ; 
from formic aldehyde or benzyl alcohol and benzene with sulphuric 
acid; and from CH,Cl, (or CHCl,;) with benzene and AIC), (to- 
gether with anthracene). 


In the preparation of diphenyl methane, 10 parts of benzyl chloride are 
digested with 6 parts of benzene and zinc dust, etc.; the latter only induces the 
reaction and when this has commenced it can be filtered off (Anmadlen, 159, 374). 
A better method is that of Friedel. It consists in digesting 10 parts benzyl 
chloride with 50 parts benzene and 3-4 parts of AlCl. 


Diphenyl methane is easily soluble in alcohol and ether, possesses 
the odor of oranges, crystallizes in needles, melts at 26.5°, and 
boils at 262°. When conducted through ignited tubes it yields 
diphenylene methane (p. 850) ; a chromic acid mixture oxidizes it 
to diphenyl! ketone. 


DIPHENYL CARBINOL. 857 


When treated with bromine in the heat it yields (C,H,;),CHBr, diphenyl-brom- 
methane, and (C,H;),CBr, diphenyl dibrom-methane; the former melts at 45°, 
and the latter is a brown crystalline mass. 

Nitrodiphenyl Methane, C,H;.CH,.C,H,.NO,. The ov¢ho-compound is pre- 
pared from o-nitrobenzyl chloride and benzene with AICl,. It is liquid and when 
oxidized by chromic acid and acetic acid yields o-nitro-benzophenone. The me¢a- 
and fara-bodies are derived from meta- and para-nitro-benzyl alcohol (p. 709) by 
means of benzene and sulphuric acid. ‘The first is an oil; the second melts at 31° 
( Berichte, 18, 2402). : 

Diphenyl methane dissolves in concentrated nitric acid yielding two dinitro- 
derivatives, the a- melting at 183°, and the 6-variety at 118° (Berichie, 21, 1347; 
23, 2578). Further nitration with nitric-sulphuric acid produces Tetranitro- 
diphenyl Methane, [C,H,(NO,),],CH,; yellow prisms, melting at 172°. It 
forms dark blue colored salts with alcoholic potash (p. 861 and Berichte, 22, © 
2445). 

Oy iets idiniteo Methane, (C,H;),C(NO,),, results from the action of N,O, 
upon benzophenoxime (similar to the formation of pseudo-nitriles, p. 109). Color- 
less leaflets, melting at 78° (Berichte, 23, 3491). 

The reduction of the a-dinitro-product yields a-Diamido-diphenyl methane, 
(C,H,.NH,),CH, (dipara); shining leaflets, melting at 85°. Its tetramethyl 
derivative, [C,H,.N(CH,),],CH,, results from dimethyl aniline by means of 
C,H,1,(CCl,H and CCl,), or with methylal (p. $53), and as a by-product in the 
manufacture of malachite green. It crystallizes in shining leaves, melts at 90°, 
and distils undecomposed. It yields a blue dyestuff by oxidation. 

The hydrogen of the group CH,, attached to dasic radicals zs very readily 
replaced by sulphur ; so that by heating with sulphur to 230° we obtain the ¢/zo- 
compound, CS[C,H,.N(CH3;),],. Benzylaniline, C,H,.CH,.NH.C,H; (Annalen, 
259, 300) reacts similarly. 

$-Diamido-diphenyl Methane, (C,H,.NH,),CH,, from the #-dinitro- 
compound, melts at 88°. 

Oxy-diphenyl Methane, C,H,.CH,.C,H,.OH (para-), Benzyl phenol, ob- 
tained from benzyl chloride and phenol, melts at 84° and boils at 320°. 

Dioxydiphenyl Methane, CH,(C,H,.OH), (dipara), is produced on fusing 
diphenyl methane disulphonic acid with KOH. It crystallizes in shining leaflets 
or needles, melts at 158° and sublimes. By stronger heating with caustic 
potash (300°), it decomposes into para-oxybenzoic acid and phenol. Its dimethyl 
ether, CH,(C,H,.0O.CH,),, is formed from anisol and methylal, and melts 
at 52°. 

Diphenyl Carbinol, (C,H,),CH.OH, Senzhydrol, is produced on heating 
diphenyl brom-methane, (C,H,),CHBr, with water to 150°, more readily from 
diphenyl ketone (C,H,),CO, with sodium amalgam, or by heating with alco- 
holic potassium hydroxide and zinc dust (together with benzpinacone). It is 
sparingly soluble in water, easily in alcohol and ether, crystallizes in silky needles, 
melts at 68°, and boils at 298° under partial decomposition into water, and denz- 
hydrol ether, [(C,H,),-CH],0, melting at 109°. 





The benzhydrol amide derivatives may be synthesized by the condensation of 
benzaldehyde with dimethyl-anilines upon heating them with hydrochloric acid 
(sulphuric acid, zinc chloride and oxalic acid produce triphenyl derivatives, 
Berichte, 21, 3293) :— 


C,H,.CHO + C,H,.NR, = C,H,.CH(OH).C,H,.NR,. 
. Dimethyl-amido-benzhydrol. 
72 


858 ORGANIC CHEMISTRY. 


Mono-amido-derivatives, such as these, dissolve in acids, forming colorless or 
slightly colored compounds. 

p-Nitrodimethyl-amidobenzhydrol, NO,.C, H,.CH(OH).C,H,.N(CH,),, results 
in the condensation of f-nitrobenzaldehyde with dimethyl] aniline on heating them 
with hydrochloric acid. Yellow needles, melting at-96°. Zinc dust and hydro- 
chloric acid reduce it to 

Unsymmetrical Dimethyldiamidobenzhydrol, H,N.C,H,.CH(OH).C,H,. 
N(CH,),,; melting at 165°. fae 

ee CH.).N.C,H 

Tetramethyl-diamidobenzhydrol, Hy N CoH yp HH.OH, has been pre- 
pared by reducing tetramethyldiamidobenzophenone (p. 859). Such diamido- 
diphenylhydrol bases are colorless, but when digested with acids yield deep blue 


colored salts, corresponding to the rosaniline salts (Berichte, 21, 3298); they very 
probably are benzhydrol or carbinol salts :— 


CAL LOL. : 
ca NLL! >CHCI-hydrochloride, 
Perfectly analogous compounds are :— 
CH;).N.CoHy\ acy ~-and (CH;).N.C,H,\ cS. 
CH,),N.C,H 1 eee Te NGL 
( At aetna ti it ( saa rate et Al 
benzophenone Chloride. thiobenzophenone. 


they are derivatives of diamidobenzophenone, and have a salt-like character. The 
first is dark-blue in color, while the second is a crystalline powder, showing a 
cantharides-green color. Its solutions are green or dark red in color (Berichée, 


20, 1732). 


-Benzophenone, Diphenyl Ketone, (C;H;),CO, is obtained 
according to the general methods and by heating mercury phenyl, 
(C,H;). Hg, with benzoyl chloride. It is prepared (along with 
benzene) on distilling calcium benzoate, or from benzoyl chloride 
and benzene with AICl;; most easily by adding AlCl, to the solu- 
tion of COCI, in benzene (Berichte, 10, 1854). It is dimorphous ; 
generally crystallizes in large rhombic prisms, melting at 48-49°, 
sometimes in rhombohedra, which melt at 27° and gradually change 
to the first modification.. It has an aromatic odor, and boils at 
295°. When fused with alkalies it decomposes into benzoic acid 
and benzene; if it be heated with zinc dust diphenyl methane is 
produced. 


PCl,; converts it into the chloride (C,H;),CCl,. A liquid, boiling at 220°. 
Hot water changes it to benzophenone. Hydroxylamine converts benzophenone 
into 

Benzophenoxime, (C,H,),C:N.OH, crystallizing in needles, melting at 140° 
(Berichte, 19, 989). An isomeric benzophenoxime could not be obtained, while 
unsymmetrical benzophenones, ¢. g., brombenzophenone and phenylethyl ketone, 
each form two oximes (pp. 727, 718). 

Benzophenoxime (like other ketone oximes, p. 727), when digested at 100° with 
sulphuric acid, with hydrochloric acid and acetic acid, etc., sustains the following 
peculiar molecular rearrangement (Berichte, 22, Ref. 591) :— _- 


C,H,.C(N.OH).C,H, — C,H,.CO.NH.C,H,, Benzanilide. 


THIOBENZOPHENONE. 859 


The isomeric benzanilide imide-chloride is produced in like manner from the imide 
chloride formed by PCI, (p. 744). Phenylhydrazine and benzophenone unite 
when their alcoholic solution is warmed, forming the phenylhydrazone, (C,H;), 
C:N,H.C,H,, crystallizing in delicate needles, melting at 137° (Berichie, 19, 
Ref. 302). is 

“Oca arisen C,H;.CO.C,H,(NO,). The three isomerides are pro- 
duced by the oxidation of the three nitrodiphenyl-methanes (p. 857). The meta 
compound has also been obtained from m-nitrobenzoyl chloride with benzene and 
AICl,. It melts at 94° (Berichte, 18, 2401). 

Dinitrobenzophenones, C,H,(NO,).CO.C,H,(NO,). The a-body is pro- 
duced by oxidizing a-dinitro-diphenylmethane, It melts at 190°. The (- and y- 
bodies are formed by the nitration of benzophenone with fuming nitric acid. The 
former melts at 190°; the latter at 149°. 

Amidobenzophenones, C,H;.CO.C,H,(NH,), Benzoanilines. The three 
isomerides are produced by the reduction of the three nitrobenzophenones with 
tin and hydrochloric acid. The ortho melts at 106°, and condenses with acetone, 
by the action of caustic soda (same as o-amido benzaldehyde, p. 720), forming 
y-phenyl-a-methylquinoline (Berichte, 18, 2405) :— 


ae /C(CoH,):CH.CO.CH, /&(CoHs):€ 


3 as 4+ H,0. 
Si aM Ee SS. pee Seas 





Meta-amidobenzophenone melts at 87°. The Jara compound is produced when 
benzanilide or phthalanile is heated with benzoyl chloride and zinc chloride; the 
anilides formed at first being saponified (p. 858). Colorless needles or leaflets, © 
melting at 124° (Berichte, 18, 2404). 

Upon methylating 4 amidvbenzophenone we obtain Dimethyl 4 amidobenzo- 
phenone, C,H;.CO.C,H,.N(CH,),. It can also be prepared by the decomposi- 
tion of malachite green with hydrochloric acid ( Berichie, 21, 3293). 

Diamidobenzophenones are formed by reducing dinitrobenzophenones, and 
by the decomposition of the rosanilines. 

a-Diamidobenzophenone, CO(C,H,.NH,)., is produced from a-dinitroben- 
zophenone and by the breaking down of pararosaniline. It consists of large 
plates, melting at 237° and forms substantive tetrazo dyestuffs (Berichte, 22, 988). 

Tetramethyl-diamidobenzophenone, CO Ce HO NICHES results upon 

me 

heating hexamethyl violet with hydrochloric acid (Berichte, 19, 109). It is 
technically prepared by the action of COCI, upon dimethyl aniline in the presence 
of AIC],, and serves for the production of hexamethyl violet. From alcohol it 
crystallizes in yellow leaflets, melting at 173° (Berichte, 22, 1876). Being a 
ketone it unites with hydroxylamine and phenylhydrazine (Berichte, 20, 1111). 
Dimethylaniline (and PCI,) converts it into methyl violet, while it yields Victoria 
blue (p. 876) with phenylnaphthylamine, C,,H,.NH.C,H,. 

When heated with ammonium chloride and zinc chloride a base is produced, 
the salts. of which have a beautiful yellow color. The hydrochloride, 
(CH,)q.N CoH C:NH.HCI, crystallizing in golden yellow leaflets, is auramine, 
(CHs).N.C, Hy 
important as a cotton dye. Cotton mordanted with tannin is colored a beautiful 
yellow by this salt. Perfectly analogous dyestuffs are obtained from the primary 
anilines and diamines (Berichte, 20, 2844). 

Thiobenzophenone, (C,H,),CS, is derived from benzene by means of 
CSCI, and AICI. It is a reddish-brown oil, Hydroxylamine converts it into 
benzophenoxime, and with hydroxylamine it yields a hydrazone ( Berichie, 21, 341). 


860 ORGANIC CHEMISTRY. 


The Zhiobenzophenone (melting at 146°), derived from benzophenone chlor- 
imide and potassium sulphide, appears to be a polymeride. 

Tetramethyldiamido-thiobenzophenone, CS[C,H,.N(CH,), ],, results from 
the action of hydrogen sulphide or carbon disulphide upon the auramines; the 
imide group is displaced. It is technically prepared from dimethylaniline and 
CSCl, (Berichte, 20, 1731 and 2857). It consists of ruby-red crystalline leaflets 
or a cantharides-green crystalline powder, melting at 162° (202°). In transmitted 
light its benzene and carbon disulphide solutions show a red color, while they are 
green in reflected light. When boiled with hydrochloric acid hydrogen sulphide 
splits off and tetramethyldiamido-benzophenone results. 





Oxybenzophenones, C,H,.CO.C,H,(OH), Benzoyl Phenols. The fara is 
obtained from #-amidobenzophenone with nitrous acid (Berichte, 18, 2404) and 
from phenol with benzoyl chloride or C,H,.CCl, (p. 854). It is soluble in hot 
water. It melts at 134°, and when fused with caustic potash decomposes into 
benzene and para-oxybenzoic acid. 

Dioxybenzophenones, CO(C,H,.OH),. The dipara is obtained from dioxy- 
diphenyl methane by oxidizing the dibenzoy] ester with chromic acid in glacial 
acetic acid and saponifying with alkalies; also by the decomposition of aurine, 
benzaurine, phenolphtalein, and rosaniline (Berichte, 16, 1931) on heating with 
water or caustic alkali. It crystallizes from hot water in needles or leaflets, melts 
at 210°, and decomposes on fusion with caustic potash into para oxy-benzoic acid 
and phenol. It yields an acetoxime with hydroxylamine. 

The diortho-compound is formed by fusing diphenylene ketone with caustic 
potash (Berich/e, 19, 2609). It separates in the form of an oil, that solidifies 
with difficulty. It boils about 330-340°. It combines with hydroxylamine and 
phenylhydrazine. Stronger fusion with caustic potash resolves it into phenol and 
salicylic acid. The anhydride of diortho-dioxybenzophenone is Diphenylene 
Ketone Oxide, COL Gt! DO, or CHS Gy eile Xanthone, produced 
from salicylic phenyl ether or phenylsalicylic acid by the action of concentrated 
sulphuric acid (Berichte, 21, 502). It is volatile with steam, crystallizes in yellow 
needles, melting at 174°, and boiling at 250°. It is rather singular that it does 
not unite with hydroxylamine or phenylhydrazine. When reduced with HI it 
affords methylene diphenyl oxide, CH,(C,H,),0. White leaflets, melting at 99° 
and boiling at 312°. It forms dioxy-benzophenone on fusion with KOH. 





r 


Dioxydiphenylene-Ketone Oxide, C, ,H,O, = SAN Reo C,H,.OH, 


Luxanthone, occurs together with euxanthinic acid in Indian yellow (jaune 
indien). The latter is resolved into glycuronic acid (p. 491) and euxanthone when 
heated with dilute sulphuric acid. It has been synthetically produced by the 
action of acetic anhydride upon f-resorcylic acid and hydroquinone carboxylic 
acid (Berichte, 23, 13; Annalen, 254, 265). It crystallizes in yellow needles or 
leaves, melting at 237°, and then subliming. It is reduced to methylenedipheny- 
lene oxide by distillation with zinc dust. 

Trioxybenzophenone, C,H,(OH);.CO.C,H,, is formed by fusing pyrogallol 
and benzoic acid with zinc chloride at 145°. It crystallizes in yellow needles with 
one molecule of water, and melts at 138°. It forms orange yellow dyestuffs with 
mordants. Many other polyoxybenzophenones have been obtained by analogous 
methods (Berichte, 23, Ref. 43). 


BI-DINITRO-DIPHENYL ACETIC ACID. 861 


Diphenyl Ethane, C,,H,, = (C,H,),CH.CH, (isomeric with dibenzyl), is 
obtained from benzene and paraldehyde with sulphuric acid, from /-bromethyl 
benzene, C,H;.CHBr.CH,, and benzene with zinc dust, from benzene and’ 
CH,.CHCl1, with AICI. -It is a liquid, boiling at 268-271°, and in the cold 
becomes a crystalline solid. Chromic acid oxidizes it to benzophenone. Nitric 
acid does not oxidize its side chains (Berichte, 17, Ref. 674). Diphenyl 
trichlorethane, (C,H,;),CH.CCl,, formed from benzene and chloral, consists of 
leaflets, melting at 64°. Alkalies convert it into diphenyldichlor-ethylene, melting 
at 80° and boiling at 316° (Berichte, 22, 760). Diphenyltribromethane melts at 
89°. Sodium amalgam reduces both to diphenyl ethane. 7 

Mono-chlor-aldehyde (mono-chlor-acetal or dichlorether) and benzene yield 
Diphenyl mono-chlor-ethane, (C,H;),CH.CH,Cl, a thick oil, which on boil- 
ing is converted into 

Diphenyl Ethylene, C,,H,, = (C,H;),C:CH,. This is isomeric with 
stilbene, is also formed from a dibrom-ethylene, CH,:CBr,, by means of benzene 
and AICl,, and is an oil, boiling at 277°. Chromic acid oxidizes it to diphenyl 
ketone. 

Perfectly analogous, unsaturated hydrocarbons are also obtained from toluene, 
xylene, naphthalene, etc. If diphenyl monochlorethane (or its analogues) be 
heated alone hydrochloric acid is withdrawn, and there results, not diphenyl 
ethylene, but, by molecular transposition, isomeric stilbene (and its analogues) :— 


(C,H,),CH.CH,Cl = C,H,.CH:CH.C,H, + HCl. 
; Stilbene. 


Diphenylacetaldehyde, (C,H;),.CH.CHO, is produced by the action of 
sulphuric aci¢ upon bydrobenzoin (Berichte, 22, Ref. 10). 

Diphenylaceto-nitrile, (C,H,),CH.CN, results when diphenylbrommethane is 
heated with Hg(CN), to 165°, or is obtained from diphenylacetic acid through the 
amide (Berichte, 22, Ref. 198). Crystallized from ether it forms brilliant prisms, © 
melting ‘at 72° and boiling about 184° (at 12 mm). The hydrogen of its CH- 
group is readily replaced by alkyls. Iodine, acting upon its sodium derivatives, 
produces tetraphenyl-succino-nitrile, (C,H,),C,(CN),. (Berichte, 22, 1227). 

Diphenyl Acetic Acid, C,,H,,O, = (C,H;),CH.CO,H, is formed: by the 
action of zinc dust on a mixture of phenyl-bromacetic acid (p. 754) and benzene : 


C,H, 


C,H,.CHBr.CO,H + C,H, = 6° 
¢- oh 


7oH.CO,H + HBr; 

from diphenyl brom-methane, (C,H,),CHBr, by means of the cyanide; and by 
heating benzilic acid to 150° with hydriodic acid. The acid crystallizes from water 
in needles, from alcohol in leaflets, melting at 146°. When oxidized with a chromic 
acid mixture it yields benzophenone; and when heated with soda lime we get di- 
phenyl methane. Its e¢hy/ ester melts at 58°; the methyl ester at 60° (Berichie, 


21, 1318), 

Bi-dinitro-diphenyl Acetic Acid,°17°(NO2}2>CH.CO,H. 

The ethyl ester is derived from dinitro- phenyl_-acetoacetic ester and dinitro- 
phenyl-malonic ester (pp. 764, 791) by the action of of-dinitrobrombenzene; the 
group, CO.CH, (andCO,.C,H,) being replaced. It may be similarly prepared from 

-dinitro-phenyl-acetic ester (p. 754) (Berichte, 21, 2470). It dissolves with diffi- 
culty in alcohol and ether, and crystallizes from alcohol in colorless prisms, melting 
at 154°. Alcoholic potash or soda converts the ester, by the substitution of the hy- 
drogen of the CH-group, into brilliant metallic salts, dissolving in alcohol and 
water, with a@ dark blue color. A\l methane derivatives react in like manner, pro- 
vided they contain ¢wo or three nitrophenylene groups, e. g., bi-dinitro-phenyl- 


862 ORGANIC CHEMISTRY. 


methane, [C,H,NO,),],CH, (- 857) and ternitrophenyl methane (C,H,NO,), 
CH (p. 866) (Berichte, 22, 247 6). 

Diphenyl Glycollic Acid, Benzilic Acid, (C,H,),C(OH).CO,H, is produced 
by a molecular rearrangement of benzil (see this) "when digested with alcoholic 
potassium hydroxide, and from diphenyl acetic acid by the action of bromine vapor 
and boiling with water, We can prepare it by fusing benzil with caustic potash 
(Berichte, 14, 326); or better by the action of aqueous potash and air upon ben- 
zoin (Berichte, 19, 1868). Anisilic, cuminilic and dibenzyl glycollic (see benzoin 
group) acids are perfect analogues of benzilic acid. 

Benzilic acid is very readily soluble in hot water and alcohol, crystallizes in 
needles and prisms, melts at 159°, and is of a deep red color. It dissolves with a’ 
dark red color in sulphuric acid. It yields diphenyl acetic acid when heated with 
hydriodic acid: on distilling its barium salt it breaks up into carbon dioxide and 
benzyhydrol; oxidation yields benzophenone. For the derivatives of benzilic acid, 
see Berichte, 22, 1213, 1537. 





Benzyl Toluenes, Phenyl tolyl methanes, C,,H,, = C,H;.CH,. 
C,H,.CH;. A liquid mixture of ortho- and para-benzyl toluene, 
which cannot be separated, is obtained by the action of zinc dust 
on a mixture of benzyl chloride and toluene; by heating benzyl 
chloride to 190° with water, or toluene to 250° with iodine. The 
pure fara-body has been formed by heating para-phenyl tolyl ke- 
tone with zinc dust, and is a liquid, boiling at 285°. 

When it is oxidized with a chromic acid mixture we get the cor- 
responding phenyl tolyl ketones and benzoyl benzoic acids. 

Phenyl-tolyl Ketones, C,,H,,0 = C,H,.CO.C,H,.CH;. A mixture of 
the ortho- and para-compounds is obtained when benzoyl chloride and toluene 
are heated with zinc dust (in small quantity), by the distillation of a mixture of 
calcium benzoate and para-toluate, or by heating benzoic acid and toluene with 
P,O,. The product is an oil, from which the para-body may be crystallized out 
by cooling, while the ortho-derivative remains liquid. 

The fara compound is dimorphous, crystallizing in hexagonal prisms, melting 
at 55°, and in monoclinic prisms, melting at 58-59°. The latter modification is 
the more stable. It boils at 310-312°, and is sparingly soluble in alcohol. When 
heated with soda lime it decomposes into benzene and paratoluic acid; chromic 
acid converts it into parabenzoyl benzoic eat Sodium amalgam transforms para- 


ketone into phenyl paratolyl carbinol,<° H® SCH.OH, consisting of shining 
needles, melting at 52°. 7 
Phenyl-ortho-tolyl Ketone is a liquid and boils about 316°. 


A characteristic feature is the ability of the ortho-, but not the 
para-derivatives, to change readily to anthracene and its derivatives, 
in consequence of an ortho-condensation of the two benzene nuclei 
(p. 850). Thus anthracene is produced on conducting phenyl- 
_ tolyl methane through an ignited tube or upon heating the ketone 
with zinc dust, and we obtain anthraquinone (see anthracene) on 
heating ortho-phenyl-tolyl-ketone with lead oxide. 

Other diphenyl ketones, containing a methyl group in the ortho 
position, relatively to the ketone group, are prepared in a similar 
- manner, see Berichte, 18, 1797. 


BENZOYL BENZOIC ACIDS. Sa 


Benzoyl Benzoic Acids, C,,H,O, = C,H;.CO.C,H,.CO,H, 
result from the oxidation of the phenyl tolyl methanes or phenyl- 
tolyl ketones, and can be synthesized by the methods given upon 

. 856. r os 
The para-acid crystallizes and sublimes in leaflets, melting at 
194°. The mefa-acid, from isophthalic chloride and benzene, con- 
sists of needles, melting at 161°. The ortho-acid is most readily 
obtained from phthalic anhydride, benzene and AICI; (p. 856):— 


/CO /CO.C,H; 


It crystallizes with 1 molecule of H,O, which is lost at 110°, and 
it then melts at 127°. Heated to 180° with phosphorus pentoxide, 
water is eliminated, and anthraquinone is produced; in the same 
manner we get anthraquinone sulphonic acid by digestion with 
fuming sulphuric acid. Anthracene is produced when it is heated 
with zinc dust. With benzene and aluminium chloride orthoben- 
zoyl-benzoic acid yields phthalophenone, with phenol and stannic 
chloride oxyphthalophenone (see phthaleins). 





If tin and hydrochloric acid or sodium amalgam be allowed to act on the 
alcoholic solution of the para-acid we obtain Para-benzhydryl-benzoic Acid, 
C,H;.CH(OH).C,H,.CO,H, melting at 165°, and passing back into benzoyl 
benzoic acid when oxidized. Heated to 160° with hydriodic acid, it yields ben- 
zyl benzoic acid, C,H;.CH,.C,H,.CO,H, which is also produced in small 
quantity from benzyl toluene by oxidation with nitric acid. This melts at 157°, 
and is rather readily soluble in hot water. Chromic acid oxidizes it to benzoyl 
benzoic acid. Diphenyl methane is produced on heating it with soda-lime. 

In the same manner ortho-benzoyl benzoic acid forms ortho-benzhydryl-ben- 
zoic acid, C,H,.CH(OH).C,H,.CO,H, by reduction. This acid, however, does 
not exist in a free condition, but at the moment of its liberation from its salts de- 
composes, like all the y-oxyacids, into water and its lactone, Phenyl phihalide :-— 


C,H C,H 
"ON oo ee 
Noon. A a 


this is similar to the formation of phthalide (p. 772), from o-oxymethyl benzoic 
acid. The lactone, C,,H, .Oz, is insoluble in water, crystallizes from hot alcohol 
and ether in needles, and melts at 115°. It is only after protracted warming with 
alkalies that it can be transformed into salts of orthobenzhydryl-benzoic acid. Like 
orthophenyl-tolyl ketone and ortho-benzyl benzoic acid, it is easily changed into 
anthraquinone. 





Ditolyl Methane, cH, 2 pene Ditolyl Ketone, co’ GeHa-CHs 
\C,H,.CH, \C, Cn; 
Ditolyl Ethane, CH,.CH(C,H,.CH,),, ete. (Berichte, 18, 665), are produced 
like the phenyl compounds and yield derivatives that correspond very closely to 


864 ORGANIC CHEMISTRY. 


them. Ditolyl chlor-ethane, CH,Cl.CH(C,H,.CH,),, yields on the one hand (by 
alcoholic potash) ditolyl ethylene, CH,:C(C,H,.CH,),, upon the other, by aid of 
heat (through molecular rearrangement), dimethyl stilbene, CH,.C,H,CH:CH. 
C,H,.CH, (comp. p. 861). 

Tolu-benzoic Acids, COC CH CH The para-acid is produced by oxi- 


dizing ditolyl methane and ditolyl ethane (together with ditoly] ketone). It melts 
at 228°, p-Tolu-o-benzoic acid results (analogous to o-benzoyl benzoic acid) from 
phthalic anhydride, toluene and AICI,. It contains one molecule of water of crys- 
tallization and when anhydrous melts at 146°. It forms 6-methyl anthracene when 
heated with zinc dust. Zinc and hydrochloric acid reduce it to an oxyacid, which 
changes, on liberation, into its lactone, 

CH.C,H,.CH, 


1 ia 
Tolylphthalide, C,H, O, melting at 129°. Xylene and mesitylene 
\CO,/ 
yield similar derivatives with phthalic anhydride (Berichée, 19, Ref. 686). 





Dibenzylbenzenes, C,H sonatas The ortho and fara compounds are 
by-products in the formation of diphenyl methane from benzyl chloride, and me- 
thylal with benzene (p. 853). The former melts at 78°; the latter at 86°. 

Dibenzoylbenzenes, CIC oct’ phthalophenones, phenylene di- 
phenyl ketones. The ortho and para derivatives are produced by the oxidation of 
the corresponding dibenzylbenzenes. 

The ta and para compounds may be obtained from meta- and para-phthalyl 
chlorides with benzene and AICI, (p. 856) :— 


C,H,(COCl), + 2C,H, = C,H,(CO.C,H,), + 2HCl, 


whereas, the so-called orthophthalyl chloride yields diphenylphthalide. 

Orthophthalophenone melts at 146°; meta or isophthalophenone at 100°; 
terephthalophenone at 160°. Hydroxylamine yields ketoximes with them 
(Berichte, 19, 146, 153). ; 





2. TRIPHENYL METHANE DERIVATIVES. 
These contain three benzene nuclei attached to 1 carbon-atom :— 


C H ) os C,H;\ 
(CeH;)3CH cH tf? CH (CH,.C,H,), 7-7 
Triphenyl Diphenyl-tolyl Phenylditolyl 
Methane. Methane. Methane. 


These are the parent hydrocarbons from which originate the ros- 
aniline dyes, the malachite-greens, the aurines and phthaleins. 
They may be synthesized by methods analogous to those employed 
with the diphenyl methane derivatives :— : 

1, from benzal chloride, C,H;.CHCl, (or C,H;.CCl,) and the 
benzenes with zinc dust or aluminium chloride :— 


C,H,.CHCl, + 2C,H, = C,H,.CH(C,H,), + 2HCl; 


TRIPHENYL METHANE. 865 


2, from benzhydrol (p. 857), and the benzenes with P.O; :— 
(C,H,),CH.OH + C,H, = (C,H,),CH.C,H, + H,0; 
3, from chloroform (or CCl,) and benzene with AlCl, :— 
3C,H, + CHCl, + (C,H,),CH + 3HCI. 


A better means is the condensation of benzaldehyde with anilines 
(their salts) and phenols, in which we have produced amido- and 
phenol-derivatives of triphenyl methane (p. 867). Sulphuric acid, 
zinc chloride, potassium bisulphate (Berichte, 16, 2541), and anhy- 
drous oxalic acid serve as reagents to induce the condensation 
(Berichte, 17, 1078). 


Benzaldehyde cannot be made to condense with the benzenes by the action of 
sulphuric acid. This condensation only takes place, in slight degree, by the ap- 
plication of intense heat, and the use of zinc chloride (Berichie, 19, 1876). How- 
ever, substituted benzaldehydes, as m- and f-nitrobenzaldehyde (also terephthal- 
dehyde) condense very readily with benzenes by the aid of sulphuric acid, forming 
nitrotriphenylmethanes (Berichée, 21, 188; 23, 1622). For the éondénsations of 
benzaldehyde with phenols, see Berichte, 22, 1943. 


‘ (1) Triphenyl Methane, (C,H;);CH = C,,Hy,, is the product 
of the reaction between benzal chloride, C,H;.CHCl,, and mercury 
diphenyl, Hg(C,H;)., and is most easily prepared from chloroform 
and benzene, aided by AIC]. 


Preparation.—One part of AlCl, is gradually added to a mixture consisting of 
one part of chloroform and five parts of benzene, and the temperature raised to 
60°, until the evolution of hydrogen chloride ceases (30 hours). The product is 
poured into water, and the oil, which separates, is fractionated. Diphenyl methane 
is produced at the same time (Annalen, 227, 107; Berichte, 18, Ref. 327). It is 
furthermore obtained from diamido- and triamido-triphenyl methane, by dissolving 
the latter in sulphuric acid, introducing nitrous acid and boiling with alcohol (p. 
632 a Annalen, 206, 152). 


Triphenyl methane dissolves with » difficulty in cold alcohol and 
glacial acetic acid, easily in ether, benzene and hot alcohol, crystal- 
lizing from the latter j in shining, thin leaflets, melting at 93°, and 
distilling about 355°. It crystallizes from hot benzene in large 
prisms, containing two molecules of benzene, and melts at 75°, 
and when exposed to the air parts with benzene and falls into a 
white powder. ° 


Bromine converts tripheny] methane (dissolved in CS,) into the dromide, (C 6H;)s 
CBr, melting at 152° (Bertchte, 18, Ref. 327). PCI; converts the carbinol into 
the chloride, melting about 105°. When heated over. 200° both decompose into 
the halogen hydride and Diphenylene phenyl methane, if er oy! SCH. C,Hy, 
which can also be obtained from fluorene alcohol (p. 851) and benzene by means 
of sulphuric acid, as well as from potassium triphenyl methane (Berichte, 22, 


866 ORGANIC CHEMISTRY. 


Ref. 660). It melts at 146°. If the bromide be heated with mercuric cyanide 
to 100° the cyanide, (C,H,),C.CN, results. It melts at 127°, and if boiled with 
glacial acetic acid and hydrochloric acid changes to Triphenyl-acetic Acid, 
(C,H;),.-C.CO,H, which begins softening at 230°, and melts at 264° (Anna/en, 
194, 260). ‘Small amounts of the acid are also obtained from trichloracetic acid 
and benzene with AIC],. 

On boiling the bromide or chloride with water -we get Triphenylcarbinol, 
(C,H,),C.OH, which is more readily obtained by the direct hydroxylation of tri- 
phenyl methane. This is accomplished by digesting the latter with chromic acid 
in a glacial acetic acid solution (Berichte, 14, 1944). It is very readily soluble 
in alcohol, ether and benzene, crystallizes in shining prisms, melting at 159°, and 
distilling above 360° without decomposition. /-Nitro-Triphenyl Methane, 
C,H,(NO,).CH(C,H,),, is prepared from /-nitro benzaldehyde and benzene, 
aided by sulphuric acid (see above). It crystallizes in white leaflets, melting at 
93°. Chromic acid, in glacial acetic acid oxidizes it to the carbino/, C,H,(NO,). 
C(OH)(C,H,),, melting at 135° (Berichte, 23, 1622). 

When triphenyl methane is dissolved in fuming nitric acid (sp. gr. 1.5) it forms 
a p-trinitro-derivative, CH(C,H,.NO,),, which crystallizes from glacial acetic acid 
and hot benzene in yellow scales, and melts at 206°. Sodium alcoholate converts 
the nitro-compound into a deep violet-colored sodium salt (p. 861) (Berichie, 21, 
1348). By the reduction of the nitro-groups (with zinc dust and glacial acetic 
acid) we obtain paraleucaniline, CH (CH NET, (p. 870). By the hydroxylation 
of the tertiary hydrogen atom of trinitrophenyl methane (by digestion with CrO, 
in glacial acetic acid) we get Trinitrotriphenyl Carbinol, (C,H,.NO,),C.OH, 
which separates from benzene or glacial acetic acid in small, colorless crystals, 
melting at 172°, and when the nitro-groups are reduced (with a little zinc dust and 
glacial acetic acid) it is transformed into pararosaniline. 





(2) Diphenyl-tolyl Methanes, (C,H,),CH(C,H,.CH,). 

The fara-compound is obtained from phenyl]-paratolyl-carbinol (p. 862) and 
benzene, and also from benzhydrol, (C,H,),CH.OH, and toluene with phosphorus 
pentoxide. It crystallizes in thin prisms, melts at 71°, and distils above 360°. It 
yields a carbinol, C,,H,,O,and an acid, C,,H,,O3, when oxidized. The tri- 
nitro-compound of diphenyl-para tolyl methane yields on reduction of the nitro- 
to amido-groups, and further oxidation, bluish-violet coloring substances which 
differ from ordinary rosaniline (Annalen, 194, 264). 


Isomeric Diphenyl-meta-tolyl Methane, (C,H;),.CH(C,H,. 
CH;), is the parent hydrocarbon of ordinary leucaniline (the 
triamido-compound), and is obtained from the latter by replacing 
the 3NH, groups by hydrogen. ‘This is effected through the diazo- 
compound (Avznalen, 194, 282). It dissolves readily in ether, 
benzene and ligroine, with difficulty in cold alcohol and wood-spirit ; 
crystallizes in spherical aggregations of united prisms, melting at 
59-5°, and distilling undecomposed above 360°. Oxidized with 
chromic acid in a glacial acetic acid solution it passes into dipheny/- 
metatolyl-carbinol, (CsH;),C(OH)(C,H,.CH;), melting at 150°. 

It dissolves in fuming nitric acid with formation of a trinitro- 
derivative, yielding on reduction common leucaniline, which is 


a ee te ee 


TETRAMETHYL-DIAMIDO-TRIPHENYL METHANE. 867 


oxidized (on heating with a few drops of hydrochloric acid), to 
rosaniline (p. 871). 

Amido-derivatives of the Triphenyl Methanes. 

o-Amido-triphenyl Methane, (C,H,),CH(C,H,.NH,), is obtained from 
benzhydrol, (C,H,;),CH.OH, and HCl-aniline, on heating with ZnCl, to 150°. 
It crystallizes in leaflets, or prisms, melting at 84°. Its dimethyl compound, 
(C,H, ),CH.C,H,.N(CH,),, is obtained from benzhydrol and dimethyl aniline 
upon heating with P,O,, also on digesting benzophenone chloride, (C,H,),CCl,, 
with dimethyl aniline. It crystallizes from alcohol in colorless needles or prisms, 
melting at 132°. It does not afford a color-base by its oxidation. (Axzalen, 
206, 144 and 155.) 

p-Amido-triphenyl Methane, (C,H,),CH.C,H,.NH,, is produced by re- 
ducing the f-nitro derivative with tin and hydrochloric acid. It crystallizes from 
ligroine in small vitreous needles, melting at 84°. When its acetyl compound is 
oxidized and saponified it yields -Amido-triphenyl Carbinol, (C,H,),C(OH) 
C,H,.NH,, the lowest analogue of the rosaniline bases. It crystallizes from a 
mixture of ether and ligroine in colorless warts, melting at 116°. It combines 
with acids (without loss of water) to form red colored salts. These, however, 
lack coloring properties. (Berichte, 23, 1621). 


Diamido-triphenyl Methane, C,H;.CH(C,H,.NH,)., the pa- 
rent substance of ma/achite-green, is obtained from benzal chloride, 
C,H;.CHCl,, and aniline with zinc dust (see below), or more easily 
from benzaldehyde with aniline hydrochloride on heating with 
zinc chloride to 120°, and boiling the first formed product with 
dilute sulphuric acid. If aniline sulphate be applied we get the 
diamido-base directly (Berichte, 15, 676) :— 


C,H,.CHO + 2C,H,.NH, = C,H,.CH(C,H,.NH,), + H,0. 


It is more readily obtained by boiling benzaldehyde with aniline 
and hydrochloric acid (Berichte, 18, Ref. 334). It crystallizes 
from benzene with 1 molecule of benzene in shining prisms or 
spherical aggregations, melting at 106°, and parting with benzene 
at 110°. ‘The free base, crystallized from ether, melts at 139°. 


It yields colorless salts with two equivalents of the acids, By their oxidation 
we can obtain a violet dye-stuff, denza/ violet, with a constitution analogous to that 
of the rosanilines (Annaden, 206, 161). If the base be diazotized and boiled with 
water it is converted into dioxy-triphenyl-methane, C,H,.CH(C,H,.OH),; the 
decomposition of the diazo-compound by alkalies produces triphenyl-methane 
(Annalen, 206, 152). 

On methylating diamidotriphenyl-methane by heating with methyl iodide and 
wood-spirit to 110° we obtain 


Tetramethyl-diamido-triphenyl Methane, C,H,.CH[C,H,. 
N(CH;).]., deucomalachite-green, which is obtained directly from 
benzaldehyde (or benzal chloride) and dimethyl aniline with zinc 
chloride (or oxalic acid) :— 


C,H,.N(CH 
C,H,.CHO +. 2C,H,.N(CH,), = CH. CHC CN CHEY 4 H,0. 


868 ORGANIC CHEMISTRY. 


Leucomalachite-green is dimorphous, and crystallizes in leaflets, 
melting at 93-94°, or in needles, which melt at 102°. ‘The first 
modification is obtained pure by crystallization from alcohol, the 
second from benzene. It yields colorless salts with two equivalents 
of the acids, and with two molecules of methyl iodide forms an 
ammonium iodide. The free base oxidizes, even in the air, more 
readily by oxidizing agents (manganese dioxide and dilute sulphuric 
acid in the cold, lead dioxide and hydrochloric acid, or chlor- 
anil) and becomes 

Tetramethyl-diamido-triphenyl Carbinol, C,H;.C(OH) 
[C,H,.N(CH;),]., which is the basis of malachite-green. It is ob- 
tained from its salts (malachite-green) by precipitation with the 
alkalies. Free carbinol crystallizes from ligroine in colorless needles 
or spherical aggregations, melting at 130°, and decomposes on 
stronger heating. Reduction with zinc and hydrochloric acid con- 
verts it again into leucomalachite-green. 

The free base yields almost colorless solutions with acids in the 
cold ; upon standing, more rapidly on heating, the solution acquires 
‘a green color and then contains the green salts—madachite-greens— 
of the anhydro-base. It is very probable that amine salts (O. and 
E. Fischer) of the carbinol are first produced, but by an inner con- 
densation water is eliminated and they change to dye-salts (mala- 
chite-greens) (Berichte, 12, 2348) free from oxygen :— 

CES are eee 
(CH,),N.C,H,” ‘OH 


C,H Be 5 Re 
Se ae) Ct | 1,0. 
(CH,),N.C,H, 


Of these salts the double salt with zinc chloride, 3(C.;H.;N,.Cl) 
2ZnCl, + 2H,O, and the oxalate, 2C,,H.,N,.3C,H,O,, form the 
commercial malachite-green or Victoria green. ‘They are mostly 
soluble in water, and crystallize in large, greenish prisms or plates. 
The alkalies precipitate the colorless carbinol base from its salts. 
Matlachite-green and brilliant green (see below) color silk and wool, 
from feeble acid baths, an intense green. ‘This also occurs with 
cotton mordanted with tannin and alumina, or tannin and tartar 
emetic. 


Malachite-green is obtained by oxidizing leucomalachite-green, prepared from 
benzaldehyde (p. 867), hence called aldehyde green (O. Fischer), or more directly, 
though less advantageously, on heating benzo-trichloride with dimethyl aniline 
and zinc chloride (Doebner) :— 


C,H,-CCl, + 2C,H,.N(CH,), — C,,H,3(CH,),N,Cl + 2HCl. 


Since success has attended the efforts made to prepare benzaldehyde the first 


PARA-NITRO-DIAMIDO-TRIPHENYL METHANE. 869 


process has been almost exclusively followed in the technical preparation of the 
color. 

Benzoy] chloride, C,H,.CO.Cl, and benzoic anhydride (Anma/en, 206, 137) are 
similarly condensed with dimethyl aniline to malachite-green. 

Benzaldehyde forms perfectly analogous green color substances with diethyl 
aniline and methyl diphenylamine, (C,H,),N.CH;. The dye-substance obtained 
from diethyl aniline shows a yellow-tinted green color. Its sulphate or zinc- 
chloride double salt constitutes what in commerce is known as brilliant green or 
solid green (new Victoria green). Dichlorbenzaldehyde, C,H,Cl,.CHO, and 
dimethyl- and diethyl-anilines yield dyes, which are applied as zxdigo substitutes 
(instead of the mixed greens derived from indigo). By condensing benzaldehyde 
and benzyl-ethyl aniline, C,H,.N(CH,).CH,.C,H,, and introducing sulphur 
into the product, the /ight greens, guinea green or acid green ( Berichte, 22, 588) 
are produced; they show the same color in artificial light. 

It reacts in the same way with ortho- and meta-dimethyl toluidine, whereas no 
condensation product is furnished by the para-dimethyl toluidine. The base from 
meta-toluidine does not yield a coloring substance when oxidized (Axnalen, 206, 
140). Salicylic aldehyde and paraoxybenzaldehyde afford green coloring sub- 
stances. Furthermore, ztromalachite-greens have been prepared from meta-, 
para-, and ortho-nitrobenzaldehydes with dimethyl aniline. They are perfectly 
analogous to ordinary malachite-green (Berichte, 15, 682). See Berichte, 22, 
3207, for the condensations with toluidines. 

The Diphenyl-diamido-triphenyl Carbinol, 


/C BENE Ca 
CoH, COM). Cit NHC 
obtained from diphenylamine and benzo-trichloride, and called viridin, readily 
yields a sulpho-acid. The alkali salts of this acid constitute the so-called a/ka/i 
green (Berichte, 15, 1580). 

By heating leucomalachite green with sulphuric acid and then further oxidizing, 
or by directly introducing sulphur into malachite green, su/pho-acids result; their 
sodium salts are applied under the names He/vetia green or acid green. 


Para-nitro-diamido-triphenyl Methane, like diamido-tri- 
phenyl methane (p. 867), is obtained from paranitrobenzaldehyde 
and aniline sulphate when heated with zinc chloride :— 


C,H,(NO,).CHO + 2C,H,.NH, = C,H,(NO,).CH(C,H,.NH,), + H,0. 


Paranitro-diamido-triphenyl Methane. 


On reduction with zinc and acetic acid this yields triamido-tri- 
phenyl methane, (C,H,.NH,),CH, paraleucaniline, 


Meta-nitro-diamido-triphenyl Methane, similarly obtained from -nitro- 
benzaldehyde, melts at 136°, and by reduction yields pseudo-leucaniline, CH 
(C,H,.NH,),, isomeric with paraleucaniline; in it the amido-group assumes the 
meta-position in one benzene nucleus, whereas, in all other diamido- and triamido- 
triphenyl methanes, the amide groups occupy the para-position (p. 870). It oxid- 
izes to a violet coloring substance, Ortholeucaniline, from o-nitro-benzaldehyde, 
is oxidized to a brown coloring substance (Berichte, 16, 1305; 17, 1889). 

Benzaldehyde and nitrobenzaldehydes also condense with o- and /-toluidine 
(Berichte, 18, 2094), whereas metatoluidine and aniline meta-derivatives only 
react with ease, provided that the amido-group is methylated (Berichte, 20, 1563). 


870 ORGANIC CHEMISTRY. 


TRIAMIDO-TRIPHENYL METHANES. ROSANILINES. 


H.N.C,H H,N.C,H,\ 
WN CH! >CHC.H,NH, WNCH >CH-CoH,(CH,).NH,. 
gee ty “triphenyl Methane, imines diphenyl-tolyl Methane, 
Paraleucaniline, Leucaniline, 


The rosaniline coloring substances are produced from these in a 
manner similar to the derivation of denzal violet and malachite green 
from diamidotriphenyl methane (p. 867). The carbinols or free 
rosantline bases result when they are pindiers (adding hydroxyl to 
the CH-group) :— 


HN. H H H H H H, 
CoH. CoH ENE, HyN.CoHy. Ce ,(CH,).N 
H,N.C,H,” SoH : H.N.C,H,” SoH 
RS Base, pr ee Base. 


These alone are colorless, but yield salts with the acids by exit of 
water (analogous to the malachite-green base) and form the vosanz- 
line dye-substances. EE. and O. Fischer contend that the salt is pro- 
duced as follows: an exit of water occurs, followed by a peculiar 
linking of the C-atom to an N-atom in the para-position, forming a 
chromogenic group which imparts to the rosanilines their dyeing 
properties eset 12, 2350) :— 


H 2N.C, H H,N.C H, C, H.(CH 
ot ring ee 
H,N.C,H, “a H,N.C,H,7 “—_\NHLHX 
Para- rosaniline Salt. Rosaniline Salt. 


By the replacement of the hydrogen of the amido-groups in the 
salts by alkyls or phenyls, the different colored rosaniline dyes re- 
sult. The common and first discovered rosanilines are derived 
from diphenyl-meta-tolyl methane, C,.H,; (p. 866), and the carbinol 
base, C..H.) (OH)N;, and can also be called salts of the anhydride 
base, C.oH,,N;; the latter is unstable in a free state, and when lib- 
erated from its salts by alkalies, absorbs water and changes imme- 
diately to the carbinol base. The derivatives of triphenyl methane, 
Cio>H,,, and of the base, C,,H,;(OH)N,; or C,,H,,;N; are termed 
pararosanilines, to distinguish them from those rosanilines just men- 
tioned. The colorless salts obtained by the reduction of the rosani- 
lines form bases, C,,H,,N; and CyH,,N;, called dewcanzlines. 

Triamido-triphenyl Methane, C,,H,.N,; = CH(C,H,.NH,)s, 
Paraleucaniline, is obtained from trinitro-triphenyl methane 
(p. 866) and from para-nitro-diamidotriphenyl methane (p. 869) 
by reduction with zine dust and acetic acid, also from para- 
rosaniline with zine dust and hydrochloric acid, and by heating 
p-amidobenzaldehyde and dimethylaniline with zinc chloride :— 


C,H,(NH,).CHO + 2C,H,;.NH, = CH(C,H,.NH,), + H,0. 


ROSANILINE. 871 


- It is thrown out of its salts as a white flocculent precipitate. When 
its diazo-compound, C,,H,,(N;Cl);, is decomposed by alcohol, it 
yields triphenyl methane, C,,H,,. Pararosaniline is the oxidation . 
product of para-leucaniline. Pseudo-leucaniline affords a violet, 
and ortho-leucaniline a brown coloring substance when oxidized 
(p. 870). 

Pararosaniline. The free base, C,)H,.N;0 = (NH,.C,H,)3C 
OH, or ‘its salts, C,yH,,N;. HX (see above), result in the oxidation 
of para-leucaniline and in the reduction of trinitrophenyl carbinol- 
(p. 866), with a little zinc dust and glacial acetic acid. It is most 
easily made by oxidizing a mixture of aniline and paratoluidine by 
arsenic acid (p. 872). In its properties and derivatives it is per- 
fectly analogous to rosaniline. Its diazochloride, C,,H,,.(OH)N,Cl,, 
yields aurine, CyyH,,O;, when boiled with water. 


In para-rosaniline and in para-leucaniline the amide groups in the three benzene 
nuclei occupy the para-position (referred to the point of union of the methane 
carbon). We infer this from the synthetic methods (from para-nitrobenzaldehyde 
and para-amidobenzaldehyde) and from their relations to the aurines and to para- 
dioxybenzophenone (p. 860) (Berichée, 14, 330). It is very probable that common 
rosaniline contains its amide-groups in the same position; as it is obtained by 
means of ortho-toluidine the methyl in it occupies the meta-position referred to the 
methane carbon. See Berichte, 22, 2573 as to the influence exerted by side- groups 
upon the dye-character of the rosanilines. 


‘ Triamido-diphenyl-tolyl Methane, Leucaniline, C,,H,,. 
N; = (NH,.C,H,),CH.C,H;(CHs;).NH,, is obtained by the reduc- 
tion of trinitro-diphenyl meta-tolyl methane (p. 866), and is ob- 
tained by digesting the fuchsine salts with ammonium sulphide, or 
zinc dust and hydrochloric acid. The alkalies throw it out from 
its salts as a white, flocculent precipitate, which separates from water 
in small crystals. It yields colorless crystalline salts with three - 
equivalents of acid. By diazotizing and replacing the diazo-groups 
by hydrogen (best by dissolving in concentrated sulphuric acid, 
conducting nitrous acid into the same, and boiling with alcohol, p. 
632), leucaniline is changed into diphenyl-meta-tolyl methane. 
Oxidizing agents convert it into rosaniline (its salts). 


The oxidation of the leucanilines to rosanilines succeeds best when they are 
heated with a concentrated arsenic acid solution, or with metallic oxides to 130— 
140°, or by boiling the alcoholic solution with chloranil. Paraleucaniline and 
common leucaniline are also converted into coloring substances by heating them 
with a few drops of hydrochloric acid upon a platinum foil. This behavior rapidly 
distinguishes the second from some isomerides (Annalen, 194, 284). 


Rosaniline, C oH,,N;0. The rosaniline salts, C,)H,)N;.HX (p. 
870), are obtained in the oxidation of leucaniline, and are techni- 
cally prepared by oxidizing a mixture of aniline and ortho- and 
para-toluidine (see below). Alkalies precipitate the free dase (the 


872 ORGANIC CHEMISTRY. 


carbinol), C..H.,N,O0, from the salt solution; it crystallizes from 
alcohol and hot water in colorless needles or plates. It reddens on 
_ exposure, and when heated suffers decomposition. Its diazo-com- 
pounds, ¢. g., CyH,,(OH)N,Cl,, are produced when nitrous acid 
acts on the rosaniline salts, and when boiled with water they afford 
rosolic acid, C.)H,,O3. 

Free rosaniline, C.H,,N,O, is a base, which will expel ammonia 
from the ammonium salts. It combines with one and three equiva- 
lents of acids, undergoing an anhydride formation (p. 870), and 
yields salts, ¢. g., CopHigN;. HCl and C,,Hj,N3.3HCl + 4H,O. The 
latter are yellow-brown in color and not very stable; water decom- 
poses them into the stable, monaczd salts with intense colors. These 
are applied as dyes. They are most readily soluble in water and 
alcohol, and crystallize readily in metallic, greenish crystals. Their 
solutions are carmine red in color, and stain animal tissue directly 
violet-red, while vegetable fibre (cotton) must first be mordanted 
(tannin). The commercial f/wchsine (magenta) consists chiefly of 
the hydrochloride or acetate, C.H,,N;.C,H,O,. The fatty acid 
salts, insoluble in water and produced by dissolving the free rosani- 
line base in fatty acids, are employed in decorative printing. 

All the rosanilines are changed to colorless leucanilines when 
treated with reducing agents (heating to 120° with ammonium sul- 
phide). When heated to 200° with hydrochloric or hydriodic 
acid, the rosanilines are broken up into their component anilines. 
Upon boiling with hydrochloric acid pararosaniline breaks down 
into aniline and diamidobenzophenone (p. 859), and rosaniline 
into toluidine and diamidobenzophenone. 





Preparation.—Technically the rosaniline salts are obtained by oxidizing 
aniline oil (a mixture of aniline with para- and ortho-toluidine) with metallic salts 
(tin chloride, mercuric nitrate) or more advantageously with arsenic acid. If 
pure aniline be employed no coloring substance is formed. When pure aniline 
and paratoluidine are used pararosaniline results :— 

2C,H;.NH, + C,H,.NH, + 30 = C,H,,N,0 + 2H,0; 
Paratoluidine. Pararosaniline, 
whereas common rosaniline is obtained from aniline, paratoluidine and ortho- 
toluidine (Berichte, 13, 2204; 15, 2367) :— 
C,H;.NH, + 2C,H,.NH, + 30 = C,,H,,N,0 + 2H,0. 
Rosaniline, 

The reaction probably occurs in such a manner that para-amido benzaldehyde 
is first produced from the paratoluidine, and this then (like para-nitrobenzalde- 
hyde, p. 869) condenses with two aniline molecules to the leuco-bases :— 


NH,.C,H,.CHO + 2C,H,.NH, = NH,.C,H,.CH(C,Hy.NH,), + H,O, 
which further oxidizes to rosaniline. 


ALKYLIC ROSANILINES. 873 


An interesting formation of pararosaniline is that of heating aniline with carbon 
tetrachloride to 230° when the latter furnishes the linking carbon atom, and there 
ensues a reaction analogous to that of the formation of triphenyl methane from 
benzene and CCl,H or CCl, (865). The hydroiodide of pararosaniline results by 
using iodoform, CHI, (Caro). 

In the preparation of rosaniline according to the arsenic acid method (Girard 
and Medloc) aniline oil, or better, the proper mixture of aniline and toluidine is 
heated to 180-200° for 7-10 hours with a concentrated arsenic acid (3¢ part) solu- 
tion in iron retorts with agitators until the mass assumes a metallic lustre. The 
product, consisting chiefly of rosaniline arsenite, is extracted with water and fil- 
tered. When the solution cools a violet dye-substance separates, and upon the addi- 
tion of common salt rosaniline hydrochloride crystallizes out. The crystals thus 
obtained contain arsenic, but are freed from it by repeated crystallizations. 

According to another method (by Coupier) applied technically, the oxidizing 
agent is either nitrobenzene or nitrotoluene. 

To obtain red, heat aniline oil (a mixture of aniline, - and o-toluidine), one 
half of it being converted into hydrochloride, with 50 per cent. nitrobenzene and 


a little ferrous chloride or ammonium vanadate to 180-190° in an oil bath. Extract’ ~ 


the rosaniline hydrochloride with water. In these changes the nitrobenzene acts 
as an oxidizer, and does not take part in the formation of the rosaniline (Lange, 
Berichte, 18, 1918). 


The commercial dyestuffs, obtained as described, are really salts 
of rosaniline, C,,)H,,N;, and apparently contain, although in slight 
quantity, salts of pararosaniline, C,,H,,N;, and the homologous base, 
C,,H.,N;. In addition to the rosaniline the fusion also contains 
other violet and brown dyes, such as mauvein (viol-aniline), an 
azine dyestuff, and chrysaniline, an acridine derivative. The fuch- 
sine absolutely free from arsenic, which is obtained from it by a 
transposition with sodium chloride, is called ~wdine. Salt precipi- 
tates red-brown dye-substances from the mother liquors. 


Verguin (1859) first prepared rosaniline upon a large scale and introduced it 
into commerce under the name fuchsine. A. W. Hofmann has studied it scien- 
tifically since 1861; he proved the fuchsine salts to be salts of a base C,,H,,N3. 
H,O. The true constitution of the rosanilines—the proof that they were deriva- 
tives of triphenylmethane—was demonstrated analytically and synthetically by Emil 
and Otto Fischer (1876, Annalen, 194, 242), although preliminary investigations 
in this direction had been previously made by Caro and Graebe. (erichée, 11, 
1116, 1348). 





Alkylic Rosanitines. 

When the rosaniline salts are heated with alkyl iodides or chlo- 
rides (and the alcohols) the hydrogen of the amido-groups can be 
replaced by alkyls. Of the trialkylic compounds— 


CoH (OH)N; (CH) and C,9H, ,(OH)N;(C,H,)s, 
resulting in this manner, the methyl base yields reddish-violet- 
colored salts and the ethyl base pure violet salts (Hofmann’s Violet, 


Dahlia); these dissolve with difficulty in water, but dissolve easily 
in alcohol. fi 


73 


874 : ORGANIC CHEMISTRY. 


The introduction of more methyl affords higher methylated dyes 
until hexamethyl rosaniline is reached; its color changes with the 
number of methyl groups, from red to violet. 


Hexamethyl-rosaniline is capable of uniting with CH,I (1 molecule) to form 
a green colored salt C,,H,,N,(CH,),1.CH,I, that at 120° again eliminates methyl 
iodide and yields a bluish violet iodide, C,,H,,N;.(CH;),I. The picrate, a dark 
green powder, and the crystalline ZnCl,-double salt, readily soluble in water, con- 
stituted the zodide green or night green of commerce, but at present are sup- 
planted by the cheaper methyl- and malachite-greens. 

Similarly, hexamethyl pararosaniline, C,,H,,(OH)N;(CHy), (methyl violet, see 
below), when heated with methyl chloride (methyl iodide or methyl nitrate) yields 
so-called methyl green; its hydrochloride, C,)H,,.N,Cl(CH;).(CH,Cl), as the 
zinc chloride double salt, forms the commercial dye. It occurs as a bright gold and 
green mass. At 100-120° methyl green loses methyl chloride and becomes violet. 
At present both are almost entirely replaced by malachite green. 

Aldehyde green, another green rosaniline dye, has been prepared by heating 
rosaniline with aldehyde and sulphuric acid, and by further action of sodium hy- 
posulphite. It is very probably a quinaldine (Berichte, 19, 749). 

The phenylated rosanilines are obtained by heating rosaniline hydrochloride 
with aniline or toluidines (p. 603), or the free base with aniline and some benzoic 
acid. ‘The triphenyl-rosaniline hydrochloride, C,,H,,(C,H,;),N,.HCl, appeared 
in commerce as anz/ine blue, a bluish-brown crystalline powder with copper lustre, 
soluble in alcohol but not in water. To dissolve it in the latter sulpho-salts are 
prepared, which exhibit different shades of blue (so/udle b/ue) corresponding to 
the number of sulpho-groups in them. At present diphenylamine blue and other 
dyes have taken its place. Diphenylamine results on distilling tripheny]-rosaniline. 


\ 





Pararosaniline Derivatives. Instead of first preparing rosaniline 
and then adding alkyl, it was suggested that the same compounds 
could be obtained by directly oxidizing alkyl anilines (dimethyl 
aniline, diphenylmethylamine). The resulting dyes, according to 
their method of preparation, are derivatives of pararosaniline, 
C,,H,;N;. -They are obtained by oxidizing trimethyl aniline upon 
digesting it with copper chloride (or copper sulphate) and potas- 
sium chlorate at 50o-60°. On a small scale the oxidation is best 
effected by means of chloranil, C,Cl,O, (p. 701). The reaction very 
likely proceeds as follows: A methyl group splits off and is 
oxidized to formic aldehyde, which then condenses three molecules 
of the alkyl anilines :— 


CH,O + 3C,H;-N(CHs), + O, = C(OH)[C,H,.N(CH5).]; + 2H,0. 


The methyl violet thus formed occurs in commerce in the form of 
hydrochloride, an amorphous bright green mass, easily soluble in 
water and alcohol. It consists chiefly of penta- and hexamethyl- 
rosaniline, and also contains.the tri- and tetramethyl compounds, 
which are separated by fractional crystallization with difficulty 


PARAROSANILINE DERIVATIVES. 875 


(Berichte, 19, 107). As the number of methyl groups increases the 
violet color assumes a deeper blue tint. 


The following methyl] derivatives have been obtained in a pure state :— 
Tetra-methyl Para-leucaniline, H,N.C,H CHC 6° a NICH ps is ob- 
tained by reducing /-nitro-malachite-green (p. 869), formed from para-nitrobenz- 
aldehyde and dimethyl aniline. It melts at 152°. It is oxidized to Tetra- 
methyl Violet, C,H,,(CH;),N;.HCl. The acetate of paraleucaniline may be 
oxidized to a green dye (a malachite-green, as one NH,-group is linked by acetyl) 
(Berichte, 16, 708). 

Pentamethyl-para- leucaniline, C,,H,,(CH;),N;, has been obtained from 
the reduction product of commercial methy! violet (a mixture of penta- and hexa- 
methyl violet) by means of the acetate. It melts at 116°, and when oxidized 
yields Penta-methyl Violet, C,,H,,(CH,),;N,;.HCl. When its acezaze is oxid- 
ized it yields a green dye (Berichte, 16, 2906). 

Hexamethyl-paraleucaniline, C,,H,,(CH,),N;, Zeuco-violet, is obtained 
pure on heating ortho-formic ester, CH(O.C,H,),, with dimethyl aniline (3 mole- 
cules) and zine chloride, and from tetramethyldiamidobenzophenone (p. 859) 
with dimethyl aniline and PCl,. If separated from its HCl-salt it crystallizes in 
silvery leaflets, and melts at 173°. If oxidized it yields Hexamethyl Violet :— 


Re / C,H,4.N(CH,) 
CigH, (CH) «Ns. HCl = (CH) ,N.C, mare H.N(CH,) Cl 3 


this possesses a blue tint. Its carbinol base, C,,H,,(OH)N,(CH,),, crystallized 
from ether, melts at 195°. ' 

All three leucanilines yield the iodo-methylate, C,,H,,(CH,),N,.3CH;I, when 
they are heated with much methyl] iodide and methyl alcohol. This melts at 185°, 
and heated to 130° regenerates hexamethyl-para-leucaniline. 

The methyl violets are reduced to leuco-compounds when heated to 120° with 
ammonium sulphide. Protracted boiling with hydrochloric acid causes them to 
lose one molecule of dimethylaniline and break down. Thus from pentamethyl 


violet we obtain trimethyl-diamidobenzophenone, Coes at cts i> and 


from hexamethyl violet, tetramethyldiamido-benzophenone (p. 859) (Berichte, 19, 
108) 


Pure hexamethyl pararosaniline, distinguished from the lower 
methyl derivatives by great power of crystallization and the blue 
color of its salts, hence called Crystal Violet, is produced on a large 
scale. by the condensation of tetramethyldiamidobenzophenone 
(from dimethyl aniline and COCI,, p. 859) with dimethyl ani- 
line :— 


C,H,.N(CH /CoH,-N(CH 
Cox Fe Vhs a, H,.N(CH,), = C(OH)Z CH N(CH’, 
\c,H,-N(CH,), \C,H,.N(CH,), 


It may therefore be directly obtained by heating dimethylaniline 
with COCI, and AlCl, or ZnCl, (Berichte, 18, 767; Ref. 7). 
Formic acid, formic ester, chlorcarbonic ester, perchlormethyl 
mercaptan, CSCl,, etc., act the same as phosgene. 


876 ORGANIC CHEMISTRY. 


Tetramethyl-diamido benzophenene condenses similarly with 
other bases. It yields with phenyl-a-napthylamine, C,H,.NH. 
C,H, tetramethyl -naphthyl-rosaniline C(OH)% / 1 CoH. CH) 

10* +79 ey by > pee Oe" Tj. ‘NE. tk 
The zinc chloride double salt of the latter is Victoria Blue, used 
for cotton dyeing (see Berichte, 22, 1888). 

Diphenylamine Blue can be obtained by heating diphenylamine, (C,H;), HN, with 
carbon hexachloride, C,Cl,, or oxalic acid, to 120°. It is identical with triphenyl- 
pararosaniline, C(OH)(C, H,.NH.C,H,;) (Berichte, 23, 1964), obtained by the 


action of aniline upon pararosaniline. At present it is only the sodium salts of its 
mono- and disulpho-acids that are applied as 4/kalt Blue and Water Blue in dyeing. 


Perchlorformic ester, CClO,CCl,, in a similar manner converts di- 
phenyl methylamine, (C,H;).N.CHs;, into “77methyl-triphenyl-para- 


rosaniline, C(OH)(CHANG Cit )s (Berichte, 19, 278). Phos- - 


gene converts triphenylamine into the hydrochloride of hexaphenyl 
pararosaniline, CCOH)[C.Hy.N(C,H;)2|3 (Berichte, 19, 758). Z77- 
carbazol Carbinol, C(OH)(C,,H,NH), (Berichte, 20, 1904), 1 
produced by heating together carbazol and oxalic acid (Berichte, 
20, 1904). It is analogous to the triphenylamine derivative. 

By converting rosaniline, by means of the tridiazo-compound 
into the ¢vthydrazine derivative, there results Roshydrazine, C(OH) 
(C,H;.NH.NH,);; this by condensation with aldehydes and ketones 
yields red and blue dyestuffs (Berichte, 20, 1557). 





2. PHENOL DERIVATIVES OF THE TRIPHENYL 
METHANES. 


These possess a constitution perfectly analogous to that of the 
amido-derivatives, as they contain hydroxyls in the positions held 
by the amido-groups. They are synthetically produced in a similar 
manner by the condensation of the phenols, and on the other 
hand may be obtained from the amido-compounds by means of the 
diazo-derivatives. Their leuco-derivatives (p. 870), are oxidized 
to carbinols, RsC.OH, having usually the properties of a dye-sub- 
stance. Those compounds, in which but two benzene nuclei are 
hydroxylated, and which correspond to the diamido or malachite- 
green compounds, are termed Jdenzeines, whereas the derivatives 
with three hydroxylated benzene nuclei are called aurines or rosolic 
acids :— 


/C,H,.0H /C,H,.0H 
CH CHC Cyt on Cols-COW) Cy OF 
Leuco- Lath Benzeine. 
HO.C,Hy HOCH o. 
CH.C,H,.OH \C(OH).C,H,.OH, 
HO.C,H,% HO.C,H,” 


"i acéa. aurine. Aurine, 


AURINES AND ROSOLIC ACIDS. 877. 


Benzeines. 

Dioxy-triphenyl Methane, C,,H,,0, = C,H,;.CH(C,H,.OH),, leuco- 
benzeine, formerly called leucobenzaurine, is obtained from diamido-triphenyl 
methane (p. 867), with nitrous acid and by reducing benzaurine with zinc and hy- 
drochloric acid as well as by the condensation of benzaldehyde and phenol (2 
molecules) with sulphuric acid (Berichie, 22, 1944). It crystallizes from dilute 
alcohol in yellow needles or prisms, melting at 161°, When oxidized it yields 
benzeine. 

Dioxy-triphenyl Carbinol, C,,H,,0, = C,H,.C(OH)(C,H,.OH),, Phenol 
Benzeine, is only stable as an anhydride, C,,H,,O,, formerly called denzaurine. 
It is produced in the condensation of benzotrichloride and phenol (similar to 
the formation of malachite-green) (Doebner, Annalen, 217, 223) :-— 


C,H,.CCl, + 2C,H,.0OH + H,O = C,,H,,0, + 3HCl. 


All mono- and polyhydric phenols, in which the para position with reference to 
a hydroxyl group is not substituted, ¢. g., o- and m-cresol, a-naphthol, resorcinol 
and pyrocatechin (but not J-cresol, 3-naphthol, hydroquinone etc.) (Berichée, 23, 
Ref. 340), react in the same manner with the formation of benzeines. 

The benzeines are generally red-colored compounds with metallic lustre. They 
dissolve on boiling with sodium bisulphite; acids reprecipitate them. Alkalies 
dissolve them with the formation of red or violet-colored salts. The carbon di- 
oxide of the air decomposes the latter. 

Phenol benzeine (see above) breaks down, when fused with alkalies, into ben- 
zene and dioxybenzophenone, and this latter decomposes further into paraoxy- 
benzoic acid and phenol. The other benzeines react similarly. 

a-Naphthol Benzeine, 2 C.H,.C(OH)< Hon )- H,0, from benzo- 
trichloride and naphthol (Azna/en, 257, 58), dissolves with a dark green color, in 
alkalies; acids color it reddish-yellow. It is extensively employed as a delicate 
indicator (Chem. Zeitschr., 1890, 605). : 

The benzeines, from phenols, possess but feeble dyeing properties, as their 
alkali salts are even decomposed by carbon dioxide, On the other hand the 
diamidobenzeines from benzotrichloride and m-amidophenols, combining the ben- 
zeine character with that of the malachite greens, are called vosamines, and in 
their salts with acids are very intense, true dyestuffs (Berichte, 22, 3001) :— 


NH, 
ht 
C,H, 
C,H,,.CCl, + aC WH, st C.H,.C(OH)¢ SO + 3HCl. 
C,H; 
NH, 


In a similar manner, dimethyl-and-diethyl-7z-amidophenol yield ‘etramethy/- 
and ¢etraethyl-rosamines, which find application as violet red dye substances. 
They are strongly fluorescent. 





AURINES AND ROSOLIC ACIDS. 


These compounds correspond perfectly to the rosanilines. They 
contain three hydroxylated benzene nuclei (p, 876) and in the free 
state are peculiar carbinol anhydrides. They are incompletely fixed 


878 _ ORGANIC CHEMISTRY. 


by the fibre of the material and are only applied in the form of 
lakes. 


Trioxy-triphenyl Methane, C,,H,,0, = CH(C,H,.0H),, Leucaurine. 
This is obtained in the reduction of aurine, its carbinol anhydride, by means of 
zinc dust. It dissolves in alcohol and acetic acid, and crystallizes in colorless 
needles, which become colored on exposure to the air. 

Aurine, C,,H,,O; (para-rosolic acid), is produced on boiling the diazo- 
hydrochloride of pararosaniline with water, when the carbinol formed at first 
splits off water (Annalen, 194, 301) :— 


CIN, GH 6 / CHa NC! a4. HO.CsHyS 6 /CoHi\ 
GIN,.C.H, 4” \OH y HO.C,H,/ ~———_O; 


Diazochloride. Aurine. 


also by the condensation of dioxybenzophenone chloride (from /-dioxybenzo- 
phenone, p. 860) with phenol :— 


CCl,(C,H,-OH), + C,H;.OH. = C,gH,,0,; + 2HCl, 


and by the condensation of phenol with formic acid on heating with zinc chloride. 
It is made by heating phenol with oxalic and sulphuric acids; the combining car- 
bon atom is derived from the oxalic acid. 

The method of Kolbe and Schmitt (1861) is that technically employed for the 
manufacture of aurine or yellow corallin. It consists in heating phenol (1 part) 
and anhydrous oxalic acid (24 part) with sulphuric acid (1% part) to 130-150°, 
until the liberation of gas ceases (Anma/en, 202, 185). On extracting with water 
there remains a resinous metallic green mass which forms a yellow powder. It 
contains, besides aurine, various other, quite similar, substances, from which the 
first can be separated either by means of sulphurous acid (Azmalen, 194, 123), or 
by precipitation as aurine-ammonia, when NH, is conducted into the alcoholic 
solution (Anzalen, 196, 177). 

Aurine dissolves in glacial acetic acid and alcohol, crystallizes in dark red 
needles or prisms with metallic lustre, and decomposes when heated above 
220°. Acids precipitate it from the alkaline fuchsine-red solutions. When am- 
monia is conducted into the alcoholic solution, the ammonium salt, C,,I1,, 
(NH,),O,, separates in dark red needles with a steel-blue lustre. With the 
primary alkaline sulphites it also yields colorless, crystalline derivatives, decom- 
posable by acids and alkalies. urine forms crystalline compounds with hydro- 
chloric acid. Water decomposes them. Digested with zinc dust and hydrochloric 
acid or acetic acid, aurine is reduced to leucaurine, C,,H,,O,. Heated to 250° 
with water it breaks up into dioxybenzophenone and phenol :— 


C,)H,,0,-+ H,O = CO(C,H,.0H), + C,H,.OH. 


Aurine is changed to pararosaniline when it is heated with aqueous ammonia 
to 150°. An intermediate product (having I or 2 amide groups) is the so-called 
Peonine (red corallin). With aniline we obtain triphenyl-rosaniline, and the inter- 
mediate product is Azudine. 

Leuco-rosolic Acid, C,H,,0, = (HO.C,H,),.CH.C,H,(CH;).OH, trioxy- 
dipheny]-tolyl methane, and Rosolic Acid, C,,H,,O3, corresponding to leuco- 
aniline and rosaniline, are constituted similarly to leucaurine and aurine, and resem- 
ble them in all their reactions. Rosolic acid, like aurine, is obtained by boiling the 
diazochloride of rosaniline with water and by oxidizing a mixture of phenol and 
cresol, C,H ,(CH,)OH, with arsenic acid and sulphuric acid, whereby the linking 
methane carbon is furnished by the methyl group. When rosolic acid is digested 
with alcohol and zinc dust, it is reduced to leucorosolic acid. 





“PHTHALIDES. 879 


The so-called Pittica/ belongs to the aurine series. It was first obtained in 
oxidizing the fractions of beech-wood tar, boiling at high temperatures. It con- 
sists of the dark blue salts of Zupzittonic acid (Eupitton), which, in its uncombined 
state, shows an orange-yellow color. It can be synthesized (analogous to rosolic 
acid) by oxidizing a mixture of the dimethyl ester of pyrogallic acid and methyl 


pyrogallic acid (p. 695) :— 
O.CH 0.CH 
2C,H, { hos a)e + CgH,(CHs) { oa s)2 — C560, + 3H). 

Eupitton is, therefore, an aurine, into which six methoxyl groups have been 

introduced (comp. Berichte, 21, 1371) :— 
Cy5Hg0) = CypHs(O.CH,) 05. 

Eupitton forms orange-yellow crystals, melting with decomposition at 200°. It 
dissolves with a deep blue color in alkalies yielding salts, which are precipitated 
by excess of alkali. When heated with ammonia it suffers a replacement of its 


hydroxyls by amido-groups, just like aurine, and affords a body resembling rosani- 
line, which must be considered as hexamethoxyl-rosaniline. 


e 





CARBOXYL DERIVATIVES OF THE TRIPHENYL METHANES. 
PHTHALIDES. ; 


Of the many possible carboxyl derivatives of the triphenyl me- 
thanes (their amido- and phenol derivatives), there is one group of 
compounds of particular interest. These contain a carboxyl in the 
benzene nucleus in the ortho position (in relation to the combining 
methane carbon).* 

By oxidation they yield carbinol acids, which, however (like all 
y-oxyacids), are not stable, but immediately sustain a loss of water 
and pass into their anhydrides (lactones) :— 


C,H,CO,H C,H,.CO,H 
(CHR (CHdsCC tetra 
Ortho-carboxylic Acid. CH Carbinol-carboxylic Acid. 
(C.H,),C% “4 * 500 

Anhydride. 


These anhydrides bear exactly the same relation to the carbinol- 
carboxylic acids that the so-called Phthalide bears to the unstable 
ortho-oxy-methyl benzoic acid (p. 772). It is, therefore, conve- 
nient, to regard the compounds belonging here as derivatives of 
phthalide, produced by the substitution of phenyls (oxy- and amido- 
phenyls) for the hydrogen of the CH,-group :— 








CoH <a s)2 0 CoH, Cos OF) 29 CoH <ACoMa NHahs 0, 


Dipheny] phthalide, er ee Diamido-dipheny! phthalide, 
o- Phthalophenone. Dioxyphthalophenone. Digmidophthalephenoiie. 





* See further, A. Baeyer, Annalen, 202, 36; 212, 347. 


880 ORGANIC CHEMISTRY. 


They are reduced to ortho-carboxylic acids, and may be obtained 
from phthalic acid in the same manner as phthalide, hence, their 
name. They are produced by the condensation of o-phthalyl chloride 
(or o-phthalic anhydride) with benzenes, by the action of AlCl, :— 


GHC gO ee et eee ChH,C Gy 2 50 + 2HCl. 


In using phthalic anhydride, we first get o-benzoyl benzoic acid (p. 863). On 
permitting benzene and AICI, to further act upon the latter, the product will be 
diphenylphthalide (Berichte, 14, 1865) :— 


/CO.C,H 


CeHa< CO,H 


Aa Mig don Gey ht 0 4. 34,0: 
The diphenolphthalides (phthaleins) are analogously produced by 
the condensation of phthalic anhydride with phenols (p. 881). 


o-Benzoyl benzoic acid reacts similarly with phenols (on heating to 200°), and 
in this way phthalophenones can be obtained with one benzene and one phenol 
residue (Berichte, 14, 1859). 





Diphenyl Phthalide, Phthalophenone, C,,H,,O,, the anhy- 
dride of triphenyl carbinol-ortho-carboxylic acid, is obtained from 
phthalyl chloride with benzene and AICI], (Aznalen, 202, 50), or 
with mercury diphenyl, and crystallizes from alcohol in leaflets, 
melting at 115°. When boiled with alkalies it dissolves to salts of 
triphenyl carbinol-ortho-carboxylic acid, which is again separated 
as anhydride (phthalophenone) by acids. 


If the alkaline solution of the carbinol acid be boiled with zinc dust, we get 
Triphenyl-methane-carboxylic Acid, (C,H,;),CH.C,H,.CO,H, melting at 
156°, and when carbon dioxide splits off it yields triphenyl methane. The same 
product is obtained from phenylphthalide (p. 863) and benzene with AICI, (Be- 
richte, 19, Ref. 687). 

Phthalophenone dissolves in nitric acid, yielding a dinitro product, whose di- 
amido-derivative is converted by nitrous acid into dioxyphthalophenone (phenol 
phthalein) (Anzalen, 202, 68). 

An interesting reaction is that triphenyl-methane carboxylic acid can, by the 
elimination of water, yield phenylanthranol, a derivative of anthracene :— 


H 
= cH Ces eile 5 
Ct, eo» a C.4 oP OCH, + 0. 
HO.cO” cr 
\ S Soe 


The derivatives of the acid deport themselves similarly (the so-called phthalins, 
p. 882); the resulting anthracene compounds are known as phthalidins (see 
these). 





PHTHALEINS. 881 


_ Oxyphthalophenone, C,,H,,(OH)O,, Benzene-phenol-phthalide, can be ob- 
tained from phenol, in the same manner that phthalophenone is prepared from 
orthobenzoyl-benzoic acid with benzene. It melts at 155°. It forms the transition 
to the phthaleins, containing two phenol residues. It dissolves in alkalies with 
a violet-red color, which disappears on heating, because the anhydride group is 
ruptured and the salt of the carbinol acid produced; this by reduction with zinc 
dust yields— 

Oxy-triphenyl-methane Carboxylic Acid, Cote ehos. wy This 
is a phthalin. Concentrated sulphuric acid abstracts water from ‘t and converts it 
into its phthalidin (an anthracene derivative) (see above). Sulphuric acid decom- 
poses oxyphthalophenone at 100° into phenol and o-benzoyl-benzoic acid. Fusion 
with potassium hydroxide converts it into benzoic acid and oxybenzophenone. 





The Phthaleins, the derivatives of phthalide containing two 
phenol residues, are particularly important, and are dyes which are 
of great technical value. A. v. Baeyer discovered them in 1871. 
They result from the condensation of phthalic anhydride (1 mol.) 
with phenols (2 mols.) on heating with sulphuric acid, or better, 
with ZnCl, to 120° (or with oxalic acid, p. 864) :— 


/C,H,.0H 
C—C,H,.0H 
co. ¥ 6774 
e:n.¢ & NOi4+ 96. Be ON = CH + H,0, 
: cane oh pained, 5 *\co:0 F 
Phenol-phthalein. 
/CoH3(OH)\ 6 
C,H,¢ ©°o + 2C,H,(OH), = C,H Cntenstenee + 2H,0 
4 4 “phe 4 . 
: Se Rascéciael, g . CO O : 


Resorcinol-phthalein. 


The phthaleins derived from di- and polyvalent phenols are all 
anhydrides, formed by the elimination of water from two phenol- 
hydroxyls (Aunalen, 212, 347). 


The reaction proceeds as in the case of diphenylphthalide (p. 880) ; it may be 
assumed that oxybenzoyl-benzoic acid is first formed, and this then acts with a 
second molecule of the phenol. If, however, phthalic anhydride be heated to 
150°, with but one molecule of phenol and sulphuric acid, anthraquinone deriva- 
tives are produced :— 


co co 
CoHA< Gg >? + C,H,.0H = CoH AC EG >CoHy.OH + H,0. 


Oxyanthraquinone. 

The free phthaleins are generally colorless, crystalline bodies. 
They dissolve in the alkalies with intense colorations, and are again 
separated from their solutions by acids (even CO,). The addition 
of concentrated caustic alkali causes the colors to disappear, because 
by the rupture of the anhydride group salts of the colorless carbinol 
acids are formed (p. 879). On diluting with water the colors 

74 


882 ORGANIC CHEMISTRY. 


reappear. The phthaleins obtained from resorcinol and phthalic 
anhydride (or the anhydrides of polybasic fatty acids, p. 883) 
exhibit an intense fluorescence in, these solutions, and are therefore 
termed fluoresceins. 


It appears the linking carbon atom (of phthalic acid) in them occupies the meta- 
position referred to the two hydroxyls of the resorcinol, and, therefore, only those 
meta-dioxybenzenes yield fluoresceins in which the meta-position is unoccupied 
(Berichte, 15, 1375). 


If the alkaline solutions of the phthaleins be reduced with zinc 
dust, we obtain the non-coloring carboxylic acids (p. 879)—the 
phthalins :— 


C(C,H,.0H) CH(C,H,.0H) 
CHI Air? Ob i a Mas 
Neate % “\CO.OH 
Phthalein. Phthalin. 


The phthaleins may be compared to the aurines, and the phthalins to the leuc- 
aurines (p. 876); in place of the hydroxyl of the latter the phthalins contain a 
carboxyl group. The hydroxyl, however, in the leucaurines is found in the para- 
position, while, in accordance with their method of production, the phthalins and 
phthaleins contain the ‘CO-group in the ortho position. 


The phthalins dissolve in alkalies, oxidize, however, readily in 
alkaline solution (even in the air, moré quickly by MnO, or 
MnO,K), to phthaleins. Another interesting reaction is the con- 
version of the phthalins, by mixing them with sulphuric acid, into 
the so-called phthalidins (p. 882), which by oxidation yield the 
phthalideins (oxanthranol derivatives) (see Anthranol). 


Phenol-phthalein, C,,H,,0,, Dioxyphthalophenone, is also formed from 
phthalophenone when nitrous acid acts on the diamido-compound (p. 880). It 
is obtained on heating phthalic anhydride (3 parts) with phenol (4 parts) and tin 
chloride (4 parts), or with sulphuric acid to 115—120° for eight hours. The pro- 
duct is boiled with water, dissolved in sodium hydroxide and precipitated by 
acetic acid (Annalen, 202, 68). It is a yellow powder, crystallizing from alcohol 
in colorless crusts, and melting at 250°. It dissolves in the alkalies with a red 
color (see above). It is used as an indicator in alkalimetry, especially in deter- 
mining carbon dioxide with baryta (Berichte, 17, 1077, 1097). 

Acetic anhydride converts it into a diacetate, melting at 143°, and bromine into 
a tetrabromide, C,,H,)Br,O,. On fusion with alkalies it decomposes into benzoic 
acid and dioxybenzophenone (p. 860). Boiling with alkaline hydroxides and 
zinc dust changes phthalein into Phenol-phthalin, C,,H,,O,, crystallizing from 
hot water in needles, and melting at 225°. It dissolves in alkalies without colora- 
tion; the solution oxidizes to phenol-phthalein in the air, more quickly with potas- 
sium ferricyanide or permanganate. 

Resorcinol-phthalein, C,,H,,O, + H,O, Fluorescein, is prepared by 
heating phthalic anhydride (5 parts) with resorcinol (7 parts) to 200°. When 
precipitated from its salts it is a yellowish-red powder, and when crystallized 
(C,H, .0;) from alcohol it is dark red in color. It decomposes about 290°. It 
dissolves in alcohol with a yellow-red color and green fluorescence. Its con- 
centrated alkali solution is dark red, but on dilution it gradually becomes yellow, 


DIMETHYLANILINE PHTHALEIN. 883 


and then exhibits a magnificent yellowish-green fluorescence. When fused with 
caustic soda it decomposes into resorcinol and mono-resorcinol phthalein, which 
further splits up into phthalic acid (benzoic acid) and resorcinol. Resorcinol- 
phthalin, Fluorescin, C,,H,,0,, formed by reduction with zinc dust, is a color- 
less, amorphous substance, which is again oxidized to fluorescein, when its alkaline 
solution is exposed to the air. 

If bromine be allowed to act on fluorescein suspended in glacial acetic acid, 
we obtain substitution products, of which Tetrabromfluorescein, C,,H,Br,O,, 
is the commercially important dye, Eosin (Caro). When thrown out of solution 
it is a yellowish-red precipitate; crystallized from alcohol it forms red crystals. 
The potassium salt, C,,H,K,Br,O;, containing 6 and 5 molecules of H,O, is a 
red-brown powder with shining leaflets, and constitutes the eosin of commerce, 
soluble in water, and imparting to wool and silk a beautiful rose color (similar to 
cochineal). A benzyl derivative of fluorescein is the sodium salt of commercial 
Chrysolin, which dyes wool and silk directly, imparting to them a color resemb- 
ling turmeric. 

Phosphorus pentachloride converts fluorescein into Fluorescein chloride, 

JE& = (CeH;Cl),0 
Goran foo (Annalen, 183, 18). Its halogen atoms are very re- 
\co.0 
active. It is used for the preparation of rhodamine (see below). 
: /CLCoHy(OH)s]e 
Pyrocatechin-phthalein, C,,H,,O, = C,Hyo , is pro- 
‘CO.0 
duced when phthalic anhydride and pyrocatechin are heated to 140-150° with 
zinc chloride (Berichte, 22, 2197). It is a yellow, non-crystallizable mass. It 
dissolves in the caustic alkalies with a blue color, in the alkaline carbonates with 
a violet color. From its acid esters we would infer the presence of four hydroxyl 
groups init; hence it does not form an inner anhydride. 

Pyrogallol-phthalein, Gallein, C,,H,,O, (see Anualen, 209, 249), is ob- 
tained on heating pyrogallic acid with phthalic anhydride to 200°. It dissolves 
with a dark red color in alcohol, and with a beautiful blue color in the alkalies. 
Zinc dust reduces it to Aydrogallein, C,,H,,0,, and then to gallin, C,,H,,0,, — 
which corresponds to phenol-phthalin. 

Like all phthalins (p. 880), it is converted by sulphuric acid into the anthracene 
derivatives, Coerulin, C,,H,,O,, and Coerulein, C,,H,O,. The latter dissolves 
in the alkalies with a green color, and finds application as a green dye. 





Chlorinated phthalic acids can be substituted for phthalic acid in the preparation 
of the preceding compounds. Various fluoresceins and eosins result. They ac- 
quire a violet-red color with the increasing number of halogen atoms (Zrythrosin, 
Phloxin, etc). 

Phthalic anhydride also reacts with dimethylaniline, yielding 
| 7eCoHa-NRo)s 


as 
CO.O 
phthalyl chloride we get an isomeric body, the so-called Phthal-green, which is 
probably a phthalidin, and is derived from anthracene (Azna/en, 206, 92). 

The phenols can combine with the anhydrides of dibasic fatty acids (oxalic, 
succinic, maleic) and with tartaric acid, citric acid, etc. (Berichte, 15, 883, 18, 
2864), yielding analogous phthaleins and phthalins. Succinyl fluorescein, 
C,,H,,0;, from succinic acid and resorcinol, yields a tetrabrom.derivative, 
C,,H,Br,O,, very similar to Zosin. 


Dimethylaniline-phthalein, C,,H,,N,0, = C,H With 


884 ORGANIC CHEMISTRY. 


Rhodamines. 

The rhodamines, the phthaleins of # amido phenol, C,H ,(NH,).OH, and its 
derivatives, are of special importance. They are violet-red, magnificently fluores- 
cent dyestuffs. In constitution they are perfectly analogous to the fluoresceins; 
they contain two amido groups in place of the two hydroxyls :— 


CoH, 00;(OH), CaoHioO(NH,), 


Fluorescein. Rhodamine. 


They correspond in all particulars to the rosamines (p. 877), and like them con- 
tain salt-forming groups of negative and positive nature. The szwp/est rhodamine 
is formed when m- amidophenol hydrochloride and phthalic anhydride are heated 
to 180-190° with sulphuric acid (Berichte, 21, Ref. 682) :— 


UNE, 
C,H, 
By ZOOS sei WN ONG 2H,O 
6*4\ CO/ + 2C¢ 4. OH > ‘s 4° ae + 2,0. 
co—o Cet, 
8 a 
NH, 


The hydrochloride salt forms metallic green leaflets. Its solutions are yellow in 
color and highly fluorescent. Zhe alkylic rhodamines possess more intense colors. 
They are produced when the salt is heated with alkyl iodides. A better course to 
pursue in this preparation is the condensation of alkylic #- amido phenols (p. 
681) and phenyl-s-amido phenol (m- oxydiphenylamine, p. 603) (Berichie, 21, 
Ref. 682, 920; 22, Ref. 788). Still another procedure consists in rearranging 
flourescein chloride (p. 883) by heating it with dialkylamines (Aerich/e, 22, Ref. 
625, 789 

Thad acid yields 9 . 
- Hay gee H,.N(CHs). ; 

uccino-rhodamine, - O, is apparently the com- 
CO. er \c, H,.N(CH,),7 


mercial rhodamine S. 





3. Derivatives with benzene nuclei joined by two or more carbon- 
atoms ( p. 842). 


THE DIBENZYL GROUP. 


C,H,.CH, C,H,.CH C,H,.C 
I ||| 
C,H3.CH, C,H,.CH C,H,.C 
Dibenzyl. ; Toluylene. Tolane. 
C,H,.CH.OH C,H,.CH.OH C,H,£O C,H,.CH, 
| | 
C,H,.CH.OH C,H,.CO C,H,.CO C,H,.CO 
Hydrobenzoin, Benzoin. Benzil. Desoxybenzoin. 


Dibenzyl, C,,H,, (symmetrical diphenyl ethane), is prepared by 
the action of sodium or (copper) upon benzyl chloride, C,H;. 
CH,Cl, or of AlCl; upon benzene and ethylene chloride, and by 





STILBENE, TOLUYLENE. 885 


heating stilbene and tolane, or benzoin and desoxybenzoin with 
hydriodic acid. It crystallizes in large prisms, melting at 52°, and 
boiling at 284°. It/forms stilbene and toluene when heated to 
500°. Chromic acid and potassium permanganate oxidize it 
directly to benzoic acid. 


It yields two dinitro-compounds by nitration. 

pp-Dinitrodibenzyl, NO,.G,H,.CH,.CH,.C, H,.NO,, has also been obtained 
by the action of Stannous chloride upon g-nitrobenzyl chloride, NO,.C,H,. 
CH,Cl. It crystallizes in yellow needles and melts at 179° (Anna/en, 238, 272). 
Diamidodibenzyl, H,N.C,H,.C,H,.C,H,.NH,, and its tetramethy] derivative 
are, in distinction to the corresponding diphenylmethane derivatives, bases that lack 
coloring power (Berichte, 20, 914). 


Stilbene, Toluylene, C,,H,, = C,H;.CH:CH.C,H;, symmetri-, 
cal diphenyl ethylene, is produced in various ways, thus: by distil- 
ling benzyl sulphide and disulphide; by the action of sodium upon 
bitter-almond oil or benzal chloride, C,H;.CHCl,; by conduct- 
ing dibenzyl or toluene vapors over heated lead oxide ; by heating 
diphenyl monochlorethane alone or diphenyl trichlorethane with 
zinc dust, by reducing tolane with zinc dust and glacial acetic 
acid, or sodium and alcohol. An interesting method for its pro- 
duction is that of distilling fumaric and cinnamic phenyl esters 
(Berichte, 18, 1945). It crystallizes in large monoclinic leaflets or 
prisms, dissolves easily in hot alcohol, melts at 120°, and distils at 
306°. 


When heated with hydriodic acid it yields dibenzyl, C,,H,,. Chromic acid 
oxidizes it to bitter-almond oil and benzoic acid. It is immediately attacked by 
potassium permanganate, while phenanthrene does not react. 

Bromine combines with stilbene, forming Stilbene Dibromide, C,H, CHBr. 
CHBr.C,H,, dibromdibenzyl. It is also prepared from dibenzyl by the action of 
bromine and from the two hydrobenzoins by means of PBr,. It consists of silky 
needles, melting at 237°. Alcoholic potassium hydroxide converts it into brom- 
stilbene, (C,H,),C,HBr (melting at 25°), and then into tolane. 

With chlorine, stilbene (in chloroform solution) yields a-Stilbene Chloride, \ 
(C,H,),C,H,Cl,, which is also obtained from hydro- and isohydrobenzoin with 
PCl,. It melts at 192°. $-Stilbene Chloride is produced at the same time 
from hydrobenzoin. It melts at 93°, and after heating to 200°, yields the a-com- 
pound on crystallizing (Anmalen, 198, 131). 

The action of alcoholic potash upon o-nitrobenzyl chloride (p. 584) gives rise 
to two alloisomeric o-Dinitro-stilbenes, (C,H,.NO,),.C,H,, melting at 126° 
and 127°. The first is the maleinoid or cis variety, while the second represents 
the ¢rans-form (Berichte, 21, 2071; 23, 2073). g-Nitrobenzyl chloride also 
yields two alloisomeric p-Dinitro-stilbenes ( Berichte, 23, 1938). The principal por- 
tion of the product melts at 250° (280°), and upon reduction yields 4/-Diamido- 
stilbene, H,N.C,H,.C,H,.C,H,.NH,, melting at 227°. It can also be obtained 
from f-nitrotoluene by the action of caustic soda and further reduction with stan- 
nous chloride (Berichfe, 19, 3238). It combines similarly to benzidine with the 
naphthol sulphonic acids, forming substantive blue azo-dyes (Berichte, 22, Ref. 


3II). 


886 ORGANIC CHEMISTRY. — 


Tolane, C,,H,,— C,H;.C=C.C,H;, Diphenyl Acetylene, is pro- 
duced from stilbene bromide on boiling with alcoholic potash. It 
is easily soluble in alcohol and ether, and consists of large crystals, 
melting at 60°. Chromic acid oxidizes it to benzoic acid. 


Two tolane dichlorides, C,,H,,Cl,, result on conducting.chlorine into tolane 
(in chloroform solution). They can also be prepared by reducing tolane tetra- 
chloride with iron and acetic acid (Berichte, 17, 1165, 833); the a- melts at 143°, 
the 8- at 63°. The first is supposed to be the plane symmetrical, maleinoid form, the 
second the fumaroid form (Aumadlen, 248, 18). Tolane also yields two dibro- 
mides, C,,H,)Br,, with bromine, the a-variety melting at 208°, the £- at 64°. 
Both regenerate tolane on.treatment with alcoholic potash. 

Tolane Tetrachloride, C,,H,9Cl,, is produced from chlorobenzil (p. 889) 
with PCl,, by chlorinating toluene (together with C,H,.CCl,) and by heating 
C,H,.CCl, with copper. It consists of brilliant crystals, which become porce- 
lanous at 100° and melt at 163°. Heated with sulphuric acid to 165°, or glacial 
acetic acid to 200°, it yields benzil. 





Hydrobenzoins, C,,H,,O, = C,H;.CH(OH).CH(OH).C,H,. 
Toluylene Glycols. ‘Two isomeric bodies—hydrobenzoin and iso- 
hydrobenzoin—are produced when zinc and alcoholic hydrochloric 
acid act upon oil of almonds, or when the latter is treated with 
sodium amalgam. Both are also obtained from stilbene bromide 
or chloride, on converting the latter by silver acetate or benzoate 
into esters, and saponifying these with alcoholic ammonia. With 
potassium acetate, isohydrobenzoin is almost the sole product. 
Hydrobenzoin predominates (with a little isohydrobenzoin) when 
. sodium amalgam acts on benzoin. This is also the best method for 
its preparation (Annalen, 248, 36). 


PBr, converts both into the same stilbene bromide (melting at 237°); and with 
PCI, both yield a-stilbene chloride (the -chloride is also produced from hydro- 
benzoin). Chromic acid oxidizes both to bitter-almond oil and benzoic acid, but 
with nitric acid benzoin and benzil are the products. All these reactions prove 
that the two hydrobenzoins possess the same structural formula (see 4zna/en, 198, 
191), and that relations analogous to those observed with the dialkyl succinic 
acids, the tolane chlorides, etc., are also present here. Stereochemically considered 
hydrobenzoin is the fumaroid, and isohydrobenzoin the malenoid form (Azza/en, 
258, 186). 

Tidrstcnivin dissolves with difficulty in water, is readily soluble in alcohol, 
crystallizes in large, shining, rhombic plates, melting at 134° and sublimes without 
decomposition. The diacetate, C,,H,,(O.C,H,O),, is obtained from benzaldehyde 
and acetyl chloride by means of zinc dust; it consists of large prisms, melting at 
134°. Diphenyl aldehyde (p. 861) and hydrobenzoin-anhydride, (C,H, ),C,H,O, 
melting at 132° (see Aznalen, 258, 186), are produced when hydrobenzoin is 
boiled with sulphuric acid (20%). 

Lsohydrobenzoin is more easily soluble in water than the preceding isomeride. 
It crystallizes in shining, four-sided prisms which contain water of crystallization, 


BENZOIN. 887 


and rapidly effloresce on exposure. It crystallizes from alcohol in an anhydrous 
form, and melts at 119.5°. Its déace¢ate is dimorphous, and crystallizes in shining 
leaflets, melting at 118°, or in rhombic prisms melting at 106°. Isohydrobenzoin, 
boiled with sulphuric acid, yields its anhydride, (C,H,;),C,H,O, melting at 
102° (together with a little diphenyl aldehyde). 


Benzoin, C,,H,,0, = C,H;.CH(OH).CO.C,H;, a ketone alco- 
hol, is produced when hydro- and isohydrobenzoin are oxidized 
with concentrated nitric acid, and by the action of potassium 
cyanide upon benzaldehyde in alcoholic solution (Berichte, 21, 
1296) :— 

9°) C,H,.CH.OH 

2C,H,.CHO = 
C,H,.CO 


All aromatic aldehydes afford the latter reaction; this is also true of furfurol 
(p. 524). It is analogous to the condensation of the ketones to pinacones 
(p. 202) and to the conversion of aldehydes into alcohols and acids by alcoholic 
potash. The products are termed Jenzoins, and are capable of reducing Fehling’s 
solution, even at ordinary temperatures, when they are oxidized to benzils 
(diketones). 

Benzoin dissolves with difficulty in water, cold alcohol and ether; it crystallizes 
in shining prisms, and melts at 134°. Nascent hydrogen converts it into hydro- 
benzoin. When its alcoholic solution is digested with phenylhydrazine it forms 
the hydrazone, C,,H,,O(N,H.C,H,), melting at 155°. When oxidized with 
chromic acid, it breaks up into benzaldehyde and benzoic acid. Hydrobenzoin 
and benzil (along with benzilic acid) are produced on boiling with alcoholic 
potash :— ; 

C,H,.CH.OH C,H,;.CH.OH C,H;.CO | 


Besa = +f 
C,H,.CO C,H,.CH.OH  C,H,.CO 


Benzoin. Hydrobenzoin. Benzil. 


Anisoin, from anisic aldehyde, and cuminoin, from cumin aldehyde, are very 
similar to benzoin, and yield perfectly analogous derivatives (desoxybenzoins, 
benzils and benzilic acids) (Berichte, 14, 323). CSCI, converts the benzoins into 
beautifully colored compounds, called desaurines (Berichte, 21, 2445). 

Desoxybenzoin, C,,H,,0 = C,H,.CO.CH,.C,H,, phenyl-benzyl ketone, is 
obtained by reducing benzoin or chlorobenzil, C,H;.CO.CCI,.C,H,, with zinc and 
hydrochloric acid; by heating monobromtoluylene with water to 180-190°; by 
distilling a mixture of calcium benzoate and calcium phenyl-acetate :-— 


— = Cg M cue : 

C,H,.CO.OH + C,H;.CH,.CO.OH = CHLCH 7 + CO, + H,O; 
further, when AICI, acts upon a mixture of alphatoluic chloride, C,H;.CH,.CO.Cl 
and benzene (Berichte, 19, 1064); and most easily by the reduction of ben- 

zoin with zinc and hydrochloric acid (Berichte, 21, 1296). 

Phenyl-benzyl ketone crystallizes from alcohol in large plates, melting at 60° 
and boiling at 314°. One H-atom of its CH,-group can be replaced by sodium 
and alkyls, but not the second (Berichte, 21, 1297 ; 23, 2071). Nitrous acid, or 
amyl nitrite, converts it into zsonitroso-desoxybenzoin, melting at 135°, and identi- 
cal with benzil monoxime (see below), It forms an oxime, melting at 98°, with 
hydroxylamine. Bromine converts desoxybenzoin into Desylbromide, (C,H;), 
C,HBrO, melting at 55° (Berichte, 21, 1355). It yields dibenzyl when heated 


888 ORGANIC CHEMISTRY. 


with hydriodic acid. Sodium amalgam converts it into toluylene hydrate, C,,H,,0 = 
C,H;.CH(OH).CH,.C,H,, melting at 62°. Nitric acid again oxidizes it to desoxy- 
benzoin. See Berichte, 22, 1229, for methyl desoxybenzoins. 


Benzil, C,,H,,O, = C,H;.CO.CO.C,H;, Dzbenzoyl, an a-dike- 
tone, is produced in the oxidation of benzoin with chlorine ; and by 
heating toluylene bromide with water and silver oxide (together with 
toluylene). It crystallizes from ether in large, six-sided prisms, 
melting at go° and boiling at 347°. 


Benzil-dihydrazone, (C,H;),C,(N,H.C,H;)., is produced on digesting phenyl- 
hydrazine hydrochloride and benzil. It melts at 225° (Anma/len, 232, 230). It 
forms triphenyl-osotriazone when heated to 210° (p. 553). An isomeric dihydra- 
zone has not been prepared (Berichte, 21, 2806). 

One molecule of hydroxylamine, acting upon benzil, produces two alloisomeric 

C,H;.CO . 
benzil-monoximes, aif , the a- melting at 138°, and the y- at 114°. 
C,H;.C:N.OH 

The former passes into the latter by heating it to 100° with alcohol, or upon dis- 
solving it in glacial acetic acid with hydrochloric acid. a-Monoxime and hydroxyl- 
amine form a-benzil dioxime, while the y-monoxime yields y-benzil dioxime. The 
expected 6-benzil monoxime has not been discovered (Berichie, 22, 540, 700). 
See Berichte, 22, 1998, for the benzyl ethers of the benzil monoximes. 

Two molecules of hydroxylamine convert benzil into two alloisomeric benzil 

C,H,.C:N.OH 
dioximes, | , the a- melting at 237°, and the £- at 207°. A third 
C,H, .O:N.OH 
y-benzil dioxime has been prepared from 6-benzil monoxime and hydroxylamine 
(see above); it melts below 100°, loses its water of crystallization, and then re- 
melts at 164—166°, passing at the same time into the B-dioxime (Berich/e, 22,709). 
When the three dioximes are heated to 100° with hydrochloric acid, they are re- 
solved into 2NH,.OH and benzil. They yield three different diacidyl esters with 
acid anhydrides. By elimination of water they all form the same anhydride, 
(C,H;).C,N,O, melting at 94°. Potassium ferricyanide, in alkaline solution, oxid- 


izes all three to the same oxide, (C,H ieee melting at 114°; when rap- 


idly distilled, it becomes phenyl-cyanate. Carbanilido-derivatives are produced 
by the union of the three benzil dioximes with phenyl-cyanate Gteag 22, 3111). 
Glacial acetic acid and hydrochloric acid acting upon (-benzil dioxime rearranges 
it to oxanilide, C,H,.NH.CO.CO.NH.C,H, (see benzophenoxime, p. 858), 
whereas a-benzil dioxime yields dibenzenyl azoxime (p. 718) (Berichie, 22, Ref. 
2). 
Har peaching theories, based on van’t Hoff’s ideas have been proposed to ex- 
plain the differences in the three structurally identical benzil dioximes (Berichée, 
21, 946, 3510; 22, 705); but they have proved insufficient (Berichte, 23, 2405). 
At the present writing the inclination is to refer the isomerism tothe nitrogen atom 
of the hydroxylamine (p. 719). It has been attempted to construct theories of 
great import upon very few facts.* Chromic acid oxidizes it to benzoic acid. 
When benzil is allowed to stand for some time, with alcohols and some potas- 
sium cyanide, it sustains a decomposition into benzoic ester and benzaldehyde, 
which further changes to benzoic acid. Furil, but not isatin, reacts similarly. 





* « Hypotheses non fingo,”’—Vez¢on. 


DIBENZYL CARBOXYLIC ACID. 889 


When digested with PCI, benzil yields chlorobenzil, C,H,.CO.CCI,.C,H,, 
melting at 61°. Benzil, when heated with alcoholic potash, is converted into ben- 
zilic acid (p. 862). In this case a molecular rearrangement takes place similar to 
that observed with the pinacones. 

Isobenzil, C,,H,,O,, is isomeric with the preceding, and is obtained from ben- 
zoyl chloride, C,H,.CO.Cl, in alcoholic solution, by means of sodium amalgam. 
It forms, in distinction to benzil, w7¢e needles, melting at 156° and boiling at 314°. 
It forms $-benzil dioxime with hydroxylamine (Berichie, 21, 808). 

Anisil, (CH,.0.C,H,4),C,O,, from anisoin and cuminil, (C,H ,.C,H,),C,0,, 
from cuminoin (above), behave like benzil. When they are boiled or fused with 
caustic potash, they afford amistlic acid, (CH;.0.C,H,),C(OH).CO,H, and 
cuminilic acid, (C,H ,.C,H,),C(OH).CO,H. Anisil forms two dioximes with 
hydroxylamine (Berichte, 22, 372). 

Pinacones and Pinacolines, 

Nascent hydrogen, acting on the benzo-ketones, converts them, through a con- 
densation of two molecules, into the Azmacones (together with slight quantities of 
the secondary alcohols), which are also bivalent alcohols (glycols). In this 
behavior they resemble the ketones of the fatty series (p. 202). From benzo- 
phenone we get benzhydrol (p. 857) and benzpinacone :— 

Y 


(C,H,),C.OH 
(C,H,),CO yields (C,H,),CH.OH and 
Benzophenone. Benzhydrol. (C, H ; ) ,C.OH 
Benzpinacone. 


These pinacones, just like those ofthe fatty series, readily part with water (by 
heating with sulphuric or hydrochloric acid, or by the action of all reagents, which 
otherwise act upon hydroxyl—acetyl chloride, hydriodic acid and PCI,) and by an 
atomic rearrangement become pinacoline ketones :— 


(C,H,;),-C.0H 
. yields (C,H,),C.CO.C,H, + H,O. 
(C,H;),.C.0H Benzpinacoline. 


An analogous change occurs in the conversion of benzil into benzilic acid (see 
above), and of phenanthraquinone into diphenylene glycollic acid (p. 851). There- 
fore, the conception of the pinacone bodies may be further extended to all alco- 
hols having two adjacent OH-groups (comp. Ammalen, 198, 144). 

Benzpinacone, C,,H,,O,, formed from benzophenone by the action of zinc 
and sulphuric acid (Berichte, 14, 1402), crystallizes from alcohol in shining, small 
prisms, melting at 185° and splitting into benzophenone and benzhydrol. It sus- 
tains a like change when boiled with alcoholic potash. 

On heating benzpinacone with hydrochloric or dilute sulphuric acid to 200°, 
by the action of methyl chloride upon it, or of zinc dust and acetyl chloride upon 
benzophenone, we get two 

Benzpinacolines, C,,H,,O—the a-, melting at 205°, the 3-variety, at 179° 
(Berichte, 17,912). Both decompose into triphenyl methane, (C,H,),CH, and 
benzoic acid, on boiling with alcoholic potash. 





Carboxyl Derivatives. 

C,H,.CH, 

Dibenzyl Carboxylic Acid, : , Benzylphenyl Acetic Acid, re- 
: C,H,;.CH.CO,H 

sults upon introducing benzyl into benzyl cyanide, etc. It melts at 91°, and boils 

about 335° (Berichte, 21, 1315). 


890 ORGANIC CHEMISTRY. 


Diphenyl Acrylic Acid, a-Phenyl Cinnamic Acid, C,H,.CH:C(C,H,). 
CO,H, formed by the condensation of phenyl-acetic acid, C,H,.CH,.CO,H, 
with benzaldehyde, melts at 170°. Sodium amalgam converts it into dibenzy] 
carboxylic acid. 

o-Benzil Carboxylic Acid, C,H,.CO.CO.C, H,.CO,H, exists in two alloiso- 
meric forms, resulting from the oxidation of desoxybenzoin carboxylic acid. The 
yellow colored modification melts at 141°, the whzfe at 125-130°. Both afford 
the same ethyl ester, and the same monoxime (melting at 160°) (Berichde, 23, 
1344, 2079). 

o-Desoxybenzoin Carboxylic Acid, C,H,;.CH,.COQO.C,H,.CO,H, may be 
obtained by boiling benzylidene phthalide with alkalies. It crystallizes with one 
molecule of water, and melts at 75°. The corresponding lactone, Benzylidene 

OW, a is 
Phthalide, C,H Ro Dh (see p. 352), results from the condensation of 
‘coo 
phthalic anhydride with phenyl-acetic acid (Berichte, 18, 3470). It melts at 99°. 
It forms salts of desoxybenzoin carboxylic acid when boiled with alkalies. 


Dicarboxylic Acids. 

Diphenyl-succinic Acid, C,,H,,0,, Dibenzyl-dicarboxylic Acid, occurs, 
similarly to the dialkyl succinic acids (p. 419) and hydrobenzoin, in two alloiso- 
meric forms. The a-actd is produced on heating phenyl-bromacetic acid with 
alcoholic CNK (Berichte, 23, 117), also (together with the f-acid), from the 
anhydride of stilbene dicarboxylic acid (Berichte, 14, 1802; Annalen, 259, 61). 
Its dinitrile, (C,H,;).C,H,(CN),, is obtained from phenyl-brom-acetonitrile with 
potassium cyanide. The acid crystallizes from water in prisms, containing one 
molecule of water, melts at 185° when rapidly heated, loses water and remelts at 
220°, When heated to 200° with hydrochloric acid it changes to the f-acid. Its 
anhydride, melting at 116°, is readily produced by means of acetyl chloride. 

The isomeric 8-Dibenzyl-dicarboxylic Acid is produced from the anhydride 
of stilbene dicarboxylic acid: with sodium amalgam; and from dicyan stilbene, 
(C,H,;),C,(CN),, when heated with sodium amalgam or when heated with 
hydrochloric acid. It is insoluble in water and melts at 229°, when it yields 
water and the anhydride of the a-acid. It also yields the azhydride (but with 
more difficulty) when heated with acetyl chloride (Berichte, 23, Ref. 574, 646). 
It melts at 112°, ; 

U1, .0.COLN 
Stilbene Dicarboxylic Acid, C,,H,,O, = | , if separated from 
C;H,-C.CO,H 
its salts, at once decomposes into water and its anhydride, melting at 155°. The 
nitrile, (C,H,;),C,(CN),, dicyanstilbene, is derived from phenyl-brom-acetic nitrile, 
C,H;.CHBr.CN (Berichte, 14, 1797), with alcoholic potassium cyanide. It 
melts at 158°. It passes into salts of stilbene dicarboxylic acid when boiled with 
alkalies. 

Diphthalyl Acid, HCO,.C,H,.CO.CO.C,H,.CO,H, 0o-Benzil-dicarboxylic 
Acid, from diphthalyl by oxidation, or by the action of zinc dust and acetic acid 
upon phthalic anhydride and further oxidation (Berichte, 21, Ref. 7) is only 
known in a single white modification (see benzylic acid), melting at 270°. It 
however, yields two series of dialkyl esters, white and yellow colored (Berichie, 
23, 1347, 2080). It forms the anhydride, C,,H,O;, when heated to 200° with 


acetic anhydride; it melts at 165°. When heated with hydriodic acid it is reduced 
. Cig YS = CCAS : : 
to Diphthalyl, Occ 0 Retz <0 4500, which may be obtained by the 


condensation of phthalic anhydride with phthalide (p. 772), aided by sodium 
acetate. It melts at 334° (Berichte, 19, Ref. 695). 


ft 


DIPHENACYL, DIBENZOYL ETHANE. ; 89 I 


Tetraphenyl Ethane, C,,H,, — (C,H,),CH.CH(C,H,),, is obtained from 
benzophenone by heating with zinc dust (along with diphenyl] methane and tetra- 
phenyl-ethylene) ; from benzpinacone and benzpinacoline with hydriodic acid and 
phosphorus; from benzhydrol chloride, (C,H,),CHCI, by the action of zinc; from 
tetraphenyl ethylene by sodium and alcohol, and from tetrabromethane or stilbene 
bromide by means of benzene and AICI, (Berichte, 18, 657). It crystallizes from 
acetic acid or benzene in large prisms, melting at 209°. 

Tetraphenyl Ethylene, C,,H,, = (C,H;),C:C(C,H,;),, formed together 
with tetraphenyl ethane, from benzophenone, is also obtained on heating benzo- 
phenone chloride, (C;H;),CCl,, with silver. It crystallizes from benzene in fine 
needles, melting at 221°. Both hydrocarbons are split into two molecules of 
benzophenone when oxidized. 

(C.H,),C.CN 
Tetraphenyl Ethylene Cyanide, - _, is obtained from dipheny]l- 
(C,H,),C.CN 
acetic nitrile (p. 861) by means of metallic sodium and iodine (erichie, 22, 
1227). Its acid, tetraphenyl-succinic acid, (C,H,),C,(CO,H),, has been ob- 
tained from diphenyl chloracetic ester and melts at 261°. 





Derivatives, containing benzene nuclei linked by a chain of three or four carbon 
atoms, are :— 

Dibenzyl Ketone, (C,H,.CH,),CO, produced on distilling calcium alpha- 
toluate; it melts at 30° and boils at 320°. It forms an oxime with hydroxy- 
lamine, melting at 119°. One hydrogen atom of each of the two CH ,-groups can 
be replaced by alkyls (Berichte, 21, 1317). When reduced with hydriodic acid it 
forms Dibenzyl methane, (C,H,.CH,),CH,, boiling at 290-300°, 

Dibenzoyl Methane, (C,H; CO),CH,, is formed upon boiling dibenzoyl acetic 
acid with water. It crystallizes in large plates, melting at 81°, and distilling without 
decomposition (Berichte, 20,655). The rearrangement of its isonitroso derivative, 
(C,H;.CO),C:N.OH, or its bromide, results in the production of 

Diphenyl Triketone, C,H;.CO.CO.CO.C,H;. A brown oil, boiling at 289° 
(175 mm. pressure). It solidifies to a golden yellow mass, melting at 70°. In the 
air it combines with water to a colorless hydrate (Berichte, 23, 3378). 

Tribenzoyl Methane, (C,H;.CO).CH, obtained from dibenzoyl methane and 
benzoyl chloride with sodium ethylate, melts at 225°. It does not possess acid 
properties (see dibenzoyl acetone (p. 731) (Berichte, 21, 1153). 

Dibenzyl Acetic Acid, (C,H;.CH,),.CH.CO,H, is derived from dibenzoyl- 
malonic acid. It melts at 87°, and is insoluble in water. Its #z¢ri/e melts at 90°; 
its Cll-group cannot be substituted (Perichie, 2, 1328). 

Dibenzyl Glycollic Acid, C,,H,,0,; = (C,H,.CH,),C(OH).CO,H, Oxa- 
tolylic Acid, is produced from dibenzyl ketone by means of CNK and hydro- 
chloric acid, and when vulpic and pulvic acids are boiled with dilute alkalies. It 
is almost insoluble in water, and crystallizes from alcohol in prisms, melting at 
156°. When boiled with concentrated potassium hydroxide it decomposes into 
oxalic acid and two molecules of toluene (Annaden, 219, 41). 

Dibenzoyl Acetic Acid, (C,H,.CO),CH.CO,H (p. 765), breaks down into 
dibenzoyl methane. 





C,H,.CO.CH, 
Diphenacyl, | - , Dibenzoyl Ethane, is produced by the decom- 
C,H,.CO.CH, 
position of phenacyl-benzoyl acetic ester (p. 765). It consists of needles, melting 
at 145° (Berichte, 21, 3056). Being a y-diketone it can eliminate water and yield 


892 ORGANIC CHEMISTRY. 


diphenylfurfurane, and with P,S, form diphenylthiophene, and with ammonia 
diphenylpyrrol (p. 731). 
C,H,:COCH.C,H,; 
Bidesyl, | , dibenzoyl-diphenyl ethane, results when desyl- 
Celi, O-CH.C,H, 
bromide acts upon sodium desoxybenzoin (p. 887). It crystallizes from hot 
benzene, in needles, melting at 255°. /sod¢desy/, formed simultaneously, melts at 
161° (Berichte, 21,1355). Bidesyl is identical with hydro-oxy-lepidene. Bidesy] 
and isobidesyl, being y-diketones, form tetraphenyl pyrrol (p. 543) when heated 
with ammonia. Concentrated hydrochloric acid converts them into tetraphenyl 
furfurane, C,(C,H,),O (p. 524) with lepidene ( Berichte, 22, 855, 2880). 
C,H,;.CO.CH.CO,H 
Dibenzoyl Succinic Acid, C,,H,,O, — | . Its diethyl 
C,H,;.CO.CH.CO,H 
ester is obtained from sodium benzoyl acetic ester (p. 763) by the action of iodine, 
just as we form di-aceto-succinic ester from aceto-acetic ester. On boiling the 
ester with dilute sulphuric acid we get (by saponification and elimination of 
water) its anhydride the momo-/actone C,,H,,O, (corresponding to carbopyro- 
tritartaric acid), which very probably represents diphenyl-furfurane dicarboxylic 
ester. 

Vulpic Acid,C,,H,,O,, is intimately related to dibenzyl acetic acid, and oc- 
curs in the lichen Cetraria vulpina and in a certain moss (12 per cent.), from 
which it may be extracted by chloroform or lime water. It is sparingly soluble 
in water and ether, crystallizes from alcohol in yellow prisms, melting at 110° and 
subliming. When boiled with lime water it is converted into methyl alcohol and 
pulvic acid, C,,H,,0,;. The latter melts at 214°, and when boiled with alkalies 
yields 2CO, and dibenzyl glycollic acid. When boiled with ammonia and zinc 
dust it forms Hydrocornicularic Acid, C,,H,,0O,. This breaks down into toluene 
and phenyl succinic acid when heated with caustic potash (Berichte, 14, 1686). 

Diphenacyl Malonic Ester, (C,H;.CO.CH,)C(CO,R),, is produced by the 
interaction of acetophenone bromide and sodmalonic ester. The free acid loses 
carbon dioxide and forms Diphenacyl Acetic Acid, (C;H,.CO.CH,),CH.CO,H, 
which by the action of ammonia and the production of a closed ring by the group 
CO.CH,.CHR.CH,.CO, yields diphenyl pyridine carboxylic acid. 





ANTHRACENE GROUP. 


The members of this group contain two benzene nuclei, joined 
to each other by two doubly united carbon-atoms. In each ben- 
zene nucleus two ortho-positions are occupied. Therefore, we may 
designate them D¢ortho-diphenylene Derivatives (p. 850) ; usually, 
however, their names are derived from anthracene, from which 
they were first obtained :— 


CH, CG CH 
Roe et Grn ie ee SC Ce” SClH 
6 cH .* of 4 6 en aie A 6 aX Ly” 6°" 4 
Diphenylene Dimethylene Diphenylene Diketone Anthracene. 
Hydranthracene. Anthraquinone. 


Hydranthracene passes readily into anthracene by the loss of two 
hydrogen atoms; whereby we may suppose a mutual union of the 


ANTHRACENE GROUP. 893 _ 


two methane carbons takes place. ‘Therefore, anthracene is mostly 
formed by its synthetic methods. Of the numerous syntheses of 
anthracene and diphenylene derivatives, analogous to those of the 
diphenyl methane derivatives (comp. p. 852), only such will be 
noticed, as are necessary for the establishment of the constitution 
of the compounds. 


Hydranthracene is obtained from ortho-brom-benzyl bromide, C,H, Br.CH, Br, 
by the action of sodium upon the ethereal solution; the bromine atoms of two 
molecules are withdrawn, and the residues combine (Berichte, 12, 1965) :— 


CH, Br Br CH, 
c Oe ig tl TCs H, + 4Na = CHC CH? piae H, ++ 4NaBr; 
Two molecules. a- ~Brombenzyl- Hidranthrneene. 
bromide. ‘ 


at the same time two hydrogen-atoms separate from the hydranthracene and large 
quantities of anthracene are produced. 

Anthracene is likewise obtained (together with toluene) from benzyl chloride, 
on heating it with aluminium chloride :— - 


ie ae 
3CgH,.CH,.Cl= C,H,¢ | C,H, + CoH,.CH, + 3HC, 
CH 


or with water to 200°, when dibenzyl will also be produced :— 
4C,H,.CH,Cl = C,,H,, + (C,H,;.CH,), + 4HCl. 
Anthracene (together with diphenyl methane) results also from the action of 
AICI, upon benzene and CH,Cl, (2 molecules). 


A noteworthy synthetic method is that from benzene and symmetrical tetrabrom- 
methane with AICI, (Berichte, 16, 623) :— 


BrCHBr 
CH,+ | +H, =C,Hy 
BrCHBr 


Kd " SC H, + 4HBr. 


Dimethylanthracene hydride, C,H AG CH, Ne, H,, is similarly formed 
y x 4\ CH(CH,) the 4 y 


from benzene and ethidene chloride or bromide. 
The formation of anthraquinone. or diphenylene diketone from phthalic chloride 
and benzene, by heating with zinc dust to 200°, is very evident :— 


Coc soo, 
CoH = + C,H, = CHK poole + 2HCl; 


as well as its production from ortho-benzoyl benzoic acid when the latter is heated 
with phosphoric anhydride (Berichte, 7, 578) :— 


CO.C,H, CO 

C.H.Z = CH 7 een + A: 
*\.c0.0H ae es + Hy, 

and by the distillation of calcium phthalate. In this manner the homologous 

alkyl anthraquinones are obtained from the homologous o-benzoyl benzoic acids. 
o-Benzoyl benzoic acid is directly converted into anthracene upon heating it 

with zinc dust, and o-toluyl benzoic acid (p. 864) yields 6-methyl anthracene 

(Berichte, 19, Ref. 686). 


894 : ORGANIC CHEMISTRY. 


Again, when o-tolyl-phenyl ketone, CHC Or C,H 5 (p- 862), is heated 
with lead oxide, anthraquinone is produced. If zinc dust be employed anthra- 
_ cene results. In the same manner anthracene is formed from orthotolyl-phenyl 
methane, C,H,(CH,).CH,.C,H,, and methyl anthracene, etc., from o-ditolyl- 
methane, C,H,(CH,).CH,.C,H,.CHsg, etc. (Berichte, 23, Ref. 198). 

It follows from all these syntheses (by means of ortho-derivatives of benzene), 
that in one of the benzene nuclei of anthracene and its derivatives, the two carbon- 
atoms are inserted in the ortho-position; that this is true, too, of the second nucleus 
is inferred from the production of anthracene and its hydride from o-brom-benzyl 
bromide (p. $93); also from the behavior of oxanthraquinone, C,H,.(CO),C, Hs. 

H, which is synthesized from brom-ortho-benzoyl benzoic acid, C,H,;.CO. 
C,H,Br.CO,H (from brom-phthalic acid), and when oxidized (the second 
benzene nucleus being destroyed) yields phthalic acid, C,H,(CO,H), (Berichie, 
12, 2124). 

Fe a anthracene and its derivatives possess a symmetrical constitution, 
corresponding to the symbols :— 


8 I 8 I 
Sees PZ OMS 
oe ee 
NHN” RU et 
4 


Anthracene. Anthraquinone, 


in which the numbers designate the eight affinities of the two benzene nuclei. 
The positions I, 4, 5, 8 are alike, also 2, 3, 6,7; the former (as with naphthalene, 
see this) are called the a-, the latter the 6-positions. We conclude, then, that if 
one hydrogen atom of the benzene ring be replaced two isomeric mono-derivatives 
(a and £) of anthracene and anthraquinone can be formed; whereas by the 
entrance of two similar substituting groups ten isomeric di-derivatives result 
(p. 898). By the replacement of the middle hydrogen atoms of anthracene other 
isomerides are obtained, which have been termed y-derivatives or meso-derivatives 
( Berichte, 18, 690). 

The two intermediate carbon atoms of anthracene form, with two carbon atoms 
from each of the two benzene nuclei, a closed chain consisting of six carbon atoms. 
It resembles the ring of benzene. Hence anthracene is included among the con- 
densed benzenes (see naphthalene). In most of the transformations of anthracene 
the intermediate carbon atoms are first attacked. 





Anthracene, C,,H,, is formed, in addition to the syntheses 
given, from many carbon compounds when they are exposed to a 
high heat, and for that reason it is produced in larger quantities in 
coal-tar. 


Pure anthracene is obtained from the commercial product (boiling at 340-360°) 
by crystallization from hot xylene and alcohol, or by extraction with acetic ester 
or carbon disulphide (Azna/en, 191, 288); but better by crystallization from pyri- 
dine (Berichte, 21, Ref. 75). Or, hydranthranol is first obtained from anthraquinone 
(p. aie and then boiled with water ( Journ, prac. Chemte, 23, 146; Berichte, 18, 
3934). 


ANTHRACENE. 895 


Anthracene crystallizes in colorless monoclinic tables, showing a 
beautiful blue fluorescence. It dissolves with difficulty in alcohol 
and ether, but easily in hot benzene. It melts at 213°, and 
distils above 360°. Picric acid in benzene solution unites with 
it, yielding C,,H,).2C,H,(NO,),O, crystallizing in red needles, and 
melting at 170°. 


When the cold saturated solution of anthracene in benzene is exposed to sun- 
light, a modification of anthracene, Para-anthracene, C,,H, 9, separates out in 
plates. It dissolves with difficulty in benzene, is not attacked by nitric acid or 
bromine, melts at 244°, and in so doing reverts to common anthracene. 

Anthracene Dihydride, C,,H,,, results from the action of sodium amalgam 
upon the alcoholic solution of anthracene. It melts at 107°, and boils at 305°. 
When heated with hydriodic acid and amorphous phosphorus to 220° Anthra- 
cene hexahydride, C,,H,,, results. It melts at 63°, and boils at 290°. Anthra- 
cene perhydride, C,,H,,, is another. precict It melts at 88°, and boils at 
270° (Berichte, 21, 2510). 

Mono- and di-halogen anthracenes are obtained when chlorine and bromine 
act upon anthracene (in CS, solution). The two middle carbon atoms are substi- 
tuted. Nitroanthracene could not be obtained. Nitric acid (concentrated and 
diluted, and also in alcoholic solution) oxidizes it to anthraquinone and dinitro- 
anthraquinone. 

$B-Amido-anthracene, C,,H,.NH,, called anthramine, is formed on heating 
B-anthrol (see below) with alcoholic ammonia to 170°. It forms yellow leaflets, 
melting at 237°. Meso-amido-anthracene, C,H,(C,H.NH,)C,H,, is pre- 
pared by heating anthranol with ammonia. Golden yellow leaflets, decomposing 
at 115° (Berichte, 23, 2523). 

When anthracene is dissolved in sulphuric acid two Disulphonic Acids, 
C,,H,(SO,H), (a and), are produced. These, fused with caustic potash, yield 
two dioxy- -anthracenes and also the corresponding sale Seat cacge tee 


Oa C,,H,.OH :— 


CH ySOH) 
wey NC. HOH and CH. 7 Nc, Hy. 
Noles / st43 an 6 *\ da | es 

Anthrol. eee 


Two isomeric compounds (a and #) correspond to the first formula; they are 
phenols and are called anthro/s. -Anthrol has been obtained from anthracene- 
sulphonic acid (from $-anthraquinone sulphonic acid) and by the reduction of 
oxyanthraquinone. It crystallizes in leaflets, dissolving with a yellow color in the 
alkalies, and in sulphuric acid with a blue color when heated. After the intro- 
duction of the acetyl group in OH (compare oxidation of phenols, p. 686) chromic 
acid and acetic acid oxidize it to oxyanthraquinone. 

Anthranol has the second formula; it is produced by the careful reduction of 
anthraquinone with tin and acetic acid (Berichie, 20, 1854). It crystallizes from 
alcohol in shining needles, melting with decomposition at 165°. Chromic acid 
oxidizes it to anthraquinone, Hydroxylamine converts it into anthraquinone oxime 
(Berichte, 20, 613). For additional derivatives see Berichte, 21, 1176. 

The reduction of anthraquinone with zine dust yields 


'/ CH(OH)\, / CH(OH)\, 
Hydranthranol, CoH,C (Gly) CoH, and C,H, ¢ “(GT €.He 


896 ORGANIC CHEMISTRY. 


Oxanthranol. These form a/ky/ compounds with caustic potash and the alkylo- 
gens (Berichte, 18, 2150) :— 


CR(OH ‘ CR(OH 
CHR GH. Coe amd CHAK ONG) DCH. 
Alkyl Hydranthranols. Alkyl-oxanthranols, 


The former, when boiled with hydrochloric acid, part with water and yield 


Kd, CoHas the latter are also reduced to alkyl 
anthracenes by zinc dust, but with hydriodic acid to alkyl anthra-hydrides, 

CRH 
CoHAC CH. SC.Has etc. (Annalen, 212, 67). 

Derivatives of anthranol, in which the hydrogen of the CH-group is replaced 
by phenyls, are the so-called phthalidins and appear on mixing the triphenyl-car- 
boxylic acids with sulphuric acid (p. 880). When oxidized they pass into phenyl- 
oxanthranols, CHC Gp, CoH. (the phthalideins) and yield phenyl 
anthracene (p. 901), if ignited with zinc dust. Phenyl anthranol resembles 
anthranol, and melts at 141-144°. Benzyloxanthranol is described in Berichie, 
23, 2527. 

Dioxyanthracenes, C,,H,(OH),. Of the ten possible isomeric diphenols 
(pp. 894 and 898), two with the formula, HO.C,H,.C,H,.C,H,.OH, have been 
derived from the two anthracene disulphonic acids by fusion with caustic potash. 
By oxidizing their acetates with chromic acid (see above) and saponifying, they 
yield the corresponding dioxyanthraquinones; the 6-compound (called chrysazol) 
yields chrysazin, the a-compound (rufol) anthrarufin (p. 900). A third (called 
ftavol) is obtained from /-anthraquinone-disulphonic acid. 


alkyl anthracenes, C,H 





Anthraquinone, C,,H,O, = C,H,.C,O0,.C,H,, Diphenylene di- 
ketone (p. 892), is produced very readily, in addition to the synthetic 
methods given, by oxidizing anthracene, anthrahydride, dichlor- and 
dibrom-anthracene with nitric or chromic acid. We can obtain it by 
adding pulverized potassium bichromate to a hot glacial acetic acid 
solution of anthracene (Amna/en, Sup., 7, 285) or with less expense 
by oxidation with the theoretical amount of a chromic acid mixture. 

Anthraquinone sublimes in yellow needles, melting at 277°, and 
is soluble in hot benzene and nitric acid. It is very stable, and is 
altered with difficulty by oxidizing agents. Sulphurous acid does 
not reduce it (unlike the true quinones, v. p. 698). 


It reverts to anthracene if heated to 150° with hydriodic acid, or with zinc dust 
and ammonia. When fused with potassium hydroxide (at 250°), it decomposes 
into two molecules of benzoic acid; heated with soda-lime it yields benzene and 
a little diphenyl. By its union with one molecule of hydroxylamine it forms an- 
thraquinone-oxime, C, ,H ,O(N.OH), subliming at 200°. 

When anthraquinone is digested with bromine at 100° it becomes Dibrom- 
anthraquinone, C,,H,Br,O,, subliming in yellow needles. It is more easily 
obtained by oxidizing with nitric acid; dichloranthraquinone is similarly formed. 


OXYANTHRAQUINONES. 897 


It yields alizarin if heated to 160° with caustic potash, A monobrom-anthra- 
quinone (3) has been obtained from tribrom-anthracene by oxidation, and melts 
at 187°. 

Dinitroanthraquinone, C,,H,(NO,),0,, is formed (with anthraquinone) 
on digesting anthracene with dilute nitric acid (1 part with 3 parts water). It 
consists of yellow needles or leaflets, melting at 280°, and like picric acid mani- 
fests the property of forming crystalline combinations (Fritsche’s Reagent) with 
many hydrocarbons. The mononitroquinone is obtained when anthraquinone is 
boiled with concentrated nitric acid. It is a light yellow powder, melting at 230° 
(Berichte, 16, 363). Various dyes are obtained from it through the action of sul- 
phurie acid (Berichte, 17, 891). 

Heated to 250-260° with concentrated sulphuric acid anthraquinone yields p- 
Anthraquinone-mono-sulphonic acid, C,,H,O,.SO,H, which crystallizes 
from water in yellow leaflets; fused with ‘potassium hydroxide it forms oxanthra- 
quinone. Protracted heating with 4-5 parts sulphuric acid yields two disul- 
phonic acids, C,,H,O,(SO,H), (aand #). The first may be synthesized by 
heating o-benzoyl benzoic acid (p. 863) with fuming sulphuric acid. Fused with 
potassium hydroxide it yields anthraflavic acid (20H) and flavopurpurin (30H), 
while the second furnishes isoanthraflavic acid (20H) and anthrapurpurin (30H). 
Two isomeric Anthraquinone-disulphonic Acids (y and 4) are obtained from 
the two anthracene-disulphonic acids by oxidation with nitric acid, and if fused 
with caustic potash yield chrysazin and anthrarufin; trioxyquinone is produced si- 
multaneously, together with oxychrysazin and oxyanthrarufin (p. 898). 

Anthraquinone is reduced, when digested with zinc dust and an alkaline a 2 
droxide, to 


Anthrahydroquinone, C,H ae res a H,, which is precipitated in yel- 
\cC(OH ur 
low flakes by hydrochloric acid. If exposed to the air it again oxidizes to anthra- 
quinone, 





The Oxyanthraquinones, corresponding to the phenols, are 
derived by introducing hydroxyl into anthraquinone.. There are 
two mono-oxy-anthraquinones, C,H,.C,O,.C,H;.OH (a and #) and 
ten dioxy-anthraquinones (p. 894); the latter are important as 
dyes. They originate from the brom (chlor) anthraquinones and 
the sulphonic acids on fusion with alkalies, when the substituting 
groups are replaced by hydroxyls. 


By stronger fusion there generally ensues an additional entrance of hydroxyl 
(oxy- and dioxyanthraquinones result from the mono-sulphonic acid); the same 
is true in the fusion of the oxy-quinones—but, as it appears, this is only true for 
those derivatives which contain but one hydroxyl in each benzene nucleus 
(Berichte, 11, 1613). 

The oxyanthraquinones (like anthraquinone) may be synthetically prepared on 
heating poe anhydride with phenols (mono- and poly-valent) and sulphuric 
acid to 150° (p. 881) :— 


CoH, < 6930 4+ C,H,(OH), =C HC 69 >CeH2(OH), 4+ H,0. 
Pyrocatechin (x, 2). Alizarin (1, 2). 


75 


898 ORGANIC CHEMISTRY. 


The di- and tetra-oxyquinones are also produced from the oxy- and dioxyben- 
zoic acids, when heated with sulphuric acid, but it seems only the meta deriva- 
tives are reactive (Berichte, 18, 2142). Metaoxybenzoic acid yields three dioxy- 
anthraquinones :— 


2C,H,(OH).CO,H = HO.CH¢ Go >CoH,- OH + 2H,0. 
Metaoxybenzoic Acid. Dioxyanthraquinone. 


Continued fusion with alkalies causes the oxyanthraquinones to separate into 
their component oxybenzoic acids (same as anthraquinone decomposes into ben- 
zoic acid) and this reaction aids in the determination of the position of the iso- 
merides ( Berichte, 12, 1293). 

Individual hydroxyls in the oxyanthraquinones are reduced by heating the latter 
with stannous chloride and sodium hydroxide (Ammna/en, 183, 216). Heated to 
150-200° with ammonia water single OH-groups are replaced by amide groups ; 
these are further eliminated by diazotizing (Aunalen, 183, 202). All anthra- 
quinones are reduced to anthracene when heated with zinc dust. 

Oxyanthraquinones, C\,H,O, = C,,H,(O,).OH. 

Ordinary Oxyanthraquinone (/3) is obtained from brom-anthraquinone and 
anthraquinone-sulphonic acid, and also from phthalic anhydride with phenol 
(together with erythro-oxyanthraquinone). It crystallizes in sulphur-yellow 
needles, melting at 302°, and sublimes in leaflets. Isomeric erythro-oxyanthra- 
quinone (a) forms yellow needles, melting at 173-180°, and sublimes at 150°. 
Both oxyanthraquinones yield dioxyanthraquinone (alizarin), when fused with 
caustic potash. 


Dioxyanthraquinones, CyHsO, == Cyy4He(O.)(OH),. 

The ten possible isomerides (p. 894) are known. Four of them 
contain the 2OH-groups in one and the same benzene nucleus: 
alizarin (from pyrocatechin) has the structure (2, 2), purpur-oxy- 
anthin is (1, 3), quinizarin (from hydroquinone) is (1, 4); and 
hystazarin is (2, 3). | 

Only those dioxy- and polyoxyanthraquinones possess distinct 
coloring-power, in which the two free hydroxyls occupy the posi- 
tion (1, 2) (Berichte, 21, 435, 1164). Consult Berichte, 19, 2327 
for the spectra of the dioxyanthraquinones. 

1. Alizarin, dioxyanthraquinone (1, 2), is the coloring ingre- 
dient of the root of the madder (Rudia tinctorium), in which it is 
contained as ruberythric acid (identical with morindin from J/o- 
rinda citrifolia). ‘Through the action of a ferment in the madder 
root, ruberythric acid decomposes when boiled with dilute acids or 
alkalies, or by standing with water, into glucose and alizarin :— 


CoH 9,0}, + 2H,O = C,,H,O, + 2C,H,,0¢. 


This decomposition into alizarin and glucose takes place in the madder root 
even when it is allowed to lie exposed to the air for some time. This was the 
basis for obtaining alizarin formerly, and of the application of madder root in 
dyeing. Later, different madder preparations were employed, in which the con. 
version into alizarin was more complete. Thus gerancin was obtained by treating 
madder root with sulphuric acid, which decomposes the ruberythic acid, but does 


OXYANTHRAQUINONES. 899 


not alter the alizarin produced. At present artificial alizarin is employed almost 
exclusively. 


Artificial alizarin was first obtained by Graebe and Liebermann, 
in 1868, when they heated dibrom-anthraquinone with potassium 
hydroxide. It is also produced from dichlor- and monobrom-an- 
thraquinone, from the two oxy-anthraquinones and anthraquinone 
sulphonic acid, by fusion with caustic-potash at 250-270°. At pres- . 
ent it is manufactured on a large scale by these methods. The 
fusion is dissolved in water, the alizarin precipitated by hydro- 
chloric acid and purified by recrystallization or sublimation. Ali- 
zarin also results on heating phthalic anhydride with pyrocatechin 
and sulphuric acid (p. 897). 

Alizarin crystallizes from alcohol in reddish-yellow prisms or 
needles, containing three molecules of water, which escape at 100°. 
It melts at 282°, and sublimes in orange-red needles. It dissolves 
readily in alcohol and ether, and sparingly in hot water. In con- 
centrated sulphuric acid it dissolves with a dark-red color and is 
precipitated by water unchanged. Its diacetate melts at 160°. 

Alizarin is a diphenol, and like the substituted phenols behaves 
asanacid, It dissolves with a purple-red color in the alkalies ; lime 
and barium salts throw out the corresponding salts as blue precipi- 
tates. Alums and tin salts produce red-colored precipitates (mad- 
der lakes) ; while ferric salts form blackish-violet precipitates. 


This property of alizarin yielding colored compounds with metallic oxides is 
the basis of its application in dyeing and cotton printing. The goods are mor- 
danted with alumina (by immersing them in aluminium-acetate, then heating, 
whereby aluminium hydroxide is deposited on the fibres) and then dipped into the 
solution of alizarin; the resulting alizarin-aluminate is fixed by the fibres. In 
dyeing with turkey-red it is customary to mordant the cloth with oil and alum. 


Alizarin-amide, C, 4S en 2, obtained by heating alizarin with water 


to 200°, crystallizes in needles, having metallic lustre, melts at 225° and sublimes, 
Heated with hydrochloric acid to 250°, or by fusion with potassium hydroxide, it 
yields alizarin; when diazotized it changes to oxyanthraquinone (p. 897). 

B-Nitro-alizarin, Cte Go CHINO, )(OH), (2, 2, 3—NO, in 3), 4é- 
sarin-orange, is produced by the action of vapors of hyponitric acid (NO,) upon 
alizarin, or of nitric acid upon the glacial acetic acid solution (Berichte, 12, 584). 
It crystallizes from chloroform in orange-red leaflets with green reflex, and melts at 
244°. It dissolves in alkalies with a violet-red color, and forms lakes. 

It yields phthalic acid when oxidized with nitric acid. Isomeric a-nztro-alizarin 
(1, 2, 4) is obtained by the nitration of diaceto-alizarin. It melts at 195°, and 
passes readily into purpurin. 

$-Amido-alizarin results by the reduction of (-nitroalizarin. Acetic anhy- 
dride converts it into an ethenyl compound, which proves that the amido-group 
occupies an ortho position relatively to a hydroxyl group ees 18, 1666). 

When /-nitro-alizarin is heated with glycerol and sulphuric acid to roo° we 
obtain a/izarin-blue, C\,HgNO,4, a derivative of anthraquinoline (see this) (Berichte, 
18, 447). eee : : : ae 


goo ORGANIC CHEMISTRY, 


Of the alizarin isomerides (p. 897) quinizarin (1, 4), purpuroxanthin (1, 3), 
and hystazarin (2, 3) (erichte, 21, 2501) contain both hydroxyls in one benzene 
nucleus—whereas anthraflavic acid, iso-anthraflavic acid, metabenz- 
dioxyanthraquinone (from m-oxybenzoic acid, p. 897), anthrarufin and chry- 
sazin have the two hydroxyls in the two benzene nuclei. _ 

Chrysazin is obtained from its tetranitro-compound, C,,H,(NO,),(O,)(OH),, 
the so-called chrysammic acid, by reduction and the replacement of the amid- 
groups. ‘This latter acid is obtained when aloés are digested with concentrated 
nitric acid. 


Trioxyanthraquinones, C,,H;O0,(OH);. 
These are produced on oxidizing dioxyanthraquinones or upon 
fusing them with alkalies (p. 897). 


2 

1. Purpurin, CHS cs YCgH(OH), (1, 2, 4), is present with alizarin in 
the madder root, and is. separated from it by a boiling alum solution, which. does 
not dissolve the latter. It is prepared artificially by heating alizarin and quini- 
zarin with manganese dioxide and sulphuric acid to 150°; purpuroxanthin is 
oxidized to purpurin by simply exposing its alkaline solution to the air. It is also 
obtained from tribrom-anthraquinone. Purpurin crystallizes with one molecule 
of water, in reddish-yellow needles or prisms, which, at 100°, lose water and 
then sublime. It dissolves with a pure red color in hot water, alcohol, ether and 
the alkalies. Lime and baryta water yield purple-red precipitates. Cloth pre- 
viously acted on by mordants is dyed the same as by alizarin. It oxidizes to 
phthalic and oxalic acids when boiled with nitric acid ; it yields anthracene upon 
distillation with zinc dust. Its ¢viacefate melts at 190-193°. 

Purpurin-amide, C,,H;0,(0H),NH, (see alizarinamide, p. 899), is obtained 
on digesting purpurin with aqueous ammonia at 150°; it crystallizes in brownish- 
green needles, with metallic lustre, and passes into purpuroxanthin by the replace- 
ment of the amido-group by hydrogen. 

Flavopurpurin, anthrapurpurin and oxy-chrysazin are isomerides of 
purpurin. See Berichte, 21, 1164, for their ethers. 

Its tetraoxyanthraquinones, C,H,(OH),.(C,0,)C,H,(OH),, are the so-called 
anthrachrysone, obtained by heating symmetrical dioxybenzoic acid with sul- 
phuric acid (p. 898), and rufiopin, C,,H,O,, obtained from opianic acid (p. 
794) and proto-catechuic acid with sulphuric acid. Both yield anthracene when 
heated with zinc dust. 

A Pentaoxyanthraquinone, C,,H,O, = C,H,.(OH),(CO),C, H(OH)., is 
formed (together with anthrachrysone and rufigallic acid) when gallic acid and 
symmetrical dioxybenzoic acid are heated with sulphuric acid (Berichte, 19, 751). 

Rufigallic Acid, C,,H,O, + 2H,O, is a hexa-oxy-anthraquinone, which is 
formed when gallic and digallic acids are heated with sulphuric acid. It consists 
of reddish-brown crystals, losing water at 120°, and subliming in red needles. It 
dissolves with an indigo-blue color in concentrated potassium hydroxide. Sodium 
amalgam reduces it to alizarin. 





Alkylic Anthracenes :-— 


CR C 
(1) CHK Coe and (2) CHE de root. 
y-Derivatives. a- and B-Derivatives. 


The derivatives of the first type, called y-derivatives, meso-derivatives, are pro- 
duced from the alkyl hydranthranols (p. 896), on boiling with alcohol and some 


METHYL-ANTHRACENE, got 


hydrochloric acid or picric acid. They unite to characteristic compounds with 
picric acid (Annalen, 212, 100). 

y-Ethyl-anthracene, C,,H,(C, gH), melts at 60°, isobutyl-anthracene at 
57°, and amyl-anthracene at 59°. Chromic acid ‘oxidizes the last to amyl- 
oxyanthranol. The phenyl anthracene, C,,H,(C,H,), corresponding to these 
alkyl derivatives, is obtained from phenyl anthranol (p. 896), on ignition with zinc 
dust. It melts at 152°. 

Compounds of the formula 2 can exist in two isomeric forms (a and f). At 
present but one methyl] anthracene is known. 


Methyl-anthracene, C,,H,.CH,, is obtained on conducting the 
vapors of ditolyl- methane and ditolyl-ethane through a red-hot tube 
(p. 893); also on heating emodin (see below), and chrysophanic 
acid with zinc dust, as well as by prolonged boiling of benzoyl xy- 
lene, C.H,.CO.C jH,(CH,)». It occurs in crude anthracene, and is 
obtained from oil of turpentine on exposure toa red heat. It re- 
sembles anthracene, crystallizes from alcohol in yellow leaflets, and 
melts at 190°. It yields a crystalline compound with picric acid, 
and this consists of dark-red needles. Anthraquinone-carboxylic 
acid is produced when methyl-anthracene, dissolved in glacial acetic 
acid, is oxidized by chromic acid. Concentrated nitric acid con- 
verts it into Methyl-anthraquinone, which is also present in 
crude anthraquinone, and melts at 177°. 


Chrysophanic Acid, C,,H;(CH;)(O,)(OH), = C,,H,,O,, Rheinic Acid, 
is the dioxyquinone of methyl anthracene. It exists in the lichen Parmelia 
parietina, in the senna leaves (of the Cassia varieties) and in the root of rhubarb 
(from the Rheum variety), from which it may be extracted by means of ether or 
alkalies. It crystallizes in golden yellow needles or prisms, melting at 162°, and 
subliming with partial decomposition. It dissolves in alkalies with a purple-red 
color. Zinc dust reduces it to methyl anthracene. 

Chrysarobin, C,,H,,O,, a reduction product of chrysophanic acid, occurs in 
in goa- and arroroba-powder. It is a yellow-colored powder. Air oxidizes its 
alkaline solution to chrysophanic acid. ‘The same occurs in the animal organism 
( Berichte, 21, 447). 

Methyl-alizarin, C,,H,,O,4, is an isomeric dioxymethylanthraquinone. It is 
obtained by fusing methyl-anthraquinone sulphonic acid with alkalies. It is very 
similar to alizarin, melting at 250-252°, and readily subliming in red needles. 
In alkalies it dissolves with a bluish-violet color. 

Emodin, C,,H,,O, = C,,H,(CH,)O,(OH),, is a trioxy-quinone of methyl 
anthracene, It occurs with chrysophanic acid in the bark of wild cherry and in 
the root of rhubarb. If distilled with zinc dust it yields methyl-anthracene. It 
consists of orange-red crystals, melting at 245-250°. 

Dimethyl-anthracene, C,,H,(CH,),, has been obtained from the portions 
of aniline oil boiling at high temperatures. It consists of shining leaflets, melting 
at 224-225°. If oxidized it yields a quinone anda mono- and dicarboxylic acid. 
Isomeric dimethyl anthracenes have been obtained from xylyl chloride, C,H, 

CH,).CH,Cl, on heating it with water (melting at 200°), from toluene “and 

> Cl, with AICl, (M. P. 225°) and from ethylidene chloride, CH,.CHCI,, and 
benzene with AICI,. The latter contains the two methyl groups linked to the two 
intermediate carbon atoms, and melts at 179°. 

See Berichte, 20, 1364, upon the dimethyl anthraquinones, C,,H,0,(CH;),. 


go2 ORGANIC CHEMISTRY. 


Anthracene Carboxylic Acids :— 





c(CO,H) CH, 
CHA tae SCH CHC di DE oHs COoH. 
y-Acid. a- and B-Acid. 


y-Anthracene Carboxylic Acid (its chloride) is formed when anthracene is 
heated with phosgene to 200° (Berichte, 20, 701). It is sparingly soluble in hot 
water, readily in alcohol, crystallizes in yellowish needles, and melts at 206°, with 
decomposition into carbon dioxide and anthracene. Chromic acid in acetic acid 
solution oxidizes it to anthraquinone. 

The a- and f-acids are formed from the anthracene-mono-sulphonic acids by 
means of the cyanides, and from the anthraquinone carboxylic acids by reduction 
with ammonia and zinc dust; the a-acid melts at 260°, the B-acid at 280°. 

The anthraquinone carboxylic acids, C,H,(C,0,)C,H,.CO,H, are pro- 
duced by oxidizing the a- and (-carboxylic acids and methyl-anthraquinone with 
chromic acid in acetic acid. Both melt at 285°. 

Pseudo-purpurin, C,,H,O, = C,,H,O,(OH),.CO,H, purpurin carboxylic 
acid, occurs in crude purpurin (from madder), and crystallizes from chloroform in 
red leaflets, melting at 218-220°. Further heating to 180° or boiling with caustic 
potash decomposes it into carbon dioxide and purpurin. 





LIndene and Hydrindene Group. 

Indene and Hydrindene (formerly called indonaphthene and hydrindonaphthene) 
may be considered the transition members from benzene to naphthalene. They 
contain besides the benzene ring, a five-membered carbon ring (two C-atoms in 
common with the benzene nucleus), hence may be compared with indol and 
hydrindol (p. 827) with which they have many analogies (see Roser, Anna/en, 


247, 129)* :— 


a : a 
/CHY / CH 
CoH Gye 7CHB CHa Gy YCHAB. 
hace Hydrindene. 


The following keto-derivatives attach themselves to the preceding :— 


CON /CO\. 
Cai he cn C,H, CH,, ete. 
ZA CO 4 2 
Bt ah Sie a $a 


1. Indene, C,H,, occurs together with coumarone (p. $25) in that fraction of 
coal-tar boiling at 176°-182°. After the removal of naphthalene, it can be ex- 
tracted as a picric acid compound ( BerichZe, 23, 3276). Itis a clear oil, boiling 
at 177-178°; its sp. gr. = 1.040 at 15°. It resembles coumarone; sulphuric acid 
converts it into a resin. Bromine converts it into a dibromide, C,H,Br,, that 
melts at 44°. Sodium in absolute alcohol reduces it to hydrindene, C,H, (see 
above), boiling at 176°. 

y-Methyl Indene, C,H, Sy 3)» was first prepared from y-methyl indene car- 
boxylic acid (see below). It is a liquid with an odor resembling that of naph- 





* C. Koenig, Theorie und Geschichte der 5-gliedrigen Kohlenstoffringe. 


INDENE AND HYDRINDENE GROUP. 903 


thalene. It boils at 205° (Anmalen, 247, 159). It can be directly synthesized 
(in slight amount) by condensing benzylacetone with sulphuric acid (Berichte, 23, 
1882) :— j 


cH oe. oe CHC cH +00. 
CO—CH, me gY Aaa 
Benzyl Acetone. y-Methyl Indene. 


Some derivatives of cinnamic aldehyde deport themselves similarly. Nitro- 
a-methyl cinnamic aldehyde, C,H,(NO,).CH:C(CH,).CHO, may be reduced to 
amido-/3-methyl indene (Aerichte, 22, 1830), and nitro-a ethyl cinnamic aldehyde 
to amido--ethyl indene. The reaction is analogous to the formation of the couma- 
rone and indol derivatives. 

2. The formation of the carboxyl derivatives of indene (compare the formation 
of coumarilic acid by the method of Hantzsch, p. 825), proceeds in a manner 
analogous to the formation of alkyl indenes. Thus, benzylacetoacetic ester readily 
changes, when digested with sulphuric acid, to y-methyl indene-3-carboxylic acid 
(Berichte, 20, 1574; Annalen, 247, 157) :— 


C,H,’ “H2\cu.co,H 


= CBS Cas 

CO.CH, Sa A ae eee 

It melts at 200°, and decomposes further into carbon dioxide and y-methyl indene 

(see above). 
3. The hydrindene derivatives have been obtained in the same manner as the 

tetra- and pentamethylene derivatives (p. 578): by the action of o-xylylene 

bromide (p. 573) upon malonic ester and sodium alcoholate (Baeyer and Perkin, 


Berichte, 17, 125) :— 
CH,Br co,R CH CO,R 
CHA se oe ern 8 mee ; 
CH,Br co,R NcH,/ >CO,R 


The resulting ether is saponified, and we then obtain Hydrindo-naphthene 
Dicarboxylic Acid, C,H,(CO,H),, melting at 199°, and decomposing into car- 
bon dioxide and hydrindene carboxylic acid, C,H,.CO,H, which melts at 130°, 
and distils without decomposition. 

The latter is also produced by the saponification of acetyl hydrindene-carboxylic 


ester, CH. 60 CL Conk obtained from o-xylylene bromide and aceto- 


+ 2HBr. 


acetic ester (Berichte, 18, 378). Potassium permanganate oxidizes hydrindene 
carboxylic acid to carbophenyl glyoxylic acid (p. 765). 

4. Keto-derivatives of indene and hydrindene result (1) by condensing phthalic 
esters and fatty acid esters with sodium (W. Wislicenus, Berichte, 21, Ref. 642; 
Annalen, 246, 347) :— 


CO.0.C,H 
CH. COOCH 4. CH,.0O:C. His 


CoHid Gg yCH.CO,.C,H, 4. 2C,H,.OH. 


The diketohydrindene-carboxylic ester thus formed melts at 75-78°, and readily 
decomposes into ay-diketohydrindene, C,H 60 CH» colorless needles, melt- 


ing at 129-131° with decomposition. It dissolves quite easily in dilute alkalies 
with an intense yellow color (Berichte, 22, Ref. 581; Annalen, 252, 72). 


904 ORGANIC CHEMISTRY. 


Phthalic acid ester and propionic ester yield S-A/ethyl-diketohydrindene, C,H, 
(CO),CH.CH,, melting at 85° (Berichfe, 22, 581). 

(2) By the inner condensation of cinnamic acid derivatives, aided by sulphuric 
acid. ‘Thus, dibromindone is derived from (-dibromcinnamic acid (p. 810) 
(Roser, Anznalen, 247, 140) :— 


Cc i 
CoH CBRCELCO,H = CHF > 
Dibromindone, C,H,Br,O, consists of orange-yellow colored needles, with 
an odor resembling that of quinone. It volatilizes quite readily with steam, and 
melts at 123°. 
Hydrindone could not be obtained from hydrocinnamic acid in this way; 
a-methyl hydrocinnamic acid (p. 814), on the contrary, passes very readily into 
B-methyl hydrindone (v. Miller, Berichée, 23, ee — 


CBr +- H,0O. 


CH 
C,H,A 0 > GILCH, = Gia: é. Sc CH, + H,0. 
CO.OH 


m- and ~-Bromhydrocinnamic acids yield in this way m- and p-bromhydrindone, 


CH, 
CoH Br = CH, 


CO. 
Hydrindone, C,H * e CH, has been prepared by aeponitying o-cyan- 
CH, 


benzyl-acetic ester, C,H,(CN). “CH,: -CH,.CO,R, with hydrochloric acid (Berichte, 
22, 2019); also by distilling calcium O- -hydrécinnamic carboxylate. Hydrindone 
forms colorless crystals, with an odor like that of phthalide. It melts at 40° and 
boils about 244°. Its oxime melts at 146°; the hydrazone at 120°. 

(3) The formation of ketoindene derivatives from naphthalene derivatives is 
rather remarkable; a six-membered benzene-ring is rearranged to a ring of five 
members—similar to the production of pentamethylene derivatives from the ben- 
zenes, or diphenylene glycollic acid from phenanthraquinone. This change occurs 
by the action of chlorine or hypochlorous acid upon the naphthols, and naphtho- 
quinones, amidonaphthols, etc. The first product eens of naphthalene keto- 
derivatives with the groups —CO.CO— or CO.CCI,—; these sustain the decom- 
position (Zincke, Berichte, 20, 1265, 2890; 21, 2379, 2719). Thus dichlor-£- 
naphthoquinone and water yield first dichlorindene oxycarboxylic acid, which by 
oxidation (with elimination of carbon dioxide and two hydrogen atoms) forms 
dichlorindone :— 


Caer. 
JOO — CO OH) po 
H | C,H,2 SCCl C,H 
“SOC] == OCl lo ee Sen se 
Dichlor-8-naphtho- Dichlorindene-oxy- Dichlorindone. 
quinone. carboxylic Acid. 


Dichlorindone, C,H,Cl,O, resembles dibromindone perfectly, and like the 
latter is produced by he i inner condensation of dichlorcinnamic acid, oH ,.CCl: 
CCl.CO,H (from phenyl propiolic acid). It consists of golden yellow needles, 
with an odor like that of quinone. It melts at 90° (Berichte, 20, 1265). 


NATHTHALENE GROUP. 905 


4. DERIVATIVES WITH CONDENSED BENZENE NUCLEI. 


The hydrocarbons belonging here contain two or more benzene 
nuclei so combined that every two nuclei have two adjoining carbon 
atoms in common, as seen in the following structural formulas of 
the nuclei of naphthalene, C,.H,, and phenanthrene, C,,H,):— 


C CC C=C 
Satay Se Fb a * pra ip 
Ct At ¢ C—C C 
Hoe: cues oe 4 
ges Ve, & C—C C—C 
a7 Xe Se 

C C C=C 

Naphthalene Nucleus. ’ Phenanthrene Nucleus, 


Phenanthrene, with three benzene rings, can also be considered 
as a diphenyl, C,H;—C,H;, in which two carbon atoms, C=C, in 
union with each other are inserted in the two ortho-positions of the 
two benzene nuclei, in such a manner that a third benzene ring is 
the result. 

Pyrene, CyHy, Chrysene, CysHy, Picene, C»Hy, also acenaph- 
thene, C\,Hy, fluoranthene, C,;Hy, and other hydrocarbons have a 
similar structure; they are all found in those portions of coal-tar 
which boil at high temperatures. 


1. NAPHTHALENE GROUP. 


Naphthalene, C,,H;, the parent substance of this group shows 
the greatest similarity to benzene in its entire deportment. Like 
benzene it is produced by the action of intense heat upon many 
carbon compounds, especially if they be conducted, in form of 
vapor, through tubes raised to a red heat. It is, therefore, present 
in coal-tar. Numerous derivatives are obtained from it by the 
replacement of its hydrogen atoms. Only the most important of 
these will be mentioned.* But few direct synthetic methods are 
known at present for naphthalene or its derivatives :— 

(1) It is derived from phenylene butylene, C,H;.CH,.CH,. 
CH:CH.,, and its dibromide, on leading their vapors over heated 
lime. The side-chain of four carbon atoms closes, forming a 
benzene ring :— 

| CH:CH | 
C,H,.CH,.CH,.CHBr.CH,Br = CoHyC d + 2HBr + H,. 
CH:CH 





* See, further, Reverdin and Nélting, Ueber die Constitution des Naphtalins, 2 
Aufl., 1887. 
76 


906 ORGANIC CHEMISTRY. 


(2) A direct synthesis of the second benzene ring also ensues in a manner 
analogous to the formation of the trimethylene and tetramethylene ring (p. 519), 
and of the hydrindene ring (p. 902) when o-xylylene bromide acts upon 
disodium-acetylene-tetracarboxylic ester (p. 481) (Baeyer and Perkin, Berichée, 
17, 448) :-— 

/CH,Br CNa(CO,.R), iS (COR) ‘ 
C,H, = SiS) + 2NaBr. 
‘\CH,Br  CNa(CO,.R), CH,—C(CO,R), 


First, we get the ester of tetrahydro-naphthalene-tetracarboxylic acid, and this 
by saponification yields tetrahydro-naphthalene dicarboxylic acid. Naphthalene 
results from the distillation of its silver salt. Corresponding experiments with 
m- and p-xylylene bromide did not yield ring-shaped chains (Berichte, 21, 36; 
23, 109). 

It is i oubtfil, according to recent investigations, whether naphthalene deriv- 
atives are really produced upon heating benzyl aceto-acetic ester with sulphuric 
acid (Berichte, 20, 1575; 16, 516). 


(3) What is further noteworthy is the formation of a-naphthol 
from phenyl-isocrotonic acid (p. 813), by its elimination of water 
when boiled (Fittig, Berichte, 16, 43) :— 


ee i Moke 

C,H,.CH:CH.CH,.CO.OH = CH, | +-H,0. 
C(OH):CH 

beni thol. 


Phenylisocrotonic acid is readily obtained from phenyl paraconic acid (p. 793), 
and the corresponding chlornaphthols are then similarly derived from the chlor- 
phenyl-paraconic acids (Berichte, 21, Ref.-733; 21, 3444). .a- and #-Methyl 
paraconic acids yield methyl-a-naphthols (Berichte, 23, 96). 

Acetyl-a-naphthol is prepared in an analogous manner from (-benzal-lzevulinic 
acid (p. 817). 

- (4) An interesting formation of a-naphthylamine is the condensation of aniline 
with furfurane upon heating aniline with pyromucic acid and zinc chloride 
(Berichte, 20, Ref. 221) :— 


Ly CH:CH 
C,H;(NH,) 05 a | a CoH (NH, )C | 
Aniline. CH:CH SCH: CH 
Furfurane. a-Naphthylamine. 





_. Constitution.—Naphthalene consists of two symmetrically con- 
densed benzene nuclei (p. 905) (Erlenmeyer and Graebe, 1866) 
and its structure may be expressed by the symbols— 


B Sects: Ree he oe 
(= 2: 
6 J/~/3 se Bs \ Pa 

54 a, a, 


in which the numbers indicate the eight affinities of the two ben- 


NAPHTHALENE GROUP. 907 


zene nuclei. According to this representation the positions 1, 4, 5 
and 8 are of equal value, while the same may be said of 2, 3, 6 and 
7 (same as in anthracene and anthraquinone, p. 894) ; the former are 
termed the a-positions, the latter the #. It follows, that by the 
replacement of hydrogen in naphthalene two series of isomeric 
mono-derivatives, C,,H,X (a and #) can be derived, and with the 
di-derivatives, C,,H,X,, there are altogether ten isomerides possible. 


These inferences relative to the number of isomerides and the accepted struc- 
ture of the naphthalene nucleus are fully demonstrated by numerous reactions. 
The presence of a benzene ring in naphthalene follows from its syntheses and 
from its oxidation to phthalic acid, C,H,(CO,H),, in which the 2 carbon-atoms 
of the carboxyl groups occupy the ortho-position. That there is a second benzene 
ring is shown by the fact that in the destruction of the first ring (by oxidations) 
phthalic acid or its derivatives are formed. Thus, by destroying the one ring we 
obtain nitro-phthalic acid, C,H,(NO,)(CO,H),, from nitro-naphthalene, C,,H, 
(NO,); if, however, we reduce nitronaphthalene to its amide and oxidize the latter, 
the benzene ring containing the amido-group will be obliterated and a benzene 
derivative—phthalic acid, C,H,(CO,H),—is again produced :— 


NO, 


NO, NH, 
Pater. ate Nae ee 
(1 | 2] yields{ x | ( 1] 2]yields = 2] 


Nitronaphthalene. Nitrophthalic Acid. Amido-naphthalene. Phthalic Acid. 


The oxidation of the chlorinated naphthalenes led to perfectly analogous results 
(Graebe, Anna/len, 149, 20). 

The existence of two isomeric series of naphthalene mono-derivatives, C,,H,X, 
indicates the presence of the two different positions (a and #). Atterberg pro- 
duced ( Berichte, 9, 1736 and 10, 547) adirect proof that there are four a-positions 
in naphthalene (two in each benzene nucleus). 

That the a-positions correspond to I (= 4, 5, 8) follows from the fact that the 
a-derivatives alone are capable of yielding a true quinone (a-naphthaquinone) 
(Liebermann, Annalen, 163, 225). Nédlting and Reverdin succeeded in showing 
that the a-positions were contiguous to the two carbon atoms held in common by 
both benzene nuclei (Berichte, 13, 36). An evidence of this is the formation of 
a-naphthol from phenyl isocrotonic acid (p. 906). For additional determinations 
of constitution, consult Erdmann, Annaden, 227, 306. 

Two adjacent positions (a and , or I, 2) in naphthalene have the character of 
the benzene ortho-position; their derivatives are adapted for the various anhy- 
dride formations and ortho-condensations. — ; 

The positions (1,8) or (4, 5), called the Ze77z positions, manifest a similar deport- 
ment. They are especially suitable for the production of anhydrides. They differ 
from the benzene ortho-position in that they incline to the formation of lactones 
and sulphones (Berichte, 22, 3333), and are incapable of yielding a phenazine with 
phenanthraquinone (see perinaphthylene diamine, p. 913). 

Notwithstanding that naphthalene derivatives possess, in a general way, the char- 
acter of benzene, they yet exhibit many differences. To express this in the formula 
showing their constitution, E. Bamberger assumes that the two benzene rings in naph- 
thalene are differently constructed from the usual benzene ring, and proposes a 
formula similar to Baeyer’s central benzene formula, with “ peculiar potential 
or central linkages” of the fourth C-valences (Berichte, 23, 1124; Ref. 337 and 


go8 ‘ORGANIC CHEMISTRY. 


692; compare Claus, Jour. prk. Chemie, 42, 24, 458). According to this idea, 
the two middle C-atoms of naphthalene are not directly combined, but show two 
potential or central valences. 





Naphthalene, C,,H;, occurs in coal-tar, and is obtained by 
crystallization from that portion boiling from 180-200°. It is puri- 
fied by distillation with steam and sublimation. It dissolves with 
difficulty in cold alcohol, readily in hot alcohol and in ether. It 
crystallizes and sublimes in shining leaves, melting at 79°, and 
boiling at 218°. It is very easily volatilized, distils with aqueous 
vapor and possesses a peculiar odor. It forms a crystalline com- 
pound, C,,H;.C,H,(NO,);.OH, with picric acid, which crystallizes 
from alcohol in needles, melting at 149°. When boiled with dilute 
nitric acid it is oxidized to phthalic acid. Chromic acid slowly 
destroys it (p. 783). Nearly all the naphthalene derivatives behave 
similarly. 

Derivatives of indonaphthene (p. 903) and of phthalide are among the inter- 
er oxidation products of the various naphthalene compounds (Zerichie, 19, 
1150) :-— 

CH:CH CH 


CoH | _ yields C,H Ce SCH and C,H 7 SH 0. 
*: * \CHICH ‘AN CH 6H Co 
Naphthalene Indonaphthene. Phthalide. 





Naphthalene Hydrides. Like benzene, naphthalene forms additive products 
with hydrogen. The di- and tetra-hydrides result from the action of metallic so- 
dium upon its amyl-alcohol solution. Higher derivatives are produced if naphtha- 
lene be heated with hydriodic acid or PH,I and phosphorus. 

Naphthalene Dihydride, C,,)H,,, is an oil, boiling at 211°. It becomes a solid 
on cooling, and then melts at +15° et 

Naphthalene Tetrahydride, C,,H,,, is derived from a@7-tetrahydro-a-naph- 
thylamine by the substitution of its amido-group; its four H-atoms are, therefore, 
combined in one benzene ring (erichée, 22, 631). It is an oil with an odor re- 
sembling that of naphthalene. It boils at 206°. 

When naphthalene has had four hydrogen atoms added to one benzene ring, its 
character is similar to that of the fatty compounds, whereas the non-hydrogenized 
benzene ring manifests the character of benzene, and the abnormalities which other- 
wise distinguish the naphthalene nucleus, disappear (p. 907). Tetrahydronaph- 
thalene resembles butyl benzene, C,H;.C,Hg, in every particular. The same de- 
portment is noticed with the tetrahydrides of naphthalene derivatives, as well as 
with those of the naphthylamines (p. 911) and naphthols (p. 916) (Bamberger, 
Berichte, 23,1124; Ref. 337). 

When chlorine is conducted over naphthalene it melts and yields chlorine addi- 
tive products (p. 581). The dichloride, C,)H,Cl,, is a yellow oil, readily decom- 
posing into hydrogen chloride and chlor- naphthalene, C,)H,Cl. The ¢etrach/oride, 


NAPHTHALENE GROUP. 9°09 


C,,H,Cl,, crystallizes from chloroform in large rhombohedra, melting at 182°. 
When boiled with alkalies it breaks down into 2HCI and dichlornaphthalene, 
C,)H,Cl,. 





fTalogen Derivatives. 

a-Chlor-naphthalene, C,,H,Cl, is produced in chlorinating boiling naph- 
thalene; from naphthalene dichloride (see below) by means of alcoholic potash ; 
from a-naphthalene sulphonic acid with PCl;,and from a-amido-naphthalene by 
means of nitrous acid. Itis a liquid, boiling about 263°. $-Chlor-naphthalene, 
from 3-naphthol and $-naphthylamine, forms pearly leaflets, melts at 61°, and boils 
at 257°. Perchlor-naphthalene, C,,Cl,, the final chlorination product, melts 
about 203°, and boils near 400°. 

a-Brom-naphthalene, C,,H,Br, is produced by bromination; it is a liquid, 
and boils at 280°. 8-Brom-naphthalene, from $-naphthylamine and £-naphthol, 
consists of brilliant leaflets, melting at 68°- 

a-Iodo-naphthalene, C,,H,I, produced by action of iodine upon naphthyl 
mercury, solidifies only on cooling, and boils about 305°. {-Iodo-naphthalene, 
from 3-naphthylamine, melts at 54°. 

a-Fluor naphthalene, C,,H, FI, from a-naphthylamine, boils at 212°, 8-Fluor- 
naphthalene melts at 59°, and boils at 212° (Berichte, 22, 1846). 





Homologous naphthalenes result from the brom-naphthalenes by the action of 
alkylogens and sodium, or more easily from naphthalene and alkyl bromides 
assisted by AICI], Methyl naphthalene occurs in slight amounts (Zerichie, 21, 
Ref. 355). The methylated naphthalenes are present in coal-tar. 

a-Methyl-naphthalene, C,,H,.CH,, from a-brom-naphthalene and a-naphthyl- 
acetic acid’ (p. 923), is liquid, and boils at 240-242°. {-Methyl-naphthalene, 
from coal.tar, melts at 32°, and boils at 242° (Berichte, 17, 842). 


Dimethyl-naphthalene, C,,H,(CH,),, from dibromnaphthalene and coal-— 


tar, boils at 251°. 

a-Ethyl-naphthalene, C,,H,.C,H,, from a-brom-naphthalene, boils near 259°. 
. $-Ethyl-naphthalene, from (-brom-naphthalene, and from naphthalene by 
. means of ethyl iodide and aluminium chloride, boils about 250° (Berichte, 21, 
Ref. 356). 

Acenaphthene, C,,Hj9, is obtained by conducting a-ethyl naphthalene (or 
benzene and ethylene) through a red-hot tube, or by the action of alcoholic potash 
upon,a@ brom-ethyl naphthalene, C,)H,.C,H, Br (from a-ethyl naphthalene with 
bromine at 180°) :— 


{ \—cH, 
CyoHy-CH,CH, = 9-4 Hs 
NSA 


this is similar to the formation of naphthalene from phenyl butylene (p. 905). 
Inasmuch as acenaphthene is oxidized by a chromic acid mixture to naphthalic 
acid (p. 923) the side-chain C,H, must be arranged in the two peri-positions 
(1 and 8, p. 907) of naphthalene (Berichie, 20, 237 and 657). Consult Berichte, 
21, 1461, upon nitro- and amido-acenaphthenes. 


te 


gto ORGANIC CHEMISTRY. 


Acenaphthene occurs in coal-tar, and it separates on cooling from the fraction 
boiling at 260-280°. It orystallizes from hot alcohol in long needles, melting at 
95°, and boiling at 277°. Chromic acid oxidizes it to naphthalic acid, C,H, 
(CO,H),. It unites with picric acid to form long red needles of Ci. C; H, 
(NO,),-OH, melting at 161°. If the vapors of acenaphthene be passed over 
ignited plumbic oxide, two hydrogen atoms split off and there results Acetylene 


Naphthalene, Cote || , acenaphthylene, crystallizing from alcohol in yellow 
CH 
plates, subliming even at the ordinary temperature, melting at 92°, and boiling 


with partial decomposition at 270°. Its picric acid derivative melts at 202°. 
Chromic acid oxidizes it to naphthalic acid. . 





Nitroso-naphthalene, C,,H,(NO), results from the action of nitrosyl bromide 
upon mercury dinaphthyl in carbon disulphide solution. Ligroine throws it out 
of its benzene solution in yellow warts, which redden on exposure. It melts at 
89°, decomposes at 134°, possesses a pungent odor, and is readily volatilized in 
aqueous vapor. It dissolves in sulphuric acid with a cherry-red color. Sulphuric 
acid imparts a deep-blue color to its solution in phenol (comp. p. 591). 


a-Nitro-naphthalene,*C,,H,(NO,), is produced by dissolving 
naphthalene in glacial acetic acid, adding nitric acid and digesting 
for about half an hour. 

It crystallizes from alcohol in yellow prisms, melts at 61°, and 
boils at 304°. Chromic acid oxidizes it to a-nitrophthalic acid. 


B-Nitronaphthalene, C,,H,(NO,), is derived from B-nitronaphthylamine 
through the diazo-compound. it crystallizes in yellow needles, melting at 79°. 
It yields 8-naphthylamine by reduction ( Berich/e, 20, 891). 

Two Dinitro-naphthalenes, C,,H,(NO,),, are produced when nitronaph- 
thalene is boiled with nitric acid and sulphuric acid. The so-called a-compound 
(1, 5) consists of colorless prisms, melting at 214°; the {-body crystallizes in 
rhombic plates, and melts at 170°. The two NO,-groups occupy the two a-posi- 
tions and very probably the peri-position (1, 8) (as in acenaphthene and naphthalic 
acid). A third y-dinitronaphthalene (2, 4) from dinitronaphthylamine (1, 2, 4) 
melts at 144° (Berichte, 20, 973). On boiling the dinitro-naphthalenes with 
fuming nitric acid, three dinitro- and two tetra-nitronaphthalenes result. 





Amido-naphthalenes, CyH,.NH,. 

a-Amido-naphthalene,—a-naphihylamine, results from the re- 
duction of a-nitronaphthalene, and is obtained on heating a-naph- 
thol with ZnCl,—CaCl,-ammonia (p. 593). It consists of colorless 
needles or prisms, readily soluble in alcohol, melting at 50°, and 
boiling at 300°. It acquires a red color on exposure to the air, 
sublimes readily and possesses a pungent odor. It forms crystalline 


AMIDO-NAPHTHALENE. git 


salts with acids. Oxidizing agents (chromic acid, ferric chloride, 
silver nitrate) produce a blue precipitate in the solutions of the 
salts: in a short time this changes into a red powder—oxynaphtha- 
mine, C,H,NO. When boiled with chromic acid, naphthylamine ° 
yields a-naphthoquinone. es 


The nitration of the acet-compound (melting at 159°) produces two nitro-com- 
pounds; these by saponification with caustic potash change to two ntronaphthyl- 
amines, C,,H,(NO,).NH,, @ and £ (Berichte, 19, 796). The a-compound (a, 
a, or I, 4) dissolves with difficulty in alcohol, crystallizes in orange yellow 
needles, and melts at 191°. It affords a-naphthoquinone upon oxidation; the 
elimination of its amido-group gives rise to ordinary a-nitronaphthalene. When 
boiled with potassium hydroxide nitronaphthylamine yields a-nitronaphthol. The 
B-nitronaphthylamine (af or 1, 2) melts at 144°, and when boiled with caustic 
potash, passes into #-nitronaphthol. Nitrous acid and alcohol convert it into 
f-nitronaphthalene (BerichZe, 19, 802). 


f-Amido-naphthalene, §-naphthylamine, is readily obtained by 
heating #-naphthol with ZnCl,-ammonia to 200° (dinaphthylamine 
is also produced). It crystallizes from hot water in leaflets, with 
mother-of-pearl lustre, melts at 112° and boils at 299°. It is odor- 
less. Oxidizing agents do not color it. Potassium permanganate 
oxidizes it to phthalic acid. 


y-Nitronaphthylamine, C,,H,(NO,)NHhg, is produced by nitrating acet-(- 
naphthylamine and saponifying the product. It melts at 127°, and yields a-nitro- 
naphthalene with nitrous acid and alcohol. 

Various dinaphthylamines, (C,,H,),NH, are obtained upon heating the 
naphthylamines with zinc chloride or with hydrochloric acid to 179—190°, or with 
a- and B-naphthols (p. 593). $-Dinaphthylamine, a by-product in the technical 
preparation of B-naphthylamine, forms leaflets with mother-of-pearl lustre, and 
melts at 171°. When heated to 150° with concentrated hydrochloric acid it 
breaks down into $-naphthylamine and #-naphthol. Heated with sulphur it 
yields Thio-$-dinaphthylamine, C, 8 Feo C1 0H, analogous to thio- 


diphenylamine.  Dinaphthyl-carbazol, 7 ©ieH¢ SNH (p. 847) and Oxy- 
pheny P 5 Gy a P- 47 y 


dinaphthylamine, of! o17°> NH, are formed when thio--dinaphthylamine 
10'*¢6 


is heated together with copper ( Berichte, 19, 2241). 

The phenylnaphthylamines, C,,H,.NH.C,H,, result upon heating a- and 
B-naphthylamine hydrochlorides to 240° together with aniline, or more readily by 
heating a- and £-naphthol with aniline and zinc chloride. These new compounds 
combine with diazo salts, forming azo-dyes, which yield zaphthophenazines, when 
boiled with acids (Berichte, 20, 572). 

Alkylic anilines are produced analogously to the alkyl anilines by heating the 
naphthylamine hydrochlorides with alcohols (Berichte, 22, 1311). 


Hydronaphthylamines. 
Sodium acting upon the boiling amyl alcohol solution of the naphthylamines 


causes the latter to add four hydrogen atoms to one of the benzene nuclei. If this 
addition is made to the non-substituted benzene ring the naphthylamines will 


gi2 ORGANIC CHEMISTRY. 


continue to show in full degree their aromatic or benzene character; if the 
opposite should take place, the addition being in the substituted benzene nucleus, 
the naphthylamines acquiré the nature of the amine bases of the paraffin series. 
_ The first class of tetrahydro bases have therefore been designated aromatic (= ar), 
while the second are called aliphatic or alicylic (= al) (Berichte, 22,769). The 
following tetrahydro bases are thus derived from the two naphthylamines (a- and 


B) — 
H, NH, H, H.NH, H, 
H, Xf H, oe NH, a H, ee ae H.NH, 


2 ee 





La, 


H. 
a Ae SS NF SPSS 
H, H H, | H, H, 
ar-Tetrahydro- ar-Tetrahydro- al-Tetrahydro- al-Tetrahydro- 
a-Naphthylamine. B-Naphthylamine. a-Naphthylamine, B-Naphthylamine. 


The aromatic hydrobases resemble the anilines. They are feeble bases, form 
salts, having an acid reaction, with acids, are converted into diazo-compounds by 
nitrous acid, and form azo-dyes by their union with diazo-salts (Berichte, 22, 64). 

_ Arather peculiar fact is that they exercise a reducing power with salts of the 
noble metals. By oxidation all yield adipic acid, C,LH,(CO,H),, owing to the 
destruction of the unchanged benzene nucleus. 

The alicylic hydrobases manifest all the properties of the amines. They are 
strong bases, react alkaline, have an odor like that of piperidine, form neutral salts, 
do not change to diazo-derivatives under the influence of nitrous acid, but yield 
very stable nitrites, Potassium permanganate causes the rupture of the hydrogen- 
ized benzene ring, and produces o-carbon-hydrocinnamic acid, 


CO,H | 
CoH. CHtCH.CO,H (Pp. 791). 


ar-Tetrahydro-a-naphthylamine, from a-naphthylamine (see above) (Ze- 
richte, 21, 1786, 1892; 22, 625), is a colorless oil, boiling at 275°. «ar-Tetra- 
hydro-$-naphthylamine may be obtained from $-naphthylamine, together with 
the ac-eompound. It boils at 276°. 
ac-Tetrahydro-a-naphthylamine is prepared by eliminating the NH,-group 
- from the non-hydrogenized benzene nucleus of tetrahydro-(1, 5)-naphthylene- 
diamine, C,,H,(H,)(NH,),. It is a colorless oil that boils at 246°. Its odor is 
like that of piperidine. It absorbs carbon dioxide (see above) very energetically 
(Berichte, 22, 773, 963). ac-Tetrahydro-8-naphthylamine is produced. in 
__. larger quantities when $-naphthylamine is acted upon with metallic sodium. It is 
.. perfectly similar to the ac-a-compound, and boils at 249° ( Berichte, 21, 847, 1112). 
Perfectly analogous tetrahydrides are derived from the alkylic naphthylamines 
(Berichte, 22, 772, 1295, 1311). Consult Berichte, 22, 777 upon the physio- 
logical action of naphthylamine hydrides. ’ 





Diamidonaphthalenes, C,,H,(NH,),, zaphthylene diamines, are obtained 
by the reduction of dinitro- and nitroamido-naphthalenes, also by the decomposition 
of amidoazo-naphthalenes, and when dioxynaphthalenes are heated with ammonia 
(Berichte, 21, Ref. 8395 22, Ref. 42). 

(1, 2) Naphthylene Diamine (a3), from {-nitro-a-naphthylamine and 





sy : Seca 
AMIDO-NAPHTHALENE. 913 


$-naphtho-quinone dioxime (p. 921) ( BerichZe, 19, 179, 803), crystallizes in silvery 
leaflets from hot water, and melts at 98°. Being an ortho-diamine it can form 
azine derivatives (Berichte, 19, 180, 914). 

(1, 3)-Naphthylene Diamine is derived from y-dinitronaphthalene. It is a 
meta-diamine and hence forms a chrysoidine with diazobenzene sulphonic acid. ~ 

(1, 4)-Naphthylene Diamine results from the reduction of a-nitronaphthyl- 
amine, and the decomposition of a-amidoazo-naphthalene, by tin and hydrochloric 
acid. It crystallizes in brilliant scales, and melts at 120°. Ferric chloride con- 
verts it into a-naphthoquinone, and bleaching lime changes it to the dichlor- 
imide. : 
(1, 5)-Naphthylene Diamine is prepared from so-called a-dinitronaphthalene 
(p. 910) and from (1, 5)-dioxynaphthalene. It melts at 189° and then sublimes. 
Chromic acid does not oxidize it to a naphthoquinone. 

(1, 8)-Naphthylené Diamine, with the amido-groups in the peri-position 
(p. 907), is formed by reducing (-dinitronaphthalene. White needles, melting at 
66°, Ferric chloride forms a brown precipitate with it. It forms an aldehydine 
with benzaldehyde. But it differs from the orthodiamines in that it cannot yield 
a phenazine derivative with phenanthraquinone; this is because it is necessary 
to have a seven-membered ring (Berichte, 22, 861) produced. 

The naphthylene diamines resemble the naphthylamines in that they are also 
able to form Zetrahydro products, perfectly analogous to tetrahydronaphthyl- 
amines; these possess either an aromatic or alicylic character after the hydrogen 
addition (Berichte, 22, 1374). 

(1, 5)-Tetrahydronaphthylene Diamine, C,,H,(H,)(NH,),, from (1, 5)- 
naphthylene diamine, consists of colorless crystals, melting at 77° and boiling at 
264°. Its odor is like that of piperidine. It combines at the same time in a 
remarkable degree (corresponding to the different position of the 2NH,-groups) 
both the aromatic and alicylic character (Berichte, 22, 943, 1374). It contains 
an asymmetric C-atom, therefore may be resolved into a dextro- and levo-rotatory 
modification (Bamberger, Berichte, 23, 291). It yields ac-a-tetrahydronaphthy]- 
amine by the elimination of the amido-group from the non-hydrogenized benzene- 
ring. This is accomplished through the diazo-compound (see above). 





Nitrous acid (or sodium nitrite) acting upon naphthylamine salts produces 
naphthalene diazo-derivatives, perfectly analogous to the diazobenzene compounds 
(p. 631); they yield azo-dyes with the anilines and phenols (p. 644). 

The azonaphthalenes, C,,H,.N,.C,,H,, could not be prepared by reducing nitro 
napthalenes with alcoholic potash(p. 641). 

a-Azonaphthalene results upon boiling the diazo-compound C,, H,.N,.C,)H,. 
N,X, of a-amidazo-naphthalene with alcohol (p. 632) (Berichte, 18, 298, 3252). 
It crystallizes in red needles; or small steel blue prisms, melting at 190°, and sub- 
liming without difficulty. It dissolves with a blue color in concentrated sulphuric 
acid. ‘This becomes violet at 180°. Boiling alcoholic sodium hydroxide and zinc 
dust convert it into Hydrazonaphthalene, C,,H,.NH.NH.C,,H,, which forms 
colorless leaflets, melting at 275°. The latter compound, when digested with hy- 
drochloric acid, changes to the isomeric Naphtidine, H,N.C,,H,.C,)H,.NH,, 
diamido-dinaphthyl (compare benzidine, p. 844) (Berichte, 18, 3255). 

$-Amido-azo-naphthalene (see below) under similar treatment (by means of the 
diazo-compound) yields §-Oxyazonaphthalene, C,,H,.N,.C,,H,.OH (Berichte, 
19, 1281). See Berichte, 20, 612 for a3-azonaphthalene. 

Amido-azonaphthalenes, C,,H,.N,.C,,H,.NH,. 


gt4 ORGANIC CHEMISTRY. 


a-Amido-azonaphthalene is formed when nitrous acid acts upon the alcoholic 
solution of a-naphthlyamine; the diazo-amidonaphthalene, C,,H,.N,.NH.C,,H, 
(p. 636), first formed undergoes a molecular rearrangement. To prepare it add 
sodium nitrite (1 molecule) to the aqueous solution of naphthylamine hydrochloride 
(2 molecules) and neutralize with soda (Aerichte, 18, 298). It separates in the 
form of a brown precipitate (see Berichte, 22, 590). It crystallizes from alcohol 
in brownish-red needles or leaflets with green metallic lustre. It melts at 180°. 
It forms rather unstable yellow-colored salts with one equivalent of the acids. 
Concentrated acids color the salts dark in the presence of alcohol. Tin and hy- 
drochloric acid resolve a-amidoazonaphthalene into a-naphthylamine and (1, 4)- 
naphthylene diamine (p. 913). Vaphthalene Red belongs to the safranine dyes 
and is produced when a-amidoazonaphthalene is heated with naphthylamine hydro- 
chloride. 

$-Amido-azo-naphthalene, from ($-naphthylamine, forms red needles and 
melts at 156°. It is a very feeble base (Berichte, 19, 1282). 

a3Amido-azo-naphthalene results from the action of a-naphthylamine upon 
B-naphthylamine diazochloride. It crystallizes in yellowish-brown needles, 
melting at 152° (Berichte, 20, 612). 

When diazo salts act upon 6-naphthylamine products are obtained that manifest 
the behavior of the diazo-amido, as well as that of the amidazo-derivatives. They 
are probably Aydrazimido compounds (p. 640) (Berichte, 18, 3132; 20, 1167). 





Naphthyl Hydrazines, C, ,H,.NH.NH),, are derived from the diazo-chlorides 
of the two naphthylamines by the action of stannous chloride and hydrochloric acid 
(p. 653) (Berichte, 19, Ref. 303). They crystallize in colorless needles, that 
readily take on color by exposure to the air. The a-compound melts at 117°, the 
B-modification at 125°. They unite with the aldehydes and ketones forming 
hydrazides; these form naphthindol compounds (p. 923) (Zerichée, 19, Ref. 831; 
22, Ref. 672). 





Sulpho-acids. 


On digesting four parts of naphthalene with three parts sulphuric acid at 80° 
we have formed a- and 6-Naphthalene-sulphonic Acids, C,,H,.SO,;H, which 
may be separated by means of the barium or lead salts. The free “acids are 
crystalline and deliquesce readily. “When heated with sulphuric acid the a-acid 
passes into the /-variety (similar to the orthophenol-sulphonic acid); therefore, 
the latter acid is exclusively produced at higher temperatures (160°). The a-acid 
decomposes upon heating with dilute hydrochloric acid to 200°, into naphthalene 
and sulphuric acid, whereas the 3-acid remains unaltered. 

Protracted heating of naphthalene with sulphuric acid (5 parts) to 160° produces 
two Naphthalene-disulphonic Acids, C,,H,(SO,H),, a- and 8, which can be 
separated by means of their caleiu m salts. T he: a actd, containing the two sulpho- 
groups in two (-positions, serves*fol r the preparation of 6-naphthylamine sulphonic 
acid (F or d-acid); this possesses technical importance (Berichte, 21, 637). 

The chief product i in sulphonating @-nitronaphthalene is (1, 5)-nitronaphthalene 
sulphonic acid, which can also be prepared by the nitration of a-naphthalene 
sulphonic acid. In the latter reaction there is a simultaneous production of (1, 8)- 
nitronaphthalene sulphonic act » with the peri-position (Berichte, 20, 3162; 21, 
Ref. 730). ad : 

















NAPHTHOL, 915 


Naphthylamine Sulphonic Acids, C,H«(NH,).SO;H. There are 
fourteen isomerides. 

(1) The action of sulphuric acid upon a-naphthylamine produces 
almost exclusively (Berichte, 15, 5783; 21, 2370) :— 

(1, 4)-Naphthylamine Sulphonic Acid, WVaphthionic Acid, 
which is applied in the preparation of Congo red. 


It crystallizes in small needles, containing one-half molecule of water. At 14° 
it dissolves in about 4000 parts of water. Its sodium salt, C,,H,(NH,)SO,Na 
+ 4H,O, crystallizes in large plates or leaflets, which lose their water usually at 
temperatures above 100°. 

(1, 5)-Naphthylamine Sulphonic Acid, naphthalidinic acid, is formed by 
the reduction of (1, 5)-nitronaphthalene sulphonic acid. Peri-Naphthylamine 
Sulphonic Acid (1, 8) is obtained by the ‘reduction of perinitronaphthalene 
sulphonic acid, and is distinguished from the (1, 4)-acid in that its sodium salt is 
not very soluble (Berichte, 21, Ref. 730). 

The remaining four possible isomeric a-naphthylamine sulphonic acids have 
also been prepared ( Berich/e, 21, Ref. 2371). | 

(2) Four isomeric 3-naphthylamine sulphonic acids (designated a, 3, y and 4) 
have been formed by sulphonating 3 naphthylamine (erichfe, 21, 637, 3483; 
22, 412, 721). So-called F- or 5 Naphthylamine Sulphonic Acid, with the two 
side groups in the two /-positions (2,6 or 2,7) has also been obtained from 
a-naphthalene disulphonic acid (see above), and is especially applied in the prepa- 
ration of substantive tetrazo-dyes with the benzidines (p. 845) (Berichte, 21, 637). 

See Berichte, 21, 34953 22, 3327, for the naphthylamine disulphonic acids. 


Diazonaphthalene Sulphonic Acid, Cro >O, diazonaphthionic 
2 


acid, is produced by the action of nitrous acid upon naphthionic acid suspended 
in hot water or alcohol (p. 665). A yellow crystalline powder. It forms 
rocellin by combining with a-naphthol (p. 652). 

Naphthol Black is formed by the union of azonaphthalene diazo-sulphonic 


acid, C,,H,N,.C,,H Kéd> with naphthol-monosulphonic acid. 





Phenol Derivatives. 


In the phenols of naphthalene the hydroxyls are far more reactive than in the 
benzene phenols. They readily yield amido-naphthalenes with ammonia (p. 593); 
and upon heating with alcohols and hydrochloric acid naphthol ethers result 
( Berichte, 15, 1427). 


(1) a-Naphthol, C,H;.OH, results from a-naphthylamine by 
means of the diazo-compound, and upon fusing a-naphthalene- 
sulphonic acid with alkalies. Its formation from phenyl-isocrotonic 
acid (p. 906) is very noteworthy. It is soluble with difficulty in 
hot water, readily in alcohol and ether, crystallizes in shining 
needles, and has the odor of phenol. It melts at 95°, boils at 
278—280°, and is readily volatilized. Ferric chloride precipitates 
violet flakes of dinaphthol, C,>H,,.(OH,), from its aqueous solution. 
The acetate, C,H;.0.C,H;,O, melts at 46°; the ethy/ ether; C,H, 
O.C,H;, boils at 270°. 


916 ORGANIC CHEMISTRY. 


Metallic sodium converts a-naphthol in amy] alcohol solution into 

ar-Tetrahydro-a-Naphthol, C,,H,(H,).OH, which can also be prepared 
from ar-tetrahydro-a-naphthylamine by means of the diazo-compound (Serichze, 
21, 1892). It crystallizes in plates resembling those of naphthalene. It melts at 
69° and boils at 265°. It has the character of a true phenol, inasmuch as its 
hydroxyl is present in the non-hydrogenized benzene ring (Berichte, 23, 215). 

When the so-called nitroso-a-naphthols (p. 920) are oxidized with potassium 
ferricyanide two Nitro-a-naphthols, C,,H,(NO,).OH, a@ and £, result; these 
are also obtained when the two nitro-a-naphthylamines are boiled with caustic 
potash (p. 667). The a-nitro-dody (1, 4) melts at 164°; its sodium salt was 
applied as Campo Bello Yellow. Its reduction gives rise to Amido-a-naphthol, 
C,,H,(NH,).OH (1, 4), which is oxidized to a-naphthoquinone by ferric 
chloride. 

B-Nitro-a-naphthol (1, 2) is very volatile with steam, and melts at 128° 
(Berichte, 15, 1815). ; 

Dinitro-a-naphthol, C,,H;(NO,),.OH, is produced by the action of nitric 
acid upon a-naphthol, a-naphthol sulphonic acid, upon both nitro-a-naphthols, 
and upon.a-naphthylamine. It is obtained from the a-naphthol-sulphonic acid 
by digestion with common nitric acid. It is almost insoluble in water, sparingly 
soluble in alcohol and in ether, crystallizes in fine, yellow needles, and melts at 
138°. It decomposes alkaline carbonates, and forms yellow salts with one equiva- 
lent of base. The salts dye silk a beautiful golden-yellow. The sodium salt, 
C,,.H;(NO,),.ONa + H,0, finds use in dyeing, under the name of naphthalene 
yellow (Martius yellow). The fofassium salt of dinitronaphthol-sulphonic acid, 
Co HANO,); Tas obtained by the nitration of naphthol-trisulphonic acid, is 
naphthol yellow. 

Further nitration of dinitronaphthol with nitric-sulphuric acid produces Tri- 
nitronaphthol, C,,H,(NO,)3.OH, which crystallizes from glacial acetic acid in 
yellow needles or leaflets, melting at 177°. Its salts show the same color as 
naphthalene yellow. 

(1, 4)-Amido-a-naphthol, C,,H,(NH,).OH, results from the reduction of 
(1, 4)-nitronaphthol, and by the decomposition of a-naphthol orange, C,,H,(OH). 
N,.C, H,.SO,H (from a-naphthol and diazo-benzene sulphonic acid), It is very 
unstable even in the form of a salt,’ It yields a-napthoquinone by oxidation. 

(1, 2)-Amido-a-naphthol, from (1, 2)-nitronaphthol, oxidizes in the air to a- 


naphthoquinonimide, C,,H,(NH)O, or C, PF . # re ae, forming violet leaflets (e- 


richte, 18, 572). Chromic acid oxidizes it to 6-naphthoquinone. (1, 5)-Amido- 
a-naphthol is formed when naphthylamine sulphonic acid (p. 914) is heated with 
alkalies. It combines with naphthalene diazosulphonic acid to form a dye with a 
blue color (Berichte, 23, Ref. 41). 

a-Naphthol Sulphonic Acids,C, ,H,(OH).SO,H. 

Two acids (a- and #-) are produced when a-naphthol is digested with concen- 
trated sulphuric acid (2 parts.) The a-acid (Schaeffer) has the position (1, 2) ; 
ferric chloride imparts a deep blue color to it. The /-aczd is (1, 4) and is derived 
from naphthionic acid (p. 915) (Berichie, 22, 996; 21, Ref. 731). (1, 5)-Naph- 
thol Sulphonic Acid may be obtained from naphthylamine sulphonic acid. Peri- 
naphthol Sulphonic Acid (1, 8) is formed from peri-naphthylamine sulphonic 
acid by decomposing its diazo-derivative with water. It then separates as a lac- 


tone-like anhydride, Cia ‘>, naphsulphtone. This consists of shining 
5 2 


prisms, melting at 154°. It dissolves with difgculty in water and alcohol. It shows 
neutral reaction. It dissolves in the hot alkalies, forming salts of perinaphthol sul- 


_ NAPHTHOL. 917 


phonic acid ; when the latter is liberated it dissolves quite easily in water, and is 
colored dark green and then red by ferric chloride (Berich/e, 21, Ref. 731). See 
Berichte, 23, 3088, upon the a-naphthol-disulphonic acids. 


2. §-Naphthol, C,,H,.OH, from -naphthalene-sulphonic acid 
and #-naphthylamine, is readily soluble in hot water, crystallizes in 
leaflets, meiting at 122°, and boiling at 286°, and is very volatile. 
Ferric chloride imparts a greenish color to the solution and sepa- 
rates dinaphthol, C,,H,,(OH),, melting at 216°. The acefate melts 
at 61°. . 


Metallic sodium acting upon the amyl alcohol solution of (-naphthol produces 
both aromatic and alicylic tetrahydronaphthols (just as $-naphthylamine yields 
the two tetrahydrides, p. 912) (Berichte, 23, 197, 1127). 

ar-Tetrahydro-Z-naphthol, C,,H,,-OH, forms silvery white needles, melting 
at 58° and boiling at 275°. Its odor is like that of phenol, and in its entire de- 
portment it resembles the benzene phenols (Berichte, 23, 885, 1129). 

ac-Tetrahydro-@-naphthol is a viscid oil, with an odor like that of sage. It 
boils at 264°. It differs from the phenols in being insoluble in alkalies, its char- 
acter corresponds to that of the paraffin alcohols, and it closely resembles borneol 
and menthol, which possess a similar constitution (Berichée, 23, 204). 

By the oxidation of so-called a-nitroso-$-naphthol (p. 920), we obtain a-Nitro- 
B-naphthol, C,,H,(NO,).OH, which is also formed from _nitro-G-naphthyl- 
amine, when it is boiled with sodium hydroxide. It consists of brown leaflets, 
melting at 103°." Dinitro-$-naphthol, C, ,H,;(NO,),.OH, is obtained by the ni- 
tration of $-naphthol in alcoholic solution, and also from $-naphthylamine (Ze- 
richte, 17, 1171). It melts at 195° (Berichle, 23, 2542). 

Amido.f-naphthol, C,,H;(NH,).OH (1, 2), is obtained in the reduction of 
nitro-3-naphthol (1, 2) with tin and hydrochloric acid ; also from 6-naphthol orange 
(see below) or from benzene azo-3-naphthol by decomposition with tin and hydro- 
chloric acid (Berichte, 16, 2861). Its hydrochloride crystallizes in white needles ; 
it yields 6-naphthoquinone when oxidized. 

On the addition of alcoholic 6-naphthol to the solution of diazo-benzene-sul- 
phonic acid we get 6-Naphthol-azo-benzene-sulphonic Acid, C,,H,(OH).N,. 
C,H,.SO,H, whose sodium salt is the 6-Maphthol-orange—Mandarin. The diazo- 
group occupies the ortho-place referred to hydroxyl (p. 644); tin and hydrochloric 
acid decompose the azosulphonic acid into amido-$-naphthol (1, 2) and sulphanilic 
acid. By-the conjugation of diazo-naphthalene sulphonic acid (p. 915) and (- 
naphthol (above), 6-Naphthol-azo-naphthalene-sulphonic Acid, C,,H, 
(OH).N,.C, )H,.SO,H, is produced. Its sodium salt, the. so-called Pure red or 
Rocellin, is used as a substitute for archil and cochineal. The BAieberich scarlets 
are formed by the conjugation of 3-naphthol with diazo-azobenzene-sulphonic acids, 





8-Naphthol Sulphonic Acids, C,,H,(OH).SO,H. 

Four of the seven possible isomerides are known. They are applied in the prepa- 
ration of colors (Berichte, 21, 3473). 

When £-naphthol is dissolved in concentrated sulphuric acid at the ordinary 
temperature the first product is # naphthyl sulphonic acid, C,,H,.O.SO,H. By 
continuous digestion this is almost entirely changed to S-naphthol--sulphonic 
acid (Schiffer’s sulpho-acid) (probably 2, 6) (Berichte, 18, Ref: 89). $-Naph- 


918 ORGANIC CHEMISTRY. 


thol-a-sulphonic acid (Baeyer’s Acid or Crocein Acid) (2, 5) or (2, 8) (formerly 
thought to be 2,1) is produced at the same time (Berichie, 21, 3489; 22, 396, 
453). It serves for the preparation of crocein scarlet. 

The (2, 7)-8-Naphthol Sulphonic Acid (Cassella’s Acid, or F-acid) is pro- 
duced when a-naphthalene disulphonic acid is fused with caustic soda at 200-250°. 
The (2, 5)-Naphthol Sulphonic Acid (of Dahl) is made by diazotizing $-naph- 
thylamine-y-sulphonic acid. Four Amido-Naphthol-Sulphonic Acids, C,,H; 
(NH,)(OH).SO,H, have been obtained from the azo dyes, formed by the reduction 
of the products resulting from the union of these four 6-naphthol acids with diazo- 
derivatives. Two /-naphthol disulphonic acids, C,,H;(OH)(SO,H),, called R- 
and G-acid, are produced when (-naphthol is digested with sulphuric acid (4 parts) 
at 100°. They form various Ponceaus by conjugation with xylidines and cumi- 
dines. The G-acid, obtained in perfectly pure condition from ($-naphthol-a-sul- 
phonic acid (see above), is known in commerce as 3-Naphthol-y-Disulphonic 
Acid ; it yields especially valuable dyestuffs (Berichte, 21, 3478). See Berichte, 
22, 822; 23, 3045, for Thionaphthols. 





Dioxynaphthalenes, C,,H,(OH).. Six of the ten possible isomerides are known ; 
of these we mention those corresponding to the two naphthoquinones, 

a-Hydronaphthoquinone (1, 4) is obtained from a-naphthoquinone on boiling 
with hydriodic acid and phosphorus. It crystallizes from hot water in long needles, 
and melts at 173°. Chromic acid readily oxidizes it to a-naphthoquinone. 

{$-Hydronaphthoquinone (1, 2) separates in silvery leaflets, melting at 60°, 
when a solution of 3-naphthoquinone in aqueous sulphurous acid stands for some 
time. It dissolves in the alkalies with a yellow color which becomes an intense 
green upon exposure. 

(1, 5)-Dioxynaphthalene is derived from a-nitronaphthalene sulphonic acid 
and by fusing y-naphthalene disulphonic acid with caustic potash. It readily 
sublimes in thin leaflets and melts at 186°. Chromic acid oxidizes it to juglone 
(p. 919). (2, 7)-Dioxynaphthalene is obtained from a-naphthalene disulphonic 
acid, crystallizes in long. needles and melts at 190° (Berichée, 23, 519). 


Trioxynaphthalenes, CyyH;(OH);. 


Two trioxynaphthalenes, a- and 3-Hydrojuglones, occur in green walnut shells 
(Berichte, 18, 463, 2567). a-Hydrojuglone (1, 5) crystallizes in needles or 
leaflets, melting at 169°. In the air it rapidly oxidizes to juglone (see below). 
If it be distilled it changes to 6-Hydrojuglone, which dissolves in water with 
more difficulty and does not yield juglone upon oxidation. It reverts again to 
a-hydrojuglone when boiled with dilute alcoholic hydrochloric acid. The two 
hydrojuglones yield the same triacetyl compound with acetic anhydride. 





Quinones. 


In addition to ordinary a-naphthoquinone, corresponding in all respects to benzo- 
quinone, there is a 3-naphthoquinone, which represents an ortho-diketone (com- 
_ pare o-benzoquinone, p: 704). 


(1). a-Naphthoquinone, C,,H,O, (1, 4), is formed in the oxi- 
dation of a-naphthylamine, nitro-a-naphthol, diamidonaphthalene 


NAPHTHOQUINONE. 919 


(1, 4), and amido-a-naphthol (1, 4) with chromic acid; further, 
on heating naphthalene in glacial acetic acid with chromic acid 
(p. 699, Berichte, 20, 2283). It crystallizes from hot alcohol in 
yellow rhombic plates, melting at 125° and subliming under 100°. 
It possesses the usual quinone odor, is very volatile, and distils 
_ over in a current of steam, Nitric acid oxidizes it to phthalic acid, 
and by reduction forms a-naphthohydroquinone (see above). 


ar-Tetrahydro-a-naphthoquinone, C,,H,(H,)O,, is produced by the oxid- 
ation of ar-tetrahydro-a-naphthylamine (p. 912) with chromic acid. Its pro- 
nounced benzene character harmonizes with its constitution. It resembles benzo- 
quinone more closely than a- naphthoquinone. It melts at 55°, but is incapable 
of forming a hydrazone (Berichte, 23, 1131). a-Naphthoquinone and phenyl- 
hydrazine combine to Aydrazones (distinction from ordinary benzoquinone). The 
dioxime is derived from the monoxime by means of hydroxylamine. The Axnzilide, 
C,)H;(NH.C,H;)O, (p. 700), results from the union of a-naphthoquinone with 
aniline. It crystallizes in red needles, that melt at 191°. Boiling dilute goedium 
hydroxide decomposes it into aniline and 6-oxy-a-naphthoquinone, C,,H,;(O,). 
OH (1, 4, 2), naphthalene acid, that melts at 188°. 

Juglone is an a-oxy-a- -naphthoquinone, C,,H,;(O,).0H (1, 4—5 or 8). The 
best method to obtain it consists in oxidizing a-hydrojuglone with ferric chloride. 
It may be synthetically prepared by oxidizing (1, 5)-dioxynaphthalene with 
chromic acid (erichze, 20, 934). It is almost insoluble in water, consists of 
yellow needles and melts with decomposition about 150-155°. It dissolves in 
alkalies with a violet color. Zinc dust converts it into naphthalene. Nitric acid 
converts it into dinitro-oxyphthalic acid (juglonic acid) (Berichfe, 19, 164). 

The following are dioxy-a-naphthoquinones, C,jH,(OH),O :— 

Oxy-juglone, formed by the oxidation of the alkaline solution of juglone on 
exposure to the air. Golden yellow plates, that melt at 220°, with decomposition. 
Naphthalizarin, corresponding to the alizarin of anthracene, is derived from 
a-dinitronaphthalene by heating it with concentrated sulphuric acid and zinc. It 
sublimes in red needles with green metallic reflex, dissolves in ammonia with a 
bright blue color, and yields violet-colored precipitates with lime or baryta water. . 


a-Naphthoquinone Chlorimide, C,H obtained from amido-a- 


ae 
oar 

naphthol hydrochloride with a solution of Hesching lime (p. 705), consists of 
brown needles, melting at 85°. It yields a-aphthol-blue (p. 707), with dimethyl 


aniline. 


(2) §-Naphthoquinone, C,,H,O, (1, 2), is produced on oxid- 
izing amido-f-naphthol with chromic acid or with ferric chloride 
(Berichte, 17, Ref. 531). It also results from the decomposition 
of #-naphthol orange (p. 917) and further oxidation with ferric 
chloride (Berichte, 21, 3472). It crystallizes from ether or ben- 
zene in orange-colored leaflets, and decomposes at 115-120°. It 
is distinguished from the real quinones (p. 698), by being odorless 
and non-volatile. It closely resembles anthraquinone, and es- 
pecially phenanthraquinone (p. 925); like the latter it must be 
considered an ortho-diketone :— 

Hu, SOO < 
\CH:CH~ 


920 ORGANIC CHEMISTRY. 


In accordance with this view it combines with one and two mole- 
cules of H,N.OH, yielding quinoximes. 


Phenylhydrazine unites with it forming the hydrazone, C,H,O(N,H.C,H,) 
(p. 921), melting at 138°. Sulphurous acid reduces it at ordinary temperatures to 
B-naphtho-hydroquinone. Potassium permanganate oxidizes it to phthalic acid. 





Naphthoquinoximes or Nitrosonaphthols, These are produced when the 
alcoholic solutions of the naphthoquinones are boiled with hydroxylamine hydro- 
chloride, and by the action of nitrous acid upon the naphthols. ‘Their constitution 
corresponds to the formulas :— 


NO 
ens dl en.f 
10 *\ On or 10 "‘\N.OH, 
- Nitrosonaphthol. Quinoxime. 


which are probably tautomeric (pp. 674, 699). Three isomerides are produced 
according to the preceding methods :— 





/O(N-OH).CH / CCH CH:CH 
CO.CH CO.C:N.OH C(N.OH).CO 
a-Nitroso-a-naphthol. B-Nitroso-a-naphthol. a-Nitroso-8-naphthol. 
a-Naphthoquinoxime. B-Naphthoquinoxime. 


Nitrous acid acting upon a-naphthol produces both a- and /-nitroso-a-naphthol 
(Preparation, Berichte, 18, 706). The first. may be obtained from a-naphtho- 
quinone by means of hydroxylamine (Berichte, 17, 2064). Nitrous acid converts 
8-naphthol into but one compound a-z7troso-B-naphthol (Preparation, Berichze, 
18, 705), whereas (-nitroso-a-naphthol is the product if hydroxylamine be used 
(Berichte, 17, 215). The three compounds behave like feeble acids; they dissolve 
in alkaline carbonates, and are again liberated by carbon dioxide. They form 
corresponding nitronaphthols upon oxidation. 

a-Nitroso-a-naphihol or a-naphthoguinoxime consists of colorless needles, melt- 
ing at 190°. (-/Vitroso-a-naphthol (3-naphthoquinoxime) crystallizes in needles 
from hot water, and melts at 152°. a-Mitroso-B-Naphthol forms stout yellow- 
brown prisms, melts at 160°, and volatilizes with aqueous vapor (erichze, 17, 
2584). It precipitates various metals from solutions of their salts, and may be 
employed in separating cobalt from nickel (Berichte, 18, 699), iron from alumi- 
nium (Zerichie, 18, 2728), and for the determination of copper and iron (Lerichée, 
20, 283). 

The pee ethers of B-nitroso-a-naphthol and of a-nitroso--naphthol, C,,H, 
(N.O.CH,)O (derived from the silver salts with methyl iodide), are reduced to 
amidonaphthols by tin chloride (Berichte, 18, 571). The behavior of the two 
compounds toward hydroxylamine hydrochloride argues in favor of their being 
quinoximes (Berichte, 19, 341). The same conclusion is deduced from the be- 
havior of a- and 3 naphthoquinones toward methyl hydroxylamine H,N.O.CH, 
(Berichte, 18, 2225). 

J N.OH 


a-Naphthoquinone Dioxime, CoH. x OH? 'S formed upon boiling a ni- 


troso-a-naphthol with hydroxylamine hydrochloride and aqueous alcohol. It crys- 
tallizes in colorless needles and melts at 207°. Acetic anhydride converts it into 
a diacetate (Berichte, 21, 433). 


CYAN-NAPHTHALENE., g2I 


8-Naphthoquinone Dioxime, Collet NOH (Di-isonitroso-naphthalene 


hydride), is derived from -nitroso-a-naphthol, and from a-nitroso-3-naphthol by the 
action of hydroxylamine hydrochloride (Berichte, 17, 2064, 2582). It crystal- 
lizes from water in yellow needles and melts at 149°. It forms the anhydride, 
C8. { NO melting at 78°, when digested with alkalies. Stannous chloride 
reduces the dioxime to (1, 2)-naphthylenediamine. -Naphthoquinone dioxime 
colors iron and cobalt mordants brown. ‘The same may be said of other ortho- 
dioxime and ortho-oxy-oxime (1, 2) dye-substances, but not of the para-dioximes 
(Berichte, 22, 1349). . 


Quinone Phenylhydrazones. 

Phenylhydrazine hydrochloride acting upon a-naphthoquinone in glacial acetic 
acid produces a-naphthoguinone phenylhydrazone, identical with Benzene-azo- 
naphthol derived from a-naphthol and diazobenzene chloride. The two formulas, 


ZO (1 Wy 70H 


c,.H.72 ) 
10 Hg. N.NH.C,H, (4 6\.N:N.C,H, 


and Cio 


ate probably, therefore, tautomeric, and the compound reacts at the same time as 
a phenol and a base (erichie, 17, 3026). However, B-naphtho-quinone phenyl- 


hydrazone differs from benzene-azo 3 naphthol, CoHe{ x HCH (Berichte, 18, 
796; 21, 414). The toluenes exhibit a similar deportment (Berichte, 19, 2486). 





Alcohols, Ketones, Nitriles. 


a-Naphthobenzyl Alcohol, C,,H,.CH,OH, from a-naphthobenzylamine 
(from a-naphthonitrile, see below), crystallizes in long, brilliant needles, melts at 
60° and boils at 301° (Berichte, 21, 257). Chromic acid oxidizes it to 

a-Naphthaldehyde, C,,H,.CHO, a thick oil, boiling at 291° (Berichte 22, 
2148). 

b-Naphthaldehyde, C,,H,.CHO, is produced by the distillation of the calcium 
salts of $-naphthoic and formic acids, and by the oxidation of 3-naphthyl carbinol, 
C,,H,.CH,.OH (from /-cyan naphthalene). It crystallizes from hot water in 
shining leaflets, that melt at 59° (Berichte, 16, 636; 20, 1115). 

Dinaphthyl Ketones, C, ,H,.CO.C,,H,, a- and /-, result by the condensation 
of a- and /-naphthoic acids with naphthalene upon heating them with phosphorus 
pentoxide, also by the action of naphthalene and zinc upon a- and (-naphthoyl 
chloride, C,,H,.COCI (p. 855). 

a-Naphthyl-methyl Ketone, C,,H,.CO.CH,, is derived from naphthalene 
and acetyl chloride by means of aluminium chloride. It melts at 34° and boils 
about 295°. It unites with hydroxylamine and phenylhydrazine. Potassium per- 
manganate oxidizes it to naphthyl glyoxylic acid (p. 923). 

The corresponding cyanides or nitriles may be obtained by the distillation of the 
alkali salts of the naphthalene-disulphonic acids, or the phosphoric esters of the 
naphthols with potassium cyanide (Berichte, 21, Ref. 834). 

a-Cyan-naphthalene, C,,H,.CN, has also been prepared from naphthy] forma- 
mide, C,,H,.NH.COH (from naphthylamine oxalate) (comp. p. 633) as well as 
from a-naphthalene diazochloride by means of copper and potassium cyanides 
(Berichte, 20, 241). It dissolves-readily in alcohol, and forms flat needles, melt- 


77 


922 ORGANIC CHEMISTRY. 


ing at 37.5°, and distilling at 298°. ($-Cyan-naphthalene, from §-naphthalene 
sulphonic acid, crystallizes in yellow prisms, melts at 61°, and distils at 304°. 

Similarly, two naphthalene-dicyanides, C,,H,(CN),, are produced from the 
two naphthalene disulphonie acids. Both sublime in shining needles; the a-com- 
pound melts at 268° and is almost insoluble in the ordinary solvents; the (-di- 
cyanide dissolves in hot alcohol, and melts at 297°. 

Naphthalene carboxylic acids are produced on saponifying the cyan-naphtha- 
lenes with alcoholic potassium hydroxide. 





Naphthalene Carboxylic Acids. 

a-Naphthoic Acid, C,,H,.CO,H, from a-cyan-naphthalene, by 
saponification with alcoholic soda at 160° (Berichte, a0, 242; 21, 
Ref. 834), is also prepared by fusing potassium a-naphthalene sul- 
phonate with sodium formate, and by the action of sodium amalgam 
on a mixture of a-brom-naphthalene and chlor-carbonic ester. It 
consists of fine needles, melting at 160°, and dissolving in hot 
water with difficulty, but readily in hot alcohol. 


The nitration of a-naphthoic acid produces two nitro-naphthoic acids, C,H, 
(NO,).CO,H, a-Mitronaphthote Acid (1, 5)i is almost totally insoluble in hot water. 
It forms delicate needles and melts at 2 39°. Potassium permanganate oxidizes it 
to a-nitrophthalic acid; boiling nitric acid converts it into a-dinitro- eG Sy 
Ferrous sulphate and ammonia reduce it to astable amido-naphthotc acid (1,5 
melting at 212° ( Berichte, 19, 1981). 

B-Nitronaphthoic Acid (1, 8) contains the two side groups in the peri-posi- 
tion. It consists of hard prisms and melts at 275°. Boiling nitric acid converts 
it into (1, 8)-dinitronaphthalene. Ferrous sulphate and ammonia reduce it to 
(1, 8)-amidonaphthoic acid, which when free passes quite readily into its inner 
anhydride, Naphthostyril, fe® » (nED- The latter forms yellowish-brown 
needles, melting at 179° (Berichte, 19, 1131). Naphthalic acid is produced by 
the rearrangement of the amido-acid through the diazo-compound into cyan- 
naphthoic acid etc. (Berichte, 20, 240). 


&-Naphthoic Acid, C,H,.CO,H, from -cyan-naphthalene, 
crystallizes from hot water in long, silky needles, and melts at 182°. 
Baryta converts it (as well as a-naphthoic acid) into naphthalene 
and carbon dioxide. 


Oxy-naphthoic Acids, C,,H,(OH).CO,H. Naphthol carboxylic acids. 
Eight of the fourteen possible isomerides are known. 

a-Naphthol Carboxylic Acid (1, 2) corresponds to salicylic acid. It is pro- 
duced in an analogous manner from a-naphthol, best by heating the sodium salt 
with CO, under pressure (p. 768). It dissolves with difficulty in hot water, crys- 
tallizes in needles and melts at 186°. Ferric chloride imparts an intense blue 
color to it (Berichte, 21, 1186). 

B-Naphthol Carboxylic Acid (2, 1—OH in 2) is derived from $-naphthol- 
‘sodium with carbon dioxide and pressure at oie § Berichte, 20, 2701), as 
well as by carefully fusing $-naphthol aldehyde, C,,H,(QH).CHO, with caustic 


NAPHTHO-FURFURANE. 923 


potash (Berichie, 15, 805). It crystallizes from dilute alcohol in needles, is 
colored violet by ferric chloride, melts at 156° when rapidly heated and decom- 
poses into CO, and naphthol. It sustains an analogous decomposition when it is 
boiled with water. 

If 8-naphthol-sodium be heated more strongly, 200-250°—in a current of 
carbon dioxide the product will be an isomeric zaphthol carboxylic acid. This is 
colored yellow and melts at 216° ( Berich/e, 23, Ref. 612). 

(1, 8)-Naphthol Carboxylic Acid is derived from (1, $)-amido-naphthoic acid 
(see above) by means of the diazo-compound. It melts at 109° and breaks down 


into water and its y-dactone, C, He Coy melting at 169°. 


a-Naphthyl-glyoxylic Acid, Naphthoyl Formic Acid, C,,H,.CO.CO,H, 
obtained from a-naphthoyl chloride by means of the cyanide (p. 762), and from 
a-naphthyl methyl ketone by oxidation with permanganate, melts at 113°, and 
yields a-naphthyl acetic acid, C,,H,.CH,.CO,H, when reduced; this melts at 
ae ; 

Naphthalene Dicarboxylic Acids, C,,H,(CO,H),. Six of the ten possible 
isomerides are known. When acenaphthene and ace-naphthylene are oxidized with 
chromic acid we get Naphthalic Acid (1, 8), which contains the carboxyl groups 
in the peri-position. It crystallizes in smal] needles, which decompose at 140- 
150°, without melting, into water, and its anhydride, C,,H,(CO),O, that crys- 
tallizes from alcohol in needles, and melts at 266°. It is perfectly analogous to 
phthalic anhydride (Berichte, 20, 240). 

Tetrahydro-naphthalene Dicarboxylic Acid, CsA Gon (8, 8), ob- 
tained by saponifying the ethyl ester of the tetracarboxylic acid (p. 906), melts at 
199° and decomposes into water and its anhydride, that melts at 184°. 

Naphthalene Tetracarboxylic Acid, C,,H,(CO,H), (1, 8-4, 5), with the 
carboxyl groups in the two peri-positions of naphthalene, results when pyrenic acid 
is carefully oxidized by potassium permanganate (erichZe, 20, 365). It forms 
shining needles and yields naphthalene upon distillation with lime. 





Derivatives of Naphtho-furfurane and Naphthindol (p. 825). 


/ CHN / CHS 
Cre OG SCH Cio nu SN: 
Naphtho-furfurane. Naphthopyrrol. 


The naphthofurfurane derivatives (@ and /3) are derived, analogously to the ben- 
zofurfurane compounds, by the action of sodium a- and #-naphthol upon chlor- 
acetoacetic ester (p. $17). One derivative is formed from each, whereas according 
to the naphthalene formula two (1, 2) and (1, 8), and (2,1) and (2, 3) isomerides 
are possible with each. The first products are methyl-naphtho-furfurane carboxy- 
lic esters, C,,Hg:C,O(CH,).CO,R; by saponification these yield the free acids, 
from which by loss of carbon dioxide are obtained the methyl naphtho-furfur- 
anes, C,,H,:C,HO(CH,) (Berich/e, 19, 1301). 

The naphthindol or naphthopyrrol derivatives, like the indol derivatives, are 
prepared from the compounds of a- and {-naphthylhydrazines with aldehydes, 
ketones and ketonic acids, when they are heated together with zinc chloride (Be- 
richte, 19, Ref. 831; 20, Ref. 428). a-Naphthindol, C,,H,:C,H,N, crystal- 
lizes in leaflets and melts at 175°. $-Naphthindol is a liquid and boils above 
360°. ) 


924 ORGANIC CHEMISTRY. 


See Berichte, 21, 114, for 8-Naphthoxindol and 6-Naphthisatin. 
Thionaphthene and Thiophtene bear the same relation to naphthalene that 
thiophene bears to benzene :— 


CH : CH CH 
Cie. SCH and hee Ce. 
ee / C 
Thionaphthene. x I oe 
Ne \s/ 
Thiophtene. 


Thionaphthene, C,H,S, has already been given as benzothiophene (p. 826). 

Thiophtene, C,H,5., consisting of two condensed thiophene nuclei, is pro- 
duced when citric acid is heated with P,S, (p.529). It is an oil, boiling at 225°. 
(Berichte, 19, 2444). 





2. PHENANTHRENE GROUP. 


Phenanthrene, C,,H, (p. 905), occurs in coal-tar and in the 
so-called ‘‘stubb,’’ a mass of substance obtained (together with fluor- 
anthene) in the distillation of mercury ores in Idria. It is prepared 
synthetically (with diphenyl, anthracene and other hydrocarbons) 
from various benzene compounds, by conducting their vapors 
through a red-hot tube, ¢. g., from toluene, stilbene, diphenyl and 
ethylene, from dibenzyl and ortho-ditolyl :— 


C,H,.CH, “6 HCH. C,H,.CH 
| and | yield | I + 2H,. 
C,H,.CH, . C,H,.CH, C,H,.C 
Dibenzyl, o-Ditolyl. Phenanthrene. 


Sodium acting on ortho-brom benzylbromide, C,H,Br.CH,.Br, 
also produces it (together with anthracene, p. 893). It also appears 
in the condensation of coumarone with benzene upon the applica- 
tion of heat (Berichte, 23, 85). 


Phenanthrene is obtained from crude anthracene by taking that fraction boiling 
at 320-350°, concentrating it by further distillation, and crystallizing from alcohol, 
_ when anthracene will separate first. The phenanthrene i is obtained from its picric 
acid compound, or by oxidation with chromic acid, when the anthracene will be 
_ first attacked (Annaden, 196, 34; Berichte, 19, 761). 


Phenanthrene crystallizes in colorless, shining leaflets or plates, 
melting at 99°, boiling at 340°; and subliming readily. It dissolves 
in 50 parts of alcohol at 14°, and i in to parts (95 per cent.) on boil- 
ing, and readily in ether and benzene. ‘The solutions exhibit a blue 
fluorescence. The picric acid compound, Ci.Hyo. CsH.(NO,)3.0OH, 
separates in yellow needles on mixing the alcoholic solutions, and 


PHENANTHRAQUINONE. 925 


melts at 144°. Phenanthrene is oxidized by boiling with chromic 
acid to phenanthraquinone, then to diphenic acid. 


Phenanthrene must, from its formation from dibenzyl and ortho-brombenzyl 
bromide, be considered a diphenyl derivative, in which two ortho-places of the 
two benzene nuclei are unjted by the group C,H,; the latter, therefore, forms, 
with the four carbon atoms of the two benzene rings, a third normal benzene ring. 
So-called phenanthraquinone, the oxidation product of phenanthrene, must be 
regarded as an ortho-diketone (p. 699), because further oxidation converts it into 
diphenic acid (p. 849), in which the two carboxyl groups are inserted in two ortho- 
places of diphenyl :— 


C,H,.CH C,H,.CO C,H,.CO,H 
| I | | 

C,H,CH C,H,.CO C,H,.CO,H 

Phenanthrene. Phenanthraquinone, Diphenic Acid, 





Hydrogen additive products result upon heating phenanthrene with hydriodic acid 
and phosphorus. The ¢etra-hydride, C 1sHyy, boils at 310°, and solidifies on cool- 
ing. The Per-hydride, C,,H,,4, melts at -3° and boils at 270-275° ( Berichte, 22, 
779). Chlorine produces substitution products, of which the octo-chloride, C,H, C 
melts at 270-280°, and by further chlorination (comp. p. 580) is split into hexa- 
chlorbenzene, C,Cl,, and CCl,. Bromine combines with phenanthrene in CS, 
solution, yielding the dibromide, C,,H,,-Br,, which melts at 98°, with decom- 
position, and readily breaks up into hydrogen bromide and dromphenanthrene, 
C,,H,Br. This melts at 63°, and is oxidized to phenanthraquinone by chromic 
acid. 

Ordinary nitric acid converts phenanthrene into three nitrophenanthrenes, 
C,,H,(NO,), which yield three amido-phenanthrenes, C,,H,(NH,), by reduction. 

Two phenanthrene-sulphonic acids, C\4Hy.SO,H, are produced on digesting 
phenanthrene with sulphuric acid. If these be distilled with yellow prussiate of 
potash we obtain two cyanides, C,,Hy,.CN, yielding the corresponding carboxylic 

acids. 


Phenanthraquinone, C,,H,O,, an ortho-diketone (see above), 
is formed in the action of chromic acid upon phenanthrene in 
glacial acetic acid solution; most readily by heating it with a 
chromic acid mixture (A4unalen, 196, 38). It crystallizes from 
alcohol in long, orange-yellow needles, melts at 198°, and distils 
without decomposition. It is not very soluble in hot water or cold 
alcohol, but readily in hot alcohol, ether and benzene. It dissolves 
in concentrated sulphuric acid with a dark green color, and is re- 
precipitated by water. By adding toluene containing thiotolene 
and sulphuric acid to the acetic acid solution of phenanthraquinone 
a bluish-green coloration is produced (p. 572). 


Like B-naphthoquinone phenanthraquinone is odorless, not volatile in steam, 
and is readily reduced by sulphurous acid. Like the latter, too, it ‘unites with one 


926 ORGANIC CHEMISTRY. 


and two molecules of H,N.OH. The monoxime, C,,H,O(N,OH), consists of 
golden yellow needles, melting at 158°, and dissolving with a red color in sul- 
phuric acid. If it is heated together with glacial acetic acid and hydrochloric acid 
to 130° it sustains the transposition of ketoximes (p. 727), and forms dipheni- 


mide, Cyl, <g> NH (Berichte, 22, Ref. 591). The dioxime forms an anhy- 


dride, C,H vie oy melting at 181°. An isomeric monoxime or dioxime has 


not been prepared (p. 727) (Berichte, 22, 1985). 

Phenanthraquinone forms phenazine derivatives with ortho-diamines. Being 
a ketone it also combines with primary sodium sulphite to form the crystalline 
derivative, C,,H,O,.SO,HNa -++ 2H,O, from which it is again separated by 
alkalies or acids. By oxidation with chromic acid, or by boiling with alcoholic 
potash, phenanthraquinone is oxidized to diphenic acid; ignition with soda-lime 
produces diphenylene ketone (p. 851), fluorene and diphenyl. Diphenylene 
glycollic acid (p. 851), fluorene alcohol and diphenylene ketone are obtained on 
boiling with aqueous soda-lye. Ignited with zinc dust we obtain phenanthrene. 

On digesting phenanthraquinone with concentrated sulphurous acid it changes 
to Dioxyphenanthrene, C,,H,(OH), (phenanthrene hydroquinone), which 
crystallizes from hot water in colorless needles that turn brown on exposure, and 
reoxidize to phenanthraquinone. The diacetate crystallizes from benzene in 
plates, melting at 202°. 

By saponifying the two phenanthrene cyanides we obtain two Phenanthrene- 
carboxylic Acids, C,,H,,O, :-— 


C,H,.CH CHC 
() L. Wand (®) | | 
CO,H—C,H,.CH C,H,.C.CO,H. 
The a-acid melts at 266°, and is oxidized to phenanthraquinone carboxylic acid, 
C,,H,(O,)CO,H, by chromic acid; the Z-acid melts at 251°, and yields 
phenanthraquinone. 


Retene, C,,H,,, is a derivative of phenanthrene. It represents a methyl 
isopropyl phenanthrene (Berichte, 18, 1027; Ref. 558) :-— 


CH, \ CHick. 

CH, Doe ell, ee 
C,H,.CH HH ,.CO 
Retene, Retene Quinone. 


Retene occurs in the tar of highly resinous pines, and in some mineral resins. 
It is isolated from those portions that boil at elevated temperatures. It is very 
soluble in alcohol and benzene. It crystallizes in leaflets with mother-of-pearl 
lustre, melts at 98°, and boils about 390°. It is very volatile in steam, Its picric 
acid compound forms orange-yellow needles, melting at 123°. Chromic acid in 
glacial acetic acid solution oxidizes retene to retene quinone, C,,H,,O, (see 
above)—a red powder, crystallizing in orange-red needles that melt at 197°. It 
dissolves in caustic potash with a dark-red color; this disappears upon shaking in 
contact with air. It yields retene by the distillation with zinc dust. It resembles 
phenanthraquinone in its entire deportment. It is an orthodiketone. Sulphurous 
acid reduces it on application of heat to Retene Hydroquinone, C,,H,(OH),; 


FLUORANTHENE, 927 


air reoxidizes it to retene quinone. Hydroxylamine converts it into a quinone 
oxime, C,,H,,O(N.OH), and quinone dioxime, C,,H,,.(N.OH),, golden yellow 


leaflets, that melt at 129°. It forms retene phenazine, C,H 6\ 7 C,H, ) 
(p. 629) with o-phenylenediamine. of 
Sodium hydroxide converts retene quinone into two rather unstable acids— 


Retene Diphenic Acid, CuPhi< cote and Retene Glycollic Acid, C,,H,,. 
2 


CH(OH).CO,H (see p. 851). Potassium permanganate oxidizes retene 
quinone to diphenylene ketone dicarboxylic acid (p. 852) and retene ketone, 
CH,.(C,H,).CoHy. 

A Ke 
quinone with lead oxide. When the latter is distilled with zinc dust the product 
is retene fluorene, C,,H,, (p. 851). Pearly leaflets, melting at 97° (Berichie, 
18, 1754). 

Retene Dodecahydride, C,,H, 9, a blue fluorescent oil, boiling at 336° 
(Berichte, 22, 780), is formed when retene is heated with hydriodic acid and 
phosphorus to 250°. It is identical with dehydrofichtelite. 

Fichtelite, C,,H,,, occurs together with retene in the peat of fossil pines. It 
crystallizes from ligroine and alcohol in vitreous prisms. It melts at 46° (Berich/e, 
22, 498, 635). When heated to 150° with iodine it loses two hydrogen atoms 
and forms Dehydrofichtelite, C,,H,9, identical with retene dodecahydride. 
Fichtelite is, therefore, retene perhydride, C,,H,, (Berichte, 22, 3369). 


CO, which can be more easily prepared by distilling retene 


Besides the hydrocarbons with high boiling points which have 
been derived from coal-tar and already described; naphthalene, 
C,H, (B. P. 218°); methyl-naphthalene, C,,Hy) (240°) ; acenaph- 
thene, C,,H,) (278°) ; fluorene, C\;Hy» (305°); phenanthrene, C,,Hyo 
(340°), and anthracene, C,,Hy (360°), we have the following : 
fluoranthene, C,,;H,, pyrene, C,sHy,and chrysene, C,sH,,. These 
have been isolated from the so-called crude phenanthrene, the 
fraction boiling above 360°. 


Fluoranthene and pyrene occur chiefly in the first fractions. They are separated 
by fractional distillation under diminished pressure ; fluoranthene boiling at 250° 
under 60 mm. pressure; pyrene at 260°. ‘Their perfect separation is then effected 
by the fractional crystallization of their picric acid derivatives (Anma/en, 200, 1). 
The portions boiling at the most elevated temperatures consist mainly of pyrene 
and chrysene, which are separated by means of carbon disulphide (which dissolves 
pyrene) and by the crystallization of their picric acid combinations (Anma/en, 158, 
285 and 299). 

Pyrene and fluoranthene (idryl) also occur in the “ stubb-fat”’ obtained from the 
distillation of the “stubb ” (p. 924 

Fluoranthene, C,,H, 9, Idryl,crystallizes from alcohol in needles or plates, melt- 
ing at 109-110°, and dissolves readily in hot alcohol, ether and carbon disulphide, 
It dissolves with a blue color in warm sulphuric acid. Its picric acid nh ac 
C,H, 9-C, H,(NO,),OH, consists of reddish-yellow needles, is sparingly soluble in 
ether, and melts at 182°. Fuming nitric acid converts idryl into the trinitro-com- 
pound, C,,H,(NO,)s, melting above 300°, Fluoranthraquinone, C,,H,O,, 
is obtained by oxidizing idryl with chromic acid. It crystallizes from alcohol in 
small, red needles, melting at 188°, and dissolves, like phenanthrene, in alkaline 
bisulphites. Ifthe quinone be further oxidized (with elimination of CO,) we ob- 
tain diphenylene-ketone carboxylic acid. 


928 ORGANIC CHEMISTRY. 


The constitution of fluoranthene and of fluoranthoquinone probably corresponds 
‘to the formulas (Auzalen, 200, 20) : — 


OY Ct H 
¥ "Ge l 6 #\ . 6 “Yoo 
C,H : CO Ope | 
cH cH fo Oe a 800, 
Fluoranthene. Fluoranthoquinone. Diphenylene-ketone 
Carboxylic Acid. 


Pyrene, C, ,H,, is sparingly soluble in hot alcohol (33 parts), readily in ether, 
benzene and carbon disulphide, crystallizes in colorléss leaflets or plates, and melts 
at 148°. ‘The picric acid compound crystallizes from alcohol in long needles, and 
melts at 222°. Chromic acid oxidizes it to Pyrenquinone, C,,H,O,, a brick-red 
powder, which is almost completely decomposed when heated. 

Pyrenic Acid, C,,H,O,, results upon further oxidation of pyrenquinone. It is 
an ortho-dicarboxylic acid. It forms an anhydride or imide compound quite 
readily. It consists of golden yellow leaflets, and at 120° breaks down into water 
and its anhydride. Being a ketone it combines with one molecule of phenylhydra- 
zine (Berichte, 19, 1997). When pyrenic acid is distilled with lime, it forms Py- 
rene Ketone, C,,H,(CO), crystallizing in yellow plates that melt at 141°. Being 
a ketone, it combines with phenylhydrazine and sodium bisulphite. Potassium per- 
manganate oxidizes pyrenic acid to naphthalene tetracarboxylic acid (p. 923), and 
pyrene ketone to naphthalic acid, which yields naphthalene upon distillation with 
lime. 

Pyrene is, therefore, very probably a naphthalene, in which both peri-positions 
(1, 8 and 4, 5) are replaced by two groups, CH.CH.CH, so that four symmetrical 
condensed benzene nuclei are produced (Berichte, 20, 365; Annalen, 240, 147). 

Chrysene, C,,FI,, (p. 927), is generally colored yellow (hence the name), but 
can be rendered perfectly colorless by the action of different reagents. It is very 
sparingly soluble in alcohol, ether and carbon disulphide, and rather readily soluble 
in hot benzene and glacial acetic acid; it melts at 250°, and boils at 436°. It 
crystallizes and sublimes in silvery leaflets, which exhibit an intense violet fluores- 
cence. The picric acid compound crystallizes from hot benzene in red needles, and 
is decomposed by alcohol. When digested with chromic acid and glacial acetic acid 
it oxidizes to so-called Chrysoquinone, C,,H,,O, (a diketone), which crystallizes 
in red needles, melting at 235°, and dissolving in sulphuric acid with a blue color ; 
water reprecipitates chrysoquinone. It unites as a ketone with primary sodium 
sulphite. Sulphurous acid reduces it to the hydroquinone, C,,H,)(OH),. 

Chrysoketone,C, ,H,,O (compare retene ketone), results when chrysoquinone 
is distilled with lead oxide. It crystallizes in bright red colored needles, melting 
at 132°.. Hydriodic acid and phosphorus, upon application of heat, reduce it to 
chrysofluorene, C,,H,, (melting at 187°). : 

Chrysenic Acid, C,,H,,0, (phenylnaphthyl carboxylic acid), is produced 
when chrysene is fused with caustic alkali. It forms silver-white leaflets and melts 
at 186°.. When it is dissolved in sulphuric acid it reverts to chrysoketone (Ze- 
richte, 23, 2440). 

Chrysene is prepared synthetically from benzyl-naphthyl-ketone, C,H,.CH,. 
CO.C,,H, (from phenyl acetic chloride, C,H,.CH,.COCI, and naphthalene with 
AIC1,), if the latter be converted by heating with hydriodic acid and phosphorus 
into the hydrocarbon, C,H;.CH,.CH,.C,,H,, and then distilling this through a 
red-hot tube—just as phenanthrene is produced from dibenzyl :— 


C,H;.CH,  C,H,CH 


Led ok + an. 
O.4H,.CH,- > C,H CH 


PICENE. 929 


Chrysene is similarly formed by heating naphthalene with coumarone, C,H, 


/ CHN 


O pou 2—just as phenanthrene is obtained from coumarone and benzene (p. 


924) (Berichte, 23, 84). Therefore, chrysene consists, in all probability, of four un- 
symmetrical, condensed benzene nuclei; and chrysoquinone and chrysoketone 
would then have the following formulas (see Berichte, 23, 2433) :— 


C, ,.H,—CO Cio 


6 
l Sco. 
C,H,— CO go" 4 
Chrysoquinone. Chrysoketone. 


The liquid Zydride, C, ,H,,, boiling about 360°, is produced when chrysene is 
heated together with hydriodic acid and phosphorus. A later product is Chrysene 
Perhydride, C,H, , crystallizing in white needles, melting at 115° and boiling 
about 353° (Berichte, 22, 135). 

Naphanthracene, C,,H,., from naphanthraquinone, C,,H,,O,, on digest- 
ing it with zinc dust and ammonia, is isomeric with chrysene. It is produced by the 
condensation of naphtoyl-o-benzoic acid (from phthalic anhydride with naphtha- 
lene and AICI, p. 863) upon heating it with sulphuric acid, just as anthraquinone 
is derived from o-benzoyl-benzoic acid (p. 893) (Berichte, 19, 2209) : 


Cc CO CO.G3H 
CHL | SCR, OCS See ee 
NCH \co% \co.OH 
Naphanthracene, Naphanthraquinone. Naphtoyl-o-benzoic acid. 


Naphanthracene crystallizes from alcohol in colorless leaves, having a strong 
‘greenish-yellow fluorescence. It melts at 141° and sublimes. It combines with 
two molecules of picric acid, C,,H,,.2C,H,(NO,),0, forming red needles melt- 
ing at 133°. Naphanthraquinone, C,,H,,O, (see above), crystallizes and sub- 
limes in yellow needles or leaflets and melts at 168°. It dissolves with a brown 
color in concentrated sulphuric acid; water reprecipitates it unchanged. 





Picene, C,,H,,, is a hydrocarbon formed hy the distillation of lignite, coal- 
tar and petroleum residues. It is very sparingly soluble in most of the solvents, 
but most readily in crude cumene, crystallizes in blue fluorescent leaflets, melting 
at 338°, and boils at 519°. It dissolves with a green color in sulphuric acid and 
is oxidized by chromic acid to an orange-red guinone, C,.H,,0,. When heated 
to 250° with hydriodic acid and phosphorus Picene Perhydride, C,,H,.,, is 
produced. It forms white needles melting at 175° and boiling above 360° Be- 
richte, 22, 781). 





DERIVATIVES OF NUCLEI CONTAINING NITROGEN. 


A. Derivatives of five-membered nuclei containing nitrogen. 
The five-membered parent nuclei and their derivatives were 
almost entirely disposed of before the aromatic compounds were 
taken up. Mention must, however, be made of the phenylated 
diazoles: of pyrazole and of glyoxaline (p. 551). 
78 


930 ORGANIC CHEMISTRY. 


1. PHENYLATED PYRAZOLES. 
The parent nuclei of the derivatives belonging to this class are :— 


4 5 

CH = (at CH,—CH CH,—CO 

l \NH Wee hae. L a SNH 
CH = N11 CH = N% H = N” 

, Petasetes. Pyrazoline. 5-Pyrazolon. 


The positions of substituting groups in these parent nuclei are designated by 
the numbers 1-5, corresponding to the notation of the pyrazole nucleus. Pyrazo- 
line and pyrazolidine (p. 551) bear the same relation to pyrazole as pyrroline and 
pyrrolidine to pyrrol (p. 549). The nucleus of pyrazolon or ketopyrazoline, con- 
taining oxygen, corresponds to pyrrolidon and the pyridine and lutidine of the 
pyridine group (p. 944). The term 5-fyrazolon serves to distinguish this from 
the possible 3- and 4-pyrazolons, in which the oxygen occupies positions 3 and 4. 


The pyrazole compounds (formerly called quinazine derivatives) 
were discovered by L. Knorr in 1883 (Berichte, 16, 2597; An- 
nalen, 238, 137). Antipyrine belongs to this group. It has great 
technical value. 


1. Pyrazole-derivatives, in which oxygen is not present, are produced :— 


(1) By heating the £-diketones,*—CO.CHR.CO—of the benzene and paraffin 
series with primary phenylhydrazines. The immediate products are the phenyl- 
hydrazones (p. 656); these eliminate water and a closed ring results, Thus, 
benzoyl acetone (p. 731) and phenylhydrazine yield Diphenylmethyl Pyrazole 
(Berichte, 18, 2135) :— 


C,H,.CO.CH,.CO.CH, + H,N.HN.C,H, = 


CoHy.CC 
N= NCH; 
(1, 3, 5)-Diphenyl-methyl Pyrazole. 


In like manner we obtain (1, 3, 5)-pheny/ dimethyl pyrazole, from acetyl acetone, 
CH;.CO.CH,.CO.CH, (Berichte, 20, 1104); and benzyl phenyl methyl-pyrazole 
(Berichte, 18, 2137) from phenylacetyl acetone, C,H,.CH,.CO.CH,.CO.CH, 
(p- 731). (1, 3, 5)-77iphenyl pyrazole is derived from dibenzoyl methane, C,H,. 
CO.CH,.CO.C,H, (p. 891) (Berichte, 21, 1206). 

Pyrazole carboxylic esters are formed in an analogous manner from /-diketone 
carboxylic esters. For example, benzoyl aceto-acetic ester (p. 816) and phenyl 
hydrazine yield (1, 3, 5)-diphenyl methyl-pyrazole-4-carboxylic ester (Berichte, 18, 
311) :— 





* The y-diketones combine with the phenylhydrazines, forming pyridazine com- 
pounds (p. 954), whereas the derivatives of the a-diketones with two molecules of 
phenylhydrazine remain unchanged. 





PHENYLATED PYRAZOLES. 931 


; CO.R 
C.H..co.cH/ ©Y2 H.N.HN.C.H. = 
64*5 \, CO.CH, + H, 6**5 CO,R 
| /S=CCH, 
CHSCK | e + 2H,0. 
-Diph 1- hyl-4- 1 
Dik ek Dem a daa AF Pu Sige 


The corresponding nitro-derivatives (Berichte, 18, 2256) are similarly formed 
from o- and /-nitro-benzoyl aceto-acetic ester. The free acid results upon saponi- 
fying the ester; when it loses carbon dioxide it passes into (1, 3, 5)-diphenyl- 
methyl-pyrazole (see above) (erichte, 20, 1096). Under like treatment acetyl 
aceto-acetic ester, CH,.CO.CH(CO.CH,).CO,R, furnishes (1, 3, 5)-phenyldimethyl 
pyrazole-4-carboxylic ester, from which by saponification and elimination of car- 
bon dioxide, it is possible to obtain (1, 3, 5)-phenyldimethyl pyrazole, C,HN, 
(C,H;) (CH;), (Berichte, 20, 1101). Further, benzoyl pyroracemic ester C,H,. 
CO.CH,.CO.CO,H (p. 765), becomes diphenylpyrazole-carboxylic ester, which 
then yields (1, 3)-diphenyl pyrazole, C, H,N,(C,H;), (Berichte, 20, 2185). 

2. The £- or (1, 3)-ketone aldehydes react like the 6-diketones. Thus we obtain 
from acetylaldehyde, CH,.CO.CH,CHO, (1, 5)-phenyl methyl pyrazole, from 
propionyl aldehyde, CH,.CH,.CO.CH,.CHO, phenyl ethyl pyrazole (Berichte, 
21, 1147), from propionyl propionic aldehyde, CH,.CH,.CO.CH(CH,).CHO, 
phenylmethylethyl pyrazole (Berichte, 22, 3276), and from benzoyl aldehyde, 
C,H,.CO.CH,.CHO (p. 730), (1, 5)-diphenylpyrazole (Berichte, 21, 1138), etc. 

Epichlorhydrin conducts itself in asimilar manner with the formation of 1-phenyl- 
pyrazole, which may also be prepared from phenyl pyrazole tricarboxylic acid 
(Berichte, 22, 180, Ref. 238, 554). It is a yellow oil; when it has been solidified 
it remelts at 11° and boils at 246°. 

3. From the unsaturated ketones and aldehydes, CHR:CR.COR and CHR:CR. 
COH, when they are heated with the phenylhydrazines. The phenylhydrazine 
formed at first loses, when distilled, two hydrogen atoms, and yields the correspond- 
ing pyrazole derivative; the pyrazoline compound, isomeric with the latter, is formed 
simultaneously by mere molecular re-arrangement of the phenyl-hydrazone (47- 
nalen, 238,141; Berichte, 20, 1097). In this way benzal acetone, CH,.CO.CH: 
CH.C,H, (p. 805) and phenylhydrazine form (1, 5, 3)-diphenylmethyl pyrazole 
and pyrazoline (Berichte, 20, 1100) :— 








CH,.C—CH ='CH.C,H, CH,.C.CH,—CH.C,H, 
| yields 
N—NH.C,H, N.C,H, 
Phenylhydrazine-benzal Diphenylmethyl 
Acetone, : Pyrazoline. 
CH,.C-CH =C.C,H, 
and | a. Ss 
N N.C 6 H 5 
Diphenylmethyl 
Pyrazole. - 


The latter is isomeric with (1, 3, 5)-diphenylmethyl pyrazole. Under similar 
treatment ethidene acetone, CH,.CO.CH:CH.CH, (p. 195), yields phenyl dimethyl- 
pyrazoline (Berichte, 22,1105). Cinnamic aldehyde forms (1, 5)-diphenylpyrazo- 
line, and (1, 3, 5)-¢riphenylpyrazoline is obtained from benzalacetophenone, C,H;. 
CH:CH.CO.C,H, (Berichte, 21, 1201). 

Pyrazole carboxylic esters are similarly derived from umsaturated ketone car- 
boxylic acids (their esters); the pyrazoles can be prepared from these. ‘Thus, 


932 ORGANIC CHEMISTRY. 


benzal aceto-acetic ester and phenylhydrazine yield (1, 5, 3)-diphenyl methyl pyra- 
sole-4-carboxylic-ester :— 
CO,H 
CH,.CO.C = CH.C,H, + H,N.NH.C,H, = 
CO,H 
CH,.C—C = C.C,H, 
| + H,O + H,° 





N CoH, 
Diphenylmethyl-pyrazole 
Carboxylic Ester. 


(1, 5, 3)-Diphenylmethyl-pyrazole (see above) results upon saponifying the ester 
and eliminating carbon dioxide (Aza/en, 238,139). Ethidene aceto acetic ester 
yields (1, 3, 5)-phenyldimethyl-4-carboxylic ester ; when this is saponified and loses 
carbon dioxide it forms (1, 3, 5)-phenyldimethyl-pyrazole (Berichte, 22, 1101). 

The unsaturated aldehydes react very much like the unsaturated ketones. Acro- 
lein-phenylhydrazide yields 1-phenyl pyrazoline (Annalen, 239, 195) :— 


CH—CH=CH, CH.CH,.CII, 





| 
N—NH.C,H, N 





The phenyl pyrazoles are feeble bases; water readily decomposes their salts; 
they volatilize with steam from acid solutions. Nitrous acid does not affect them. 
Sodium, acting upon their alcoholic solution, converts them into the corresponding 
pyrazolines. The latter are also weak bases; oxidizing agents (nitrous acid, 
chromic acid and ferric chloride) convert them into fuchsine-red dyes— pyrazole 
reaction of Knorr (Aznalen, 238, 200). 

2. The oxygen-containing Ayrazo/on-derivatives (see above) are produced, if 
B-ketonic acids, R.CO.CH,.CO,H, be substituted for $-diketones in the formation 
of the phenylpyrazoles, or if, instead of unsaturated ketones, aldehydes and ketone 
carboxylic acids, unsaturated acids be allowed to react with phenylhydrazines. 
Acetoacetic ester and phenylhydrazine condense to ahydrazone, which, upon being 
heated, splits off alcohol and forms (1, 3)-pheny/-methyi pyrazolon ( Annalen, 238, 


146) :— 


CH,.C—CH,.CO.0.C,H, CH,.C—CH,—CO 
1 ie l + C,H,.OH.. 
N—NH.C,H, | IES 8 91 | 
Phenylhydrazine Aceto-acetic Ester. . (1, 3)-Phenylmethyl Pyrazolon. 


(1, 3)-Diphenylpyrazolon is similarly formed from benzoyl acetic ester, C, H;. 
CO.CH,.CO,.C,H, (Berichte, 20, 2545; 21, Ref. 201). The phenylhydrazide 
of unsaturated phenylacrylic acid, C,H,.CH:CH.CO.NH.NH.C,H,, when dis- 
tilled, loses two hydrogen atoms and forms (1, 5)-Diphenylpyrazolon, C,,H,, 
N,O=C,,H,,N,0 + H, (Berichte, 20, 1107). Oxalylacetic ester (p. 435) 
(Berichte, 19, 3227) and succino-succinic ester (p. 795) (Berichte, 17, 2053) re- 
act analogously. The ester of phenylformyl acetic acid (a S-aldehydic acid) reacts 


PHENYLDIMETHYL PYRAZOLON. 933 


similarly to the esters of 3-ketonic acids with the formation of (1, 4)-diphenyl- 
pyrazolon (Berichte, 20, 2933) :-— 


(60.0.0, H, 
CyH,.CHE + H,N.HN.C,H,= 
CHO 
Phenylformyl Acetic Ester. 
OO. N.CoH, 
C.H,.CHC l + C,H,.0H + H,0. 
CH=N 


(1, 4)-Dipheny] pyrazolon. 


As the CH,-group of the pyrazolon compounds, obtained from acetyl- and ben- 
zoyl-acetic esters, is retained unaltered, all mono- and di-substituted acetoacetic acid 
esters ( ¢.g., methyl- and dimethyl-acetoacetic ester, acetosuccinic ester, etc.), are 
capable of yielding pyrazolon compounds with primary phenylhydrazines. On the 
other hand, the unsymmetrical -compounds (not the a-derivatives, p. 657), from 
the alkylic phenylhydrazines, are able to form derivatives of the isopyrazolon nu- 
cleus (antipyrine compounds). Tolylhydrazine, naphthylhydrazine, etc., react in 
the same manner as phenylhydrazine (Berichte, 17,549). Hydrazobenzene,C,H,. 
NH.NH.C,H,, reacts just the same as the (-alkyl phenylhydrazines (p. 649). 


(1, 3)-Phenylmethyl Pyrazolon, C;H,O(CH;)N,(C,H; = 
C,,H,)N,O, resulting from acetoacetic ester and phenylhydrazine 
(Annalen, 238, 147), crystallizes from hot water in prisms, melting 
at 127° and boiling at 287°. It manifests the feeble basic character 
of the pyrazole bases, and at the same time the acid nature of 
acetoacetic ether. It is soluble in acids and alkalies. The hydro- 
gen of its CH,-group will answer all the reactions of the same 
group in aceto-acetic ester; it can be replaced by metals, alkyls, 
etc. Ferric chloride or platinic chloride oxidizes the pyrazolon to 
pyrazole blue (see below). This reaction serves for the recognition 
of all pyrazolon compounds containing the CH,-group intact. 

When (1,-3)-phenylmethyl pyrazolon is heated to too° with me- 
thyl iodide and methyl alcohol, it sustains a partial transposition 
and forms 

Phenyldimethyl Pyrazolon, C,,H,,.N,O = C,;H(CH;),.N,(C, 
H;)O (1, 2,3), Antipyrine. ‘This is derived from the unaltered iso- 
pyrazolon nucleus (with a different arrangement of the hydrogen 
atoms), and may be directly synthesized by heating acetoacetic 
ester with a@-methyl-phenyl-hydrazine, C,H;.NH.OH.CH, (see 
below) (Aznalen, 238, 160, 203; Berichte, 20, Ref. 609) :— 


CH,.CO.CH,.CO.0.C,H, + CH,.NH.NH.C,H, = 
CH,.C = CH.CO 
\ | + C,H,.0OH + H,O. 
CH,—N Ses . 
Antipyrine. 





Antipyrine, rather singularly, is very soluble in water, alcohol 
and chloroform. It crystallizes from ether and toluene in shining 
leaflets, melting at 113°. It is astrong monacid base, that forms 


934 ORGANIC CHEMISTRY. 


salts with ease. Ferric chloride colors its aqueous solution red, and 
nitrous acid imparts a bluish-green color to it (Azna/len, 238, 203). 
It is used as an antipyretic. 


Many derivatives are obtained by the substitution of the hydrogen of the CH, 
group in phenylmethylpyrazolon. Compounds like benzylidene- phenylmethy]- 
pyrazolon are formed upon heating it together with aldehydes. ‘These are red 
dye-substances. They correspond to the indogenides of pseudoindoxyl (p. 833). 
Bi-phenylmethyl Pyrazolon is formed by moderated oxidation or by the action of 
iodine upon silver phenylmethyl pyrazolon. It can also be obtained synthetically 
from diaceto-succinic ester, and two molecules of phenylhydrazine. Pyrazole 
Llue (Annalen, 238, 171) is even formed in the cold by further oxidation with 
ferric chloride, etc. :— 


CO—CH 





Conc =e N.C, H,. 
tT MN OOCH,CH Cen’! 
Bi-(1, 3)- Phenylmethyl Pyrazolon. 
05 Sa ge SE GR yg 
‘ah: en ceria i Nae 
Sr C.CH,.CH,.C = N~ 
Pyrazole Blue. 


Pyrazole blue results directly upon boiling phenylmethylpyrazolon with ferric 
chloride. In properties and constitution it is very similar to indigo blue. 


Phenylmethyl pyrazolon exhibits great similarity also to barbituric 
acid (malonyl urea, p. 441). Its isonitroso-, nitro- and amido- 
derivatives correspond perfectly to violuric acid, dilituric acid, and 
the uramile of the uric acid group. When the amido group Is oxid- 
ized rubazonic acid is produced ; this corresponds to purpuric acid 
(Annalen, 238, 192). Rubazonic acid and phenylhydrazine unite 
to a hydrazone, that is identical with an azo-compound derived from 
phenylmethyl pyrazolon and benzene diazochloride (Berichte, 21, 
1201). 


2, PHENYLATED GLYOXALINES (p. 929). 


The alkyl glyoxalines have been discussed. The phenylated 
glyoxalines will be here considered. Lophine, C,,H,.N., and 
Amarine, C,,H,,N,, belong in this class. They are tripheny] deri- 
vatives of glyoxaline and dihydroglyoxaline, and bear a close rela- 
tion to hydrobenzamide (p. 717) and triphenyl-cyanide, (C,H;.CN)s 
ite 18, 1849, 3085) :— 


C,H,.C.NH, 
CH.C,H, | >CH.C,H, [cca 
C,H,CH: are C,H,.C.NH~ C,H,.C.NH7 
‘Hydrobénzamide. Amarine. ” Lophine. 


Triphenyl Glyoxaline, C,;N,H(C,H;);, ZLophine, is produced 
when amarine or hydrobenzamide is subjected to distillation, or if 
the former be oxidized with chromic acid (in glacial acetic acid), 


PHENYLATED GLYOXALINES. ’ 935 


or from cyanphenine, (C,H,;.CN) , by the action of nascent hydro- 
gen (with disengagement of NH;). It may be prepared syntheti- 
cally by acting with ammonia upon an alcoholic solution of benzil, 

with benzaldehyde, in the same manner as glyoxalethylins are ob- 
tained from glyoxal with aldehydes (p. 552). Lophine is not 
readily soluble in alcohol, crystallizes in long needles, and melts at 
275°. It yields crystalline salts with one equivalent of the acids. 

It exhibits the property of phosphorescing in marked degree when 
shaken with alcoholic potash ; it is then decomposed into ammonia 
and benzoic acid (p. 189). Like the glyoxalines, it does not form 
an acetate. 

Triphenyl Dihydroglyoxaline, C,;N,H;(C,H;);, Amarine, re- 
sults from a rearrangement of the isomeric hydrobenzamide, caused 
by boiling it with caustic potash or upon heating it to 130°. It 
crystallizes from alcohol and ether in prisms, melting at 113°. It 
reacts (in alcoholic solution) alkaline, and with one equivalent of 
the acids yields salts which are sparingly soluble in water. Amarine 
affords dialkyl derivatives when it is heated with alkyl iodides, 
whereas only mono-alkyl compounds result with lophine. 


3. PHENYLATED TRIAZOLES (p. 553). 


CH =N = CH 
NH, Osotriazone. 1 ‘NH, Triazole. 
CH =N CH = N¥ 


Triphenyl Osotriazone, C,N;(C,H;);, from benzil dihydra- 
zone, consists of pearly leaflets, melting at 122° (Berichte, 21, 
2806). 

The diketo derivatives of Tetrahydrotriazole, C,N;,H,, have 
been called urazoles (p. 553). 





In conclusion,mention must be made of the dzazole ring. Its phenyl 
aX 

pe iA CX, 
and considered such, result in the action of phosgene gas upon the 
a-acid or urea- derivatives of the as ae he og (Berichte, 21, 


derivatives, formerly termed phenyl carbizines, C,H 


24563; 23, 2843) :— hb 
C,H,.NH.NH.CO. CH, =f. ee ==:C,H, roan 2 
a-Acetythydrasine, Ae eee ch. 2HCl. 
| oe 


ae aaa Biazolon, 


936 ORGANIC CHEMISTRY. 


Phenyl Biazolon, C,H;.C,N,0,H, is analogously formed from 
formyl phenylhydrazine (p. 658), and was formerly designated 
formylphenyl carbizine. It melts at 73° and boils at 255°. 
Phenyl Methyl Biazolon, C,H;.C,N,O,.CH, (see above), melts 
at 94° and boils at 280°. 

The phenyl biazolons are quite stable towards acids, even when 
heated with the latter. Boiling alkalies decompose them into their 
components. 





B. Derivatives of six-membered Nuclei, containing Nitrogen. Pyri- 
dine and Quinoline Group. 


Pyridine, C;H;N, and Quinoline, C,H,N, are two basic bodies, 
which command particular interest, because they have been recog- 
nized as the parent substances of many alkaloids. In their entire 
deportment they closely resemble the benzene compounds. They 
are quite stable towards oxidizing agents (nitric acid, chromic 
acid, potassium permanganate). By replacing the hydrogen in 
them with alkyls (especially methyls) they yield a series of homo- 
logous compounds—the Pyridine and Quinoline bases, e. g., CsH, 
(CH;)N, and C;H;,(CH;),N, from which the acids (mono-, di- and 
tri-carboxylic acids) result on oxidizing the methyl groups. By 
.elimination of the carboxyls from the acids, the stable parent 
nuclei, pyridine and quinoline, are regenerated. This deportment, 
characteristic of benzene compounds, is explained by the constitu- 
tion of pyridine and quinoline. Both contain a closed chain con- 
sisting of five carbon-atoms and one nitrogen-atom. This ring is 
remarkably stable, and is very similar to the benzene ring. 


Pyridine, C,H,N, may be regarded as a benzene in which one CH-group is re- 
placed by a nitrogen-atom, whereas quinoline, C,H,N, is derived in a similar 
manner from naphthalene, C,,H,, by a change in one of the benzene rings :— 


i H H H 
C C C 
@™ ‘ itso. 
HC CH Fits. ste Gee 
eee ee 
HC CH . rit Git 
Sax VIN 4 
Ny Co mea 
Pyridine. H 
Quinoline. 


These constitutional formulas have been proved by numerous syntheses of 
pyridine and quinoline, as well as of their derivatives (Kdrner, 1869). The forma- 
tion of pyridine from quinoline is rather remarkable. The latter is oxidized, the 
benzene nucleus is destroyed (as with naphthalene, p. 907) the a- 3-pyridine- 


r 
ed 


PYRIDINE GROUP. 937 


dicarboxylic acid, C;H Fi: Se H),, formed, and when it splits off 2CO, pyridine 
is produced :— 


CH = CH—C—CH = CH CH — CH—C—CO,H CH = CH—CH 


| | | | 
CH= N —C—CH = CH dex = N _t co,n bus = N _ty 
Quinoline. Pyridine Dicarboxylic Acid. Pyridine. 


Since the nitrogen-atom in the pyridine and quinoline bases is 
joined with three affinities to carbon, these compounds are tertiary 
amines, which combine with alkyl iodides, yielding ammonium 
iodides. Further, it follows, from the accepted structural formulas, 
that the pyridine and quinoline derivatives are capable, like ben- 
zene, of yielding hydrogen addition products; thus from pyridine, 
we obtain a hexa- hydride, C sa Hel, identical with the alkaloid 
piperidine, C;H,,N = C,Hy:N 


Many of the transpositions of the pyridine nucleus, and the methods employed 
in its formation find their simplest explanation in the fact that the nitrogen atom 
present in the nucleus is in direct union with the carbon atom opposite to it 
(occupying the para position), as indicated in the formulas :— 


ch rege Cee 
a PP i Sh, 
HC CH HC Cc 
| | and | freed 
HC CH HC GC 
ee Ne ee 
N N CH 
Pyridine. Quinoline, 


(See Berichte, 17, 2871; 20, 801; 2, 1967). It is undetermined whether 
these prismatic or diagonal formulas are isomeric or tautomeric with the preceding 
ring-shaped formulas (as in analogous cases), In schemes showing the manner of 
union of the atoms in pyridine and quinoline—schemes analogous to the benzene 
hexagon—this difference disappears. 





1. PYRIDINE GROUP—C,H,,_;N. * 
PYRIDINE, C,;H,N. 
Picolines—C,H,N == C,;H,(CH;)N—Methy] pyridines. 


Lutidines—C,H,N = C;H, Pace ee pyridines. 
Collidines—C,H,,N = C;H,(CH;),N—Trimethyl pyridines. 


The following bases, isolated from coal-tar, have not been well studied and are 
included here: Parvoline, CoH,,N (B. P., 188°), Corindine, C\H,,N (at 
211°), and Brion C,,H,,N (at 230°). 





* Buchka, Die Chemie des Pyridins und seiner Derivate, 1890. 


938 ORGANIC CHEMISTRY. 


The. pyridine bases arise in the dry distillation of nitrogenous 
carbon compounds and occur simultaneously with the quinoline 
bases in coal-tar (along with the isomeric anilines) and especially 
in bone-oil. 


To obtain the pyridine bases from Dippel’s oil (p. 539), concentrate the dilute 
sulphuric acid solution (when any pyrrol which has dissolved will be volatilized 
or resinified), separate the pyridine bases by means of concentrated sodium hy- 
droxide, dehydrate them with caustic soda and subject the product to fractional 
distillation (Berichte, 12, 1989). At present the pyridine bases are mainly 


obtained from coal-tar (Annalen, 247, 1). They occur in the “ purifying acid,” \ 


from which they can be easily isolated ba ah Aitis 20, 127; 21, 1006). 


Again, the pyridines, as well as quinoline bases, are obtained by 
the distillation of the alkaloids (cinchonine) with caustic alkali, or 
by oxidizing the quinoline bases and alkaloids to pyridine carboxylic 
acids, e. g., C;H,;N(CO,H),., which split off carbon dioxide (see 
above) and yield pyridines. 


Synthetic methods for the production of the pyridines :— 


(1) B-Methyl Pyridine, C,H,(CH,)N, is prepared from acrolein-ammonia, 
C,H,.NO, by, elimination of water (p. 199), or by heating trichlor- or tribrom- 
allyl with alcoholic ammonia to 250°, and from ope and acetamide by heating 
with P.O; (Berichte, 18, 3094) :— 


2C,H,O + NH, = C,H,(CH,)N + 2H,0. 


(2) (1, 4)-Methyl Ethyl Pyridine, C,H,(CH,)(C,H;)N, aldehyde collidine, 
aldehydine (p- 943), results when ethidene chloride or bromide is heated with 
alcoholic ammonia (Berichte, 18, 920), from aldehyde by the rearrangement of 
the oxytetraldine formed at first, but most readily from aldehyde ammonia upon 
heating it with paraldehyde ( Berichte, 20, 444) :— 


H 
4C,H,O + NH, = C,H, (cit,) N + 4H,0. 


A methyl propylpyridine is analogously obtained from propionic aldehyde and 
acetamide (erichte, 21, 279). 

(3) The fact that chlor- and brom-pyridine can be produced by heating potas- 
sium pyrrol with CHCl, and CHBr, is of interest. Pyrrol and sodium ethylate 
may be used as a substitute for potassium pyrrol (Berichte, 18, 723). Pyridine 
results if CH,I, be used (Berichte, 18, 3316); and with benzal chloride the pro- 
duct is $-phenylpyridine (Aerichte, 20, 191). Pyridine and alkylpyridines 
(Berichte, 19, 2196) are similarly formed from a- and (-alkylpyrrols, C,H,R.NH 
(p- 540) upon digesting them with concentrated hydrochloric acid. In all. these 
reactions the entering C-atom assumes the (-position relatively to the pyrrol 
nitrogen (Berichte, 20, 194). The reaction occurs more readily by using pyrrol- 
carboxylic acid (Berichte, 21, 2856). Alkyl indols sustain similar transpositions ; 
quinoline derivatives result. 

(4) A very ready synthesis of the pyridine nucleus occurs upon heating penta- 





7) hee 


PYRIDINE GROUP. 939 


methylene diamine hydrochloride (p. 313); Azpertdine (hexhydropyridine) is pro- 
duced (Ladenburg, Berichte, 18, 3100) :— 


_CH,—CH,.NH;, oH —CH 
CH,< . + HCl = CH,¢ NH + NH,Cl. 
CH,—CH,.NH, CH,—CH,” 


Pyridine is formed when the piperidine is heated with concentrated sulphuric 
acid. Six hydrogen atoms are eliminated (p. 951). Trimethylenediamine yields 
trimethylenimine and $-methylpyridine (Berichte, 23, 2727). 


(5) A method frequently pursued in synthesizing pyridine deriv- 
atives consists in the condensation of acetoacetic ester with an 
aldehyde-ammonia, or with an aldehyde and ammonia. This leads 
to the formation of dicarboxylic esters of alkyl dihydropyridines. 
Reaction of Hantzsch (Aunalen, 215, 1; Berichte, 18, 2579). 


(1, 3, 5)-Trimethyldihydropyridine-dicarboxylic Ester (dihydrocollidine 
dicarboxylic ester), C,H,N(CH;).(CO,R),, forms upon digesting acetoacetic 
ester (2 molecules) with aldehyde ammonia (1 molecule), or with acetaldehyde 
and ammonia :— 

CH, CH, 

RO,C.CH, | 
CHO CH,.CO,R RO,C.C—CH—C.CO,R 
CH;.CO | 4 I | + 3H,0. 

NH, CO.CH, CH,.C—NH—C.CH, 


The entering aldehyde radical takes the para-position relatively to nitrogen (2e- 
richte, 17,1521), The three methyls occupy the positions (1, 3, 5), the two car- 
boxyls are in (2, 4) (Berichte, 18, 1745). Thetwo added hydrogen atoms are in 
union with the nitrogen and the y-C-atoms (Berichte, 18, 2579 and 620). Nitrous 
acid oxidizes the dihydro compound to the ester of normal Trimethyl—pyridine- 
carboxylic Acid, C, N(CH,),(CO,R),; this yields a series of pyridine deriva- 
tives. 

The reaction proceeds in a perfectly analogous manner with propyl aldehyde, 
isobutyl aldehyde, ~-butyl aldehyde and valeric aldehyde, with the formation of 
dimethyl alkyl derivatives, C;H,N(CH,),R(CO,R), ort 21, Ref. 638). 
The aromatic aldehydes behave in the same way; benzaldehyde affords dimethyl- 
phenyl-dihydropyridine dicarboxylic ester (Berichte, 17, 1515). Cinnamic alde- 
hyde (Berichte, 19, Ref. 18) and m-nitrobenzaldehyde react likewise. Primary 
amines act the same as ammonia ; it is very probable that 7-alkyl derivatives are 
produced in such cases. The ammonia can also be attached to acetoacetic ester. 
Paramidoacetoacetic ester (2 molecules), paraldehyde (1 molecule) and a little 
sulphuric acid form (1, 3, 5)-trimethyl-dihydropyridine-dicarboxylic ester :—2C, 
H,,NO, + C,H,O=C,,H,,NO, + NH,+H,O. On heating the para-amide 
ester alone, or its hydrochloride, we get oxy-dimethyl pyridine-monocarboxylic 
ester, C; H,ON(CH,),-CO.,R, which, by the loss of the carboxyl group, forms 
pseudolutidostyril (p. 945) (Berichte, 21, 445). 

Aceto-acetic ester reacts in the same manner with hexamethylenetetramine as 
with aldehydes and ammonia, the products being hydrolutidine dicarboxylic esters 
(Berichte, 21, 2740). 

6. In Hantzsch’s reaction one molecule of acetoacetic ester can be replaced by 
one molecule of aldehyde, the products then being dialkylmonocarboxylic esters. 
Thus, we obtain (1, 3)-Dimethyl Pyridine-2-Carboxylic Ester (erichte, 18, 


940 ORGANIC CHEMISTRY. 


2020) on mixing acetoacetic ester (I molecule) with aldehyde ammonia and acet- 
aldehyde (1 molecule each) :— 
CH, CH, 
| | 
CH, CHO CH,.CO,R CH—C=C.CO,R 
| = || | + 3H,0 + H,. 


‘CHO @H,  -CO.CH, © CH-N=C.CH, 
Ester of Lutidine Carboxylic Acid. 


7. The pyrone derivatives (p. 958) may be rearranged to pyridine and oxy- 
pyridine compounds by heating them together with ammonia. ‘This is an inter- 
esting reaction. 

8. The rearrangement of acetone dicarboxylic ester by means of ammonia into 
oxyamido-glutaminic ester and glutazine, a derivative of trioxypyridine, is based 
upon analogous reactions (Berichte, 19, 2708; 20, 2655) :— 


/CH,.CO,.C,H /CH,.CO.NH 
Pt ALC, ATOR NCA COLCH. 
/CH,.COX, 


Dioxypyridine carboxylic acid (citrazinic acid) (p. 947) is produced in a similar 
manner from citramide upon digesting it with sulphuric acid :— 


CH,.CO.NH, /CH,.CO\ 
C(OH)(CO,H)< yields C(CO,H) N + H,O+NH,. 
\CH,.CO.NH, \.CH,.CO 








The pyridine bases are colorless liquids with a peculiar odor. 
Pyridine, C;H;N, is miscible with water. ‘The solubility of the 
higher members grows rapidly less. They form crystalline salts with 
one equivalent of the acids. ‘They form double salts with mercuric 
and auric chlorides ; these serve for the separation of the individual 
bases (Aunalen, 247, 1). They are attacked with difficulty when 
boiled with nitric or chromic acid, and by this behavior are easily 
distinguished from the isomeric anilines. In the homologous pyri- 
dines, however, the alkyls are oxidized to carboxyls by a potassium 
permanganate solution. 


The pyridines combine, as tertiary bases with the alkyl iodides, yielding ammo- 
nium iodides (Berichte, 18, 591). The ammonium hydroxides, obtained from the 
latter by means of silver oxide, sustain a complicated decomposition when exposed 
to heat. Consult Berichte, 17, 1027, 19, 31, upon the deportment of the ammo- 
nium hydroxides of the pyridine-carboxylic acids. 

If the ammonium iodides be heated with caustic soda, an extremely pungent 
odor is developed— Reaction for the pyridine bases (Berichte, 17,1908). Someof 
the pyridines yield hydrides with nascent hydrogen (p. 937); their ammonium 
hydroxides are decomposed by further reactions into trimethylamine and a hydro- 
carbon (see piperidine and conine). 


a 


PYRIDINE. 941 


Pyridine heated with hydriodic acid to 300°, yields normal pentane, C,H,,., 
and collidine, under the same treatment, yields normal octane (Berichte, 16, 591). 
Metallic sodium causes the pyridines to undergo a peculiar polymerization, and 
they then yield dipyridine bases. 





Tsomerides. ; 

The derivatives produced by the replacement of the hydrogen atoms in pyri- 
dine can easily be deduced in their possible isomerisms from the given structural 
formulas (p. 937), and are perfectly analogous to the isomerisms of the benzene 
derivatives. Representing the five hydrogen atoms, or the affinities of the pyri- 
dine nucleus, with numbers or letters, corresponding to the diagram— 








2 I a 
3 es 
/CH = CHS Ps %. 
CHC CH ag cH ory y™ 
sees pa’ 


then the positions, I and 5, also 2 and 4 (as in benzene), are similar (p. 560). 
The first may be designated the ortho-, the latter, the meta-positions—while the 
position 3, occurring only once, corresponds to the para of benzene. From this 
we conclude, that the mono-derivatives of pyridine, C;H,(X)N, can exist in 
three series, while six isomerides are possible with the di-derivatives C,H,(X,)N. 
This is verified by the existence of three methyl, three propyl- and phenyl-pyri- 
dines, C;H,(R)N, of three pyridine-mono-carboxylic acids, C;H,(CO,H)N, of 
six dicarboxylic acids, etc. For practical reasons the isomerides are called a-, £-, 
and y-derivatives, corresponding with the second diagram. *a-Pyridine carboxylic 
acid (picolinic acid) corresponds to the position 1; the #-acid (nicotinic acid) to 
the position 2, and the y-acid (isonicotinic acid) to position 3. ‘This determination 
of place for the pyridine derivatives is evident from the manner in which the 
three phenyl] pyridines, C;H,(C,H,)N, are produced, the a- and f- being derived 
from the two naphthoquinolines. See Skraup, Monatshefte fiir Chemie, Iv, 
437, 595 and Berichte, 17, 1518; 18, 1745. 

The behavior of the pyridine dicarboxylic acids, C;H,N(CO,H),., leads to a 
simpler deduction of the position of their atoms (Ladenburg, Berichée, 18, 2967). 
The ortho-position of a-oxypyridine is evident from the fact that it can be formed 
by oxidizing carbostyril (Berichte, 19, 2432). Quinolinic acid (pyridine carboxylic 
acid), formed by the oxidation of quinoline, has the position (1, 2), and cinchomeronic 
acid, from isoquinoline, has the position (2,3). Quinolinic acid loses one molecule 
of carbon dioxide when heated and forms nicotinic acid, while cinchomeronic acid 
yields nicotinie acid and isonicotinic acid; therefore nicotinic acid is 8 = 2 and 
isonicotinic acid y = 3. 





Pyridine, C;H,N, can be prepared from bone-oil, and is obtained 
from all the pyridine-carboxylic acids on distillation with lime. It 
is a pungent-smelling liquid, miscible with water, of sp. gr. 1.0033 
at o°, and boiling at 114.8°. Its hydrochloride, C;H;N.HCl, is 
deliquescent, and with platinum chloride it forms a double salt, 
(C;H;N.HCl),.PtCl,, that is rather insoluble. Sodium amalgam, 
or better, sodium and alcohol, convert it into the hexahydride— 


942 ORGANIC CHEMISTRY. 


piperidine, C;H,,N (p. 950), from which, vice versa, pyridine is 
obtained by oxidation. 


Pyridine forms ammonium iodides with alkyl iodides (p. 940). It combines 
with chloracetic acid and yields Pyridine-betaine, C.H Ne ts , corres- 
y et OF 


ponding fully to ordinary betaine. The homologous pyridines yield analogous 
betaines (Berichte, 23, 2609). 

Sodium converts pyridine into polymeric Dipyridine, C,,H,,N,, an oil 
boiling at 286-290°; potassium permanganate oxidizes it to isonicotinic acid. At 
_ the same time rather large quantities of 4-Dipyridyl, C,, H,N, = NC,H,.C,H,N 
(yy), are produced; this distils at 304°, sublimes in long needles, and melts at 
114°. It crystallizes from water containing two molecules of water and melts at 
73°. It is a di-acid base. Potassium permanganate oxidizes it to isonicotinic 
acid. Jsonicotine, C,,H,,N,., is obtained from it by reduction with tin and hydro- 
chloric acid. Isomeric m-Dipyridyl, C,,H,N, (8), results from meta-dipyridyl- 
dicarboxylic acid (from phenanthroline, p. 950), boils.at 287°, and yields deliques- 
cent needles, melting at 68°. Potassium permanganate oxidizes it to nicotinic 
acid. Reduction with tin and hydrochloric acid produces micotidine. A third 
Dipyridyl (aa) has been prepared by the distillation of copper picolinate. It 
melts at 70° (Berichie, 21, 1077). 

Substitution Products.—Pyridine and its homologues are substituted with diffi- 
culty by the halogens (Berichze, 21, 1773). Nitro products have not been pre- 
pared. Bromine acts more readily upon pyridine sulphonic and carboxylic acids, 
especially upon the application of heat. The side-chains are then replaced 
(Berichte, 20, 1343). {-Chlor- and Brom-pyridine have been synthetically pre- 
pared from pyrrol by means of chloroform, etc. (p. 938). 

If pyridine (or piperidine) be heated with concentrated sulphuric acid to 330°, 
or with fuming sulphuric acid we get 6-Pyridine-sulphonic and disulphonic 
acids, C;H,N(SO,H), and C;H,N(SO,H),, which form ‘needles that dissolve 
without difficulty. $-Cyan-pyridine, C,H,N.CN, produced on distilling the 
sodium salt with potassium cyanide, crystallizes in white needles, melts at 48-409°, 
and by saponification yields nicotinic acid. 





Homologous Pyridines. 

The methylated pyridines occur in bone-oil and coal tar. They 
are synthetically prepared by heating the pyridine-ammonium- 
iodides to 300° (Ladenburg, Berichte, 17, 772):— 


C,H,N.C,H,I = C,H,(C,H,)N.HI. 


This is analogous to the formation of the homologous anilines from 
the alkyl anilines (p. 601). They also result from the alkyl piperi- 
dines by the splitting-off of hydrogen when heated with concen- 
trated sulphuric acid (p. 951). Conversely, nascent hydrogen 
(best from metallic sodium and alcohol) converts them into alkyl 
piperidines. 


Higher alkyl pyridines, with unsaturated side-chains, may be synthesized by 
condensing a-methyl pyridines and aldehydes. This can be effected by means of 


* 


METHYL-ETHYL PYRIDINE. 943 


zinc chloride. Thus, paraldehyde yields a-allyl pyridine, C; NH,.CH:CH.CH,, 
benzaldehyde forms Stilbazole, C;NH,.CH:CH.C,H, (analogous to stilbene), 
while ethyl-a-methyl pyridine yields ethyl-a-stilbazole (Berichte, 21, 818, 3099). 
a-Methyl pyridine and methylal yield, rather singularly, dipicolylmethane, CH, 
(CH,.C,H,N),. : } = 

An aldol condensation sometimes occurs between a-methyl pyridine and the 
aldehydes. Bases with hydroxylated side-chains are then produced; these are 
called Alkines and Tropines (Ladenburg, Berichte, 22, 2583; 23, 2709) :— 


C,H,N.CH, -++ CH,O = C,H,N.CH,.CH,.OH. 
a-Picolyl alkine. 


a-Picolyl methyl alkine, C;H,N.CH,.CH(OH).CH,, is similarly obtained with 
ethyl aldehyde, etc. 


1. Methyl Pyridines, C,H,(CH,)N, Picolines. 

a- and 6-Methyl Pyridine occur in bone oil, and may be separated by means 
of their PtCl, salts (Anna/len, 247, 5). . The B-body has been obtained artificially 
by different reactions. a-Picoline results when pyridine is methylated. It boils at 
130°; its sp. gr. is 0.965 at 0°, and it is oxidized by potassium permanganate to 
picolinic acid; the -body boils at 143°, and yields nicotinic acid. The picoline 
formed when strychnine is distilled is identical with B-picoline (Berichte, 23, 3151). 
y-Methyl Pyridine, from coal tar, is produced when methyl pyridine iodide is 
heated to 290°. It boils at 144°. Its sp. gr. is 0.974 at o®. It yields isonico- 
tinic acid when it is oxidized (Anna/en, 247, 11). 

Sodium and alcohol convert the three methyl pyridines into methyl piperidines. 


2. Dimethylpyridines, C;H,(CH,),N, Lutidines. 

There are six isomerides. Several occur in that fraction of bone-oil boiling at 
150-170°. aa-Lutidine occurs in the greatest abundance; associated with it are 
ay- and af-lutidines (Berichte, 21, 1006). aa-Lutidine boils at 142°; its specific 
gravity is 0.942 at 0°. It yields aa-pyridine carboxylic acid when oxidized 
(Annalen, 247, 28). ay-Lutidine, from coal tar, boils at 157°; its sp. gr. is 
0.9493 at 0°. It yields ay-pyridine dicarboxylic acid when oxidized. £-Luti- 
dine, from the corresponding dimethyl pyridine carboxylic acid, boils at 170°, 
and when oxidized becomes dinicotinic acid (Berichte, 23, 1113). 


3. Ethyl Pyridines, C,H 4(C,H,)N. : 

a-Ethyl pyridine is prepared, together with the y-, on heating pyridine-ethyl 
iodide (to 290°). It boils at 148°; its sp. gr. is 0.949 at 0°, and yields picolinic 
acid when oxidized (Annalen, 247, 13). (-Ethyl pyridine has been obtained 
from cinchonine and brucine on heating with caustic potash. It boils at 166°, and 
yields nicotinic acid when oxidized. y-Ethyl pyridine, produced together with 
the a- and {3-, boils at 165°, and yields isonicotinic acid when oxidized. Its sp. gr. 
is 0.952 at 0°. Sodium and alcohol convert all three isomerides into ethyl 
piperidines, 


4. Trimethyl Pyridines, C;H,(CH,),N, Collidines. 

Sym. (I, 3, 5)- collidine was first obtained by distilling sym. collidine dicar- 
boxylic acid with lime. It is present in coal tar. It boils at 172°, and turns 
brown on exposure to the air. When oxidized it yields pyridine tricarboxylic acid 
(Berichte, 20, Ref. 106; Annalen, 21, 1011). 

(1,4)- Methyl-Ethyl Pyridine, C;H,(CH,)(C,H,)N, has been prepared 
from various aldehyde compounds, hence called aldehydine or aldehydcollidine. 
It boils at 178°, and when oxidized forms (1, 4)- pyridine-dicarboxylic acid 


944 ORGANIC CHEMISTRY. 


- (Annalen, 247, 41). See Annalen, 247, 46, for two additional methyl ethyl 
pyridines. 


Propyl Pyridines, C;H,(C,H,)N. : 
a-Propyl Pyridine, Conyrine, is produced on heating conine hydrochloride 
with zinc dust, and is obtained on heating inactive a-propyl piperidine (Aznad/en, 
247, 20). It is a bright blue, flourescent oil, boiling at 167°. If oxidized, it 

yields picolinic acid. Heated with hydriodic acid it again forms conine. 

B-Propyl Pyridine appears to be a base, formed by distilling nicotine, C, ,H,, 
N,, through an ignited tube. It boils at 170°, and is oxidized to nicotinic acid. 

a-Isopropyl Pyridine, C,H,(C,H,)N, is produced together with the y-com- 
pound when pyridine propyl iodide or isopropyl iodide is heated to 290° (Annalen, 
247, 22). It boils at 158°. When oxidized it forms picolinic acid. Sodium and 
alcohol change it to isopropyl piperidine (p. 952). y-Isopropyl pyridine boils at 
177°, and yields isonicotinic acid when oxidized (p. 946). See Berichte, 23, 685, 
for the dimethyl! ethyl pyridine, obtained from propionic aldehyde. 





a-Vinyl Pyridine, C,H,(C,H,)N, results when pyridine vapors are con- 
ducted together with ethylene through a tube heated to redness, as well as from 
_a-picolyl alkine by the loss of water, and from pyridine acrylic acid. It is a liquid 
with a sweet odor, and boils at 160°. It yields picolinic acid when oxidized 
(Berichte, 20, 1644). 

a-Allyl Pyridine, C,H ,(C,H,)N, is produced when a-picoline and paralde- 
hyde are heated to 200° (Annalen, 247, 26). Its odor is like that of conyrine. 
It boils at 190°. Sodium and alcohol convert it into a-propyl piperidine (in- 
active conine, p. 952). é 





Phenyl Pyridines, C;H,(C,H;)N. 

a- and 3-Phenyl pyridine have been obtained from a- and $-naphtho-quino- 
line (see these). By the oxidation of the latter we get a- and £3 phenyl-pyridine- 
dicarboxylic acids, C;H NY Se ines and when 2CO, split off from these 
the phenyl pyridines are produced (p. 950). 

_a-Phenyl pyridine boils at 267°, and when oxidized with chromic acid yields 
picolinic acid; $-phenyl pyridine boils at 270°, and yields nicotinic acid. 
y-Pheny]l pyridine, formed from aceto-acetic ester, etc. (p. 939), boils at 275°, 
and yields isonicotinic acid by oxidation. It consists of colorless needles melting 
at 77°. Metallic sodium and alcohol reduce it to y-phenyl piperidine (p. 952). 


Pyridyl Alkines (p. 943). 

a-Picolyl Alkine, C,;NH,.CH,.CH,.OH, from a-picoline and formic aldehyde, 
is a thick syrup, boiling at 179° under 22 mm: pressure. a-Picolyl methyl-alkine, 
C;H,N.CH,.CH(OH).CH,, derived from acetaldehyde, boils at 179° under 18 
mm. pressure. For additional pyridyl alkines consult Berichte, 23, 2709, 2725. 





Oxy-derivatives of the Pyridines. 


These resemble the phenols in deportment, especially the amidophenols. They 
are formed by analogous reactions, with special ease from the oxypyridine carboxylic _ 


DIOXYPYRIDINES. 945 
e 


acids by the elimination of the carboxyl groups. They form salts with bases and 
acids. Ferric chloride imparts a red color to nearly all their solutions. On the 
other hand, different oxypiperidines and oxypiperidinic acids manifest the deport- 
ment of imides or lactams. They must be viewed as 4efo or acz-compounds of 
the dihydro-pyridines, and are called therefore pyrzdones (lutidones), corresponding 
to the formulas :— 


ACH — CO /CO . CH /CH=CHN 
CHC CH — cH NH CHC Gy_¢H SNE COf CH — CH NH. 
a-Pyridone, B-Pyridone (?) : y-Pyridone. 


It is undetermined whether these formulas are isomeric or tautomeric with the 
hydroxyl formulas: However, isomeric alky] compounds of both types are known 
(Berichte, 22, 73). 

1. Oxypyridines, C,5H,(OH)N or Pyridones. Three Isomerides. a-Oxypyri- 
dine, a~-Pyridone (1 =5), is obtained from oxyquinolinic acid (p. 948) and from 
oxy-nicotinic acid (from coumalic acid, p. 947), by the elimination of carbon 
dioxide ( Berichie, 18, 317; 19, 2433). It dissolves readily in water and alcohol, 
crystallizes in needles, melting at 106°. Ferric chloride colors it red. Bromine 
water converts it into a dibromoxypyridine, C,H, Br,(OH)N, melting at 206°. 

B-Oxypyridine is formed when /-pyridine sulphonic acid is fused with caustic 
potash. It is very soluble in water and alcohol, crystallizes in needles, melts at — 
124°, and can be distilled without decomposition. Its e¢hy/ ether, C,5H,(O.C,H;)N, 
is produced by the action of alcoholic potash upon (-brompyridine. Hydriodic 
acid again decomposes it, at 110°, into B-oxypyridine (Berichte, 17, 1896; 18, 
Ref. 634). 

y-Oxypyridine, y-Pyridone, is produced by heating oxypicolinic acid (from 
comanic acid, p. 958) and ammon-chelidonic acid. It is very soluble in water, 
soluble with difficulty in ether, crystallizes'in plates with 1H,O, and when an- 
hydrous melts at 148°. Ferric chloride colors it yellow. Methyl iodide converts 
it into the hydroiodide of #-methyl pyridone, a crystalline mass, melting at 89°. It 
can also be obtained from methyl ammon-chelidonic acid, hence its methyl] group 
is attached to nitrogen. Hydriodic acid does not even decompose it at 165°. 
y-Methoxy-pyridine, C,H ,(O.CH,)N, is isomeric with if. This compound may 
be prepared by heating chlorpyridine with sodium ethylate. It boils at 190°, reacts 
alkaline, and is broken down when heated to 100° with hydriodic acid: (Berichée, 
18, 930, Ref. 382). . 

2. Oxylutidines, C;H,(CH,),(OH)N or Lutidones, C,H,O(CH,),NH. 


Pseudo-lutido-styril, CH, Oe CH ~ (CH, - NH, (3, 5)-Dimethyl-a-pyridone, 





is obtained from the ammonium hydrate of collidine dicarboxylic ester, C,(CH,),N 
(CO,.C,H,;), (p.. 949), by a complex transposition (Berichte, 17, 2903); and 
also from the amido-aceto-acetic ester condensation product (p. 940) (Berichie, 22, 
447). It crystallizes in minute needles, that melt at 180° and boil about 305°. It 
forms (1, 3)-lutidine when distilled with zinc dust. 

(2, 6)-Dimethyl-y pyridone, COC CtcH cH NE y-Lutidone, results from 
lutidone dicarboxylic acid and oxy-lutidine dicarboxylic acid by the elimination 
of the carboxyl groups. It crystallizes with 1% molecules of water; when an- 
hydrous it melts at 225° and boils at 350° (Berichte, 20, 156). It forms (2, 4)- 
lutidine when distilled with zinc dust. 

3. Dioxypyridines, C,H,(OH),N. . 

Three isomeric bodies have been obtained from pyridine disulphonic acid, 
djbrom-pyridine and dioxypicolinic acid (Berichte, 18, Ref. 633). 


79 3 


946 ORGANIC CHEMISTRY. 
« 

4. (1, 3, 5)-Trioxypyridine, C,H,(OH),N, or Triketohexahydropyridine, 
CO «CH co DNH. Triketopiperidine, bears the same relation to pyridine that 
phloroglucin bears to benzene (p. 695). It can be obtained by boiling glutazine 
with hydrochloric acid. It is a microcrystalline yellow product, that swells up at 
220-230° and then decomposes. Heated with ammonia it forms Glutazine, 
C;H,N,; which can also be prepared by heating acetone dicarboxylic ester with 
ammonia (p. 940) (Berichte, 19, 2708; 20, 2655). 

Pyromecazonic Acid, C,H,(OH),N, is an isomeric trioxpyridine, obtained 
from pyromeconic acid. Ferric chloride colors it a dark indigo blue. 





Pyridine Carboxyl Compounds. 


The pyridine carboxylic acids are obtained from the homologous 
pyridines by oxidizing them with potassium permanganate, and are 
also formed by oxidizing the quinolines and alkaloids (with nitric 
acid, chromic acid or potassium permanganate). The lower acids 
can be prepared from the polycarboxylic acids, e. g., C;(CH3)3;N 
(CO,H), and C;N(CO,H);, by the partial elimination of single car- 
boxyls, and by completely removing the latter (by heating with 
lime) all the acids yield pyridine or its homologues. As these acids 
represent combinations of carboxyl with the basic pyridine radical, 
they therein manifest a deportment analogous to that of the amido- 
acids, and are also capable of forming salts with acids. The basic 
character of these acids diminishes with the increase in number of 
carboxyls, and disappears entirely in the penta-carboxylic acid. 
Those pyridine- (and quinoline) carboxylic acids, containing a car- 
boxyl in the a-position, are colored red by ferrous sulphate. 


1, Pyridine-mono-carboxylic Acids, CSH;NO, = C,H,N(CO,H). 

a-Pyridine-carboxylic Acid (1 or ortho), Picolinic Acid, was first obtained 
by the oxidation of a-picoline. It is very readily soluble in alcohol and water, 
crystallizes in white needles, which melt at 135-136°, and sublime. Ferrous 
sulphate imparts a faint yellow color to their solutions. By the action of sodium 
amalgam, ammonia is split off, and the acid, C,H,O,, formed; this melts at 85°. 

B-Pyridine Carboxylic Acid (2 or meta), Nicotinic Acid, was first obtained 
by oxidizing nicotine. It is also prepared from 3-methyl and ethyl pyridine, from 
$-cyanpyridine and from the three pyridine dicarboxylic acids (quinolinic, cincho- 
meronic and isocinchomeronic acids) by the elimination of a CO,-group. The 
easiest course to pursue in preparing the acid consists in heating quinolinic acid 
with hydrochloric acid to 180°. It crystallizes from hot water in needles or’warty 
masses, and melts at 228-220°. 

y-Pyridine-carboxylic Acid (3 or para), Isonicotinic Acid, is obtained by 
oxidizing y-methyl- and ethyl-pyridine, and from the dicarboxylic acids, cincho- 
meronic and lutidinic acids, by the splitting-off of CO,. It is almost insoluble in 
hot alcohol, forms fine needles when crystallized from hot water, and sublimes in 
small plates without previous melting. When heated in a closed tube it melts at 


304°. 


QUINOLINIC ACID. 947 


Pyridine Fatty Acids. 

The known acids of this group are a-pyridyl acrylic acid and a-pyridyl lactic 
acid, which appear to be closely related to anhydroecgonine and ecgonine—deriva- 
tives of cocaine (Berichte, 23, 224). 

a-Pyridyl Acrylic Acid, C,H,N.CH:CH.CO,H, is formed together with 
a-pyridyl lactic acid from the’ condensation product of a-picoline and chloral by 
the action of caustic potash. It crystallizes in minute needles, melting at 202°. 
a-Pyridyl Lactic Acid, C;H,N.CH,.CH(OH).CO,H, consists of fine needles, 
melting at 146°. 


Oxypyridine Monocarboxylic Acids. 

y-Oxypicolinic Acid, C;H,(OH)N(CO,H) (ya), has been obtained, in a syn- 
thetic manner, from comanic acid, (p. 958), on digesting with ammonia. It 
crystallizes in shining leaflets, containing one molecule of water. It melts at 250°, 
and decomposes into CO, and y-pyridone (p. 945). 

a’-Oxynicotinic Acid, C;H,(OH)N(CO,H)(a’{) or a-Pyridone-f/-carboxylic 
acid, C,;H,0(NH)CO,H (p. 945), i is produced when ammonia acts upon coumalic 
acid ester (Berichte, 17, 2390); also when oxyquinolinic acid (p. 948) is heated 
to 200°. It dissolves with difficulty i in water and alcohol, crystallizes in delicate 
needles, and melts at 303°, breaking down at the same time into CO, and a-pyri- 
done. Sodium amalgam eliminates its nitrogen as ammonia. Methyl-oxy nicotinic 
acid is obtained from it by the action of methyl iodide and caustic potash. This” 
acid can also be derived from coumalic acid by means of methylamine. Sodium 
amalgam will cause it to split off methylamine. Therefore, its methyl group is 
attached to nitrogen, and the acid is an a-methy/pyridon carboxylic acid, C, Hs O- 
(N.CH,).CO,H (Berichte, 18, 318). 

Dioxypicolinic Acid, C sH,(OH),N(CO, H), Comenamic Acid, is derived from 
comenic acid (p. 959) by aid of ammonia. It crystallizes in plates, containing two 
molecules of water. Ferric chloride imparts a purple-red color to its solution. 
Oxalimide (p. 407) is obtained from it by the action of nitrous acid in glacial 
acetic acid (Borah 19, 3228). 

Dioxyisonicotinic Acid, C;H,(OH),N(CO,H), Citrazinic Acid, is formed 
when citramide is heated with hydrochloric or sulphuric acid. It is a bright 
yellow insoluble powder, which decomposes without melting on being heated 
beyond 300°. Its alkaline solution acquires a deep blue color on exposure to the 
air. It yields y-pyridine carboxylic acid by the reduction of its hydroxyl groups. 
See Berichte, 23, 831, as to its constitution. 


Methyl Pyridine Monocarboxylic Acids. 

ay-Picoline Carboxylic Acid, C;H,(CH,)N(CO,H)(CH, in y), is obtained on 
heating uvitonic acid (p. 949) to 280°. It sublimes without previously fusing, and 
when oxidized becomes lutidinic acid (p. 948). 

By-Methyl-Pyridine-Carboxylic Acid (CH, in y) results on heating methyl 
quinolinic acid to 170°, or when it is boiled with “glacial acetic acid. It melts at 
209-210°, and is oxidized to cinchomeronic acid. 

Lutidine Carboxylic Acid, C;H,(CH;),N(CO,H)(afy-CO,H in £8). Its 
ethyl ester results -in the condensation of aceto-acetic ester with aldehyde and 
aldehyde-ammonia (p. 939). The free acid contains two molecules of water of 
crystallization, yields ay-lutidine by the elimination of carbon dioxide, and when 
oxidized forms a/y-pyridine tricarboxylic acid (p. 949). - 


2. Pyridine Dicarboxylic Acids, C,H;NO, = C;H,N(CO,H),. 


The six possible isomerides (p. 941) are ee (Berichte, 19, 293). 
1. Quinolinic Acid (a@ or I, 2) is obtained from quinoline and from 1 and 4 
methyl-quinoline by oxidation with potassium permanganate (Berich¢e, 19, 31). 


948 ORGANIC CHEMISTRY. 


‘It is sparingly soluble in water and alcohol, crystallizes in shining, short prisms, 
melts at 190°, and decomposes (by slowly heating to 160°) into CO, and nicotinic 
acid (Berichte, 19, 2767). Ferrous sulphate imparts a reddish-yellow color to its 
solution. Its azhydride is produced when it is heated with acetic anhydride. 
This melts at 134°. Its derivatives are similar to those formed by phthalic 
anhydride (Berichte, 20, 1209). : 

2. Cinchomeronic Acid ((y or 2, 3) is obtained from quinine, cinchonine and 
cinchonidine, by oxidation with nitric acid and by the oxidation of Sy-methy]l- 
pyridine carboxylic acid with potassium permanganate. It also results from 
pyridine tricarboxylic acid and from apophyllenic acid. It crystallizes from water 
in prisms containing hydrochloric acid, and melts at 266°, with decomposition into 
CO,, y-pyridine carboxylic acid and a little nicotinic acid. When heated with 
acetic anhydride it yields its anhydride, C,H, N(CO),O, melting at 67°. Sodium 
amalgam decomposes it into NH, and cinchonic acid, C,H,O,;, which breaks up 
into CO,, and dimethylfumaric anhydride (p. 430) on application of heat 
(Berichte, 18, 2968). 

Cotarnine, C,,H,,NOQOs3, boiled with nitric acid, yields Apophyllenic Acid, 
C,H,NO, (Berichte, 19, Ref. 706). This is methylated cinchomeronic acid, in 
which the methyl group is attached to the nitrogen atom, and has the formula, 


C,H,(CO,H)N(CH,)¢ 5° (comp. betaine, p. 316). It melts with decomposition 


at 242°, and when heated to 250° with hydrochloric acid decomposes into methyl 
chloride and cinchomeronic acid. 

3- Lutidinic Acid (ay or 1, 3) is produced together with isocinchomeronic 
acid by oxidizing ay-lutidine and picoline carboxylic acid with potassium perman- 
ganate (Anunalen, 247, 37). It crystallizes with a molecule of water in micro- 
scopic needles, receives a blood-red color from ferrous sulphate, melis at 235°, 
and breaks up into CO, and y-pyridine carboxylic acid. 

4. Isocinchomeronic Acid (a3’=1, 4) is obtained from pyridine tricar- 
boxylic acid (Berichte, 19, 1311) and aldehyde collidine. It crystallizes from 
acidulated hot water, with one or one and a half molecules of water, in microscopic 
leaflets, which melt at 236°, and when heated to 220° together with glacial acetic 
acid decomposes into CO, and nicotinic acid. Ferrous sulphate imparts a reddish- 
yellow color to"the solution. 

5. Dipicolinic Acid (aa’ = 1,5) results when aa/-lutidine (p. 943) is oxidized 
with potassium permanganate (Anunalen, 247, 33). It crystallizes in shining 
leaflets, melts at 225°, and at 227° decomposes into two molecules of carbon di- 
oxide and pyridine (together with a slight amount of picolinic acid). 

6. Dinicotinic Acid (3’ = 2, 4) may be prepared from symmetrical pyridine 
tetracarboxylic acid, from (1, 2, 4)-pyridine tricarboxylic acid on boiling with 
glacial acetic acid (Serichie, 19, 286), and from (-lutidine (p. 943). It dis- 
solves with difficulty in water, consists of minute crystals, melts at 314°, and breaks 
down into carbon dioxide and nicotinic acid (Berichze, 23, 1114). 


Oxypyridine Dicarboxylic Acids, C;H,(OH)N(CO,H),. 

a-Oxyquinolinic Acid (1, 2, 5—OH in 5), obtained by fusing quinolinic acid 
with KOH (Berichée, 16,2158), also from amidocarbostyril by oxidation with per- 
manganate (Berichte, 19, 2432), consists of thick crystals, which char at 254°, but 
do not melt. When heated to 195° with water it decomposes into carbon dioxide 
and oxypyridine carboxylic acid (see above); the silver salt yields a-oxy-pyridine 
when heated. Ferric chloride colors it a deep red. 

Ammon-chelidonic Acid (1, 5, 3—OH in 3), chelidamic acid, formed from 
chelidonic acid with ammonia, is a white, rather insoluble powder that breaks down 
into carbon dioxide and y-pyridone when heated above 230°. 


PYRIDINE TRICARBOXYLIC ACID. 949 


Methyl Ammon-chelidonic Acid, C;H,O(N.CH,)(CO,H),, obtained by the 
aid of methylamine, yields #-methyl pyridone by decomposition (p. 945). 


Picoline Dicarboxylic Acids, C,H,(CH,)N(CO,H),. 

1. Methyl-quinolinic Acid (1, 2, 3—CH, in 3) is produced upon oxidizing 
y-methyl-quinoline with potassium permanganate, as an intermediate product to 
the tricarboxylic acid. It crystallizes from water in plates or prisms, is colored 
yellow by ferrous sulphate, melts about 186° with decomposition, and yields (even 
on boiling with glacial acetic acid) carbon dioxide and (y-methylpyridine car- 
boxylic acid (p. 947). 

2. Uvitonic Acid is formed when ammonia acts upon pyroracemic acid, con- 
sists of microscopic leaflets, is colored violet-red by ferrous sulphate, melts at 244°, 
and above 280° decomposes into CO, and picoline-carboxylic acid. 

(1, 3, 5)-Trimethyl-(2, 4)-pyridine Dicarboxylic Acid, C,(CH,;),N(CO,H),, 
Collidine dicarboxylic acid. The diethyl ester is prepared by the oxidation of di- 
hydro-collidine dicarboxylic ester (from aceto-acetic ester with aldehyde ammonia, 
(p. 939) in alcholic solution with nitrous acid. The free acid, obtained by saponi- 
fying the ester, crystallizes in little needles, and decomposes when strongly heated 
without melting. Distilled with lime it yields a (1, 3, 5)-trimethyl pyridine (p. 
943). By successively oxidizing its methyl groups with potassium permanganate 
we obtain: lutidine tricarboxylic acid, C,(CH,),N(CO,H),, picoline-tetra- 
carboxylic acid, C,(CH,)N(CO,H),, and pyridine pentacarboxylic acid, 
C,N(CO,H),. The separation of but one carboxyl from collidine-dicarboxylic 
acid yields collidine-monocarboxylic acid, C; H(CH,),N(CO,H) (Aunaien, 
225, 133), which by successive oxidation forms lutidine-dicarboxylic acid, 
(C,H(CH,),N(CO,H),, picoline-tricarboxylic acid, C, H(CH,)N(CO,H),, 
and pyridine-tetracarboxylic acid, C; HN(CO,H),. 





. 


(3) Pyridine Tricarboxylic Acids, C§H,NO, = C,H,N(CO,H);. 

1. aBy-Pyridine Tricarboxylic acid (1, 2, 3) (tricarbopyridinic acid, carbo- 
cinchomeronic acid), is obtained by completely oxidizing quinine, cinchonine, 
quinidine and cinchonidine, with potassium permanganate, and by the same treat- 
ment of y-methy] quinoline, methyl-quinolinic acid (see above) and cinchoninic acid 
(p. 972). It is very soluble in hot water, crystallizes in plates with 114 molecules 
of H,O, becomes anhydrous at 115—120°, chars and melts when rapidly heated at 
249-250°, with decomposition. At 180° it gradually breaks up (more readily on 
boiling with glacial acetic acid) into carbon dioxide and cinchomeronic acid. 
Ferrous sulphate gives it a faint red color. It is very probably identical with Ber- 
beronic Acid, formed from the alkaloid berberine by oxidation. 

2. a33/-Pyridine Tricarboxylic Acid (1, 2,4) is obtained from /-ethyl quin- 
oline and 3-quinoline-carboxylic acid by oxidation with MnO,K. It is colored 
reddish-yellow by ferrous sulphate, and softens with liberation of CO,, about 145° - 
(p. 948). It is very soluble in water and forms needles on crystallizing. 

3. Symmetrical aay- Pyridine Tricarboxylic Acid (1, 3,5) is obtained upon 
oxidizing symmetrical collidine (p. 943) and uvitonic acid (see above) with potas- 
sium permanganate. It crystallizes with two molecules of water. In an. anhy- 
drous state it melts at 227°, with decomposition into carbon dioxide and isonico- 
tinic acid (Annalen, 228, 29). aaf-Pyridine Dicarboxylic Acid (1, 2, 5) results 
when the corresponding lutidine carboxylic acid is oxidized with potassium per- 
manganate. It crystallizes in leaflets containing two molecules of water. It melts 
at 100° in its water of crystallization, and at 130° breaks down into carbon dioxide 
and isocinchomeronic acid (Berichte, 19, 1309). 


950 a ORGANIC CHEMISTRY. 


4. Pyridine Tetra-Carboxylic Acids, C,H,NO, = C,;HN(CO,H),. 

The aafBy-Acid is produced in the oxidation of collidine carboxylic acid and 
flavenol (p. 971). It forms needles, containing two molecules of water. It loses 
water very slowly above 115°, and when anhydrous melts at 227°. Ferric chlor- 
ide colors it cherry-red (Berichte, 17, 2927). Symmetrical aaBf-acid is derived 
from the corresponding lutidine dicarboxylic acid (from aceto-acetic ester and iso- 
butylaldehyde etc.) by oxidation. It consists of minute needles, containing one 
molecule of water, and at 150° breaks down into carbon dioxide and dinicotinic 
acid. Ferrous sulphate imparts a blood-red coloration to its solution (Berichte, 
19, 284). 

5. Ptiaine Pentacarboxylic Acid, C,N(CO,H),; = C,,H,;NO,,, is 
formed by the oxidation of synthetic collidine dicarboxylic acid and from the acids 
obtained in its oxidation. It crystallizes in microscopic needles, containing two 
molecules of water. It dissolves very readily in water, blackens at 200°, and de- 
composes, without melting, at 220°. Ferrous chloride imparts to its solutions a 
dark red color. 





C,H,N.CO,H 
Phenylpyridine Dicarboxylic Acids, . . +. There are two iso- 
C,H,.CO,H 
meric acids, a- and 3-, which have been prepared by oxidizing a- and /-naphtho- 
quinoline (p. 974) with potassium permanganate. They yield a- and y-phenyl- 
pyridine by the loss of two molecules of carbon dioxide. : 
C,H,.N.00,H 
Dipyridyl-dicarbonic Acids, . . . Two isomeric acids, a- and 
C,;H,.N.CO,H 
B-, have been formed by oxidizing the two phenanthrolines with potassium per- 
manganate. Two dipyridyls are formed by the loss of two molecules of carbon 
dioxide (p. 942). 





Hydropyridine Derivatives. 


The pyridines yield hydrogen additive products, similar to those produced by 
benzene. They form when tin and hydrochloric acid act upon the pyridines, or 
more readily by the action of sodium upon the alcoholic solution; the hexa-hydro- 
derivatives are then the direct products. Even oxypyridines.are reduced by so- 
dium and alcohol to hexa-hydro pyridines (Berichte, 20, 250). Several natural 
alkaloids belong to this class of hydropyridines; they are especially interesting. 


a ictte ts kip ‘ 
Hexahydro-pyridine, C;H,N = cH.’ CH’ CH. NH, Pi- 


peridine, occurs attached to piperic acid as piperine (see below) in 
pepper. It may be artificially prepared by reducing pyridine, also 
by distilling the hydrochloride of pentamethylene diamine (p. 313), 
or by the action of sodium upon an alcoholic solution of trimethy- 
lene cyanide (p. 311). 


Piperidine is a liquid that dissolves quite easily in water and alcohol. Its odor 
is like that of pepper. It boils at 106°. It shows a strong alkaline reaction. Its 
salts with the acids crystallize well. When piperidine is heated to 300° with sul- 


METHYL-PIPERIDINE. : 951 


phuric acid, or to 260° with nitrobenzene, or upon boiling it with silver oxide, it 
loses six hydrogen atoms and changes to. piperidine. Nitrous acid converts it 
into the #z¢voso-compound, C,H,):N.NO, boiling at 218°. 

Piperidine is very reactive with brom- and iodo-benzenes, forming 2-phenyl- 
piperidines with them (erichte, 21, 1921). This power of combination is mate- 
rially diminished with a-methyl piperidine (Berichze, 23, 1388). 

Potassium permanganate oxidizes piperidine to d-amidovaleric and y-amidobuty- 
ric acids. The homologous piperidines are analogously oxidized (Berichée, 21, 2237 ; 
22, 1035). 6-Amidovaleric acid loses water and yields oxypiperidine or pipert- 
done, C;H,ON (p. 945), a crystalline base, melting at 40° and boiling at 256°. 
It is a violent poison, resembling strychnine. The acid itself is not poisonous. 
Pyrrolidon, from y-amido-butyric acid, is also a strychnine-like poison (Berichte, 
23, 2772). 

Disodidyls, C,H,,)N.C,H,,N, are produced upon reducing the dipyridyls, 
(C;H,N),, with sodium and absolute alcohol (Berichte, 21, 2929). The same 
may be done with hexahydro-dipyridyls (p. 953). 

Piperidine is an imide base. It contains the NH-group and can form a/Ay/ and 
acid derivatives. The alkyl compounds (the hydroiodides) result by the union of 
piperidine with alkyl iodides. 

n-Methylpiperidine, C;H,,N.CH,, and ”-Ethy/ Piperidine, C,;H,)N.C,H;, 
are alkaline liquids, boiling at 107° and 128° respectively. With methyl iodide 
methyl piperidine forms dimethy! piperidine ammonium iodide, C,H,,N(CH,),I. 
Potassium hydroxide, upon distillation with the latter, causes the decomposition of 
its ring structure and yields Dimethyl piperidine, C,H ,N(CH;), = CH,:CH.CH,. 
CH,.CH,.N(CH,),. This is a base, boiling at 118°. It reunites with methyl 
. iodide to the ammonium iodide, C;H,.N(CH,),1; silver oxide converts this into 
the hydroxide, C;H.N(CH,),.OH, which on the application of heat breaks down 
into trimethylamine and Piferylene, C,H, == CH,:CH.CH,.CH:CH, (boiling at 
42°). This is the method pursued by Hofmann in building up the piperidine 
bases ( Berichte, 16, 2058; 19, 2628). 

n-Phenyl Piperidine, C;H,,:N.C,H,, from piperidine and brombenzene, is 
a liquid boiling about 250° (Berichte, 21, 2279, 2287). 

n-Acetyl Piperidine, C,H,,N.C,H,O, from piperidine by means of acetyl 
chloride, boils at 226°. Benzoyl Piperidine, C;H,,N.COC,H,, is a solid. 
Piperidine urethanes, C,H,,N.CO.OR, result from the action of chlorcarbonic 
ester. When these acid derivatives are oxidized the “piperidine nucleus is torn 
asunder; saturated amido acids result (Berichée, 17, 2544; 19, 500). : 

Piperine, C,,H,,NO, = C,H,,N.C,,H,O,, the alkaloid, is an acid derivative 
of piperidine with piperic acid (p, 822). It occurs in different varieties of pepper 
(e.g., Papaver niger), It is artificially produced by the action of piperic acid chlo- 
ride upon piperidine. It crystallizes in prisms and melts at 128°. It dissolves 
with a deep-red color in sulphuric acid. It is a-very feeble base, and is decom- 
posed by boiling alcohol into piperidine and piperic acid. 





Sodium and alcohol reduce the homologous pyridines to omo/ogous piperidines. 
They are known as Pipecolines, C;H,(CH,)NH, lupetidines, C,H,(CH;),. 
NH, etc. (Ladenburg, Berichte, 18, 920). 

a-Methyl Piperidine, C;H,(CH,)(NH), a-Hydropicoline, boils at 118°. 

$-Methyl Piperidine, 8-Hydropicoline, boils at 126°, a-Ethyl Piperidine, 
C,;H,(C,H,;)NH, boils at 143°. : 


952 ORGANIC CHEMISTRY. 


a-Propyl Piperidine, C;H,(C;H;)NH — C,H,,N, has been ob- 
tained by the action of sodium and alcohol upon a-allyl pyridine 
(p- 944). It boils at 167°. In properties and action it is very 
similar to conine. Its optical inactivity alone distinguishes it from 
the latter. By careful crystallization of its tartrate (induced by a 
small crystal of conine tartrate) it may be resolved (like inactive 
racemic acid, p. 478) into two optically active modifications, one 
of which is lzevo-rotatory and the other dextro-rotatory. Zhe latter 
ts identical with conine—the first synthesis of an active alkaloid 
(Ladenburg, Berichte, 19, 2584; 22, 1405). 

Conine, C,H,,N, dextro-rotatory a-normal propyl piperidine, 
C;H,(C;H,)NH, occurs in hemlock (Conium maculatum), chiefly 
in the seeds, and is obtained by extraction with acetic acid or 
distillation with soda. It is a colorless liquid, having the odor of 
hemlock, and boiling at 167-168°; its sp. gr. is 0.886 at o°. It 
deviates the plane of polarization to the right (a4, — 13.8°). Its 
hydrochloride melts at 217°. 


As secondary amine it yields alkyl and acid derivatives. If its zztrosamine, 
C,H,,N(NO) (azoconydrine), be digested with P,O, it forms Conylene, C,H,,, 
boiling at 125°. Benzoyl Conine, C,H,,N.CO.C,H,, is oxidized by permanga- 
nate of potassium to homo-coninic acid and amidovaleric acid. This nucleus is 
ruptured in the reaction (Berichte, 19, 506). Dimethyl conine iodide, C,H,,N 
(CH,).CH,I, obtained from methyl] conine and methyl-iodide, manifests the same 
deportment as the piperidine derivative (see above), and finally decomposes into 
trimethylamine and conylene, C, H,,. 

Conydrine, C,H,,NO, is an oxyconine and is intimately related to conine, 
occurring with the latter in hemlock and in the distillation it passes over last. It 
crystallizes in leaflets at 120°, distils at 226°, and sublimes about 100°. It reverts 
to conine when heated with hydriodic acid (Berichte, 18, 130). 

a-Isopropyl Piperidine, C,;H,(C,H,)NH, is derived from a-isopropyl pyri- 
dine by the action of sodium and alcohol. It is very similar to conine and boils 
at 160°. 

y-Phenyl Piperidine, C; H,(C,H,)NH, from y-phenyl piperidine, boils about 
256° (Berichte, 20, 2590). 

See Berichte, 23, Ref. 645 for the benzylpiperidines. 





Tetrahydropyridines, C;H,(H,)N, Piperideines. 

a-Methyl Piperideine, C,H,(CH,)N, and a-Ethyl Piperideine, C,H,(C, 
H,)N, have been prepared by the action of bromine and sodium hydrate upon 
methyl and ethyl piperidine (Berichte, 20, 1645). 

A dipiperideine, C,,H,,N,, has been similarly derived from piperidine 
(Berichte, 22, 1322, 1377). 

a-Propyl Piperideine, C,H,(C,H,)N. The three isomeric bodies a-, (-, 
y-coniceins, have been obtained from conydrine, C,H,,NO (see above), by heating 
it with P,O, or to 220° with hydrochloric acid, and also by the action of bromine 
and sodium hydrate upon conine. They are again reduced to conine when 
heated with hydriodic acid (Berichte, 23, 680 and 2141). 


DIAZINES, OR AZINES. 953 


Paraconine, C,H,,N, is a propyl tetrahydropyridine. It is formed from nor- 
mal butyraldehyde and butylidene chloride upon heating them with alcoholic 
ammonia. It is a colorless liquid, with stupefying odor. It boils at 168-170° 
(Berichte, 14, 2105). 

Tropine and tropidine are also tetrahydropyridine derivatives. 


Tropine, C,H,,NO, obtained by the decomposition of the 
alkaloid atropine, crystallizes from ether in plates, melts at 63°, 
and boils at 229° When heated with concentrated hydrochloric 
acid or with glacial acetic acid to 180°, water separates, and it 
yields tropidine, C,H,,;N, which can also be produced by heating 
anhydroecgonine with hydrochloric acid to 280° (Berichte 23, 1389). 
It isan oil with an odor like conine. It boilsat 162°. Hydro- 
bromic acid, acting upon it in the cold, causes it to revert to tropine. 
(Berichte 23, 1780, 2225). 


Tropine is an 2-methyl-a-oxy-ethyl-tetrahydropyridine and belongs to the a/kines 
(p. 315), while tropidine is an #-Methyl-a-viny]-tetrahydropyridine (Ladenburg, 
Berichte 20, 1648; 23, 2587) :— 


C,H,N(CH,).CH,.CH,OH and C,H,N(CH,).CH: CH,. 
Tropine. ropidine. 


Tropidine forms hydrotropidine, C,H,,N, by reduction; the distillation of its 
hydrochloride yields methyl chloride and Norhydrotropine, C,H,,N. The 
latter compound is isomeric with a-ethyl piperidine (see above) and when distilled 
with zinc yields a-ethyl pyridine, C;H,N.C,H;. Anhydroecgonine, C,H,N 
(CH,).CH: CH.CO,H, is a carboxyl. derivative of rome: by the loss of car- 
bon dioxide it forms tropidine. 

Triacetonine is closely related to tropidine (p. 209). 


Nicotine, C,,H,,N, = C;H,N.C;H,.N, is a hexahydrodipyridyl. 
It is found in the leaves of the tobacco plant, and may be obtained 
by distilling the residue from the aqueous extract with lime. It is 
an oil, readily soluble in water and alcohol. Its odor is very pene- 
trating. It becomes brown in color on exposure to the air. Its 
specific gravity at 15° is torr. It boils at 241°. It is a powerful 
diacid base and is poisonous. Chromic acid or potassium perman- 
ganate oxidizes it to nicotinic acid. Sodium, acting upon its alco- 
holic solution, converts it into dipiperidyl, C,H. .N, (p. 951). 


Nicotidine and Isonicotine, C,,H,,N,, are isomeric with nicotine. They 
result from the reduction of J- and m-dipyridyl (p. 942) (Berichte, 16, 2521). 





DIAZINES, OR AZINES. 


These compounds bear the same relation to pyridine, that the “ five-membered ” 
diazoles or azoles bear to pyrrol (p. 551). They contain a “‘ six-membered ” ring, 
consisting of four C-atoms and two N-atoms—C,H,N,. They may be considered 
pyridine derivatives, in which a CH-group has been replaced by nitrogen. There 

80 


954 ORGANIC CHEMISTRY. 


are three isomeric diazine nuclei—the orthodiazines, metadiazines and paradia- 
zines, corresponding to the relative position of the two N-atoms. ‘The usual desig- 
nations are pyridazine, pyrimidine and pyrazine* :— 


H 
N C N 
\ SOS OS 
HC CH N N CH 
I | | ll 
HC CTL HC CH HC CH 
ba oh in et ab ee 
C & 
H H 
Paradiazine Metadiazine Orthodiazine 
Pyrazine. Pyrimidine. Pyridazine. 


1. Paradiazine or Pyrazine Compounds. 


These contain the two nitrogen atoms in the para position. They were formerly 
called etines or aldines (Berichte, 19, 2524; 20, 431; 21, 20). They are pro- 
duced by the following methods :— 

1. By reducing the isonitroso ketones and isonitroso acetoacetic esters with tin 
and hydrochloric acid. The amido-ketone compounds formed at first sustain an 
immediate condensation. Thus, isonitroso acetone (p. 206) yields dimethylpyra- 
zine (ketine) (Berichte, 15, 1059) :— 


2CH,.CO.CH(N.OH) + 6H = C,H,(CH,),N, + 4H,0, 


CH,.CO.CH,.NH, ites pe ioe : 4 2H,O + H,. 
or — 
+ NH,.CH,.CO.CH, N — CH = G.CH, 
Dimethyl Pyrazine. 


Again, reronete acetone, CH,.CO.C(N.OH).CH, (p. 209) yields tetra- 
methyl pyrazine, C,(CH,),N, (dimethy! ketine), and isonitrosomethy! propyl 
ketone, CH ,.CO.C(N.OH).C o. gives rise to dimethyl ethyl pyrazine, C,(CH;), 
(C, H,).N, (diethyl OR (Berichte, 14,1463). Dimethyl pyrazine dicarboxylic 
ester, © (CH,) oN, (CO,)R,, was similarly prepared from isonitroso acetoacetic 
_ ester (Berichie, 1. 1051). 

Tetraphenylpyrazine is obtained from benziloxime (p. 888). Isonitrosoaceto- 
phenone, C,H ;.CO.CH(N.OH) (p. 728) may be condensed to isoamidoaceto- 
phenone, C, ‘H, °CO. CH,.NH,, which ammonia will convert into diphenyl pytazine 
(isoindol) (Berichte, ar, 1278, 1947; 22, 562). 

2. By the action of ammonia upon brom- keto-derivatives, R.CO.CBr.HR. Thus, 
brom ged: acetophenone, C,H,.CO.CH,Br, yields diphenylpyrazine, C,H,(C, 

H,),N,, and brom- or oxy- Jevulinic acid, CH,CO.CH Br.CH,.CO,H (p. 344) 
yields tetramethyl pyrazine- with the simultaneous liberation of carbon dioxide. 
With aniline, on the other hand, the a-brom ketones form indol derivatives 
(p. 828) (Berichte, 21, 123). 

Pyrazines or paradiazines are diacid bases with a narcotic odor (resembling car- 
bylamine). They are mostly liquids and volatilize quite readily with steam. 

Free Pyrazine, C,H,N,, appears to be produced when ammonia acts upon 
chloracetal, CH,Cl. CH(OR), (Berichte 21, 1481). 





_ * Widmann uses the terms piazine, miazine, otazine ( Jour. pr. Chem., 38, 18 5). 
Compare Knorr, Berichte, 22, 2083; Hantzsch, Annalen, 249, I. 


METADIAZINES OR PYRIMIDINE DERIVATIVES. 955 


Dimethyl Pyrazine, C,H,(CH,),N,, Ketine, from isonitrosoacetone (see 
above) boils with decomposition about 170-180°. Tetramethyl Pyrazine, C, 
(CH,),N,, Dimethyl Ketine, from isonitrosomethyl acetone and from lzvulinic 
acid, crystallizes with three molecules of water in brilliant needles. When an- 
hydrous it melts at 86° and boils at 190°. Diphenyl Pyrazine, C,H,(C,H,), 
N,, from bromacetophenone and amidoacetophenone, was formerly called isoindol 
(Berichte 21,1279). It forms shining needles or leaflets and melts at 195°. 

Dimethyl pyrazine DicarboxylicAcid,C,(CH,),N,(CO,H),, from isonitroso- 
aceto-acetic ester (see above) (ketine di-carboxylic acid), is produced by oxidizing, 
dimethyl ethyl pyrazine with potassium permanganate (Zerich/e 20, 2524). It 
melts about 195° and decomposes into carbon dioxide and dimethyl pyrazine (?). 


Hydropyrazines. Piperazines. 


Diethylene diamine, described p. 313, may be claimed as a hexahydropyra- 
zine, C,H, .N, = HN< Ch CED>NH. It sustains the same relation to pyrazine, 
that piperidine bears to pyridine, hence it is called Piferazine. Formerly it was 
described as a liquid boiling at 170° (Berichte, 23, 326). According to A. W. 
Hofmann it is a crystalline solid melting at 104°, and boiling at 145-146°. Ben- 
zoyl chloride converts it into the dibenzoy/ derivative, melting at 191° (Berichte, 
23, 3297). It is identical with e/hy/enimine (C,H,NH),, which was first obtained 
as a carbonate, a porcelanous mass, melting at 159-163° (Berichte, 21, 758; 
23, 3303, 3718). Spermine on the contrary seems to have the simple formula 


ix n/CH:CH 


n-Diphenyl Piperazine, C,H, CCH Giz? DN CoH isa diethylene diphenyl 
a, 


2 
diamine or diethylene aniline, resulting from the interaction of ethylene bromide 


and aniline (Berichte, 22, 1387, 1778; 23, 1977). It melts at 163°. 
Dihydropyrazine, C,H,N,, derivatives are produced by the condensation of 

ethylene diamine with ortho diketones, just as the analogous quinoxalines and 

phenazines are obtained from the ortho phenylene diamines (p. 593). For exam- 

ple, denzt/ yields Diphenyldihydropyrazine (Berichte, 20, 267) :— 

CH,.NH, CO.C,H; CH,.N:C.C,H, 

| = [ ” +280. 

CH,.NH, CO.C,;H; CH,.N:C.C,H, 


A series of compounds which have been described as hefo- or azi-piperazines 
are mainly amid-anhydrides of amido-acids or glycocolls (p. 368). Thus, glycine 
anhydride may be termed a diketo-piperazine :-— 


(HN.CH,.CO), = HNZCH2CON ny 


\.CO.CH, 
Glycine Anhydride. Diketopiperazine. 
Phenylglycin-anhydride (C,H,;.N.CH,.CO) is 
/CH,.CON, 


n-Diphenyldiketopiperazine, CoHs-N< CO.CH, /NE.CeH os etc. For dif- 


ferent groups of similar derivatives see Abenius, Berichte, 21, 1664; 23, Ref. 244, 
and Bischof, Berichte, 22, 1810 and 23, 2005-2055; Berichte, 23, 1972. 


2. Metadiazines or Pyrimidine Derivatives. 


These contain the two nitrogen atoms of thé six-membered nucleus in the meta- 
position (p. 954). Thus far only amido- and oxy-derivatives have been prepared. 
1. Amido-pyrimidines are the so-called cyan-alkines, formed by the polymeri- 


} 


956 ORGANIC CHEMISTRY. 


zation of the cyan-alkyls (nitriles) when heated to 150° with metallic sodium. 
Thus, cyanmethane, CH,CN, yields cyanmethine, C,H,N,, cyan- -ethane, 
C,H,CN, cyanethine, C pHi eNes and cyan-propane, C,H, CN, yields cyan-propine, 
C..H,,N , ete. 

"The constitution of the cyan-alkines was made evident by the fact that the 
oxy-base obtained by the action of nitrous acid upon cyanmethine is identical with 
dimethyl-oxypyrimidine (E. v. Meyer, /r. pr. Chem., 39, 265; Berichte, 22, Ref. 
328) :— 


CH CH 
yn oo cy : yn = Cg : 
ag : DCH yields CHC : SON. 
nae ane 
\ a 
NH, OH 
Cyan-methine. Oxy-dimethyl-pyrimidine. 
Amido-dimethyl- 
Pyrimidine. 


The so-called cyan-ethine (see above) is amido-diethyl-methyl-pyrimidine, 
C,H: CON CNE »}SC.CH, A confirmation of this formula is afforded by 
the synthesis of acetyl cyan-ethine from acetamidine, CH,.C(NH).NH,, on boiling 
the latter with acetic anhydride (Berichte, 22,1600). Analogous cyan alkines are 
produced by the action of sodium upon a mixture of two alkylcyanides. The 
course of the reaction remains unexplained ; it may be that dicyanalkyls are pro- 
duced at first, and these then further combine with a cyanalkyl to form cyan- 
alkines (Berichte, 22, Ref. 327). The sodium alcoholates react in the same 
manner as metallic sodium (Berichte, 23, Ref. 630). 

The cyanalkines, or amido-pyrimidines, are crystalline and strongly alkaline 
bases. They form salts with one equivalent of the acids. They are converted 
into oxypyrimidines by the action of nitrous acid upon heating them with hydro- 
chloric acid to 200°. 

Cyanmethine, C,H,N;, melts at 180°. Cyanethine, C,H,,N, = C,H,,N,.- 
NH,, crystallizes in white leaflets, melts at 189°, and boils with partial decomposition 
at 280°. The oxy-base, C,H,,N,.OH, melting at 156°, forms the chloride, 
C,H,,N,Cl, by the action of. PCI,. Nascent hydrogen converts the latter into 
cyanconine, C,H,,N., very similar to conine. It is really methyl diethyl- 
pyrimidine (Berichte, 22, Ref. 328). 

Cyan methine- ethine, C,H,,Ng, resulting from the action of sodium upon a 
mixture of cyanmethane and ‘cyanethane, consists of shining leaflets, that melt at 
165°, and begin to sublime about 100°. The character of the side-chains in this 
compound has not yet been established. ( Four. prk. Ch., 39, 267.) 

(2) The oxymetadiazines or oxypyrimidines are formed when the amidines 
of the paraffin and benzene series act upon acetoacetic ester and analogous 
f-ketone derivatives (the hydrochlorides are mixed in equivalent quantity with 
acetoacetic ester and 10 per cent. sodium hydroxide) (Pinner, Berichte, 22, 
1612, 1633; 23, 3820) :— 


yok, 
NH  CO.CH NutCe: 

RCO + Ri tases RACE Be + R/.0H + H,0. 
NH, CH,.CO,R/’ AN=CC 


OH 
Alkyl methyl-oxy-pyrimidine. 


See Serichie, 22, 2610 for the course of the reaction. Alkyl oxypyrimidine 


OXAZINE AND MORPHOLINE GROUP. 957 


carboxylic acids are analogously derived by the use of oxalacetic ester, 
cog 2 a R Dibasic ketonic acids, such as aceto-glutaric ester and diaceto- 
succinic ester, Teact similarly, while succino-succinic ester forms a quinazoline 
derivative (Berichte, 22, 2623; 23, 2934.) 

The oxypyrimidines are crystalline substances, soluble in nearly all solvents, 
and form salts both with acids and bases. 

Dimethyl-oxypyrimidine, CH,.CN,C,H(OH).CH,, forms needles that melt 
at 192°. Phenylmethyl-oxypyrimidine, C,H;.CN,C,H(CH,).OH, from 
benzamidine, melts at 238°. 

Uracyl, CJH,N,O,, and its derivatives, as well as malonyl] urea, alloxan and the ~ 
analogous carbamides, may be viewed as 4efo-derivatives of the hydrometadiazines 
(Berichte, 23, Ref. 643.) 

(3) All compounds obtained by the condensation of phenylhydrazine (1 molecule) 
with diaceto-succinic ester (a y-diketone, p. 328), appear to be derivatives of ortho- 
diazine or pyridazine in which the two N-atoms of the ‘six-membered ”’ ring 
are adjacent (p. 954) (Berichte, 18, 305, 1568) :— 


CH,.CO.CH.CO,R 
C,H,.NH.NH,+ —C,HN,(C,H,)(CH,),(CO,R),++-2H,0. 


CH,.CO.CH-CO,R 


If the ester be saponified and two molecules of carbon dioxide eliminated 
phenyldimethylpyridazine, C,H,N,(C,H,)(CH,)., results. | Acetophenone-ace- 
tone, C,H,.CO.CH,.CH,.CO.CH;, and phenylhydrazine yield an analogous 
compound (Berichte, 17, 914). 

The denzotriazines, C,H,:N,CH, are the only known derivatives of ¢riazine, 
C,H;N; (p. 553)- : 

The osotetrazones described (p. 326) may be considered as ¢etrazines, C;H,N,. 





OXAZINE AND MORPHOLINE GROUP. 


The oxazine ring is related in the same manner to the diazine and pyridine ring, 
as oxazole to diazole and pyrrol (p. 555) :— 


/CH:CH\, /CH,.CH.N. 
ANS cuca 7? BNWCH, On? 
Oxazine. Morpholine. 


Thus far an oxazine ring, similar to that just given, has only been shown to be 
present in the phen- or benzazoxines. 7Tetrahydro-oxazine, on the other hand, 
does exist. It is called morpholine; very probably because it is contained in mor- 
phine (Knorr, Berichte, 22, 2081). 

Morpholine, C,H, NO, tetrahydro-oxazine, is formed when dioxyethylamine, 
HN. GH CHOH? is heated to 160° with hydrochloric acid, or boiled with 
alkali. 

n-Methyl Morpholine, C,H,(CH,)NO, is similarly formed from dioxyethyl- 
methylamine, CH,.N(CH,.CH,.OH),. It is a liquid, boiling at 117°. It is very 
similar to methyl piperidine. 

n-Phenyl-morpholine, C,H,(C,H 3) NO, is obtained from dioxyethy] aniline, 
C,H,.N(CH,.CH,.OH),, melts at 53°, and boils at 270° (Berichte, 22, 2094). 


958 ORGANIC CHEMISTRY. 


PYRONE GROUP. 


The pyrone ring contains six members. It is analogous to the furfurane ring; 
but is less stable, owing to the influence of the CO-group, and in different reac- 
tions it readily breaks down into its components: acetone, acetic acid and oxalic 
acid. The conversion of most pyrone derivatives, by the action of ammonia, 
into derivatives of y-pyridone (p. 945) and pyridine, is considered rather re- 
markable :— 


KCHaCHe ee. % yey eye ee eee 
4 5 


\ CH=CH <CH cH": 


Pyrone. y-Pyridone. Pyridine. 


The following compounds are probably derivatives of the pyrone nucleus :— 

Pyrone, C,;H,0,, Pyrocomane, is formed when comanic and chelidonic acids 
are heated to 250°. One or two molecules of carbon dioxide are eliminated (Ze- 
richte, 17, Ref. 423). It is aneutral solid that dissolves quite readily in water. It 
melts at 32.5°, and boils about 315°. 

Dimethyl Pyrone, C;H,O,(CHs), (1, 5), results upon heating dehydracetic 
acid (see below) with hydriodic acid. Two’molecules of carbon dioxide are ex- 
pelled from the acid. Brilliant crystals, that melt at 132° and boil at 248°. It 
sublimes at 80° in long needles. It is very soluble in water ( Berichte, 22, 1570). 
Boiling baryta water converts it into diacetylacetone (p. 328), which ammonia 
changes to lutidone. 

Oxypyrone, C,H,0,(OH) (?), pyrocomenic acid, pyromeconic acid, is ob- 
tained by the elimination of one or two groups-of carbon dioxide from comenic 
and meconic acids by distillation. It crystallizes in large plates, melting at 121°. 
It boils at 228°, and even sublimes at 100°. It forms unstable salts with one 
equivalent of the bases (Jour. pr. Chem., 27, 260). 

Comanic Acid, C,H,0, = C,H,O,.CO,H, Pyrone Carboxylic Acid, is ob- 
tained from chelidonic acid by the loss of carbon dioxide (Berichte, 18, Ref. 381). 
It dissolves with difficulty in water. It melts at 250°, and decomposes into carbon 
dioxide and pyrone. When boiled with lime it deconaposes into acetone, oxalic 
acid and formic acid. It forms an oxypicolinic acid when digested with ammonia ; 
this breaks down into carbon dioxide and pyridone when it is heated. 

Chelidonic Acid, C,H,0, = C,H,O,(CO,H),, pyrone dicarboxylic acid, 
occurs together with malic acid in Chelzdonium majus. (Preparation, Aznalen, 57, 
274). It crystallizes in silky needles with one molecule of H,O, and melts at 220°. 
It is a dibasic acid, and forms colorless salts. An excess of alkali converts it 
into xanthochelidonic acid, C,H,O,. This yields yellow-colored salts with 
three and four equivalents of the bases; chelidonic acid is again liberated from 
them by the addition of acids (Berichte, 17, Ref. 424). 

The reduction of chelidonic acid gives rise to hydro-chelidonic acid, 
C,H,,0;, identical with acetone diacetic acid, CO(CH,.CH,.CO,H), (p. 437; 
Berichte, 22, Ref. 681). ‘ Boiling hydriodic -acid reduces chelidonic acid ‘to 
a-pimelic acid (p. 421). It does not form an acefoxime with hydroxylamine. 
Ammonia converts it into an oxy-pyridine dicarboxylic acid, C,H,NO, (cheli- 
damic acid, p. 948). 

~Coumalic Acid, C,H,O,, is identical with comanic acid. It is probably a 
CO—CH = C.CO,H 


b_ca = day 


. 


and may be regarded as a carboxylic acid of a-pyrone (Berichte, 22, 1419, 1705). 


lactone carboxylic acid, with the following constitution, 5 


DIMETHYL PYRONE DICARBOXYLIC ACID. 959 


It is produced when malic acid is heated together with concentrated sulphuric. 
acid or with zinc chloride’(p. 465) (Berichte, 17, 936, 2385). It dissolves with 
difficulty in cold water, and melts with decomposition at 206°. With an excess of 
alkali it forms yellow-colored salts. 

Comenic Acid, C,H,0, = C,H,0,(OH).CO,H, oxypyrone carboxylic acid. 
When meconic acid is heated to 120—200°, or boiled with water or hydrochloric 
acid, it decomposes into CO, and Comenic Acid. The latter is rather insoluble in 
water, and crystallizes in hard, warty masses. When digested with ammonia it 
changes to dioxypicolinic acid (comenamic acid, p. 947). (Berichte, 17, Ref. 
105, 167). 

Meconic Acid, C,H,O, = C,HO,(OH)(CO,H),., oxypyrone dicarboxylic 
acid, occurs in opium in union with morphine. The opium extract is saturated 
with marble, and calcium meconate precipitated by calcium chloride (Anna/en, 83, 
352). The salt is afterwards decomposed by hydrochloric acid. ‘The acid crys- 
tallizes with 3H,O in white laminz, which dissolve readily in hot water and alco- 
hol. When heated to 120° it decomposes into carbon dioxide and comenic acid. 
Ferric salts color the acid solutions dark red. 

In forming salts the acid generally combines with two equivalents of the bases, 
although with an excess of base, the salts are tribasic and yellow in color. 

Meconic acid also unites with ammonia, forming Comenamic Acid (Berichte, 
17, 2081). 

re Acid, C, H,O, = CH,.C O —— C.CH, 

I | ? (See Berichie, 
CH — CO — C.CO,H. 





23, Ref. 463; Annalen, 257, 253.) 

This is a by-product in the preparation of aceto-acetic ester. It can be obtained 
by long continued boiling of the ester, using at the time a return condenser. It 
dissolves with difficulty in cold water and alcohol. It crystallizes in needles from 
ether; these melt at 108° and boil at 269°. Being a ketonic acid it can unite with 
both hydroxylamine and phenylhydrazine (Berichie, 18, 453). It forms (1, 5)- 
dimethylpyrone on being heated with hydriodic acid. 

Iso-dehydracetic Acid, C,H,O,, is isomeric with the preceding and may be 
obtained by the decomposition of the condensation product, C,,H, 0, (Annalen, 
222, 9), produced by the action of sulphuric acid upon acetoacetic ester. It is 
identical with carbaceto-acetic acid (Berichte, 19, 2402), derived from the aceto- 
acetic acid by means of hydrochloric acid. It is very probably mesiten-/actone 
carboxylic acid (Berichte, 23, Ref. 734). | 

Dimethyl Pyrone Dicarboxylic Acid, C,H,O, Carbonyl Diacetic Acid. Its 
ethyl ester is produced when COC], acts upon the copper compound of aceto-acetic 
ester. Water is eliminated from the carbonyl diacetoacetic ester which is formed 
at first (Berichte, 19, 20) :-— 


CH,.CO CO.CH, Cie 6 — CCH, 


l d yields | I 
RO,.C.CH — CO — CH.CO,R RO,C.C — CO — C.CO,R. 


The diethyl ester is crystalline, very readily soluble in alcohol and ether, and 
melts at 80°. Ammonia converts it into dimethyl pyridone-dicarboxylic ester 
(Berichte, 20, 154). 







OF THE b 
VERSITY 


SALEORNIA. 7 


Se 


960 ORGANIC CHEMISTRY. 


2. QUINOLINE GROUP—C,H,,_,,N.* 
QUINOLINE, C,H,N. 


Lepidine, C,,H,N = C,H,(CH;)N—Methyl quinoline. 
Cryptidine, C,,H,,N = C,H;(CH,;).N—Dimethyl quinoline, etc. 
The quinoline bases occur with those of pyridine in bone-oil 
(p- 938), and are also obtained by distilling alkaloids (quinine, 
cinchonine, strychnine) with potassium hydroxide. The com- 
pounds /eucoline, C,H,N, tridoline, CyH,N, etc., separated from 
coal-tar are identical with the quinoline bases (Berichte, 16, 1847). 
As regards synthetic methods and isomerides, quinoline is a 
naphthalene in which a CH-group is replaced by N (p. 937). 
TES gis tak shown by synthesizing quinoline from allyl aniline (p. 602), by 
passing the latter over ignited lead oxide. This is perfectly analogous to the syn- 
thesis of indol from ethyl-aniline (p. 827, and of naphthalene from pheny! bu- 
tylene (p. 905) (K6nigs) :— 
Fae! i Cf 
C,H,.NH.CH,.CH:CH, = C,H,¢ | Sb OH. 
Che: CH 


Quinoline is also produced in the distillation of acrolein-aniline (p. 602). A 
more direct proof of the constitution of quinoline was effected through its forma- 
tion from hydrocarbostyril (p. 755); PCI, converts the latter into a dichloride, 
which upon heating with hydriodic acid. yields quinoline (just as isatin yields 
indigo, p. 836) (A. Baeyer, Berichte, 12, 1320) :— 


/CH,.CH,\ /CH:CCl\, /CH:CH\, 
CHC yy 2 CO) CHa CCL OH CH. 


Hydrocarbostyril. a8-Dichlor-quinoline. Quinoline. 


Here, as with naphthalene and pyridine, we represent the three 
replaceable-hydrogen atoms of the pyridine nucleus by a, § and 7; 


~ ee 
3, \7\ 8 


| 


NSS fo 
z5-4N 








those of the benzene nucleus with 1, 2, 3 and 4. ‘The positions 1, 
2, 3 correspond to the ortho-, meta-, and para-positions of the — 
benzene derivatives. 4 corresponds to the second meza position 
(referred to N), and is known as the Aza-position. These posi- 





* A. Reissert, Das Chinolin und seine Derivate, 1889. 


+ Another nomenclature designates the affinities of the pyridine nucleus as Py-t, 
-2, and -3; those of the benzene nucleus as B-1, -2, -3, and -4 (Berichte, 17, 960). 


QUINOLINE. 961 
\ 
tions are designated as the affinities of the benzene nucleus with 2@-, 
m-, ~- and a-. Consequently, seven mono-derivatives of quinoline 
are possible (Berichte, 19, Ref. 443). 
Of the great number of new synthetic methods of preparing 
quinoline and its derivatives the following are the most important : 
1. The condensation of the ortho-amido-compounds of such 
benzene derivatives as have an oxygen atom attached to the third 
carbon atom of the side-chain (p. 755) (A. Baeyer). 


In this way we obtain quinoline from o-amido-cinnamic aldehyde, a-methyl- 
quinoline from o-amido-cinnamic ketone, and a-oxy-quinoline from o-amido- 
cinnamic acid (p. 812). Further, o-amido-benzyl acetone yields a-methyl-hydro- 
quinoline (p. 730), o-amido-pheny] valeric acid, B-ethyl hydrocarbostyril (p. 814), 
and from these compounds the normal quinoline derivatives—a-methyl quinoline 
and (-ethyl quinoline—can be obtained by the withdrawal of 2H or O. 


2. The production of quinoline and its derivatives by heating 
anilines (or amido-benzene compounds) with glycerol and sulphuric 
acid to about 190°. This method is of universal application and 
can be very readily executed (Skraup, Berichte 14, 1002) :— 


C,H;.NH, + C,H,0,= C,H,N(C,H;) + 3H,0+H,. 


It is very probable that acrolein first results, this then combines with the aniline 
derivative yielding acrolein-aniline (see above), which is oxidized to the quinoline 
derivative by the elimination of two hydrogen atoms by sulphuric acid. Hence, 
the reaction proceeds more easily and rapidly by using a mzxture of aniline with 
nitrobenzene, which only oxidizes. Similarly, from the three toluidines (and 
nitrotoluenes) we obtain the three methylquinolines (toluquinolines), C,,H,N = 
C,H,(CH,)N(C,H,), from the naphthylamines (and nitronaphthalenes) the 
naphthoquinolines, C,,H,N, and from the diamidobenzenes (and dinitrobenzenes) 
the phenanthrolines (p. 974). It is not necessary to apply the corresponding 
nitro-compounds together with the amido-derivatives; nitro-benzene mostly suffices 
as an oxidizing agent (Berichte, 17, 188). 

Likewise, the chlor-, brom-, and nitro-quinolines result from the corresponding 
aniline derivatives. The nitranilines yield both nitro-quinolines and phenanthro- 
lines ( Berichte, 14, 2377). From the amido-sulphonic acids arise the quinoline 
sulphonic acids; from the amido-benzoic acids, quinoline carboxylic acids; from 
the amido-phenols oxyquinolines, etc. 

The Kekulé benzene formula confirms the course of these quinoline syntheses 
(p. 563) (Berichte, 23, 1020). 


3. An analogous reaction is the condensation of anilines with 
paraldehyde, aided by sulphuric or hydrochloric acid. Here 


a-methyl quinolines (quinaldines) are produced (Doebner and v. 
Miller) :— 


: CH: CH 
C,H;.NH, + 2C,H,O = C,H, 


8 
NN: cir, oe 
a-Methyl as ine, 


All aldehydes of the formula CHO.CH,R react like ferric 


962 ORGANIC CHEMISTRY. 


aldehyde with anilines. The first step in the reaction consists in 
two molecules combining to unsaturated aldehydes, CHO.CR:CH. 
CH,R, or condensing to aldols corresponding to them. These 
then act upon the anilines and form quinoline bases. 


Two aldehyde molecules always act. Their condensation is due to the influ- 
ence of the CH, group attached to the aldehyde greup. Acetaldehyde yields 
crotonaldehyde, CHO.CH:CH.CH,, propyl aldehyde yields methyl ethyl acrolein, 
CHO.C(CH,):CH(C,H;), and ethyl propyl acrolein is formed from normal 
butyraldehyde. These unsaturated aldehydes (or the aldols) then react with the 
anilines in such manner, that the aldehyde group attacks the benzene nucleus 
(and not the amido-group). Thus, a- or aZ-alkyl quinolines (Berichée, 17, 1713; 
18, 3360) result. Acetaldehyde (crotonaldehyde) forms a methyl quinoline (see 
above), a(-ethyl-methyl quinoline (Berichte, 21, 299) is derived from propyl 
aldehyde :— 


C,H,.NH, -+- CHO.C(CH), //CH:C.CH, 
| 


ire oy | + H,0 + H,. 
CH(C,H;) N=C.C,H,. 
aB-Ethyl Methy] Quinoline. 


In oxidizing these dialkyl quinolines with a chromic acid mixture it is only the 
a-alkyl that is changed to carboxyl; the resulting carboxylic acids eliminate carbon 
dioxide and yield 3-alkylquinolines (Berichte, 18, 3370). 

Unsaturated aldehydes, therefore, react (with one molecule) directly with the 
anilines. Acrolein (glycerol, see above) yields quinoline, while a-phenyl quino- 
line (Berichte, 16, 1664) is derived from cinnamic aldehyde, CHO.CH:CH.C,H,. 
m-Nitrocinnamic aldehyde reacts similarly (Berichte, 18, 1902). 

Acetone (two molecules) reacts in the same manner as the aldehydes with 
aniline hydrochlorides when aided by heat. It is very probable that mesityl oxide, 
CH,.CO.CH:C(CH,),, is the first product; therefore, as there is a simultaneous 
splitting off of one mesityl group, the products are ay-dimethyl quinolines 
(Berichte, 18, 3296; 19, 1394). 


The mixture of an aldehyde and ketone (each one molecule) re- 
acts the same as the aldehydes upon anilines. The intermediate 
products are unsaturated ketones, R.CO.CH:CH.R (or f-aldol 
ketones, R.CO.CH,.CH(OH)R (C. Beyer, Berichte 20, 1767 ; 19, 
Ref. 327). In this way ay-dialkyl quinolines are produced. 


Acetone and acetaldehyde, or acetylacetone, and aniline yield ay-dimethy]l- 
quinoline (Berichte, 21, Ref. 138) :— 


CH, CH, 
| rs 
Gat we Geach 2 cH7 “cH 4 HOt, 
CHO.CH, N=C.CH, ; 


The £-diketones react similarly (Berichte, 20, 1770; also a mixture of two 
different aldehydes, Berichte, 20, 1908, 1935). . 
_ a-Alkyl-quinoline-y-carboxylic acids are produced by the interaction of a mixture 


QUINOLINE. 963 


of pyroracemic acid and an aldehyde upon aniline (Berichte, 20, 277; 21, Ref. 
12):— 
CO,H 
CO,H 


: ; 
C,H,.NH, £CO.CH, =C,H,“ ‘SCH + 2H,0 +4 H,. 


CHO.R go’ 
N 


The carboxylic acids lose carbon dioxide and in this manner the a-alkyl quino- 
lines are produced. Pyroracemic acid alone when heated with aniline yields the 
same a-methyl quinoline-y-carboxylic acid (aniluvitonic acid, p. 972); this is be- 
cause aldehyde is formed from one molecule of the pyroracemic acid (Berichte, 
20, 1769). 


4. The direct condensation of amido-benzaldehyde with alde- 
hydes and ketones (by the action of caustic soda). The ortho- 
amido-derivatives of the unsaturated homologous benzaldehydes and 
ketones are the first products. These immediately give up water 
(see p. 721) (Friedlander, Berichte, 16, 1833). , 


Thus, with acetone we get a-methyl-quinoline :— — 


CHO CH, 
CH:CH 
CBee = CoH ee + 2H03 
NH, — CO.CH, N: 3 


with acetophenone, CH,.CO.C,H,, a-phenyl quinoline; with phenyl-ethyl 
aldehyde, C,H;.CH,.CHO, 6-phenyl quinoline; with aceto-acetic ester, a-methyl 
quinoline-G-carboxylic acid ( Berich/e, 16, 1833); with malonic ester a-oxyquino- — 
line-3-carboxylic acid (Berichte, 17, 456). o-Amidobenzophenone (p. 859) reacts 
just like o-amidobenzaldehyde; it yields ay-methyl phenyl quinoline with acetone 
and caustic soda (Berichte, 18, 2405) :— 


CO.C,H, CH, C(C,H,):CH 
4\ — CoH 
NH, CO.CH, N—— .CH, -- 2H,0. 


In acid solution it is only the amido group that takes part in the reaction ; ac- 
cording to Miller’s reaction benzoyl-a-methyl quinoline results. 

5. The condensation of aceto-acetic esters with primary and secondary anilines 
(L. Knorr, Berichte, 17, Ref. 147; Annalen, 236, 112). 

There are two phases in this reaction : (@) aceto-acetic anilide (from aniline and 
aceto-acetic ester when heated to 110°), when acted upon with concentrated acids, 
forms a-oxy-y-methyl quinoline (y-methy] carbostyril, p, 968) :— 


CO(CH,)CH, og CH): CH 


is pe iF 0: 
C,H,(NH).CO *“\n=—c(oH) ” 


— 


Methyl aceto-aceti¢ anilide by the same treatment yields By-dimethyl carbostyril 
(Berichte, 21, Ref. 628). 
(4) On the other hand (-phenyl-amido-crotonic ester, formed at the ordinary 


964 ORGANIC CHEMISTRY. 


temperatures, yields y-oxy-a-methyl quinoline (y-oxyquinaldine, p. 970) when 
heated to 240° (Conrad and Limpach, Berichte, 20, 945, 1397) :— 


C,H,0.CO.CH /C(OH):CH 
| = CHS l + C,H,.OH. 
C,H,.NH.C.CH, N——C.CH, 


Phenyl-lutidone carboxylic ester is formed simultaneously. Anisidine, C,H, 
(O.CH,).NH,, also affords methoxy-y-oxyquinaldine (Berichie, 21, 1649, 1655). 
Aceto-acetic ester and methylaniline condense to ~-methyl lepidone (= pseudo- 
carbo-styril, p. 968) (Annalen, 236, 105; Berichte, 19, Ref. 827) :— 


CH,-CO.CH, ACH;):CH 
ore tinged CoHyC | + H,0. 
C,H;.N(CH,)-CO N(CH,).CO 


Acetone dicarboxylic ester (p. 435) reacts in an analogous manner with aniline 
(and methyl aniline) ; the products in this instance are esters of y-oxyquinaldine- 
$-carboxylic acid (Berichée, 18, Ref. 469). 

At the ordinary temperature benzoyl acetic ester and aniline yield (-phenyl- 
amido-phenylacrylic ester, which heated to 250° forms y-oxy-a-phenyl quinoline 
(Berichte, 21, 521, 523). 

6. By the rearrangement of the aniline malonates or the malonanilides with 
PCl,; triquinolines being produced (analogous to the formation of a-naphthol 
from phenylisocrotonic acid, Riigheimer, Berichte, 18, 2975) :— 


/O=CCl 
C,H,.NH.CO.CH,.CO,H yields C,H, ee 
\w—=cca 


The toludines react similarly to aniline ( Berich¢e, 18, 2979), and ethyl malonic 
acid deports itself the same as malonic acid (Berichte, 20, 1235). Hippuric acid, 
C,H,.CO.NH.CH,.CO,H, under like treatment, yields chlorisoquinoline, (p. 
976). 

7. By rearranging the anil benzenyl compounds, from benzanilid-imide chlorides 
and sodium malonic or aceto-acetic ester, by the aid of heat (Just, Berichte, 19, 


979, 1462, 1541) :— 


RO.OC.CH.CO,R pe) s= C.CO,R 
| ae CoH. 
C,H,;.N:C(C,H,)_ . N C.C,H, 


a-Phenyl-y-oxy-8-quinoline carboxylic acid. 


+ ROH. 








8. The conversion of indol and alkyl indols into quinolines (p. 830) is rather re- 
markable. It occurs in consequence of the introduction of methyl, dihydroquino- 
lines resulting (E. Fischer, Berichte, 21, Ref. 17). Chlor- and brom-quinolines 
are similarly obtained by heating methyl ketol with chloroform or CBr,H and 
sodium ethylate (Berichte, 21, 1940). . 





The quinoline bases are liquids which dissolve with difficulty in 
water, alcohol and ether, and possess a penetrating odor. Like 
pyridine they are not readily attacked by nitric or chromic acid ; 


QUINOLINE. 965 


potassium permanganate, however, destroys the benzene nucleus in 
them, with production of af8-pyridiné dicarboxylic acid (quinolinic 
acid, p. 947). 

The homologous quinolines, containing the alkyl groups in the 
pyridine nucleus (a, #, 7), and those containing the substitutions in 
the benzene nucleus (0, m, ~, @), are oxidized by chromic acid in 
the presence of sulphuric acid to the corresponding quinoline car- 
boxylic acids, while potassium permanganate on the other hand 
usually oxidizes those substituted in the benzene nucleus, with the 
formation of pyridine carboxylic acids (Berichte, 19, 1194; 23, 


2252). 


Potassium permanganate converts the #- and y-alkyl quinolines (by decomposing 
the benzene nucleus) into the corresponding pyridine tricarboxylic acids, while the 
a-alkyl quinolines have their pyridine nucleus destroyed, and acid derivatives of 
o-amidobenzoic acid result. By this treatment a-phenyl quinoline yields benzoyl 
anthranilic acid, CHK Nih.CO.CH, (Berichte, 19, 1196). 

If two methyl groups are present in quinoline, the y-position will be oxidized 
with the most ease, then the , and finally the a-position (Berichte, 23, 2254). 

In the case of the a-dialkylquinolines, obtained by the action of aldehydes 
(2 molecules) upon the anilines, chromic acid only attacks the higher a-alkyl with 
the formation of 3-alkyl-a-carbonic acids (see above). 


Only the most important of the many derivatives of quinoline 
will receive notice in the succeeding paragraphs. , 





Quinoline, C,H,N, occurs in bone oil and coal tar. It results 
when many alkaloids are distilled, and is best prepared syntheti- 
cally. 


In preparing quinoline, digest a mixture of 38 grams aniline, 100 grams sul- 
phuric acid, 24 grams nitrobenzene, and 120 grams glycerol, until the reaction 
commences. Boil them for several hours, dilute with water, distil off the nitro- 
benzene in a current of aqueous vapor, supersaturate with alkali, and distil the 
quinoline with aqueous vapor. To purify it thoroughly convert it into the acid 
sulphate (Berichte, 14, 1002). 


See Berichte, 14, 1769, for the reactions and physiological action of quinoline. 


Quinoline is a colorless, strongly refracting liquid, with pene- 
trating odor. It boils at 239°; its sp. gr. = 1.095 at 20°. It 
forms crystalline and very soluble salts with one equivalent of 
acids; the characteristic bichromate, (C,H,N,)Cr,O,H,, dissolves 
with difficulty and forms yellow needles, melting at 165°. 


With the alkyl iodides quinoline, as tertiary base, produces crystalline, yellow 
ammonium iodides, which may be converted into peculiar bases (ammonium hy- 


966 ORGANIC CHEMISTRY. 


droxides), soluble in ether, on warming with caustic soda (Berichte, 17, 1953, and, 
18, 410, 1015). Tertiary dihydroquinolines also afford bases soluble in ether, 
while the iodomethylates of tertiary tetrahydroquinolines are stable towards alkalies 
(Berichte, 21, Ref. 17). Potassium permanganate oxidizes the ammonium chlo- 
rides, the pyridine nucleus being decomposed, and derivatives of o-amidobenzoic 
acid are produced (see above). 

Cyanine (C,,H,,N,I) is a blue dye, and was formerly prepared by heating 
quinoline amyl iodide with potassium hydroxide. It is only produced in the 
presence of a-methyl quinoline (Berichte, 16, 1501, 1847); the same is true of the 
red-dye (Berichte, 16, 1082) obtained from quinoline with benzotrichloride. 

Quinoline betaine, C,H,N To ae (the HCl-salt), is formed from 
quinoline and chlor-acetic acid; the free betaine melts at 171°. 

Nascent hydrogen (tin and hydrochloric acid) produces Dihydro-quino- 
line, C,H,N (melting at 161°), and liquid Tetra-hydro-quinoline, C,H,,N 
ee CHC NetcR> boiling at 245° (Berichte, 16, 727, 23, 1142). Both are 
secondary bases and form nitrosamines. The tetrahydronitrosamine rearranges 
itself quite readily to the paranitroso compound, which yields / amidoquinoline 
when reduced (Serich/e, 21, 862). The alkyl iodides and tetrahydroquinoline 
yield #-alkylhydroquinolines. 2-Methyl tetrahydroquinoline, C,H,,N.C,H,, 
so-called Kairoline, obtained by means of methyl iodide, is said to have the same 
action as kairine—a febrifuge. 

Tetrahydroquinoline (unlike piperidine, p. 950), does not react with bromben- 
zene. When heated with nitro-benzene it is readily oxidized to quinoline (Ze- 
richte, 22, 1389). 

In tetrahydroquinoline the four hydrogen atoms are attached to the pyridine 
nucleus, therefore like the a7.tetrahydro naphthylamines it possesses the character. of 
an aromatic base (of an aniline), Decahydroquinoline, C,H,,N, of alicyclic 
character, is produced when the preceding compound is further reduced by heat- 
ing with hydriodic acid. It is strongly alkaline, with a penetrating, conine-like 
odor. It melts at 48° and boils at 204° (Berichte, 23, 1142). 

The diquinolyls, C,H,N.C$H,N, result from the union of two molecules of 
quinoline. They are analogous to the dipyridyls. They consist either of two 
pyridine nuclei, two benzene nuclei or one pyridine nucleus and one benzene 
nucleus. Seven isomerides have been prepared thus far, partly through the con- 
densation of quinoline by sodium, or by conducting it through a tube heated to 
redness. Skraup has succeeded in synthesizing them from benzidine and dipheny- 
lin (p. 961), or from amidophenyl quinolines. 

On heating quinoline with sodium in air we get a-Diquinolyl, melting at 176° 

(Berichte, 20, Ref. 327.) The two pyridine nuclei in it are united to each other 
at the a-positions (Py a-Py a) C,H,: C, H,N—C,H,N: C,H, (Berichie, 19, Ref. 
7553 20, Ref. 471). 

The chlor-, brom-, and nitro-quinolines, with the substitutions in the benzene 
nucleus, are prepared synthetically, by Skraup’s reaction, from the chlor-, brom-, 
and nitro-anilines. @-Chlorquinoline, C,H,CIN, is obtained from a-oxyquino- 
line with PC], and PCI,0; it consists of long needles, fusing at 38°, and boiling 
at 266°. Itis a feeble base. Its halogen atom, in the a-position, is very reactive. 
When heated to 120° with water it regenerates a-oxyquinoline; alkyl ethers appear 
when it is acted upon by sodium alcoholates, It reacts in the same manner with 
anilines (Berichte, 18, 1532). See Berichte, 21, Ref. 232 for the action of 
bleaching lime upon quinoline and the chlorquinolines. Consult Berichie, 23, 
Ref. 110 upon bromquinolines - 

Ortho and meta (or ana)- Nitroguinolines, C,H, (NO,)N, are produced when 
quinoline is nitrated at 80° with a mixture of nitric and sulphuric acids. The 


OXYQUINOLINE. 967 


ortho- and para- have been obtained from the ortho- and paranitranilines by 
means of glycerol and sulphuric acid, while -nitraniline yields phenanthroline 
(p-974). The ortho melts at 89°, and the meta- (or ana-), when anhydrous, at 72°. 

Amido-quinolines, C,H,(H,N)N (substituted in benzene nucleus), are pro- 
duced in the reduction of the nitroquinolines with tin and hydrochloric acid and 
upon heating the oxyquinolines, C,H,(OH)N, with ammonia-zinc chloride. 

I- and 4- Quinoline Sulphonic Acids (ortho- and ana- Berichte, 20, 95), 
are formed when quinoline is heated with fuming sulphuric acid; at 300 the para 
acid is almost the exclusive product, the ortho acid apparently being converted 
into this (Berichte, 22, 1390). Ana and fara- quinoline sulphonic acids have 
been synthetically prepared from meta- and para amido-benzene sulphonic acid 
with nitrobenzene, glycerol and sulphuric acid (Berichte, 20, 1446). 

When the three quinoline sulphonic acids (their alkali salts) are distilled with po- 
tassium cyanide in a vacuum (Berichte, 22, 1391), they yield the corresponding 
cyanbenzguinolines, C,H,N(CN) (1, 3 and 4). The ortho- cyanide melts at 84°, 
the fara (3) sublimes in needles and melts at 131°, the ava (4) melts at 87° 
(Berichte, 20, 1447). The cyanides can be saponified by heating them together 
with concentrated hydrochloric acid in a sealed tube, when they yield the corres- 
ponding quinoline benzcarboxylic acids, Cj, H,N(CO,H). 





Oxyquinolines, CsH,(OH)N. 

The oxyquinolines containing the hydroxyl in the benzene nucleus, called also 
quinophenols (1, 4, and 3, or ortho, meta, and para), are synthesized from 
the three amidophenols by Skraup’s reaction. 1I- and 4-Oxyquinolines have also 
been prepared from the quinoline sulphonic acids by fusion with caustic potash. 
They resemble the phenols and like them combine with diazo-salts forming azo- 
dyes (Berichte, 21, 1642). 

1-Oxyquinoline (ortho) is also produced from r-chlorquinoline (see above) 
and is most readily prepared from 1-quinoline sulphonic acid (Berichte, 16, 712). 
It crystallizes in white needles, has the odor of saffron, melts at 75°, boils at 266°, 
and is volatile insteam. Ferric chloride imparts a dark-green color to its alcoholic 
solution. 

Nitrous acid converts it into #itroso-oxyguinoline, yellow-green needles, that by 
reduction yields amido-oxyguinoline. 1-Oxyquinoline, like the phenols and naph- 
thols, is changed by chlorine to chlorketoguinolines ( Berichte, 21, 2977). 

Tin and hydrochloric acid convert it into 1-Oxytetra-hydroquinoline, C,H, 
(OH)NH. This forms shining leaflets or needles, melting at 120°. It yields 
oxytetra-hydro-7-methyl-quinoline, C, H,(OH)N.CH,g, melting at 114°, when 
it is acted upon by methyl iodide, The hydrochloric acid salt of this base, 
C,)H,,0N.HC1+-H,0, is Kairine (erichte, 16, 720), which is applied as an 
antipyretic. 

3 Oxyquinoline (para), from para-amidophenol, melts at 190° (Berichie, 15, 
893). Its methyl ester, para-quinanisol, is prepared from /-amidoanisol by the 
reaction of Skraup. It boils at 305°. Nitrous acid converts it into o-sztroso- 
p-oxyquinoline, which, upon reduction, and further oxidation by ferric chloride, 
forms gutnoline guinone, CJH,(O,)N, crystallizing in red-brown needles (Berichie, 
21, 1887). 

Tin ae hydrochloric acid convert 3-oxyquinoline into ¢e¢ra-hydro-para-quinan- 
tsol, CsH, 9(O.CH3)N, crystallizing in stout prisms, melting at 42° and boiling 
at 283°. Most oxidizing agents (¢.g. ferric chloride) color the base and its salts 
green. The sulphate and lactate serve as antipyretics, under the name 7ha//in 
(Berichte, 18, Ref, 613, 72.) : 


968 | ORGANIC CHEMISTRY. 


_  4-Oxyquinoline (ana), from para-amidophenol and from 4-quinoline sulphonic 
acid, crystallizes in needles or prisms, melting at 235-238° with decomposition. 
Ferric chloride imparts a brown-red color to its solution. Tin and hydrochloric 

acid convert it into a tetrahydro-compound. 


The oxyquinolines, with hydroxyl in the pyridine nucleus, are 
more feeble bases and phenols than the oxybenzquinolines. 

a-Oxyquinoline, C,H,(OH)N, Carbostyril, the lactime of 
o-amido-cinnamic acid (pp. 810, 812), is most readily obtained by 
digesting o-nitro-cinnamic ester with tin and hydrochloric acid or 
alcoholic ammonium sulphide (Berichte, 14, 1916). It may also 
be prepared from a-chlorquinoline by heating it with water, and 
by digesting quinoline with a bleaching lime solution (Berichte, 
21, 619). It crystallizes from hot water (1 : 100) in fine needles, 
from alcohol in large prisms. It melts at 198-199° and sub- 
limes. 


Water decomposes its salts with alkalies and acids. Carbon dioxide separates it 
in the form of shining needles from its alkaline solution. Potassium permanganate 
oxidizes it to oxalyl anthranilic acid (p. 749). Sodium and alcohol reduce it to 
tetrahydroquinoline (Berichte, 19, 3302). o-Nitrocarbostyril is produced when 
o-nitrocoumaric acid (p. 819) is heated together with alcoholic ammonia. It melts 
at 168°. 

As in the case of oxypyridine or pyridone (p. 945), it is undetermined whether 
the lactime or lactam form should be ascribed to a-oxyquinoline; the ethers, how- 
ever, of the two forms, of carbostyril and pseudocarbostyril exist :— 


CH:CH CH:CH 
lt ha | bah Ce 

-N:C.OR NNR.CO 
Carbostyril Ether. Pseudocarbostyril Ether. 


The cardbostyril or lactime ethers, with the group, N:C(OR), are produced by the 
action of the alkyl iodides upon the undecomposed (Na- or Ag-) salts of carbo- 
styril ; the pseudocarbostyril or lactam ethers, however, by the action of the alkyl 
iodides upon free carbostyril in the presence of alkalies (Berichte, 18, 1528; 20, 
2009). ‘The lactam ethers differ from the lactime ethers in being solid crystalline 
bodies, not decomposed when heated with hydrochloric acid. ‘The methyl ether 
melts at 71°, and the ethyl at 54°. 

The lactime ethers are also formed when o-amidocinnamic esters are digested 
with alcoholic zinc chloride (p. 812) and by the action of sodium alcoholates upon 
a-chlorquinolines. They are aromatic oils, that volatilize in a current of steam. 

There are perfectly anologous isomeric ethers of Hydrocarbostyril, derived 
from tetrahydroquinoline, C,H,,N. 

a -Oxy-y-methyl quinoline, y-Methyl carbostyril, or Lepidone, C,H, 

C(CH,):CH 
“ad | , from acetoacetanilide (p. 963), manifests a similar behavior. - 
\—NH—CO 
Methyl lepidone, from acetoacetic ester and methyl aniline, melts at 131°, whereas 
methoxy-y-methyl-quinoline is a liquid (Berichte, 19, Ref. 828). y- Oxy-a-methyl 
Quinoline, y- Oxyquinaldine, from phenylamidocrotonic ester (p. 963), also forms 
two isomeric ethers (Berichte, 20, 948; 21, 1965). 


METHYL-QUINOLINE. 969 


When methyl iodide acts upon y-oxy-quinaldine, it forms an zodomethy/ate, or HI- 
CO CH 


/ 
| 
*\N(CH),.C(CH, 





salt, from which alkalies separate n-methyl quinaldone, C,H 


melting at 175° (Berichte, 22, 78). Compare lutidone. 

Kynurine, £- or y-oxy-quinoline, C,H,(OH)N, is made by heating cynu- 
renic acid (oxyquinoline carboxylic acid, p. 973), and by oxidizing cinchonine and 
cinchoninic acid with chromic acid (Berichte, 22, Ref. 758). It crystallizes in 
needles, containing three molecules of water, and when anhydrous melts at 201°. 
It forms quinoline when heated with zinc dust. Potassium permanganate oxidizes 
it to oxalylanthranilic acid (cynurenic acid, p. 749). PCI, converts it into chlor- 
quinoline, melting at 34°. 

Dioxy-quinolines, C,H,(OH),N. Two isomerides have been obtained from 
chlorcarbostyril. A rather noteworthy formation of ay-dioxyquinoline is that from 
o-amido-phenylpropiolic acid (p. 816). Nitrous acid converts it into trioxyquino- 
line, C,H,(OH),N, which may be oxidized to quinisatinic acid by ferric chloride 
and this by loss of water yields quinisatin, C,H;.NO, (p. 765). 





Quinoline Homologues, 

The monoalkylquinolines exist in seven isomeric forms (p. 961). 

(1) The seven isomeric methyl quinolines are all known. 

The four quinolines methylated in the benzene nucleus, called Toluquino- 
lines, methyl benzquinolines, or lepidines, are obtained by Skraup’s reaction 
on heating the three toluidines with nitrotoluenes, glycerol and sulphuric acid. In 
this way o- and f-toluidine yield o- and f-methyl quinoline, while #-toluidine 
affords both the meta- and ana-quinolines. The latter can be separated by means 
of their acid sulphates (Berichte, 19, Ref. 442). The isomerism of place of the 
meta- and ana-compounds is obtained from the carboxylic acids, corresponding 
to them (p. 972). Chromic acid oxidizes all four methyl quinolines to quinoline 
benzcarboxylic acids; while potassium permanganate converts the four isomerides 
(by destruction of the benzene nucleus) into @Z-pyridine dicarboxylic acid (p. 947). 

Ortho. methyl quinoline (1), from o-toluidine, boils at 248°, the meta- (2) boils 
at 250°, the para- (3) at 257°, and the ana- (4) at 250°. 

The following are methylated in the pyridine nucleus :— 


a-Methyl-quinoline, C,H,N = C,H,:C,;H,(CH;)N, Quinal- 
dine, is formed in the condensation of o-amido-benzaldehyde with 
acetone when warmed with sodium hydroxide (p. 963); by the 
reduction of o-nitrobenzal acetone (p. 806); from y-oxyquinaldine, 
and by fusing ethyl acetanilide with zinc chloride (Berichie, 23, 
1903). It may also be obtained from aniline by means of ethyl 
aldehyde. 


The most advantageous course to procure it consists in digesting 1 part of ani- 
line with 1% parts of paraldehyde and 2 parts crude hydrochloric acid, and 
then distil the product with sodium (Aerichfe, 16, 2465, 2600). As much as 25 
per cent. of quinoline is found in coal-tar, but it cannot be isolated from it 
(Berichte, 16, 1082). 


Quinaldine is a liquid with a faint odor resembling that of quino- 
line, and boils at 238°. When acted upon by potassium perman- 
ro 


97° ORGANIC CHEMISTRY. 


' ganate the pyridine ring is broken and acetyl-anthranilic acid 
results. Chromic acid oxidizes it to a@-quinoline carboxylic acid. 


Tin and hydrochloric acid reduces it to Tetrahydro-quinaldine, C,,H,,N, 
which also results by the reduction of o-nitrobenzyl acetone (p. 730). It boils 
at 247°, is a strong base, and is colored blood-red by oxidizing agents (FeCl,). 
Alkyl iodides and quinaldine (also the lepidines) unite to Peete or am- 
monium iodides; the caustic alkalies liberate the ammonium bases, C,)H, (NR),O 
from the latter (Berichte, 21, Ref. 14). When the iodomethylates ate heated 
in air contact with the concentrated alkalies peculiar red and blue dyestuffs—the 
Cyanines—are produced (Berichfe, 18, Ref. 17). 

Concentrated nitric acid converts quinaldine into o- and m- nitro-quinaldines, 
C,,H,(NO,)N, which form o- and m-amido-quinaldine by reduction (Lerichde, 
22, 224). 


y-Oxyquinaldine and m-methyl-quinaldone (p. 969). 

The CH,-group of quinaldine is very reactive. It enters readily into condensa- 
tion products with aldehydes (paraffin or benzene class) (Berichte, 20, 2041). 
Chloral yields the compound, C,H,N.CH:CH.CCl,, melting at 144°; boiling 
potassium carbonate converts it into a quinoline acrylic acid, C,H,N.CH:CH. 
CO,H, while potassium permanganate oxidizes it to a-quinoline aldehyde, 
C,H,N.CHO. MWHydrobromic acid and soda convert quinoline acrylic acid into 
a-quinoline-lactic acid, C,H,N. CH(OH).CH.CO,H and its /actone (Lerichte, 
21, Ref. 635). Consult Berichie, 22, 271, upon quinoline acrylic acids and quino- 
line aldehydes. Quinaldine and phthalic anhydride yield a beautiful yellow 
dye—quinophthalone or quinoline yellow, C,H,(C,O,):CH.N.C,H, (p. 880), 
which may be sublimed in golden-yellow needles, melting at 235°. The sodium 
salt of its sulphonic acid is the quinoline yellow of commerce. It dyes silk 
and cotton a beautiful yellow. 

8-Methyl Quinoline, C,H,(CH,)N, is produced by heating 3-methyl-a-quino- 
line carboxylic acid (from a 3-ethyl-methyl quinoline, from aniline and propionic 
aldehyde, p, 962). and by the condensation of aniline together with propionic 
aldehyde and methylal (p. 962, Perichies 20,1916). It boils at 250°. It solidifies 
in the cold and melts at 10-14°. Chromic acid oxidizes it to {-quinoline car- 
boxylic acid. 

y-Methyl-quinoline, C,H,(CH,)N, Lepidine, occurs together with quinoline 
and quinaldine in coal-tar, and is obtained on distilling cinchonine with caustic 
potash. It may be synthetically prepared by the condensation of aniline with 
methylal (3 parts) and acetone (3 parts), aided by hydrochloric acid, by the method 
of vy. Baeyer (p. 962). It possesses an odor like that of quinoline, and boils at 257°; 
it solidifies below 0°. Chromic acid oxidizes it to y-quinoline-carboxylic acid. 
Potassium permanganate first produces methyl-pyridine-dicarboxylic acid, and 
afterwards pyridine-tricarboxylic acid (ay). 


(2) Dimethyl- and Ethyl-quinolines. 

aB- Dimethyl Quinoline, C,H,;(CH;),N, is obtained from a mixture of acet- 
and propionic aldehydes (or from tiglic aldehyde) with aniline (Derichie, 22, 267). 
By-Dimethyl Quinoline, from y-dimethyl-carbostyril, melts at 65° and boils at 
290°. o- and f-Oxy-ay-dimethyl Quinolines, C,H,(OH)(CH,),N, have been 
prepared from o- and g-amidophenol with acetone (Berichte, 22, 209). o- and /- 
Toluquinaldine, C,H,(CH,),N, containing the methylene groups in the benzene 
and pyridine nuclei, are obtained from o- and -toluidine by means of paraldehyde 
(Berichte, 23, 3483). a- and 6-Ethyl Quinoline, C,H,(C,H,)N, are produced 
(similar to the alkyl pyridines, p, 942) by heating eine jodoethylate t to 280° 


PHENYL-METHYL-QUINOLINE. 971 


(Berichte, 19,2995). $8-Ethyl Quinoline is obtained from $-ethyl hydro-carbo- 
styril (p. 814), just as quinoline is prepared from hydrocarbostyril (p. 961); and 
from /3-ethyl quinoline-a-carboxylic acid (from af-propyl ethyl quinoline, prepared 
from aniline and butyraldehyde, p. 962) ( Berich¢e, 18, 3371). 

a-Ethyl Quinoline boils at 255—260°, 6-Ethyl Quinoline at 265°, and 
y-Ethyl Quinoline at 270-275°. These compounds yield the corresponding 
quinoline carboxylic acids when oxidized with a chromic acid mixture. 

Consult Berichte, 21, Ref. 138 upon the ¢rimethyl-guinolines. 





Phenyl-quinolines, C,H,(C,H,)N. 

a-Phenyl-quinoline is obtained from cinnamic aldehyde and aniline upon 
heating them with hydrochloric acid to 200° ; also by the condensation of o-amido- 
benzaldehyde with acetophenone. It consists of brilliant needles, melting at 84°, 
and boiling above 300°. Potassium permanganate oxidizes it to benzoyl anthrani- 
lic acid (p. 749) (Berichze, 19, 1196); while tin and hydrochloric acid convert 
it into a tetrahydro-compound C,H,,(C,H,;)N. $-Phenyl-quinoline is pro- 
duced in the condensation of o-amido-benzaldehyde with phenyl-acetaldehyde. 
It is an oil, which solidifies on cooling, 

y-Phenyl-quinoline is formed by heating y-phenyl-quinaldinic acid (from 
y-pheny] quinaldine, see below) to 180° ( Berichte, 19, 2430). It crystallizes from 
pure alcohol in white flakes, melting at 61°, and distilling at that temperature. It 
apparently is the parent substancé of the quinia alkaloids (Berichte, 20, 622). 

y-Phenyl-a-Methyl Quinoline, C,H,(C,H,) (CH,)N, y-phenyl quinaldine, 
results in the action of hydrochloric acid upon aniline mixed with acetophenone 
and paraldehyde (p. 961), as well as by the condensation of o-amido-benzophe- 
none and acetone by means of sodium hydroxide (p. 963) (Berichte, 18, 2406), 
also by the condensation of benzoyl acetone, CSH,;.CO.CH,.CO.CH,, with aniline, 
according to Beyer’s method (Berichte, 20,771). It melts at 99° and yields 
y-phenyl quinoline-a-carboxylic acid when its phthalone is oxidized - with chromic 
acid. This new acid affords y-phenyl quinoline (see above). 

a-Phenyl-y-methyl Quinoline, C,H,(C,H,;)(CH,)N, is produced by con- 


densing o-amido-acetophenone, C,H, NH, °» 2nd acetophenone with caustic 
2 


soda (p. 963) (Berichte, 19, 1036), as well as by distilling flavenol with zinc dust. 
It crystallizes in white leaves and melts at 65°. . = 

Upon heating acetanilide, C,H,.NH.CO.CH,, with zinc chloride to 270° (by 
condensation of 2 molecules of the ortho-amido-acetophenone which is produced 
first), we obtain Flavaniline, C,,H,,N,, applied as a beautiful yellow dye 
( Berichte, 15, 1500). It is -Amido-a-phenyl-$-methyl-quinoline. It also 
results in the condensation of o-amido-acetophenone and /-amido-acetophenone 
when digested with zinc chloride (Berichte, 19, 1038). Flavaniline forms colorless 
crystals that become yellow on exposure to the air. Its monacid salts are yellow 
in color and have been used as dyes (Berichte, 15, 1500). Nitrous acid converts 
it into so-called Flavenol, C,H,(C,H,OH)(CH,)N, a phenol, which when 
heated with zinc dust becomes ay-Phenyl-methyl-quinoline. Potassium 
permanganate oxidizes flavenol to ya-methyl-quinoline-carboxylic acid (p. 972), 
and then to methyl pyridine tricarboxylic acid and pyridine tetracarboxylic acid. 


972 ORGANIC CHEMISTRY. 


Quinoline Carboxylic Acids, 


These acids exhibit the character of amido-acids and yield salts with both bases 
and acids. 


(1) Quinoline Monocarboxylic Acids, C,,H,NO, = C,H,N.CO,H. 

There are four quinoline benzcarboxylic acids or those containing the carboxy] 
groups in the benzene nucleus. Of these the ortho, meta and para are obtained 
by oxidizing the corresponding methyl quinolines with chromic acid in a sulphuric 
acid solution. The ortho, para and ana-acids are prepared from o-, Z- and m- 
amido-benzoic acids by Skraup’s reaction, heating them with glycerol and sul- 
phuric acid to 140°, further, by heating the three cyanquinolines with hydro- 
chloric acid (p. 967). 

The place-isomerism of the ana-acid (melting about 360°) is evident from its 
formation (together with the ortho-acid) from amido-terephthalic acid by Skraup’s 
reaction (Berichte, 19, Ref. 548), from (1, 2, 3)-amidophthalic acid (together with 
the meta-acid) (Berichte, 19, Ref. 548), and from ana- quinoline sulphonic acid 
(p. 917) by means of the cyanide (Berichte, 20, 1446). The meta-acid has also 
been obtained by oxidizing 6-di-quinolyl (Berichie, 19, 2473). 

Ortho-Quinoline-Carboxylic Acid (1) is the most soluble in water and alco- 
hol. It crystallizes in white needles, melting at 187°. The meta (2) acid crys- 
tallizes in needles, melting at 284-250°. The fara-acid (3) is a white powder, 
and melts at about 291°, charring at the same time. The ama-acid (4), also pre- 
pared from meta-amido-benzoic acid, is almost insoluble in water, sublimes as a 
cyrstalline powder, and melts about 360° (338°) (Annalen, 237, 328). 

The acids containing the carboxyl in the pyridine nucleus are prepared by 
oxidizing a-, 8-, and y-methyl-quinoline with chromic acid in sulphuric acid solu- 
tion. Those acids, with a carboxyl in the a-position, are colored reddish-yellow 
by ferrous sulphate. 


a-Quinoline Carboxylic Acid, C,H,N(CO.H), Quinaldinic 
Acid, crystallizes from hot water in needles containing 2H,O; it 
effloresces in the air, melts at 156°, and further decomposes into 
carbon dioxide and quinoline. 


B-Quinoline Carboxylic Acid is produced by heating Acridic acid to 130°. 
It crystallizes, in small plates, melts at 171°, and when oxidized with potassium 
permanganate yields (a, 3, y)-pyridine tricarboxylic acid (p. 949). 


y-Quinoline Carboxylic Acid, C,H,N(CO,H), Cinchoninic 
Acid, was first produced upon oxidizing cinchonine with potassium 
permanganate or nitric acid. It crystallizes in needles, containing 
2H,O, in thick prisms, or plates with 2H,O (Berichte, 20, 1609). 
It melts when anhydrous at 254°. When distilled with lime it 
affords quinoline; potassium permanganate oxidizes it to afy-pyri- 
dine tricarboxylic acid. 


Methylquinoline Carboxylic Acids, C,H,(CH,)N(CO,H). 

y-Methyl-a-quinoline Carboxylic Acid is obtained by oxidizing flavenol (p. 
971) with potassium permanganate, and melts at 182°, with decomposition into 
CO, and y-methy] quinoline. 

a-Methyl-y-quinoline Carboxylic Acid, a-Methyl Cinchoninic Acid, is 
Aniluvitonic Acid, obtained by the condensation of pyroracemic acid with aniline 


QUINOLINE-DICARBOXYLIC ACID. - 973 


(p. 962) (Berichte, 22, 1769). It crystallizes in delicate needles containing one 
molecule of water. It melis at 240°, and breaks down into carbon dioxide and 
quinaldine (Berichte, 14, 2249). 

The homologous a-a/kyl cinchoninic acids result in the condensation of pyro- 
racemic acid and aldehyde with anilines (p. 962) (Berichte, 22, 23) 

a-Methyl-8-quinoline Carboxylic Acid, C,H,N(CH,).CO,H results from 
the condensation of o-amido-benzaldehyde with aceto-acetic ester (p. 962), and 
melts about 234°, with decomposition into carbon dioxide and quinaldine. 

The Quinaldine Carboxylic Acids (quinaldines with carboxyl in the ben- 
zene nucleus), a-Methyl quinoline-carboxylic acids (ortho, meta and para), are 
produced by the condensation of the three amido-benzoic acids with aldehyde and 
hydrochloric acid. 

(2) Oxyquinoline Carboxylic Acids, C,H ,(OH)N)CO,H. 

a-Oxyquinoline-3-Carboxylic Acid, Carbostyril-3-carboxylic Acid, results 
in the condensation of o-amido benzaldehyde with malonic acid (p. 963), melts 
above 320°, and on heating its silver salt yields CO, and carbostyril. 

a-Oxyquinoline-y-carboxylic Acid, Oxycinchoninic Acid, is formed on 
melting cinchoninic acid with potash. It melts at 310°,and decomposes into CO, 
and carbostyril, if its silver salt be distilled. 

Kynurenic Acid is also an oxy-quinoline carboxylic acid. It occurs in the 
urine of dogs. It consists of needles containing 1H,O, becomes anhydrous at 
140°, and melts at 257°. Fusion with caustic potash converts it into CO, and 
kynurine. 

o-Oxy-quinoline-m-carboxylic Acid, C,H,(OH)N(CO,H), with the hy- 
droxyl group in the ortho position of the benzene nucleus, is produced when the 
sodium salt of o-oxyquinoline (Berichte, 20, 1217) is heated with CO, under pres- 
sure (analogous to the formation of salicylic acid) :— 


C,H,(ONa)N + CO, = C,H,(OH)N(CO,Na). 


p-Oxyquinoline by the same treatment yields p-oxy-guinoline carboxylic acids 
(Berichte, 20, 2695). The ortho and para acids have also been obtained from 
o- and g-oxyquinoline by means of CCl, and caustic potash (Berichée, 20, Ref. 
564). In the same manner o-oxyquinaldine yields 0-oxyguinaldine carboxylic 
acid, C,H ,(CH,)(OH)N.CO,H (Berichte, 21, 883). 

Para-oxycinchoninic Acid, C,H,(OH)N(CO,H)(3, y), Xanthoguinic acid, 
results on fusing parasulphocinchoninic acid (on heating cinchoninic acid to 260°, 
with sulphuric acid) with KOH. It crystallizes with 1 molecule of H,O, and 
melts at 320° with decomposition into carbon dioxide and paraoxyquinoline. Its 
methyl phenol ether Quininic Acid, C,H,(O.CH,)N(CO,H), is obtained by oxi- 
dizing quinine and quinidine with chromic acid in sulphuric acid solution, crys- 
tallizes in long, yellow prisms, dissolves in alcohol with a blue fluorescence, and 
melts at 280°. When heated to 230° with hydrochloric acid it decomposes into 
methyl chloride and para-oxycinchoninic acid. 





3. Quinoline Dicarboxylic Acids, C,H;N(CO,H),. 


a$-Quinoline-dicarboxylic Acid, Acridic Acid, is produced when acridine 
is oxidized with potassium permanganate, crystallizes in needles with 2H,O, or 
plates with 1H,O, and decomposes at 120-130° into CO, and (-quinoline-carbox- 
ylic acid. ; 

ay-Quinoline-dicarboxylic Acid results when a-cinnamenyl-cinchoninic 
acid (from cinnamic aldehyde, pyroracemic acid and aniline) is oxidized with 


974 . ORGANIC CHEMISTRY. 


potassium permanganate. It melts with decomposition at 246° (Berichte, 22, 
3009). 

(1, 4)-Quinoline Dicarboxylic Acid is obtained from amidoterephthalic acid 
by the action of glycerol and sulphuric acid. It crystallizes in long needles contain- 
ing 2H,O, melts at 268-270°, and breaks down into carbon dioxide, and ortho- 
and ana- quinoline carboxylic acids (p. 972). 





Complex Quinolines. 

Just as pyridine, C;H,N, and quinoline, C,H,N, are derived from benzene, 
C,H,, and naphthalene, G 1e%2¢9 90 corresponding quinolines result from the 
higher, condensed benzenes. 

The so-called Naphtho-quinolines, C,,H, N, are derived from phenanthrene 
by the replacement of a CH-group in a terminal "benzene ring by nitrogen, whereas 
in phenanthridine the N-atom is present in the middle benzene mucleus :— 


N 
ty CAS ain ® SN, | ig ER 
Ee Te OE ea, eh eat 
ee ay ea Ae a tire 
a-Naphtho-quinoline. B-Naphtho-quinoline, N 


Phenanthridine, 


They are produced when a- and / naphthylamines are heated with glycerol, 
nitrobenzene and sulphuric acid. . 

a-Naphtho-quinoline melts at 50°, and boils at 251°. $-Naphtho-quino- 
line, melts at go°. When they are oxidized, they yield two (a- and §-) phenyl- 
pyridine dicarboxylic acids, C,H,(CO,H).C, H, N(CO,H) (this i is like the forma- 
tion of diphenic acid from phenanthrene, p. 92 5), which split off two molecules of 
carbon dioxide and become a- and 3-phenyl-pyridines (950). $-Naphtho-quinoline 
may also be obtained by removing bromine from a-brom-$-naphthylamine, or by 
the elimination of the nitro group from a-nitro. $-naphthylamine (BerichZe, 23, 1018). 

8 Naphthomethyl Quinoline, C,H,,N = C,,H,(CH,)N, -naphtho- 
quinaldine, is analogously, produced by the action of paraldehyde and sulphuric 
acid upon #-naphthylamine. Potassium permanganate oxidizes it to P-naphtho- 
quinoline carboxylic acid, C,,H,N.CO,H (Berichte, 22, 254; 23, 1231). 

Phenanthridine is isomeric with naphthoquinoline, In it one of the interme- 
diate CH-groups of phenanthrene is replaced by nitrogen. It results from the 
pyrogenic condensation of benzylidene aniline on conducting the latter through 
a tube heated to redness (Berichfe, 22, 3339) :-— 


C,H,.CH  C,H,CH 
[ts ee, ee 
C,H,.N C,H,.N 


It crystallizes in delicate white needles, melting at 104° and boiling without 
decomposition at 360°. Its salts are yellow in color. 
CH oN.CH 
Two Phenanthrolines, C,,H,N,, = | || , have been prepared by 
U;H,N.CH 
heating m- and g-diamidobenzene with glycerol, etc. These are derived from 
phenanthrene by replacement of 2 CH-groups of the terminal benzene ring by 2 
nitrogen atoms (Berichte, 16, 2522; 23, 1016). 


ISOQUINOLINE GROUP. . 975 


Phenanthroline, melting at 78°, is obtained from meta-nitraniline and meta- 
amido-quinoline by means of glycerol and sulphuric acid. Isomeric Pseudo- 
phenanthroline is also derived (in slight amount) from paranitraniline and melts 
at 173°. Potassium permanganate oxidizes the phenanthrolines to two dipyridyl 
dicarboxylic acids (Berichte, 19, 2377)- CRN. CECH 

Anthraquinoline, C,,H,,N = CoHa cH /CoHa, ee is obtained 
from anthramine (p. 895) on heating with glycerol, nitrobenzene and sulphuric 
acid. It sublimes in colorless leaflets, melts at 170°, and boils at 446°. Its solu- 
tions fluoresce very intensely. By oxidation with chromic acid in glacial acetic . 
acid, it yields a quinone corresponding to anthraquinone; the dioxy-compound of 
the latter is alizarin blue. 

When m-nitro-alizarin or amido-alizarin is heated, according to Skraup’s re- 
action, with glycerol and sulphuric acid we obtain a/izarin-blue, C, ,H,,NO, (Be- 
richte, 18, 445):— 


C,,H;(O),(OH),NH, + C,H,O; = C,H;(O),(OH),N.C,H, + 3H,0. 


The same occurs in trade in the form of a bluish-violet paste, and like alizarin 
is applied in dyeing. Since reducing agents decolorize it (zine dust, grape sugar) 
and it again separates on exposure to the air, it is adapted to the vat-dyeing. It 
combines with sodium sulphite, yielding a compound soluble in water (same as 
quinoline)—the so-called soluble alizarin-blue (Berichte, 22, Ref. 368). 

Alizarin-blue crystallizes from benzene in metallic, blue-violet needles, which 
melt at 270° and sublime. Heated with zinc dust it forms anthraquinoline, 
C,,H,,N (see this); it is, therefore, a derivative of the latter, and is similarly 
obtained from nitrealizarin and glycerol, just as quinoline is derived from nitro- 
benzene and glycerol. It unites with acids and bases to form salts; those with 
the bases are stable. 





ISOQUINOLINE GROUP. 


Isoquinoline is isomeric with and perfectly analogous to quinoline, Its N- atom- 
occupies the meta-position with reference to one of the two C- atoms, which are 
common to-both rings. It corresponds to the following scheme :— 


This constitution seems evident from the fact that when isoquinoline is oxidized — 
it forms cinchomeronic and phthalic acids (see below); the syntheses of the iso- 
quinoline nucleus also argue in its favor :— 

CH,.CO 


(1) By heating homophthalimide, CHK | (p. 791) with POCI, and then 
CO.NH 
reducing the resulting dichlorisoquinoline by heating it with hydriodic acid 
(Berichte, 19, 2354), or by heating homophthalimide with zinc dust (Berichée, 21, 
2299). 
In a like manner dimethyl homophthalimide (p. 791) and zine dust yield 
methylisoguinoline (Berichte, 20, 1105; 21, 2300);  isophthalamidine, 
CH:C.C,H, . 
HN une , forms f-pheny/ isoquinoline (Berichze, 18, 3477; 19, 830); 


q7e ORGANIC CHEMISTRY. 


and o-cyanbenzoyl cyanide is converted into benzyl chlor- oxyisoguinoline (Be- 
richte, 21, 2679). 

(2) Heating hippuric acid (p. 744) with phosphorus pentachloride and then 
reducing with hydriodic acid (Berichte, 19, 1172). This is analogous to the for- 
mation of quinoline from malonanilide (p. 964). 

Isoquinoline, C,H,N, occurs together with quinaldine and ordinary quinoline 
in the crude quinoline from coal tar. It is separated from the accompanying com- 
pounds by the crystallization of the sulphates (Berichte, 18, Ref. 384). It is very 
similar to quinoline, solidifies however at 0° to a crystalline mass, melting at 20— 
22°, and boils at 237°. Potassium permanganate oxidizes it to phthalic acid (de- 
_ stroying the pyridine nucleus) and By- pyridine dicarboxylic acid (by destroying 
the benzene nucleus), whereas quinoline yields a$- pyridine dicarboxylic acid; 
phthalimides, C,xH,(CO),NR (Berichte, 21, Ref. 786), result if the oxidation 
be moderated. 

A beautiful red dye—Quinoline Red—is produced by condensing benzotrichlo- 
ride, C,H;CCl,, with molecular quantities of quinaldine and isoquinoline when they 
are heated with zinc chloride. This compound, in all probability, has a consti- 

; / CyoH,.N S : 
iad me CO: C H, (CH,)N, analogous to that of malachite-green (Hofmann, 
Berichte, 20, 4). 

In addition to its coloring properties, it possesses the remarkable power of render- 
ing photographic plates orthochromatic. 

$B-Phenyl isoquinoline, C,H,(C,H,;)N (see above), crystallizes in leaflets, 
and melts at 104°. 





BENZO-DIAZINES. 


These are analogous to the benzopyrrols (p. 826) and denzo-diazoles (p 571). 
They contain both the benzene nucleus and the diazine nucleus, with two carbon 
atoms in common (p. 860). They exist, in accordance with the positions of the N- 
atoms, in three isomeric forms :— 


CH=CH CH=N /N=CH 
C,H” Op 2) 2 and § CH Py 
\ NEN \ Nee OH \. N=CH 
Ortho-benzdiazines Metabenzdiazines Parabenzdiazines. 
Cinnoline. Quinazoline. Quinoxaline. 


zr. Cinnoline Group. 


The Cinnoline nucleus, C,H,N,, the first representative of the ring-chains 
containing two nitrogen atoms, is known in very few derivatives. It has been ob- 
tained by a closed ring being formed from the diazo-compounds; a nitrogen atom 
enters the side chain occupying the ortho-position. 

Thus, Oxy-cinnoline Carboxylic Acid (v. Richter, Berichte, 16, 677,) is ob- 
tained from the diazo-chloride of o-amidopheny] propiolic acid (p. 815), when its 
aqueous solution is heated to 70°:— 


/&iC-CO,H /C(OH):C.CO,H ; 
C,H H,O — C,H HCL * 
ea it NN = 

: C(CH,):CH 
Methyl Cinnoline-carboxylic Acid, CyH,(CO,H) he os (Wid- 
NN 


PHENYLENE-DIAZOSULPHIDE. 977 


mann, Berichte, 17, 724), is obtained in the same way, from the diazo-chloride of 
o-amido-propenyl benzoic acid (p. 778), CgH,(CO,H) { X\Cp 


2 

Oxycinnoline-carboxylic acid, C,H,(OH)N,(CO,H), melts at 260°, with the 
separation of CO, and formation of Oxycinnoline, C,H,(OH)N,, which melts at 
225°, and when heated with zinc dust yields cinnoline. 


o-Phenylene-diazosulphide, oh He NON (p. 683), may be viewed as a cin- 


noline derivative, in which a sulphur atom replaces the group CH : CH. It sustains 
the same relation to cinnoline that thiophene bears to benzene or benzothiophene 
to naphthalene (p. $24). 


2. Quinazoline Group. 


The quinazolines contain the benzene nucleus and in addition the same ring as 
the pyrimidines. They are produced by analogous condensations. 

(1) Di-hydroquinazolines (and quinazolines) are obtained from the acidyl de- 
rivatives of 0-amido benzylamine, C,H,(NH,).CH,.NH, (p. 710), by condensation, 
effected by mere distillation (Gabriel, Berichte, 23, 2808). Thus, o-amidobenzyl- 
acetamide yields methyl dihydro quinazoline :— 


CH,.NH CH,.NH 


CHS) = C,H + H,0; 
". NNH,.CO.CH,  .” SNe Cl@RE ee 


and o-amidobenzyl formamide, C,H,(NH,).CH,.NH.CHO, dihydroqguinazoline, 
c 


while o-amido benzyl benzamide forms pheny/quinazoline, C,H, : . 
with simultaneous elimination of water and hydrogen. N= C.C,H; 

(2) Analogous acidyl compounds are produced by the action of sodium form- 
anilides (not acetanilides) upon o-nitro benzyl chloride :— 


CH,Cl ee CH NCH | 
+ Na Ne waft NaCl. 
Cc ; 


CHZ as (ae 
HO NNO, CHO 


*\No, 


When these are reduced, condensation takes place, and #-phenyl dihydro- 
quinazolines are produced (Paal, Berichte, 22, 2683). 

The o nitrobenzyl anilines yield such acidy] derivatives by the introduction of 
formyl and acetyl. Thus, o-nitro-benzyl-acetanilide forms mechyl-phenyl-dihydro- 
guinazoline (Paal, Berichte, 23, 2635, Ref. 530) :— 


CH,.N.C,H CH,.N.C,H 
CH FC tie ya CA gts xs 
-\NO,.CO.CH, ‘“N = C.CH, 

Condensation does not follow the action of nitrous acid upon the amido-benzyl 
anilines ( Berichte, 23, 2188, 2636). 

(3) Xeto-derivatives of the dihydroquinazolines are obtained from o-amido- 
benzamide, C,H,(NH,).CO.NH, (from anthranil carboxylic acid, p. 749, by the 
action of ammonia), by introducing acid radicals into it, and then condensing the 
resulting acidyl-amidobenzamides (Weddige, Berichte, 20, Ref. 630; Kérner, 
ibid.) :-— 


//CO.NH, // CO—NH 
C.H ae CNS | + H,O. 
*. ° NNELOOLCH, te 5,: Sy ia ort 
Acetyl-o-amido-benzamide. Methyl-keto-dihydroquinazoline. 


82 


978 ORGANIC CHEMISTRY. 


Benzoyl-amidobenzamide under similar treatment forms phenyl-ketodihydro- 
quinazoline. ied 

(4) Keto-derivatives of tetrahydroquinazoline are analogously obtained from 
o-amidobenzyl alcohol (p. 709) by converting it into urea derivatives (with CNK 
and HCl), and condensing the latter by digesting them with hydrochloric acid 
(Widmann, Berichte, 22, 1668, 2933) :— 


//CH,.0H / CH, NH 
CoH = CHC bas kG. 
NH,.CO.NH, NH—CO 
Oxytolyl Urea. Keto-tetraquinazoline. 


The ¢hioguinazolines are prepared by digesting o-amido-benzyl alcohol with 
mustard oils :— 


/CH,0H  N.C,H, CH,.N.C,H, 
C,H + || oe | + H,O. 
* “\NH, Cs °*N NHLCS 
Mercuric oxide will convert these new compounds into ketoquinazolines. 
(5) Benzoylene Urea, C,H,N,O,, is a aditketo-tetrahydro-quinazoline. It is 
obtained from o-amido-benzamide by the action of chlorcarbonic ester, or by 
fusing it with urea (Berichte, 22, Ref. 196) :— 


CO.NH, fia CO—NH 

CHAK + cog oe OLS | .+ 2NH,. 

NH, NH, \NH—CO 

> It also results in the oxidation of keto-tetrahydro-quinazoline with chromic 
acid (Berichte, 22, 2939). _When heated with PCI, to 160° it yields dichlor- 


quinazoline, C,H Keto which regenerates benzoylene urea with water. 





; 3. QUINOXALINE GROUP. 


The members of this group are readily synthesized by various reactions (see 
_ Hinsberg, Annalen, 237, 327) :— 

(1) By the condensation of the orthophenylene diamines with glyoxal, COH. 
COH, and ortho-diketone compounds, R.CO.CO.R. This is effected by digesting 
their aqueous solutions (Hinsberg, Berichte, 17, 319; Korner, Berichte, 17, Ref. 
573). Thus, o-phenylenediamine and glyoxal condense to quinoxaline, the 
parent substance :— 


/NH, | COH aaa 
CoHie + | ae CoH, | + 2H,0. 
NH, COH N = CH 


Quinoxaline. 


z 


— s 


* 


mp-Toluylene diamine and glyoxal yield toluquinoxaline, CSH,(CH;)N.,C,H,, 

_ while with benzil the product is diphenyl-toluquinoxaline, C,H,(CH,)N,C, 

(C,H,),, and with diacetyl dimethyl toluquinoxaline (Aerichie, 21, 1414). 
(1, 2, 4)-Triamido-benzene (p. 625) and glyoxal yield amido quinoxaline. 

(2) The action of pyrocatechol upon ethylene diamine when heated to 200° is 


QUINOXALINE GROUP. 979 


in a measure the reverse of the reaction. The product in this instance is either 
tetrahydroquinoxaline or ethylene-o-phenylene diamine :— ~ 


yan. .H,N.CH, / NH.CH, 
CoH, 2 | = C,H, | + 2H,0, 
\OH —H,N.CH, \.NH.CH, 


Quinoxaline is produced by oxidizing this with potassium ferricyanide (Merz, 
Berichte, 20, 1193; 21, 378). 

(3) By the condensation of o-phenylene diamines with oxalic acid, glyoxylic acid, 
COH.CO,H, a-ketonic acids and analogous dicarbonyl compounds, COR.CO,H. 
Thus dioxyquinoxaline results on heating with oxalic acid to 160° :— 


/NH, COOH /N = C.OH 
CoH, | = C,H, | + 2H,0. 
\NH,.  CO.0H NIN C.0 


With pyroracemic acid at 60-80° the product is methyl oxyquinoxaline, with 
benzoyl carboxylic acid, phenyloxyquinoxaline, and with dioxytartaric acid we get 
quinoxaline dicarboxylic acid, etc. :— 


/N=C.CH, /N=C.C,H, JN = C.CO,H 
C,H, | C,H, CoH, | : 
\N = C.0OH \N = C.OH \N = C.CO,H 


(4) The a-chlor- or brom-carbonyl compounds react just like the a-diketones and 
a-ketonic acids. Thus, toluylene diamine and chloracetone form methyl] toluquin- 
oxaline :— 


/NH,  CH,Cl /N = CH 
C,H, . + | = C,H, |  +H,0-+ H, + HCl; 
\NH,  CO.CH, NNLEECH: 


and if bromacetophenone be substituted in the reaction two isomeric pheny] tolu- 
quinoxalines, C,H, : N,C,H.C,H,, will result, one of which may also be prepared 
from phenacyl nitrotoluidine (Berichte, 23, 166). 

Keto-tetrahydro-toluquinoxaline is formed by the union of chloracetic ester with 
toluylene diamine (Annalen, 237, 360; 248, 71) :— 


NH, CH,Cl NH.CH, 
CA 28 =C,H,.< | + HCl +C,H,.0H. 
‘NH, CO.O.C,H, NH.CO 


(5) An analogous reaction is the reduction of o-nitrophenyl- and o0-nitrotolyl-gly- 
‘cocoll (p. 608) with tin and hydrochloric acid; the resulting amido-acid sustains 
a condensation (Berichte, 19, 6; 895; 20, 24; Hinsberg, Berichte, 22, Ref. 12) :— 


NH.CH,.CO,H /NH-CH, 
C,H,~ = C,H, 
\NH, \N = C.OH. 
Oxydihydroquinoxaline. 


(6) By the action of cyanogen gas upon the orthophenylene diamines, and sub- 


980 ORGANIC CHEMISTRY. 


sequent heating of the resulting amide derivative together with hydrochloric acid 
to 150° (Bladin, Berich/e, 18, 666) :— 


NH, CN /NH—GNH N = C.OH 
CH, +| =C,H, | and C,H, 
\NH, CN \NH—C:NH rar =: C.OH, 
re Dioxyquinoxaline. 
iamine. 


The quinoxalines that do not contain oxygen are feeble monacid 
bases, generally soluble in water, alcohol and ether. Their odor 
resembles that of quinoline. Water decomposes nearly all their 
salts. The quinoxaline nucleus is quite stable in the presence of 
oxidizing agents, while reducing agents usually effect its decompo- 
tion. The tertiary compounds are not affected by nitrous acid. The 
quinoxalines result mainly by the simple interaction of their com- 
ponents, hence serve as a means of recognizing the ortho-diamines 
(p. 626), and: also the orthodiketone derivatives by using m- 
diamidotoluene, which is easily obtained (p. 626). 


Quinoxaline resembles pyrazine (p. 954) and phenazine (p. 986) in that it con- 
tains two nitrogen atoms in the para position of the six-membered nucleus, and con- 
stitutes as it were a transition from the first to the latter, with which it has many 
analogies so far as methods of formation are concerned. Hence the three groups 
are all termed dzazznes, and quinoxaline is also known as guinazine, inasmuch as 
it bears the same relation to quinoline as pyrazine to pyridine. For the nomen- 
clature of the complex azines, see Annalen, 237, 330; Berichte, 20, 23 and 327. 

Quinoxaline, C,H,N,, may easily be obtained from o-phenylene diamine and 
glyoxal or its compounds by digesting the aqueous solution at 60°, with sodium 
bisulphite. It is a crystalline mass, melting at 27° and boiling at 229° (at 760 mm.). 
Its odor resembles that of quinoline and piperidine. It is readily soluble even in 
cold water, and when heated, or by the action of alkalies, again separates from its 
solution. It is very soluble in acids. 

Toluquinoxaline, C,H,(CH;)N, = C,H,(CH,):N,C,H,, obtained from 
mp-toluylene diamine, is a colorless liquid that assumes a brown color on exposure 
to the air. It boils about 245°. Methyl Toluguinoxaline, C,H,(CH;):N,.C,H 
(CH), from toluylene diamine and chloracetone, is very soluble in cold water, 
alcohol and ether. It melts at 54° and boils about 268°. Dimethyl Toluguin- 
oxaline, C,H,(CH,):N,C,(CHs3)., from diacetyl and toluylene diamine, melts at 
g1° and boils at 270°, Phenyl Toluguinoxaline, C,H,(CH;):N,C,H(C,H;), 
from toluylene diamine and chloracetophenone, is scarcely soluble in water and 
melts at 135°. 

Oxymethyl-toluquinoxaline, C,H,(CH,):N,C,¢ Gus, is derived from 

Sets a} \e™an On ° 
toluylene diamine and pyroracemic acid (p. 979). It sublimes in colorless needles, 
melting at 220°. It dissolves in water with difficulty. It forms colorless solutions 
with the alkalies, and with the acids yellow-colored liquids. Oxy-phenyltolu- 


quinoxaline, CaB(CH)INIC,C GH from toluylene diamine and phenyl- 


glyoxylic acid, crystallizes in yellow needles, that sublime and become white, 
melting at 196°. The alkali solutions are colorless, those with acids are yellow in 
color. 


THE ACRIDINE GROUP. 981 


Dioxytoluquinoxaline, C, H,(CH,):N Ost on: results upon heating toluylene 


diamine together with oxalic acid, as well as from dicyantoluylene diamine (see 
above) (Annalen, 237, 348). It dissolves with difficulty in water, forms white 
needles, and melts above 300°. It forms salts with bases; water, however, 
decomposes them. 





Benzotriazines (p. 957) may be obtained from o-nitrophenylhydrazine by reduc- 
ing its acidyl derivatives with zinc dust or sodium amalgam. Senzo-triazine is 
thus prepared from formyl nitrophenylhydrazine (Berichte, 22, 2806) :— 


NO, /N—CH 


CHS +3. =¢ HC ot ee + A 
NH.NH.COH —N 


Methyl benzotriazine is similarly derived from the acetyl compound. The 
benzotriazines are yellow, crystalline compounds, with a peculiar odor resembling 
that of the alkaloids. They are feeble bases. Benzotriazine, C,H,N,, melts at 65° 
and boils at 235-240°. Methyl benzotriazine, C,H,.(CH;)N,, melts at 89° and 
boils at 250-255°. 

Benzoxazines (p. 957). 


QO, CH O—-CH 
(ak: Wedge Gamer wan 2 \ ‘ 
\ N=CH \NH. CH 
Benzoxazine. - Benzmorpholine, 


Phenyl benzoxazine, C,H,(C,H,)NO, is obtained from o-nitrophenol-phen- ~ 
acyl ether, C, H,(NO,).O.CH,.CO.C,H, (from o-nitrophenol and bromacetophe- 
none), by reduction with stannous chloride and hydrochloric acid. It melts at 
103° and is a feeble base (Berichte, 23, 172). 

Benzomorpholine, C,H,NO, Phenmorpholine (see above), may be pre- 
pared by heating oxyethyl-o-amidophenol, C,H ,(NH,)O.C,H,.OH (from amidine) 
with hydrochloric acid and then with sodium hydroxide (p. 957). It is a colorless 
oil, with a characteristic odor. It boils at 28°. 

Methyl Benzomorpholine, C,H,(CH,)NO, from methyl anisidine, boils at 
261° (Berichte, 22, 2098). 





THE ACRIDINE GROUP. 


The parent substance acridine, C,,H,N, is an analogue of pyr7- 
dine and quinoline. It is an anthracene, in which N replaces an 
intermediate CH-group of normal anthracene. The third affinity 
of the nitrogen atom is combined with the opposite carbon atom 
(p. 894). The acridines may be synthesized : 

(1) From diphenylamine, and the fatty acids, or from the acid 


982 ORGANIC CHEMISTRY. 


derivatives of diphenylamine, if they be heated together with zinc 
chloride (Bernthsen, Annalen, 224, 1; Berichte, 16, 1820) :— 


N N 
C,H C,H, = C,H 
6175 ( 6." 5 6 Ac ps 


Formyl! Diphenylamine. Acridine. 


H, + H,0. 


Homologous acridines are similarly obtained from diphenylamine and the higher 

fatty acids. In them the hydrogen of the CH-group is replaced by alkyls. They 
are called meso-derivatives (Berichte, 18,690). ms-Methyl acridines are similarly 
formed when # phenyl tolylamine, C,H,.NH.C,H,.CH, (p. 624), is heated 
together with acids and zinc chloride (Berichte, 20, Ref. 376). 
* (2) An analogous reaction is the rearrangement of dinitro diphenylamine-o- 
carboxylic acid (from chlordinitrobenzene and o-amidobenzoic acid) when heated 
with sulphuric acid, or if reduced with tin and hydrochloric acid, a diamido- 
derivative being thus produced (Berichte, 8, 1444) :— 


oy / NE CaHta(NOn) 


N 
oHS = CoH | - >CoHa(NO,), + H,0. 
CO,H 


\c(OH)% 


Oxydinitro-acridine. 


The acridines are feeble bases; their salts are decomposed by boiling water. 
The oxidation of acridine with potassium permanganate affords (through the de- 
struction of a benzene nucleus) a/3-quinoline dicarboxylic acid (p. 973). 

Acridine has also been obtained from ortho-tolylaniline, CgH,.NH.C,H,.CHI,, 
by conducting the vapors through a red-hot tube (analogous to the synthesis of 
anthracene); by heating diphenylamine with chloroform and zinc chloride to 
200°, and when aniline and salicylic aldehyde are heated to 260° with zinc chlo- 
. ride (Berichte, 12, 2452). It is very soluble in alcohol and ether. It occurs in 
crude anthracene and dissolves in dilute acids with a beautiful green fluorescence. 
It readily sublimes in colorless leaflets, sublimes at 100°, melts at 110°, distils above 
360°, and has a very pungent odor. 

Dihydroacridine, CHK NCH is formed when acridine is reduced 
with sodium amalgam or zinc and hydrochloric acid. It no longer manifests basic 
properties and melts at 168°. Oxidizing agents, even silver nitrate, convert it again 
into acridine. 

The acridines yield iodides with the alcoholic iodides. Silver oxide or alkalies 
conyert them into peculiar ammonium bases which are very similar to the quinoline 
compounds (p. 965). Potassium permanganate attacks the pyridine nucleus 
present in these alkyl iodide derivatives, forming then phenyl-o-amidobenzoic 
acid, C,H,.NH.C,H,.CO,H (Berichte, 18, 2709). 

ms-Methyl Acridine, C,,H,(CH.,)N (see above), is formed when diphenyl- 
amine and glacial acetic acid are heated together with zinc chloride to 220°. It 
consists of colorless plates, melting at 114°. Its hydrochloride crystallizes in yellow 
leaflets, that dissolve with a bluish-green fluorescence. Chloral and methyl acridine 
unite to the compound, C,,H,N.CH,CH(OH).CCI,, which yields acridylacrylic 
acid, C,,H,N.CH: CH.CO,H, when digested with caustic soda. Potassium 
permanganate oxidizes this compound to ms-acridylaldehyde, C,,H,N.CHO, 
and ms-acridyl carboxylic acid, C,,H,N(CO,H) (Berichte, 20, 1541). 

ms-Phenyl Acridine, C,,H,(C,H,)N, results upon heating diphenylamine 
and benzoic acid together with zinc chloride to 260°. It crystallizes in yellow 
plates (from benzene, with one molecule of benzene), melts at 181° and distils above 


PHENOXAZINE. 983 


400°. Its salts are yellow in color, and are decomposed by water. #-Amido- and 
p-oxy diphenylamine together with benzoic acid yield the corresponding phenyl- 
amidoacridine and phenyl oxyacridine (Berich/e, 28, 692). 

Chrysaniline, C,,H,,N(NH,),. This is obtained as a by-product in the 
rosaniline manufacture. On mixing the mother liquors with nitric acid the nitrate 
separates; this is the chief constituent of the beautiful yellow dye phosphine. 
Free chrysaniline crystallizes from dilute alcohol in golden yellow needles, 
melting about 268°. It forms red colored’ salts with the acids (1 equivalent) ; 
these dye silk and wool a beautiful yellow. Their solutions exhibit a beautiful 
yellow-green fluorescence. 

Chrysaniline has been prepared synthetically by the oxidation of ortholeucaniline 
with arsenic acid ( Berichte, 17, 208; 18, 696). It is therefore -amido-phenyl- 

CH 
2-amido acridine, H,N.C,H,C nti: * 
Ne. 3 


To NN: 


When chrysaniline is diazotized and boiled with alcohol, it yields ms-phenyl- 
acridine. If heated to 180° with hydrochloric acid, an amido-group splits off 
and Chrysophenol, C,,H,,(OH)N.NH,g, is produced. ss 


N 








N 
< | wc 191g, results upon heating 
C’ —C,H, 
B-dinaphthylamine, (C,,H,),NH, and benzoic acid to 240°, together with zinc 
chloride. It melts at 297°. 
Consult Berichte, 18, 691, upon the nomenclature of the complex acridines. 


Phenyl-{-naphthyl Acridine, C,,H 


t 





Thiodiphenylamine (p. 604), diphenylene keton-oxide or xanthone (p. 860), 
and thioxanthone are analogous to acridine in constitution. They all possess a 
strong chromogenic character :— 


‘NH CO CO 
CHAK "s Ce, CHC “ CoH, CHC - SCH, 
Thiodiphenylamine. Xanthone. Thioxanthone. 


Thioxanthone, C,,H,SO, is produced in the condensation of diphenylsul- 
phide-o-carboxylic acid, C,H,S.C,H,.CO,H (from thiophenol and diazoanthranilic 
acid, see phenyl sulphide (p. 672), effected by sulphuric acid. It consists of yellow 
needles, that become colorless upon distillation. It melts at 207° and boils at 
372° ( Berichte, 23, 2469). 

Phenoxazine, C,H ay seen 4, or phenazoxine (see Berichte, 22, 2081), 


is also analogous to acridine and thiodiphenylamine. It is obtained similarly to 
thiodiphenylamine and phenazine (see below), when o-amidophenol is heated to- 
gether with pyrocatechol to 260-280°. It crystallizes from dilute alcohol in leaf- 
lets, that melt at 148°, and sublime. In its reactions it is very similar to thiodi- 
phenylamine, and it is only in its oxidation product that it shows a chromogenic 


984 |. ORGANIC CHEMISTRY. 


character (Nietzki, Berichte, 22, 3036). A reddish-violet dye (Berichte, 20, 942) 
is produced by nitration, reduction of the nitro product with tin and hydrochloric 
acid, and again oxidizing with ferric chloride (analogous to the formation of 
Lauth’s violet from thiodiphenylamine, p. 605). 

Resorufin and resazurine, products obtained from resorcinol, appear to be de- 
rivatives of phenoxazine (p. 691). 

The Oxyindamines and oxindophenols, so called by Nietzki (Organische Farb- 
stoffe, 1889, p. 139; Berichte, 21, 1736), are dyestuffs and appear to be phenoxa- 
zine derivatives. They result upon digesting nitroso-dimethyl aniline or quinone 
dichlorimide with 8-naphthol. They differ from the indophenols, which are pro- 
duced when the reaction occurs at low temperatures, in that the two benzene 
nuclei are united a second time by means of oxygen, and hence possess a consti- 
tution analogous to that of the thiodiphenylamine derivatives and the eurhodines. 
Gallocyanine and naphthol violet belong in this series. 

Gallocyanine, C,,H,,N.O, (Violet solide von Koechlin), is produced by the 
action of nitroso-dimethy] aniline upon gallic acid, catechuic acid, etc. It forms 
shining green needles and serves as a beautiful violet-colored lake in calico print- 
ing (Berichte, 21, 1740). Naphthol Violet, C,,H,,N,O, of Meldola and Witt, 
B-Naphthol Blue, New Blue, Fast Blue, Cotton Blue, results upon heating nitroso- 
- dimethyl aniline and {-naphthol. Its hydrochloride consists of bronze-colored 
needles. It dyes cotton, that has been mordanted with tannin, violet blue, similar 
to indigo (Berichte, 21, 17443; 23, 2247). 

When the free bases of these dyes are heated they become insoluble in ether, and 
change to peculiar green-blue dyes that O. Witt has named cyanamines, (Berichte, 


23, 2249). 





PHENAZINE GROUP. 


The simplest parent substance in this group is phenazine, C,.H.N,. 
In constitution it is analogous to anthracene and acridine. In it 
the two intermediate C-atoms of anthracene are replaced by two 
nitrogen atoms :— 


C, C,H,, Phenazine. 


HZ) 

Swe 

It contains in addition to the two terminal benzene rings an inter- 
mediate ring-chain, consisting of four C-atoms and two nitrogen 
atoms ; this is similar to the paradiazine or pyrazine ring. The 
constitution and nomenclature of the more complex azines may be 
seen from the following arrangement (Berichte, 20, 23, 327; Anna- 


len, 237; 33°) — 
C,H, — Phenazine or Diphenazine. 


N 
et 
Co e/ 


N ; 
CHK «CoH CH, — Methylphenazine or Toluphenazine. 


PHENAZINE GROUP. 985 


N 
& HE : >Crolle — Naphthophenazine or Phenonaphthazine. 
N% 
N : 
CH ‘ SCs — Anthraphenazine or Phenanthrazine. 
N 
Be 
CoH i 70 — Naphthazine or Dinaphthazine, etc. 


The following are the most important methods in use for the preparation of the 
azines : 

1. Condensation of ortho-phenylenediamine (p. 629) with ortho-dioxybenzenes, 
e.g, pyrocatechin, when heated to 200° (Merz and Ris, Serichte, 19, 726, 
2206) :-— 


OH HAN. JM 
CH et ae DCH, = CHC. CH, + 21,0 + Hy 
(1,2)—Dioxy- o-Phenylene Phenazine. 
benzene diamine. 


Pyrocatechine and mf-toluylene diamine (p. 626), in a similar manner yield 
methyl-phenazine or tolu-phenazine (see above). . 

2. Condensation of the ortho diamines with ortho diketones, or orthoquinones, 
é.g., B-naphthoquinone—a reaction, perfectly analogous to the formation of the 
quinoxalines (p. 979) (Hinsberg, Annalen, 237, 329). 


/NH, ne 
C,H, + ¢,,H,0; = CH, a 2s ee 
\NH, \N 
(1, 2)—Naphtho- (1, 2)—Naphtho- 
quinone. phenazine. 


Similarly o-toluylene-diamine yields with phenanthraquinone_ toluanthrazine, 
B-naphtho-quinone, tolu-naphthazine, with isatine tolu-indazine, C,H,(N,)C,H, 
N, while o-naphthylene diamine and $-naphthoquinone yield di-naphthazine, etc. 

3. A very convenient method is the conjugation of phenyl—(tolyl, etc.) —-naph- 
thylamine (p. 911) with diazobenzene sulphonic acids; the diazo group enters the 
ortho-position of the naphthylamine and azo-compounds result at first :—- 


N NH.C,H 
C,,H,.NH.C,H, + C,H, és.) = CoH RNC. HSO,H. 


Boiling dilute acids change the azo-derivatives to azines and sulphanilic acid 
(Witt, Berichte 20, 571) :— 
/ NH.C,H, J NN 
==: C,H,  — Ge RN Gt 2c 
10 *“ NuN.C,H,.SO,H. 10 ° ON 6t44 a**-Wett ins 
Naphthophenazine, 
4. The oxidation of an orthophenylene diamine, together with #-naphthol 
(Witt, Berichte, 19, 914; 20, 575) :— 
/NH, 3 ANN 
Ore NE + C,,H,-OH 2 O= C,H, a C,,H, + 3H,0. 


2 
Tolu-naphthazine. 


986 ORGANIC CHEMISTRY. 


The azines are mostly yellow-colored, feebly basic bodies that cannot be distilled 
without suffering decomposition. They dissolve in concentrated sulphuric acid 
with a red to blue color. They are again precipitated upon addition of water, the 
liquid becoming yellow in color in consequence. Ammonium sulphide reduces 


them to colorless, dihydro-compounds, C,H nce 4s Which are readily 


re-oxidized to azines. 

Phenazine, C,,H,N,., was first obtained from azo benzoates by distillation, 
and was called Azodiphenylene (p. 847). It may also be prepared from o-pheny- 
lene diamine and pyrocatechin, and by conducting aniline vapors through a 
tube heated to redness (Berichte, 19, 420, 3256). It crystallizes and sublimes in 
bright-yellow needles, melting at 171°. It dissolves in concentrated sulphuric 
acid with a blood-red color, which becomes yellow upon the addition of water 
(Berichte, 19, 2207). 

Methyl Phenazine, C,,H,(CH,)N., Zoluphenazine, from pyrocatechol and 
o-toluylene diamine (see above), consists of yellow needles, melting at 117° and 
dissolving in dilute acids (Berichte, 19, 726). 

Naphthophenazine, C,I1,(N),C,,H,, may be readily prepared from phenyl 
naphthylamine. It forms yellow needles, that melt at 142° and sublime about 
200°. It dissolves in concentrated sulphuric acid with a brownish-red color 
(Berichte, 20, 573, 2660).  Nitro-naphthophenazine, C,H,(N,)C,,H,;(NO,), 
from nitro-3-naphthoquinone and o-phenylene diamine, melts at 221° (Berichte, 23, 
175). 

Tolu-naphthazines, C,H,(N,)C,,H,. There are four possible isomerides; 
three of these are known. Two are produced by the condensation of o0-toluylene 
diamine with 3-naphthoquinone, and a third has been obtained by the decomposi- 
tion of wool-black (Berichte, 20, 577). 

Pheno- and Tolu-anthrazine, C,H ,(N.)C,,H,,andC,H,(N,)C,,Hg, are 
easily formed on mixing the warm solution of phenanthraquinone in glacial acetic 
acid with the alcoholic solution of o-phenylene and toluylene diamine, when they 
separate as yellow needles. The first melts at 217°, the second at 212°. They 
dissolve with a deep red color in concentrated acids. Their formation may be used 
to detect and separate the orthophenylene diamines (p. 629). 

a8-Naphthazine, C,,H,(N,)C,,H,, Dinaphthazine, formerly called naph- 
thase (also thought to be azonaphthalene because it was prepared by heating 
nitronaphthalene with lime or zinc dust), results upon mixing o-naphthylene 
diamine (1, 2) (p. 626) and B-naphthoquinone (1,2). It-crystallizes and sublimes 
in yellow needles, that melt at 275°. It dissolves with a violet color in concen- 
trated sulphuric acid; on adding water the solution assumes a yellow color and. 
naphthazine again separates ( Berichte, 14, 2795). 

88-Naphthazine, C,,H,(N,)C,,)H,, is produced when $-dinaphthylamine is 
further heated together with benzene diazochloride. It consists of yellow needles 
that melt at 242° ( Berichie, 23, 1333). 





The phenazines are chromogenic parent substances; they yield dyes by the 
entrance of salt-forming groups (especially the amido-group). The eurhodines and 
safranines are included in this series. 


1. Eurhodines and Toluylene-Red Group. 

The eurhodine group consists of dyes, which are derived from the phenazines 
by the introduction of one or more amido-groups (Witt, Berichte, 19, 441, 2791; 
_ 21, 2418; Kehrmann, 23, 2446; Fischer and Hepp, Berichte, 23, 841, 2787). 

‘They are formed :— 


EURHODINES AND TOLUYLENE-RED GROUP. 987 


(1) By the action of orthoamidoazo compounds (p. 643) upon a-naphthylamine 
hydrochloride * : 


nc :N.C,H, 
He +.C, 6H, NH, +0 = 
o-Amido-azo- eee a-Naphthylamine. 


ene: 
CHC Coy NH, + GH,NH, + 1,0, 


Eurhodine. 


The ortho-amido-bodies act similarly with the orthophenylene diamines (Ze- 
richte, 23, 844, 2787). 

(2) By the action of ortho-diamines (as unsymmetrical triamidobenzene, p. 
625) upon orthodiketones or orthoquinones :— 


nN 
HAN-CoHyC NH 4+ €,.H.O = oe HAC « >Cr0He + 2H,0. 
Triamido-benzene. B-Naphthoquinone. Eurhodine, 


Triamido-benzene reacts in like manner with phenanthraquinone, benzil, 
isatin, and with the diketones of the paraffin series (Berichte, 19, 446). Oxy- 
orthoquinones and orthodiamines form oxyeurhodines (Berichte, 23, 2451). — 

(3) By theaction of nitroso-dimethy] aniline upon primary and secondary anilines 
in which the para-position is occupied (as $-naphthylamine and its phenyl deriva- 
tives) (Berichte, 21, 719) :— 


(CH,),N.C,H,.NO + C,,H,.NH, + 0 = 


N 
(CH,)N.CoHyC y YCi oH, + 21,0. 
If the 6-naphthylamine be replaced by its secondary derivatives, the corresponding 
azonium bases or safranines will be produced. 

Quinone dichlorimide acts just like nitroso-dimethy] aniline ; ae ee with free 


amido groups result ( Berichte, 21, 1599) :-— 
CIN:C,H,:NC] + C,,H,.NH, = H,N.C HW N5c,, oH, + 2HCl. 


In these methods an indamine always appears at first as a by product (Berichée, 
21, 2418). 

(4) By the oxidation of ortho-phenylene diamines (2 molecules); here the two 
nitrogen atoms attack the para-positions, relatively to the two amido-groups, of a 
second molecule; if amid-groups already occupy the para-position, these will be 
displaced (Kehrmann, Berichte, 22, 1983; Nietzki, Berichte, 23, 3039). Thus, 
ferric chloride converts o-phenylenediamine into diamido phenazine (QO. Fischer, 
Berichte, 22, 355; 23, 841) :— 


CoH icy? + CHC NEE + 30=CoH,<N>CoHa Ny? + 310. 


In the same manner ¢riamidophenazine is obtained from unsymmetrical triamido- 
benzene, and éetramidophenazine from symmetrical tetramidobenzene ( Berichie, 22, 


3039), etc. 





* Indulines result by the use of paramidoazo-compounds (p. 990). 


988 ORGANIC CHEMISTRY. 


The eurhodines (mono-amido-azines) are feeble bases. Their salts are scarlet 
red in color; they have not been applied technically. They dissolve in concen- 
trated sulphuric acid with a carmine-red color, which, upon the addition of water 
passes successively into black, red, and finally red (see safranine). Ifthey be heated 
to 180° with acids their amido-group is replaced by hydroxyl, with the formation 
of phenol-like ewrhodo/s. Compounds like the last, can be synthetically prepared 
from oxyorthodiketones by means of orthodiamines (Berichte, 23, 2451). 

Amidophenazine, C,H,(N,)C,H, NH,, has been prepared from o-diamido 
phenazine upon heating it with zinc dust. It consists of red bronze needles, that 
melt at 265°. 

The ¢oluylene-red compounds, containing two amido-groups, are more important 
than the mono-amido-phenazines. They result when diamines are oxidized; 
more directly by the oxidation of indoamines having free amido groups, even upon 
boiling the aqueous acid solutions. In this way fo/uylene-b/ue (from ordinary 
m-toluylene diamine and dimethyl-Z-phenylene diamine) yields /o/uylene-red (Witt, 
1887, Berichte, 17, 931; 19, 2605; Bernthsen, Anmalen, 236, 332) :— 


oy Pe 
(CH,)aN-CoHAC | >CyH(CH,).NH + 0 = 


Toluylene Blue. 


C,H, (CH,).NH, + H,0. 


Toluylene Red. 


oft 
(CH,),N.C,H3< | 
3/2 oO 


The so called simplest toluylene-blue (from #-toluylene diamine and /-phenylene 
diamine) thus gives rise to the s¢mzplest toluylene-red :— 


H,N.C.H,{ | >C,H,(CH,).NH, + 0 = 
Simplest Toluylene Blue. 
H,N.C,H,¢ | C,H,(CH,).NH, + H,0. 


Simplest Toluylene Red. 


Methyl phenazine results by replacing the two amido groups of the latter com- 
pound by hydrogen (this is done through the diazo-derivative) ; ordinary toluylene 
‘red yields dimethylamido-methylphenazine when its NH,-group is replaced by 
similar treatment. This is proof that the toluylene-red dyes are phenazine deriv- 
atives (Bernthsen). 

o-Diamidophenazine, C,H,(N,)C,H,(NH,), (2, 3), formed by the oxida- 
tion of o-phenylene diamine with ferric chloride, consists of ruby-red or yellow- 
brown needles (Zerichze, 23, 841). (2, 7)-Diamidophenazine, H,N.C,H,(N,) 
C,H.NH.,, is prepared from dinitro-phenyl-f-phenylene diamine, C, H,(NO,),— 
NH.C,H,.NH,, and consists of dark yellow needles, melting at 280°. Tetra- 
amidophenazine, (H,N),C,H,(N,)C,H,(NH,),. from tetra-amidobenzene 
wyh ferric chloride, consists of brown-colored needles and decomposes about 
ee 

Toluylene Red, C,,H,,N,, Dimethyl diamido-toluphenazine (see above), 
crystallizes in orange-red needles. It is applied in dyeing under the name Veutra/ 
Red. Its monacid salts are rose-red in color, the diacid blue, and the triacid 
_ green; the last two are only stable in the presence of strong acids. It colors silk 

and cotton, mordanted with tannin, a scarlet-red, 


SAFRANINES. 989 


2. Safranines. 

The safranines are probably diamido-derivatives of hypothetical 
phenyl-phenazonium; their ammonium salts are dyestuffs (Witt, 
Nietzki, Bernthsen, Berichte, 20, 19, 179; 19, 3121, 3163; 21, 
1590) :— 


N N. 
CHA [Cole Coie | CoHa-NH, 
Lm rn 
T'S c{ C,H,.NH,. 
Phenyl-phenazonium Chloride. Phenosafranine Hydrochloride. 


The only known analogue of hypothetical phenyl-phenazonium 
(without side groups) has been prepared from amidophenyl-a- 
naphthylamine and phenanthraquinone (Berichte, 20, 1183). 

The safranines are produced upon oxidizing a mixture of an in- 
doamine and a primary amine (this takes place when their salts are 
boiled with water). Thus, phenylene blue and aniline yield pheno- 
safranine :— 


HN.C,H H,N 


oe + C,H, + HC! + 0, = HN.GHC >CH,+ 2HO,. 
o ‘ $ N 
5: mak 
C,H,.NH, te CNET, 
Phenylene Blue. Phenosafranine Hydrochloride. 


A simpler procedure consists in applying the components of the indamines, and 
directly oxidizing the mixture of one molecule of a f-phenylene diamine with one 
molecule of a monoamine and a molecule of a primary amine (by boiling the 
aqueous solution of their sulphates alone or with chromic acid); an indoamine 
results at first, and this then combines with the primary amine to produce the sa- 
franine (Berichte, 21, Ref. 248) :— 


H,N N 
R,N.C,H : 
RRS 8 ie C,H; + HCl + 20, a R,N-C,H,< CoH + 4H,0. 
H,N N 
Fate 
CMW, Gi. ANE, 
Diamine. Safranine Hydrochloride. | 


The formation of the safranine only occurs by this procedure, provided there is © 
a free NH,-group in the phenylene diamine, if the para-position in the first mon- 
amine and the ortho in the second primary amine are unoccupied (Berichte, 19, 
3165). Technically the mixture of the diamine and monamine is obtained by the 
reduction of amido azo-compounds (p. 644). 

The safranines are strong bases. They form salts with one, two and three 
equivalents of the acid; water decomposes the last two series. The monacid salts. 
are reddish-yellow, the diacid blue, and the triacid green in color. The addition 
of water to the green solution of the safranines in concentrated sulphuric acid 
causes the same to change to blue, violet and finally red; while the addition of 
concentrated hydrochloric or sulphuric acid to the reddish-yellow aqueous solution 


990 ORGANIC CHEMISTRY. 


of the primary salts causes the same to pass successively into violet, blue, dark 
green and eventually light green. The alcoholic solutions usually exhibit a 
strong yellowish-red fluorescence. The difficult solubility of their nitrates is note- 
worthy. Reducing agents convert safranines into leuco-compounds, which in the 
presence of alkalies are rapidly reoxidized by the air to safranines. The free 
safranine bases or hydroxides are separated from their ammonium salts with diffi- 
culty (when warmed with caustic alkalies), and generally show a red color. 

The lowest member of the safranines is 

Phenosafranine, C,,H,;N,Cl, formed from /-phenylene diamine and 
aniline. It consists of needles, green in color and having 'a metallic lustre. It dis- 
solves in water and alcohol with a beautiful red color. Baryta separates the free 
base, C,,H,,N,O, from its sulphate; an excess of baryta will substitute two | 
hydroxyls for the two amido groups, producing their saf/rano/, C,H, .N,(OH), 
(Berichte, 21, 1591). 

Ethyl- and Methyl! Safranine, C,,H,,(CH,)N,Cl, can exist in two isomeric 
forms (corresponding to their constitution and different components). Démethy/- 
and Diethyl Safranine, C,,H,,(CH;),N,Cl. Each of these bodies may occur in 
three isomeric forms (Berichée, 19, 150, 3164). 

‘Tetra-ethyl Safranine, C,,H,,(C,H,;),N,Cl. There is but one possible 
modification of this compound. It is formed from diethyl-g-phenylenediamine 
with diethyl aniline and aniline. It dyes violet and formerly was applied as 
amethyst. 

Tolu-Safranine, C,,H,,(CH,;),N,Cl, from toluylene diamine, o-toluidine (1 
molecule) and aniline (1 molecule), is the chief constituent of common safranine, 
occurring in commerce as a brown paste or yellow-red powder, employed in cotton 
and silk dyeing, as a substitute for safflor. The necessary base-mixture for its 
production is obtained from the “aniline oil for safranine.’’ This is partially 
_ diazotized and the product broken up into paratoluylene diamine and orthotoluidine 
by reduction. 

The benzidine-tetrazo-dyes have in recent years largely replaced the safranine 
dye-compounds. A violet dye, Phenylsafranine, C,,H,,(C,H;)N,Cl or C,, 
H,,(C,H;)N,Cl, is probably identical with Mauveine (Mauvaniline). The latter 
was the first aniline dye to prove valuable technically (Perkin, 1856), and is 
obtained by oxidizing aniline oil with potassium bichromate and sulphuric acid. 
Its sulphate is known in commerce under the name Roso/an. : 

Naphthalene Red, Magdala Red, C,,H,,N,Cl, is a safranine of naphtha- 
lene. It very probably is a diamido-derivative of a naphthyl-naphthazonium salt, 
~C,,H,(N,)C,,H,(C,,H,)Cl (Julius, Berichte, 19, 1365). It is produced when 
a-amido-azonaphthalene (p. 914) is heated together with naphthylamine acetate. 
It is a dark brown powder, that dissolves very readily in alcohol with a bluish-red 
coloration; the dilute solution exhibits a magnificent cinnabar-red fluorescence. 
It imparts a beautiful rose-red color to silk, Its alcoholic solution is decolorized 
when boiled with zinc dust, but again assumes a red color on exposure to the air. 





The indudines and nigrosines appear to belong to the safranine class. They are 
~ violet-blue to gray-blue dyés. They are formed upon heating various azo- and 
amido-azobenzenes with aniline hydrochlorides. The simplest induline is Azopheny/ 
Blue or Violaniline, C,,H,,N, (Induline B), which forms upon heating nitro- 
benzene, aniline, hydrochloric acid and iron filings (Coupier’s method), or amido- 
azobenzene with aniline hydrochloride (Caro) :— 


C,H,.N,.C,H,.NH, +C,H,.NH,.HCl=C,,H,,N, + NH,Cl. 


¥ 


ALKALOIDS. 991 


Here, as in analogous reactions, the first product is azophenine, C,,H,4N,, 
which represents a dianilido quinone-dianilide (p. 700). The zdudines result by 
the continued action of the azophenine upon anilines. They are also prepared by 
heating together nitroso-diphenylamine and the amine hydrochlorides. Hence, 
the indulines are anilido-anilide derivatives of the phenazines (Witt, Berichée, 
20, 2659; O. Fischer and Hepp, Berichte, 20, 2479; 21, 2617). The induline 
salts are usually insoluble in water, The easily soluble sulpho- acids have been 
used in silk dyeing as substitutes for indigo. 

The rosindulines are peculiar red dyes formed upon heating nitrosophenyl- or 
nitrosoethyl-a-naphthylamine, C,,H,.N(NO).C,H,, with the HCl-anilines, and 
by heating benzene azo-a- naphthylamines with ‘anilines (Berichte, 235-2631 ;: 23, 
Ref. 391 

se closely allied to the indulines and azophenine, are produced by 
the protracted heating of azophenine or amidophenazines alone or with ortho- 
diamines. They dissolve in alcohol with beautiful fluorescence and form greenish- 
blue colored fluorescent salts (Berichte, 23, 2789). 

Aniline Black,C,,H,,N, or C,,H,,N,(?), most probably belongs to the indu- 
lines, and is formed in the oxidation of aniline by means of potassium chlorate in 
the presence of copper or vanadium salts. It is a dark-green amorphous powder, 
insoluble in the ordinary reagents. It is used in calico printing as a black color, 
its formation being first effected upon the fibre of the material. 





Naturally occurring compounds, the constitution and synthesis of 
which have not been definitely established, will be discussed in 
special groups in the remaining pages. 





ALKALOIDS. 


By this term we know all nitrogenous vegetable compounds of 
basic character, or their derivatives, from which bases may be | 
isolated. Many of them (betaine, asparagine, theine), have, in 
accord with their constitution, been already discussed with the 
various amido-derivatives ; the most of those remaining which have 
been studied recently, show themselves to be derivatives of the 
pyridine and quinoline bases. Several have been prepared artificially 
(piperidine, conine). Only the most important members of this 
insufficiently investigated class will be mentioned here. Like the 
benzene derivatives they have much in common in their whole 
deportment. They are the chief constituents of the active principles 
of the vegetable drugs employed as medicines or poisons. 

Some alkaloids contain no oxygen, and then are generally liquid 
and volatile. Most of them do, however, contain that element, 
and are solid and non-volatile. Nearly all are tertiary amines ; 
some, however (like the hydrides of the pyridine nucleus, p. 936), 


992 ORGANIC CHEMISTRY. 


belong to the secondary amines. Tannic acid, phospho-molybdic 
acid, platinic chloride, and many double salts (like HgI.2KI) 
precipitate all these bases from their aqueous solutions. The bases 
are regained from these compounds by alkalies. 


Sparteine, C,,H,,N,, is a volatile alkaloid which does not contain oxygen. 
It occurs in Spartium scoparium, and is a colorless, thick oil, boiling at 311°. It 
has a strong alkaline reaction, is narcotic and is also a diacid base. A methyl 
group is eliminated when it is heated with hydrochloric or hydriodic acid. It 
forms y-methyl pyridine when distilled with lime (Berichte, 21, 825). Hence, 
sparteine is closely allied to dipicolyl methane, CH,(CH.C,;H,N), (from methylal 
and picoline) (Berichte, 21, 3103). 


Opium Bases. BA 

In opium, the dried juice of the green seed capsules of poppy 
(Papaver somniferum) we find not only meconic acid and meconine 
(p- 794) but a series of bases, of which may be mentioned :— 


Morphine, C,,H,,NO, Papaverine, C,,H,,NO, 
Codeine, C,,H,,NO, Narcotine, C,,H,,NO, 
‘Ehebaine, C,4H,,NO; Narceine, C,,H,.NQg. 


Morphine, C,,H,NO, + H,O, crystallizes from alcohol in 
prisms, tastes bitter, and in small ‘quantities produces sleep. It 
shows an alkaline reaction, and represents a tertiary, monacid base. 
Its officinal hydrochloride, C,,H,,NO;HCl + 4H,O, forms delicate, 
silky needles. 


The solutions of morphine and its salts are colored dark blue by ferric chloride ; 
the solution in concentrated sulphuric acid acquires a blood-red coloration on the 
addition of a little nitric acid. It contains two hydroxyl groups, C,,H,,(OH),NO, 
deports itself as a. dihydric phenol, dissolves in potassium hydroxide, and yields 
alkyl and acid derivatives. It forms quinoline, phenanthrene (with phenanthrene- 
quinoline) pyridine and pyrrol, on distillation with zinc dust. When methylated to 
its fullest extent, morphine undergoes a rearrangement similar to that of piperidine 
and conine (p. 950). The hydroxide obtained from ethyl morphine by addition 
of methyl iodide and the action of silver oxide, passes into the phenanthrene de- 
rivative (Annalen, 222, 235) on the application of heat. The nitrogen atom 
splits off in the form of dimethylamine or oxyethyl dimethylamine (CH,),N.CH,. 
CH,(OH). The latter is related to morpholine (pp. 957, 981), hence morphine 
appears to represent a phenanthrene-morpholine derivative (Knorr, Berichie, 22, 
1113; 22, Ref. 758). 

Codeine, C,,H,,NO,, Methyl Morphine, CHa (OCH )No, is con- 

se 


tained in opium, and is obtained from morphine by means of methyl iodide and 
potassium hydroxide. From ether it crystallizes in large prisms, melting at 150° 
(Berichte, 19, 794). 

Thebaine,C, ,H,,NO, = C,,H,,(O CH,),NO, consists of silvery plates, melt- 
ing at 193°. It breaks down into 2CH,Cl and morphothebaine, when heated 
with concentrated hydrochloric acid. This new isomeric base melts at 180°. 


HYDRASTINE. 993 


Silver oxide converts its methyl iodide derivative into an ammonium hydroxide, 
which breaks down quite readily on the application of. heat (Berichte, 19, 
794). 

Papaverine, C,,H,,NO, (Berichze, 18, Ref. 636), consists of colorless prisms 
melting at 148°. It very probably is a tetramethoxyl derivative of benzylisoquino- 
line (Goldschmidt, Berichte, 20, 623; 21, Ref. 653; Roser, Annalen, 254, 
357) — 


C,H,(O.CH,),.CH,.C,H,(O.CH,),N = Papaverine. 


Hot hydriodic acid decomposes it into 4CH,I and the base pafaveroline, C,,H, 
(OH),N. Potassium permanganate oxidizes it to papaveraldine, C,9H,,NO,, 
which in all probability is a ketone, ee ee 

Further oxidation gives rise to two pir ge cer age (1) that of the benzene 
nucleus whereby dimethoxy-cinchoninic acid, C)H,(O.CH,),N.CO,H and afy- 
pyridine tricarboxylic acid are produced ; (2) that of the isoquinoline nucleus, 
resulting in formation of veratric acid and ebhenicnuss acid (p. 794) (Berichte, 
21, Ref. 787). Papaverine breaks down into veratric acid and dimethyl isoquino- 
line when fused with caustic potash. Consult Berichte, 22, 102, 755, for papave- 
rine ammonium bases. 

Narcotine, C,,H,,NO,, is separated from morphine by potassium hydroxide, in 
which it is insoluble. It crystallizes from alcohol in shining prisms, and melts at 
176°. In constitution it is intimately related to papaverine. It contains not only 
the benzene, but also the isoquinoline nucleus. It very likely represents a 
meconine-hydrocotarnine (Roser, Berichte, 23, Ref. 16, 19; Annalen, 254, 
357) — 

£0: O 
rd 
Oona N(CH,) = Narcotine. 


Meconine-hydrocotarnine. 


C,H,(O CH 


When boiled with water narcotine is decomposed into meconine, C,H .O, (p. 
794), and cotarnine, C,,H,,NO,.H,O. The latter appears to be an aldehyde 
with an open pyridine chain, which in the cotarnine salts and hydro-cotarnine is 
closed up as a pyridine ring (and isoquinoline ring) (Berichte, 22, Ref. 27) :— 


poo. NH.CH, CH,.N.CH, 
C,H,O | C,H,O;¢ 
8° "6 aN. 8° "6 3\. 
CH,—CH, CH,.CH, 
Cotarnine. Hydrocotarnine. 


Potassium permanganate oxidizes cotarnine or cotarnone to cofarnic acid, : 
C,H (o>CH, ) < (cout, , which can be further changed to methyl methylene 


gallic acid, CH »(o>CH: \XCo.r Hy and gallic acid, C,H,(OH),.CO,H. 


Narceine, C,,H,,NO, (see above), appears to be a naphthalene derivative 
(Berichte, 21, Ref. 249). 

A compound allied to papaverine and narcotine is 

Hydrastine, C,,H,,NO,, which occurs together with derberine, C,pH,,NO,4 
-f- 4 %4H,0, in the roots of Hydrastis canadensis ( Berichte, 23, 404, 2897). 


83 


994 ORGANIC CHEMISTRY. 


Cinchona Bases. 


The cinchona barks contain, in addition to tannin and quinic 
acid (p. 785), a series of bases, the most important of which are: 


Quinine, C,,H,,N,0,, Conquinine, C,,H,,N,0,, 
Cinchonine, C,,H,,N,0, Cinchonidine, C,,H,,N,O0.* 


Quinine and cinchonine are present in large quantity in so-called 
Calisaya bark, while the bases conquinine or quinidine and cin- 
chonidine, isomeric with them, predominate in other varieties of 
quinia barks. 

Quinine, C,,H,,N,O,, is found as high as 2-3 per cent. in the 
yellow Calisaya bark. It crystallizes with 3H,O in prisms, or when 
anhydrous (from alcohol and ether) in silky needles, melting at 
177°. It reacts alkaline, tastes bitter, and being a diacid base forms 
primary and secondary salts. 


The neutral sulphate, (C,)H,,N,0,),H,SO, + 8H,O, and the primary 
hydrochloride, C,,\H,,N,0,.HCl + 2H,O, are employed in medicine. The 
former consists of long, shining needles, which fall to a white powder on exposure. 
It dissolves readily in dilute sulphuric acid, the solution exhibiting a beautiful blue 
fluorescence. 

When chlorine water and then ammonia are added to the solution of a quinine 
salt, there is produced a green precipitate, dissolving in an excess of ammonium 
hydroxide with an emerald-green color. On adding an alcoholic iodine solution 
to the sulphate in acetic acid, a periodide, called herapathite, is precipitated. This 
crystallizes in emerald-green plates with golden lustre, and polarizes light the same 
as tourmaline. 


Quinine is a tertiary diamine, and with metallic iodides yields 
the iodides, C,,H,,N,O,.CH,I and Co H2,N, O,.2CH,I.° The first of 
these yields the so-called methyl quinine, CH, (CH, )N,O., when 
it is boiled with caustic potash. 

Cinchonine, C,,H,.N.O, occurs principally in the gray quinia 
bark (China Huanaco) (upwards of 2.5 per cent.) It crystallizes 
from alcohol in white prisms, sublimes in needles in a current of 
hydrogen, and melts about 250°. Like quinine it seems to dissi- 
pate fever, but to a less degree. 





Quinine and cinchonine contain one hydroxyl, and the former an additional 
methoxyl group: 
CypH»(OH)N, Cio o(9-CH,)(OH)N 
Cinchonine, Quinine. 


They yield acetyl derivatives when heated with acetic anhydride. Quinine 





* The quinoidine of commerce generally consists of cinchonidine and sometimes 
of conquinine. ; 


BRUCINE. 995 


heated to 150° with hydrochloric acid splits off the methyl group, with formation 
of apoquinine, C,,H,,(OH),N,, which deports itself like a bivalent phenol. 
Phosphorus pentachloride converts cinchonine (by replacing its hydroxyl group) 
into cinchonine chloride, C,,H,,CIN,, quinine into quinine chloride, C,,H,,- 
CIN,O, and these- compounds boiled with alcoholic potash yield ci#cheme and 
guinene — 

C,,H,.N, and C,,H,,N,0, 


Cinchene. Quinene, 


which, when heated to 190° together with concentrated hydrochloric or hydro- 
bromic acid, give up ammonia and absorb water, thus forming apocinchene and 
apoquinene :-— 

C,,H,,NO C,oH,,NO,. 


Apocinchene. Apoquinene. * 


Apocinchene manifests a phenol character, and may be considered a y-phenol- 
quinoline, C, H,N.C,H,.OH (p. 971), in the benzene nucleus of which alkyls are 
yet present, C: H, N. ae H o(C,H,,)OH or C,H,N.C,,H,,.OH. It is not known in 
what manner the second N- atom in cinchonine is combined with the side-chain 
(Koenigs, Berichte, 20, 2688, 2526, 2669) (see also Skraup, Berichte, 22, Ref. 
332, 578). 

Ordation converts cinchonine into cinchoninic acid (y-quinoline carboxylic 
acid, p. 972), whereas quinine yields quininic acid, (methoxy y-quinoline carboxylic 
acid, Cy H;(O.CH,)N.CO,H, p. 973). More energetic oxidation, with potassium 
permanganate, changes cinchonine and quinine into afy-pyridine tricarboxylic acid 
and cinchomeronic acid (p. 948). If cinchonine be fused with alkalies it forms 
quinoline, C,H,N (together with -ethyl pyridine and fatty acids), but from 
quinine under like treatment we get a methyloxyquinoline, C oH, (0. CH,)N 
(p. 969). 


 - 





Bases from Strych nos. 


In the fruit of the different strychnos, principally in that of 
Strychnos nux vomica and in St. Ignatius’ bean (Strychnos Igna- 
til), are found two very poisonous bases: Strychnine and brucine. 


Strychnine, C,,H,,N,O,, crystallizes in four-sided prisms, melting at 284°, 
reacting alkaline and possessing an extremely bitter taste. It is a tertiary amine, 
and when fused with potassium hydroxide yields quinoline and indol. Consult 
Berichte, 23, 2721, upon the methyl strychnines. 

Brucine, C,,H,,N,O,, crystallizes, containing four molecules of water, in 
prisms, and melts at 178° when anhydrous. It dissolves with a red color in con- 
centrated nitric acid, On application of heat it becomes yellow and violet after 
the addition of stannous chloride. When distilled with potassium hydroxide it 
yields $-ethyl pyridine and two collidines. 

Strychnine and brucine probably contain a quinoline nucleus; in strychnine 
there is also present a phenylpyridine, and in brucine a dioxymethyl phenylpyri- 
dine (Berichte, 21, 451, 813). 


Solanum Bases. 

In some varieties of Solanum there are found three isomeric al- 
kaloids of very similar constitution, C,,H,;NO;. They are a¢ropine, 
hyoscyamine and hyoscine. If they are introduced in very small 


996 ORGANIC CHEMISTRY. 


quantity into the eye they cause dilatation of the pupil and are 
therefore employed i in the treatment of the eyes. All three decom- 
pose into tropic acid (and atropic acid, p. 813), and a base, 
C;H,,NO, when heated with hydrochloric acid or baryta water :— 


C,,H,,NO, + H,O = C,H,,NO + C,H,,O, ; 


by this reaction ¢vopine is formed from atropine and hyoscyamine, 
but from hyoscine we get isdtmeric pseudotropine. By the same 
treatment dextro-tropic acid yields dextro-atropine and levo-tropic 
acid lzvo-atropine (Berichte, 22, 2591). Conversely, inactive atro- 
pine is again recovered by evaporating share acid and atropine with 
dilute hydrochloric acid. 


Refcpine, daturine, C,,H,,NO,, is prepared from the deadly nightshade 
(Atropa belladonna) and Datura strammonium by a rearrangement of the hyos- 
cyamine present in them (Berichte, 21, 1719). It crystallizes from alcohol in 
small prisms, melting at 114°. It is optically inactive. Dextro-atropine, from 
dextro-tropic acid, forms white shining needles, melting at 110-111°; devo-atropine 
is a crystalline powder, that melts at 111°. It is similar to hyoscyamine, but not 
identical with it. The supposed rearrangement of atropine into hyoscyamine (e- 
richte, 21, 1717, 2777) is due, according to Ladenburg, to the presence of consid- 
erable hyoscyamine in the atropine ( BerichZe, 21, 3069). 

Hyoscyamine, C,,H,,NQO,, occurs in the seeds of Hyoscyamus niger, in 
Atropa belladonna and in Datura strammonium. lt crystallizes from chloro- 
form in shining needles, and melts at 108.5°. Hyoscine, C,,H,,NOs, is a 
viscous liquid found in henbane. 

Duboisine, from Dudotsia sph caaheanias, is either hyoscyamine or hyoscine 
(Berichte, 20, 1661). 

Belladonine, C,,H,;NO,, resembles these alkaloids. It occurs with atropine, 
and is likewise decomposed into tropic acid and oxy-tropine, C,H,,NO, (Berichte, 


17, 152, 383). 


Just as tropine yields atropine with atropic acid, so it is capable 
of entering combination with other acids producing ester-like deri- 
vatives, which have been called ¢ropeines (Ladenburg, Aznalen, 217, 
82). Of these phenylglycolyl-tropeine or Homatropine, C;H,N 
(CH;).C,H,.0.CO.CH(OH).C,H;, is noteworthy. It is obtained 
from tropine and mandelic acid. It is employed as a substitute for 
atropine, and is applied in the form of hydrobromide. 





a om. 


Cocaine, C,,H,.,NO,, is present in the leaves of Erythroxylon 
coca, It crystallizes in colorless prisms, melting at 98°. It is a 
very superior local aneesthetic and is applied in the form of hydro- 
chloride. When it is digested with hydrochloric acid it breaks 
down into ecgonine, C,H,;NO,, benzoic acid and methyl alco- 
hol :— 

C,,H,,NO, + 2H,0 = C,H,,NO, + C,H,0, + CH,,.OH. 


ECGONINE. 997 


It yields benzoyl ecgonine, C,H,,(C,H;O)NO;,, when boiled with 
water. Cocaine is, therefore, a methylated benzoylecgonine (see 
below). 


Conversely, cocaine can be again re-formed from ecgonine by heating it together 
with benzoic anhydride and methyl iodide, or from benzoyl ecgonine with methyl 
iodide and sodium ethylate (Merck, Berichte, 18, 295 3). It is more readily 
obtained by the etherification of benzoyl ecgonine with methyl alcohol and hydro- 
chloric acid (Einhorn, Berichte, 21, 47), or by introducing benzoyl into ecgonine 
ester (Berichte, 21, 3202, 3336). This procedure is used at present in its prepara- 
tion on a large scale, 

Crude cocaine, obtained by extracting coca-leaves, contains a series of amorph- 
ous alkaloids (cocamine, hygrine, Berichte, 21, 665. 675), from which it is sepa- 
rated with great difficulty. These associated alkaloids are also derivatives of 
ecgonine, and contain isatropic acid (isatropy] cocaine), truxillic acid and isocinna- 
mic acid ‘(p. 812) instead of benzoic acid. All eliminate ecgonine when digested 
with hydrochloric acid (Liebermann, Berichte, 21, 3196), and from this the pure 
cocaine is prepared synthetically. 

Ordinary cocaine is levo-rotatory. Dextro-Cocaine (Berichte, 23, 508, 926) 
occurs with it in slight amount. The latter is obtained pure from dextro-ecgonine 
(Berichte, 23, 468, 982). It forms prismatic crystals, melting at 43-45°. 

Ecgonine, C,H,,NO,; + H,0, produced in the decomposition of cocaine, is 
very soluble in water, more sparingly i in alcohol, and consists of prismatic crystals 
that melt at 205° (at 140° when dry). Its esters are formed when hydrochloric 
acid gas is conducted into its alcoholic solution (Berichte, 21, 3336). Benzoic 
anhydride acting on aqueous ecgonine (erichie, 21, 3198, 3372) produces 
Benzoyl Ecgonine, C,H,,(C,H,O)NO, + 4H,0. 

In the anhydrous state this melts at 195°. Ecgonine is lzevo-rotatory. It passes 
into the dextro variety when digested with caustic potash. The latter melts at 254° 
( Berichte, 23, 470, 979), and yields dextro-cocaine. 

The withdrawal of water from ecgonine (by boiling with POCI,) produces an- 
hydroecgonine, C,H,,NO,, melting at 235° (Berichte, 20, 1221). This is an 
unsaturated acid, which potassium permanganate converts into the oxyacid, 
ecgonine. a@-Ethyl pyridine results upon distilling ecgonine with lime or zinc 
dust (Berichte, 22, 1126, 1362). The preceding compounds, therefore, are deri- 
vatives of z-methy] tetrahydropyridine, in which one of the side groups is in the a- 
position (Einhorn, Berichte, 20, 1228). Lcgonineis n-methyl-tetrahydropyridine— 
B-oxy-propionic acid -— 


C,H,(H,)N(CH,).CH(OH).CH,.CO,H — Ecgonine ; 
anhydroecgonine is the corresponding acrylic acid :— 
C,H,(H,)N(CH,).CH : CH.CO,H — Anhydroecgonine, - 
and cocaine is the benzoyl-ecgonine-methy! ester :— 
C,H,(H,)NCH,.CH(O.C,H,O).CH,.CO,.CH, — Cocaine. 

Anhydroecgonine is the tetrahydro-z-methyl derivative of the pyridylacrylic 
acid (p. 947), ecgonine, the derivative of pyridyl-f-lactic acid (Berichte, 23, 
224). ‘Tropidine is obtained from anhydroecgonine by heating the latter with 
hydrochloric acid to 280°, when it loses carbon dioxide (Berichte, 23, 1338). 


Potassium permanganate oxidizes ecgonine to tropic acid, C,H,,NO, (Berichte, 
23, 2518, 2889). 


998 ORGANIC CHEMISTRY. 


There remain other alkaloids which have been poorly investigated: mention may 
be made of the following :— 

Veratrine, C,,H,,NO,, Cevadine. This occurs, together with veratric acid 
(p. 779), and other alkaloids, in the white hellebore (from V. album) and in the 
Sabadilla seeds (from V. Sabadilla). It crystallizes from alcohol in prisms, and 
melts at 205°. It dissolves in sulphuric acid with a yellow color, which gradu- 
ally changes to blood-red. -It yields {-picoline (Berichte, 23, 2707) by dry dis- 
tillation. 

Sinapine, C,,H,,NO,;, occurs as sulphocyanate in white mustard. Free 
sinapine is very soluble, and decomposable. When boiled with alkalies it decom- 
poses into choline and stzafpic acid, C,,H,,O;, which is a butylene gallic acid. 





TERPENES. 


The terpenes are hydrocarbons, analogous to turpentine oil. 
They have the formula C,H, or (C;H,),, and are contained in the 
volatile or ethereal oils obtained in the distillation of various plants 
(chiefly Coniferze and Citrus species). The terpenes that have been 
thus isolated are very numerous ; their properties vary but little, and 
they have heretofore been considered either as chemical or physical 
isomerides, according to their origin. In recent years investigators 
have succeeded’ in reducing them to a few (8-10) pure parent- 
substances, and referring them to individual groups. Their dis- 
tinction and classification depends upon the power that some pos- 
sess, of combining with one or two molecules of bromine or a halo- 
gen hydride, or with nitrosyl chloride (with two or four affinities), 
whereas others are incapable of forming addition products (see 
Wallach, Anna/len, 230, 225 ; 239, 1; 245, 241; 252, 106, etc.). 


The addition of the halogens or halogen hydrides succeeds best in a glacial acetic 
acid solution at low temperatures. The additive products revert to the terpenes 
when heated with sodium acetate (in glacial acetic acid solution). 


The 22troso-chlorides of the terpenes, Cathe No (p. 112), were first obtained 


by the action of nitrosyl chloride, NOCI, upon the pinenes and limonenes (Tilden). 
A simpler method for their preparation consists in shaking a chilled mixture of 
terpene and amyl nitrite (or ethyl nitrite) with concentrated hydrochloric acid, 
and then adding alcohol or glacial acetic acid (Wallach, Berichie, 21, Ref. 622; 
22, Ref. §83). The nitroso-chlorides are crystalline compounds, which melt above 
100°, They form 72¢ro/amines with organic bases (amines, anilines, piperidines) 
. Soe Bs thus resemble the nitrosates of the alkylenes, (p. 112) (Berichte, 21, Ref. 
534) :— 
NO NO 

Cn + NH,.C,H, = C,H, s<NILGH, + HCl. 


The elimination of hydrogen chloride in this reaction, which occurs with some 
bases, leads to the formation of Mitroso-terpenes, C,H, (NO). 
Several terpenes (as the dipentenes) unite with N,O, and form zétrosates C, 


PINENE AND CAMPHENE GROUP. 999 


H,(NO). Sage ~ O. _Terpinene and phillandrene yield mztrosttes, C,H, 
(NO)(O. 2) wit 


The terpenes are closely related, so far as constitution is con- 
cerned, to ordinary cymene, C,H, (p-methylpropyl benzene, C,H,. 
C,H,.CH;) ; they can be readily converted into it by the withdrawal 
of two hydrogen atoms (see below and p. 577). This occurs by 
their oxidation to f-toluic and terephthalic acids, C,H,(CO,H),. 
Therefore, the terpenes may be viewed as benzene additive pro- 
ducts—as dihydrocymenes, C,,H,,(H,). 


In accordance with the generally accepted structure of the benzene nucleus 
several ~-dihydrocymenes are possible; they contain in addition two divalent 
ethylene unions, and therefore can form additive products with four affinities (p. 567) 
(Compare citrene). Again, there are other terpenes which contain but wo free 
affinities, or are not capable of forming additive products (pinene, camphene, etc.). 
These very probably originate from. differently constituted benzene nuclei with 
diagonal or para-linkages (p. 564). This seems evident from their lower refractive 
power (Briihl, Berichte, 21, 145, 467). Wallach considers that the conclusions 
drawn from the molecular refractions are unreliable (Berichée, 21, Ref. 342; 22, 
Ref. 584). 





(1) PINENE AND CAMPHENE GROUP. 


These combine with but one molecule of the halogen hydrides. 
The first forms a compound with nitroso-chloride, the second does 
not. 

(1) Pinene — C,H,, — is the chief ingredient of the turpentine 
oil prepared from the different varieties of pine, of eucalyptus oil, 
juniper-berry oil, sage oil, etc. 

The resinous juice, called turpentine, exuding from various coni- 
ferze, consists of a solution of resin in turpentine oil, which distils 
with steam while the resin (colophony) remains behind. 

Oil of turpentine ‘is a colorless peculiar-smelling liquid, boiling . 
from 158—160° ; its sp. gr. equals 0,856—0.87. It is almost insoluble 
in water, is miscible with absolute alcohol and ether, dissolves 
sulphur, phosphorus, resins, caoutchouc, and, therefore, serves for 
the preparation of oil colors and varnishes. 


The turpentines, according to their origin, show some differences, especially in 
their optical rotatory power, 

The German turpentine oil (from Pinus st/vestris and Abies excelsa), the French 
(from Pinus maritima), called Terebenthene, the Venetian (from Larix europea), 
are levo-rotatory, while the English (from Pinus australis) called Australene, is 
dextro-rotatory. This is also true of the terpene from oil of: wormwood, and from 
the oil of mint. 

The basis of these various turpentine oils seems to be a Dextro-pinene and a 


1000 _ ORGANIC CHEMISTRY. 


levo-pinene (as in the case of the tartaric acids). ‘The Russian and Swedish tur- 
pentine oils consist mainly of cinene and sylvestrene (see below), 

Oil of turpentine slowly acquires oxygen from the air (with ozone formation) 
and resinifies with production of acids (formic, acetic); at the same time small 
quantities of cymene are formed. When turpentine is boiled with nitric acid, 
different fatty acids, terebinic acid, pyrocinchonic acid, toluic acid and terephthalic 
acid result. Chromic acid converts it into terebinic acid and terpenylic acid 
p. 470). | 
; Turpentine oil (pinene) heated to 250-300° is converted into dipentene, C,,H,, 
(see below) and meta-terebenthene, C,H, (boiling at 260°). Turpentine oil 
heated together with iodine in a vessel in connection with a return cooler under- 
goes a violent reaction and forms cymene, C,,H,,. The same compound is pro- 
duced on heating the dichloride, C,)H,,Cl,, when it loses two. molecules of 
hydrogen chloride. Terpene Tetrahydride, C,,H,), is produced when tur- 
pentine oil is heated with hydriodic acid or phosphonium iodide. It boils at 
170-172°. Menthene is a dihydride, C,,H,, (p. 1007). 


Pinene unites with a molecule of chlorine and bromine, forming 
liquid compounds that are not very characteristic. In the same 
manner it combines with but one molecule of hydrochloric or 
hydrobromic acid—the products being solids, which cannot absorb 
additional halogens or halogen hydrides. It is therefore very 
probable that pinene contains but one divalent union (see above). 

Pinene Dichloride, C,H,Cl,, and Pinene Dibromide, 
C,H,,Br., are unstable liquids. When heated they break down 
into halogen hydrides and cymene. . 


Pinene Hydrochloride, C,,H,,.HCI, is produced on conducting HCl gas 
into well-cooled pinene. The hydrochloride (called ‘artificial camphor) yields 
crystals resembling those of camphor, has the odor of the latter, melts at 125°, and 
‘boils at 208°, The hydrochloride of lzvo-pinene is leevo-rotatory, while that from 
dextro-pinene is dextro-rotatory. Pinene Hydrobromide, C,,H,,Br, formed like 
the hydrochloride, melts at 90° and has a higher boiling point than the chloride. 

Solid camphene (see below) results when the preceding compounds lose hydro- 
gen chloride or bromide. This occurs when they are boiled with glacial acetic 
acid and sodium acetate. 

Pinene Nitroso-chloride, C,,H,,(NO)Cl, obtained by means of nitrosy]- 
chloride, or amyl nitrite, glacial acetic acid and hydrochloric acid, melts at 103°; 
the bromide, C,,H,,(NO)Br, at 92°. Piperidine and the chloride yield V2tro- 
lamine, C,,14,,(NO).NC,H,,, but with other bases the product is /Vetrosoéer- 
pene, C,,H,;(NO), melting at 132°. 

By the prolonged, action of moist hydrogen chloride upon pinene, the latter re- 
arranges itself to dipentene, a dihydrochloride, C,,H,,Cl,, that melts at 50°, and 
is identical with dipentene-dihydrochloride (see below). 

If turpentine oil containing water be permitted to stand for some time with nitric 
acid and alcohol (Anzalen, 230, 248), or dipentene dihydrochloride, C,,H,,Cl,, 
(p. 1002), with aqueous alcohol, so called Zerpine Hydrate, C,,H,,O, + H,O, 
will result. This is readily soluble in hot water, alcohol and ether. It is odor- 
_ less, and forms large rhombic crystals, that melt at 117° in a capillary tube. Above 

100° it loses water and changes to /erpine, C,,H,,O, = C,,H,,(OH),, sub- 
_ liming in needlesythat melt at 104° and distil at 258°. ‘Terpine reacts like a 
_ glycol. When digested with nitric acid it forms a dinitric ester. 

Dihydrohaloid compounds, C,,H,,X.,, of dipentene, are formed when terpine, 


LIMONENE AND DIPENTENE GROUP. Ioo!r 


or terpine hydrate, is shaken with the haloid acids. Boiling sulphuric acid (1 part 
: 2H,O) causes terpine hydrate to lose water and form 7Zerfineo/, C,,H,,(OH) 
(p. 1007). Bromine converts it into dipentene tetrabromide, C, ,H,, Br, (melting at 
125°) ( Annalen, 230, 253; 239, 8). 

‘Terpine hydrate and terpineol lose additional water by continued heating with 
sulphuric acid and yield dipentenes, terpinenes and terpinolenes (see below). Ter- 
pineol at the same time, yields isomeric cineol (Annalen, 246, 236). 


(2) Camphene, C,H, is the solid terpene, obtained from 
pinene halogen hydride, by the elimination of the haloid acid. 
A better method to pursue in its preparation is to boil bornyl chlo- 
ride, C,,H,;Cl, with aniline. 


The camphenes from different sources differ from each other in rotatory power : 
Terecamphene, from terebenthene, is levo-rotatory, austracamphene, from Austra- 
lene, is dextro-rotatory, while Borneo-camphene (Borneen), from borneol chloride, 
is inactive. They are crystalline masses, melting at 49°, and boiling at 156~157°. 
Chromic acid oxidizes them to ordinary camphor (active and inactive). 

Camphene and hydrochloric acid form a liquid, unstable additive product, 
C,,H,,-HCl, which is readily resolved into its components. Bromine does not 
produce an additive, but rather a substitution product, C,,H,,Br. Nor is it able to 
form a nitroso-chloride. The assumption therefore that there are no divalent 
unions in camphene, but two para-unions of the benzene nucleus is, in the opinion 
of Wallach, unestablished (Berichte, 22, Ref. 585). 


2. LIMONENE AND DIPENTENE GROUP. 


These combine with two molecules of bromine or of a halogen 
hydride, but not with N,O3. 

1. Dextro-limonene, C,H, Given, hesperidene, carvene, is 
the oil of Citrus aurantia, and the chief ingredient of cedar oil, 
cumin oil and dill oil. . It occurs associated with pinene in lemon 
oil. Levo-limonene occurs together with levo-pinene (boiling at 
160°) in pine oil (from Pinus sylvestris), and may be isolated from 
it by fractional distillation (Berichte, 21, Ref. 624.) 

Both limonenes are agreeably smelling liquids, sp-gr. 0.846 at 
20°, and boil at 175-176°. They differ from each other, even in 
their derivatives, almost exclusively in their opposite rotatory 
power. 


Bromine converts each into a characteristic Tetrabromide, C,,H,, Br4, that 
crystallizes in large prisms, melting at 103°. The one is dextro- and the other 
leevo-rotatory. They combine with two molecules of the halogen hydrides to 
compounds of the type C,,H,,X,; these are identical with the dipentene deriva- 
tives; there has therefore been a rearrangement of the limonenes into dipentenes. 

The Dextro-Nitroso-cbloride, C,,,H,,(NO)CI, and the /evo-nitroso-chloride 
result by the action of amyl nitrite and hydrochloric acid upon dextro and levo- 
- limonene. Both melt at 103°. They differ from each other solely in rotatory 


84 


1002 ORGANIC CHEMISTRY. 


power. Boiling alcohol converts the lzvo-nitroso-chloride into Dextro-nitroso- 
limonene, C,,H,;(NO) (by elimination of HCl), which melts at 72° and is 
identical with dextro-carvoxime, C,,H,,(N.OH), obtained from dextro-rotatory 
carvol (p. 688) with hydroxylamine. Dextro-nitroso-chloride, on the other hand, 
yields a devo-nitroso-limonene or levo-carvoxime, which also melts at 72°, and 
otherwise corresponds perfectly with dextro carvoxime (Anumalen, 246, 227; Be- 
richie, 21, Ref. 624). Jnactive carvoxime is produced by mixing dextro- and 
lzevo-carvoxime. It melts at 93°, and is identical with nitroso-dipentene (see 
below). 

As* limonene combines four affinities quite readily (bromine or a halogen 
hydride) it must very probably contain two divalent C-unions, and is a normal 
dihydroparacymene. Its relation to carvol shows the position of the divalent 


unions, corresponding to the formula, CBee ta ee cH CH.CH, (Gold- 


schmidt, Berichte, 18, 1733). 

Dextro- and levo-limonene-nitroso chlorides can, by crystallization from chloro- 
form, be resolved into two isomeric compounds, C,>H,,.NOCI (a and ), which 
would further complicate the relations previously expressed (Berichte, 22, Ref. 


583). 


Dipentene, Cinene, C,H, inactive Zzmonene, is the most 
stable of the preceding terpenes, and is produced by heating 
pinene, camphene and limonene to 250-300° (from pinene also by 
the action of alcoholic sulphuric acid) ; it is, therefore, present in 
the Russian and Swedish turpentine oil, obtained by application 
of great heat (p. 1000). It is associated with cineol in Oleum cine, 
and is derived from terpine hydrate, terpineol and cineol by the 
withdrawal of water, and further by the distillation of caoutchouc, 
and the polymerization of the isoprene, C;H;, formed simultane- 
ously. It may be prepared pure by heating its hydrochloride with 
aniline or sodium acetate in glacial acetic acid solution. It results 
upon mixing dextro- and levo-limonene, and is, therefore, zzactive 
limonene, It is a liquid, with an agreeable lemon-like odor. 


Its sp. gr. is 0.853. It is optically inactive and boils at 175-176°. 
Although very stable, it can yet be changed into the isomeric ter- 
pinene by alcoholic sulphuric acid, or hydrochloric acid. 


Dipentene combines with two molecules of bromine or halogen hydride, forming 
compounds that differ from those of the two limonenes, and hence it is regarded 
as a peculiar isomeride. However, the same inactive compounds are also formed 
by mixing the corresponding derivatives of dextro and laevo-limonene, Never- 
theless, these synthetic derivatives (unlike the inactive racemic acid) have the 
same ae weights (in solution) as the active limonene compounds (Amua/en, 
246, 231). 

Dipentene Tetrabromide, C,,H,,Br, (see above), melts at 124-125°. Its 
crystals are entirely different from those of limonene tetrabromide (melting at 
104°). Dipentene Dihydrochloride, CiyH,,Cl,, from limonene, dipentene and 
moist pinene, consists of rhombic plates, melting at 50°. The dihkydrobromide, 
C,,H,,Br,, formed from terpine and cineol with hydrobromic acid, melts at 64° ; 
the dihydrotodide, C,)5H,,I,, consists of rhombic prisms, melting at 77°, or plates 
that fuse at 79°. Dipentene-nitroso-chloride, C,yH,,(NO)Cl, from dipentene by 


DEXTROPHELLANDRENE., 190 3 


means of amyl nitrite and hydrochloric acid, melts at 102°, is inactive and when 
digested with alcoholic potash yields inactive Vétroso-dipentene, C,,H,,(NO), 
melting at 93°. It is identical with the inactive carvoxime prepared from dextro- 
carvoxime and lzvo-carvoxime. 

(2) Terpinolene, C,,H,,, is produced when terpine hydrate, terpineol and 
cineol are boiled with dilute sulphuric acid, and by heating pinene with the con- 
centrated acid. It boils at 185-19g0°. The éetrabromide, C,,H,,Br4, is a solid 
melting at 116°. It combines with two molecules of the halogen hydrides to form 
compounds, that are probably identical with those of dipentene. 

(3) Sylvestrene, C,,H,,, occurs in Swedish and Russian turpentine oil. It 
may be obtained pure by digesting its hydrochloride with aniline, or by boiling it 
with glacial acetic acid and sodium acetate. It boils at 175 178°, and is optically 
dextro-rotatory; this also is the case with its compounds. Sulphuric acid imparts 
an intense blue color to its solutions in anhydrous acetic acid (or in acetic anhy- 
dride). Its compounds with two molecules of bromine or the haloid acids are 
different from those of all other terpenes. The ¢e¢rabromide, C,,H,,Br,, melts at 
135°. The dihydrochloride, C,yH,,Cl,, melts at 72°, the adihydrobromide, 
C,,H,,Br,, also at 72°, and the dihydroiodide, C,,H,,1,, at 67°. The mitroso- 
chloride, Cy,H,,(NO)Cl, melts at 107°. 


(3) Terpinenes and Phellandrene. 3 

These do not unite either with bromine or the haloid acids; consequently, they 
probably do not have divalent unions in the benzene nucleus. However, like 
amylene, they form nitrosites with N,O,, and are probably unsaturated in the 
side-chain (Anmalen, 239, 54; Berichte, 21, 175). » 

Terpinene, C,,H,,, results from a rearrangement of pinene, when the latter 
is shaken with a little concentrated sulphuric acid, and by boiling dipentene, ter- 
pine, phellandrene and cineol with dilute sulphuric acid (Anma/en, 239, 35). It 
occurs already formed in cardamon oil. It is very similar to dipentene, boils about 
180°, but forms liquid products with the haloid acids. It is the most stable of all 
the terpenes, and is not changed into any other terpene. Nitrous acid converts it 
into Terpinene Nitrosite, C,,H,,(NO)O.NO, melting at 155°, and yielding 
nitrolamines with bases (Berichte, 22, Ref. 585). 

Dextrophellandrene, C,,H,,, occurs in the oil of water fennel (Phellandrium 
aquaticum), etc. Lzvo-phellandrene is present in eucalyptus oil. Both boil 
about 170°, and differ merely in opposite rotatory power. Both become solid and 
crystalline when shaken with sodium nitrite and acetic acid. They are then zz¢ro- 
sites, both of which melt at 103°. In this treatment dextro-phellandrene yields 
levo-nitrosite, and levo-phellandrene, dextro-nitrosite. By mixing the two nitro- 
sites inactive nitrosite is formed; this fully agrees with the active nitrosites 
(Annalen, 246, 232, 265; Berichte, 21, Ref. 624). 

For the terpenes contained in the various ethereal oils see Berichte, 22, Ref. 582. 

Homologous terpenes have been prepared by the action of sodium upon a mixture 
of camphor chloride, C,)H,,Cl, (p. 1005), and the alkyl iodides. Ethyl Camphene, 
C,,H,;(C,H,), is a liquid with an odor resembling that of oil of turpentine, and 
boiling at I98-200°.  Isobutyl Camphene, C,,H,,(C,H,), boils at 228°. 

Sesquiterpenes are widely distributed in the ethereal oils. The sesquiterpene in 
oil of cubeba, patchouly oil, galbanum oil and sabine oil, boils at 274-275°. It 

forms a dihydrochloride, C,;H,4.2HCI, melting at 118°. It can be regenerated 
from this compound by boiling with aniline (Anna/len, 238,78; Berichte, 21, 163). 
vet alge is a diterpene, C, ;H,.,, obtained by distilling colophony. It boils at — 
31 - . . 


1004 ORGANIC CHEMISTRY. 


CAMPHOR. 


The camphors are peculiar-smelling substances, containing oxy- 
gen and intimately related to the terpenes. They are often found 
with the latter in plant secretions, and can be artificially prepared 
(in slight quantities) by oxidizing the same. They are derivatives 
of paracymene, C,,H,,, and mostly derivatives of its tetrahydride 
C,,Hs. Japan camphor, C,)H,,O, is a keto-derivative of Borneo cam- 
phor, C,.H,,O, a hydroxyl compound of tetrahydro-cymene, corre- 
sponding to the following formulas :— 





ss / CH,-CO \ / CH,-CH(OH)—C.CH, 
- -G3H,.CcH C.CH, and C,H,.CH 
or? \-CH,-CH7 \ CH, —CH 
Japan Camphor Borneo Camphor. 


The ortho-position of the oxygen atom with reference to the methyl group is evi- 
dent from the ready conversion of Japan camphor into carvacrol or oxycymene 
(p. 688), and from its analogies to carvol, a keto-derivative of a dihydrocymene 
(p. 688). Menthol C,,H,,O, bears the same relation to menthone, C,)H,,O 
(p. 1007) as Borneo camphor to Japan camphor; the one is an oxy-derivative and 
the other a keto-derivative of hexahydrocymene, C,,H,,(H), :— 


CH CH 
C,H,O a GC, #f,20d CoH (OH) & Ci 
Menthone. Menthol, 


As Japan and Borneo camphor are not capable of forming additive products 
(with bromine or haloid acids), it would appear that a double ethylene union is 
_ not present in them; their molecular refraction would also indicate it. To explain 
this behavior it may be assumed, as in the case of camphene, that the benzene 
neucleus contains a para-linkage (Briihl, Berichte, 21, 467; Wallach, Annalen, 
230, 269) corresponding to the formulas :— 











/ CH,.CO \. /CH,.CH(OH)\ 
C,H,.C tice. Cae C.CH;. 
SS CHCHS \CH,— CH, / 
Japan Camphor, - ‘Borneol. 


Common or Japan camphor is found in the camphor tree (Law- 
rus camphora) indigenous to Japan and China. It is obtained by 
distillation:with steam and sublimation. It is prepared artificially 
by oxidizing borneol with nitric acid and camphene with chromic 
acid. It is a colorless, transparent mass, crystallizes from alcohol, 
and sublimes in shining prisms, of sp. gr. 0.985. It volatilizes at 
ordinary temperatures, melts at 175°, and distils at 204°. Its alco- 
holic solution is dextro-rotatory. Camphor yields pure cymene 
(p. 577), if distilled with P,O;, and on boiling with iodine forms 
carvacrol C,,H,,O (p. 688). When boiled with nitric acid it yields 
different acids, chiefly camphoric and camphoronic acids. The 





CAMPHOR ALDEHYDE. | I005 


Camphoroxime, C\)H,(N.OH), obtained with hydroxylamine, melts 
at 115° (Berichte, 22, 605) and distils about 250°. 


Itunites likewise with phenylhydrazine to the Aydrazide C, ,H,, (N,H.C,H;). 
Camphoroxime Anhydride, C,,H,,N, results from the action of acetyl chloride 
upon camphoroxime, or of hydrogen chloride upon phenylhydrazide. It boils at 
217°. It is probably a cyanide with open chain, CH,.C(C,H,):CH, a campho- 


lene nitrile, le 13 CH:C(CH,). CN, 
The saponification of the nitrile yields campholenic acid, C,H,,CO,H (Gold- 
schmidt, Berichte, 20, 485; 21, 1129). 2 

Chlorine and bromine acting upon camphor, produce mono- and disubstitution 
products. 

PCl, converts camphor into two Camphor-dichlorides, C,,H,,Cl, melting 
at 70° and 155°. 

Two Chlornitrocamphors, C,,H,4C1(NO,)O (a and £), are produced. when 
chlorcamphor is digested with nitric acid; the copper zinc couple reduces them to 
a- and [-nitrocamphor, C,>H,,(NO,)O (Berichte, 22, Ref. 266; 23, Ref. 115). 

Bornylamine, C,,H,,.NH, = C,H,,4/ ° , a solid base, melting at 

NCH.NH, 
160°, is formed when camphor is heated together with ammonium formate to 240° - 
( Berichte, 20, 104, 483). Bornylamine shows in all respects the character of an 
alicyclic amine (p. 912). Its odor resembles that of piperidine. . It is strongly 
alkaline, absorbs carbon dioxide from the air, yields a diazoamido-derivative 
(not an azo-dye) with diazobenzene chloride, and forms a nitrite with nitrous acid 
(Berichte, 21, 1128). 

Camphylamine, C,,H,,.NH, = C,;H,;(C,H,)(CH,).CH,.NH,, is iso- 
meric with the preceding compound. It is formed when sodium and alcohol act 
upon camphoroxime. It is very probable that the benzene chain present in it is 
open. It is a liquid boiling at 195°. Its properties resemble those of the amines of 
the paraffin series (Berichte, 20, 485; 21, 1128). 


O 
Isonitroso-camphor, C,,H,,O(N.OH) = C,H, .7 : ,is obtained by 
‘C:N.OH 


the action of amyl nitrite and sodium ethylate upon camphor. A CH,-group is 
replaced. The compound melts at 153°. Nitrous acid, or sodium bisulphite and 
boiling with dilute sulphuric acid (p. 326), changes it to camphor-quinone = | 


CO 
C. Fi aw CoH. The latter resembles quinone and the (1, 2)-dike 


tones. Its odor is peculiarly sweet. It volatilizes with aqueous vapor and sub- 
limes at 60° in golden yellow needles that melt at 198° (Claisen, Beriche, 22, 
53°). 

Sodium Camphor and Sodium-Borneo-camphor separate when metallic sodium 
acts upon the benzene or toluene solution of camphor :— 


2C,,H,,O + 2Na = C,,H,,NaO + C,,H,,.ONa. 


Campholic acid, C,,H,,O,, and borneol, C,,H,,O, are similarly formed when 
camphor is heated with alcoholic potash, The alkyl iodides convert sodium cam-- 
phor into alkyl camphor. Ethyl Camphor, C,,H,,(C,H;)O, boils at 230°. 

/ CO /CO 


Camphor Aldehyde, C,H,, - oC, °° 
\\CH.CHO \.C: CH(OH) 


,melts at 77°. 





1006 ORGANIC CHEMISTRY. 


It is formed by the action of sodium or sodium ethylate and formic ester upon 
camphor (analogous to the formation of the 6-ketonaldehydes, p. 323, 730). It is 
perfectly analogous to the (-ketonaldehydes. It is acid in nature, and dissolves 
readily in the caustic alkalies (erichZe, 22, 533, 3281; 23, Ref. 39). 

The camphors, like the turpentine oils, occurring in different plants, manifest 
some differences. Matricaria camphor, C,,H,,O, or Levo-camphor, contained 
in the oil of Matricaria Parthenium, is \:evo-rotatory, and when oxidized with 
nitric acid yields levo-camphoric acid. LLzevo-camphoroxime, C,,H,,.(N.OH), 
also melts at 115°. Absinthol, C,,H,,O, from oil of wormwood (from A7‘¢e- 
mesia Absinthium), is liquid, and boils at 195°. Myristicol, C,,H,,O, from 
nutmeg-oil, boils at 235°. Pinol, C,,H,,O, a by-prodact in the preparation of 
pinene nitroso chloride, is isomeric with camphor. It boils at 183-184°. Potassium 
permanganate oxidizes it to terebinic acid, C,H,,O,. Patchouly Camphor, 
C,,H,,0, from Patchouly oil, is a sesqui-camphor. It melts at 55° and boils at 
246°. Caryophyllin, C,,H,,0,, is a polymeric camphor, contained in cloves, and 
melts above 300°. 


Borneol, Borneo Camphor, C,,H,; O= C,H,;,OH, occurs 
in Dryobalanops Camphora, a tree growing in Borneo and Sumatra. 
It is artificially prepared by acting with sodium upon the alcoholic 
solution of common camphor, and bears the same relation to the 
latter as an alcohol toa ketone. It is quite like Japan camphor, 
and has a peculiar odor resembling that of peppermint. ~Itsublimes 
in six-sided leaflets, melts at 198°, and boils at 212°. 


Nitric acid oxidizes borneol to common camphor, and then to camphoric acid. 
Borneol possesses the character of an alicyclic alcohol (of ac-tetrahydro-{- 
naphthol, p. 916) (Berichie, 23, 201). It forms esters with organic acids, xan- 
thogenates with CS, ( Berichte, 23, 213), and is especially inclined to form camphene, 
C,,H,,, by the elimination of water. The acetyl ester, C, ,H,,.0.C,H,O, boils at 
221°. Bornyl Chloride, C, ,H,,Cl, melting at 148°, is produced by means of PCI;. 
It forms borneo camphene by the elimination of HCl. 

Lzvo-borneol, C,,H,,.OH, is optically opposed to ordinary dextro-borneol. 
It is produced, together with the latter, when sodium acts upon ordinary camphor. 

Cineol and Terpineol are isomerides of borneol. 

Cineol, C,,H,,O, is the chief ingredient of worm-seed oil (Artemisia cinz), 
cajeput oil and eucalyptus oil. It boils at 176°. Its specific gravity at 16° is 
0.923. It forms an unstable hydrochloride additive product, which water resolves 
into its components. Hydrochloric acid gas conducted into heated cineol produces 
dipentene-dihydro-chloride, C,,H,,.2HCl (p. 1002); hydriodic acid gas forms the 
dipentene-dihydro-iodide, C,,H,,.2HI (melting at 78°). P,S, converts cineol into 
cymene. See Berichte, 21, 460, 23, Ref. 642, upon the constitution of cineol. 
Potassium permanganate oxidizes cineol to cineolic acid, C,)H,,O;, melting at 
197° (Berichte, 21, Ref. 625; 23, Ref. 641). 

Terpineol, C,)H,,0O, formed by boiling terpine and terpine hydrate (p. 1000) 
with aqueous mineral acids, is a thick liquid with a peculiar odor. It boils at 
215-218°. It is also produced when pinene stands in contact with alcoholic sul- 
phuric acid; by further absorption of water it yields terpine hydrate. See Berichie, 
- 21, 463, in regard to its constitution. 


Menthol, Mentha Camphor, C,,H.O = CyHy.OH, oxy- 
hexahydrocymene (p. 1004), is the chief component of peppermint 
oil (from Mentha piperita), from which it separates in crystalline 


CAMPHORIC ACID. 1007 


form on cooling. It possesses, like borneol, the character of an 
alicyclic alcohol. It melts at 42°, boils at 213°, and-ts levo- 
rotatory. It forms es¢ers with acids and readily parts “with water. 
With concentrated hydrochloric acid, or PCI, it yields liquid men- 
thol chloride, C\Hy,Cl, boiling at 264°. 


Menthene, C,,H,g, is produced when the chloride is acted upon by alkalies, or 
when menthol is distilled with P,O,.. It boils at 167°. Chromic acid oxidizes 
menthol to dextro- and evo-menthone, C,jH,,0, which sustain the same relation 
to menthol that ordinary camphor bears to borneol. The menthones are liquids 
with an odor resembling that of peppermint. They boil at 206°. They form ox- 
imes with hydroxylamine. Dextro-menthone Oxime, C,)H,,(N.OH), is liquid. 
Lavo-menthone Oxime melts at 58°. Acids cause the menthones to change 
readily from one modification to the other (Berichte, 22, Ref. 261). Their activity 
is due to the asymmetry of a carbon atom (Amna/len, 250, 362). 





The oxidation of the camphors produces different acids, whose constitution has 
not yet been explained. 

Campholic Acid, C,,H,,0,, is produced on distilling camphor over heated 
soda-lime, or with alcoholic potash. It melts at 95° and volatilizes with steam. 
Nitric acid oxidizes it to camphoric and camphoronic acids. 


Camphoric Acid, C,,H,,O, = C;H,,(CO,H),, is obtained by 
boiling camphor with nitric acid (Annalen, 163, 323). It crystal- 
lizes from hot water in colorless leaflets, melts at 178°, and decom- 
poses into water and its anhydride, CsH\y(CO),0; the latter sub- 
limes readily in shining needles, melts at 217°, and boils at 270°. 


The acid from common camphor is dextro-rotatory, that from Matricaria cam- 
phor is, however, lzevo-rotatory and melts at 197°. The inactive meso-camphoric 
acid is produced on mixing the two acids. It melts at 113°, and is derived from 
ordinary camphoric acid by heating the latter with hydrochloric acid to 140°. 

By the fusion of camphoric acid with potash we get isopropyl succinic acid, 
C,H,(C,H,)(CO,H),. 3 k - ; 

From its constitution camphoric acid may be considered either as an unsaturated 
methylpropyl adipic acid, C,H ,(CH,)(C,H,)O, (Annalen, 220, 278), or, inas- 
much as it cannot form additive compounds, it may be regarded as methyl-pro- 
pyl tetramethylene dicarboxylic acid, in accordance with the formulas :— 


CHC CH,.C(CH,).CO,H 
or . 
CH(C,H,).CH,.CO,H CH,.C(C,H,).CO,H 


Camphoronic Acid, C,H,,O0,; + H,O, is produced by the further oxidation 
of camphoric acid ; it occurs in the mother liquor. It loses its water of crystal- 
lization at 100-120°, and melts at 135°. It is tribasic, yields isobutyric acid when 


fused with potash, and appears to be an isopropyl tricarballylic acid (Berichée, 
Ref. 71 and 18, 328). 


1008 ORGANIC CHEMISTRY. 


RESINS. 


The resins are closely related to the terpenes, and occur with 
them in plants, and are also produced by their oxidation in the air. 
Their natural, thick solutions in the essential oils and turpentines 
are called da/sams, whereas the real gum resins are amorphous, 
mostly vitreous bodies. Their solutions in alcohol, ether or tur- 
pentine oils constitute the commercial varnishes. . 

- Most natural resins appear to consist of a mixture of different, 
peculiar acids, the resin acids. The alkalies dissolve them, forming 
resin soaps, from.which acids again precipitate the resém acids. By 
their fusion with alkalies we obtain different benzene derivatives 
(resorcinol, phloroglucin, proto-catechuic acid); and when they 
are distilled with zinc dust they yield benzenes, naphthalenes, etc. 


Colophony is found in turpentine (p. 999), and, in the distillation of the latter, 
remains as a fused mass. It consists principally of Abietic Acid, C,,H,,O, 
(Sylvic acid), which can be extracted by hot alcohol, crystallizes in leaflets, and 
melts at 139° (147°). When oxidized it yields trimellitic, isophthalic and tere- 
binic acids. 

Gallipot Resin, from Pinus maritima, contains pimaric acid, C,,H;,O,, 
which is very similar to sylvic acid and passes into the latter when distilled in 
vacuo. It melts at 210°. The latest investigations show that pimaric acid con- 
sists of three isomerides ( Berichze, 19, 2167). 

Gum lac, obtained from East India fig trees, constitutes what is known as shel- 
lac when fused. This is employed in the preparation of sealing wax and varnishes. 

Amber is a fossil resin, found in peat-bogs. It consists of succinic acid, two 
resin acids and a volatile oil. . After fusion it dissolves easily in alcohol and tur- 
pentine oil, and serves for the preparation of varnishes. 

To the gum resins, occurring mixed with vegetable gums, and gum in the juice 
of plants, Baten gamboge, euphorbium, asafoetida, caoutchouc and gutta percha. 





GLUCOSIDES. 


_ These substances occur in plants and split into sugars (mostly 
grape sugar), and other bodies (alcohols, aldehydes, phenols), when 
acted on by acids or ferments. Therefore they are assumed to be 
ethereal derivatives of the glucoses. Various members of this series, 
obtainable also by synthesis, have already received notice in con- 
nection with the products they yield when they are decomposed. 
_. The following have not been fully investigated :— 


ZEsculin, C,;H,,O4, is contained in the bark of the horse chestnut ; it crystal- 
lizes in fine needles with 114 molecules H,O, melts when anhydrous at 205°, and 
is decomposed by acids or ferments into glucoses and ezsculetin, C,H,O, (Dioxy- 
coumarin, p. 822), Daphnin, C,,H,,O, + 2H,O, is isomeric with esculin, 


BITTER PRINCIPLES. 1009 


and is obtained from the bark of Daphne alpina. It melts at 200°, and breaks 
down into glucose and daphnetin (Dioxycoumarin, p. 823). 

Arbutin, C,,H 607s and Methyl Arbutin, C2 HO. are found in the leaves 
of Arbutus uva ursi. By their decomposition, we get, besides grape sugar, hydro- 
quinone or methyl hydroquinone. Arbutin crystallizes in fine needles, with %-I 
molecule of water, melts at 187° (Berichte, 16, 1925) in the anhydrous state, and 
is colored a deep blue by ferric chloride. Methyl Arbutin contains 1 molecule of 
water, and melts at 176°. It is formed artificially from arbutin by the action of 
methyl iodide and potash. 

Hesperidin, C,,H,,O,,, is present in the unripe fruit of oranges, lemons, etc. 
It separates from “alcohol in fine needles, melts at 251°, and is decomposed into 
grape sugar and Hesperitin, C,,H ,,O,, which by further boiling with potassium 
hydroxide breaks up into hesperitinic acid (isoferulic acid, p. 821), and phloro- 
glucin, C,H,.(OH),. 

Phloridzin, GH 0p occurs in the root bark of various fruit trees, crystal- 
lizes with 2H,O in fine prisms, and when anhydrous melts at 108°. By decom- 
position it yields grape sugar and Phloretin, C,,H,,O,, (colorless leaflets), which 
alkalies convert into phloretic acid (p. 775), and phloroglucin. 

Quercitrin, C,,;H,,O.9, is found in the bark of Quercus tinctoria, and is 
applied as a yellow dye under the name Qwzercitrone. It consists of yellow 
needles or leaflets, which are decomposed into isodulcitol and Quercitin, 
C,H, .0;, + 3H,0. The latter forms an hexa-ethyl and octo-acetyl derivative 
(Berichte, 17, 1680). Fused with alkalies it yields quercitinic acid, C1 5H 100, 
protocatechuic acid and phloroglucin. 

Saponin, C,,H,,O,,, in the roots of Saponaria officinalis, is a white amor- 
phous powder, provoking sneezing, and in aqueous solution forms a strong lather. 
Its decomposition products are glucose and sapogenin, C,,H,,O,. 


Glucosides whose decomposition products belong to the fatty series are :— 


Convolvulin, C,,H,,0,,, derived from the roots of Jalap (from Convolvulus 
éurga). It is a gummy mass, and is a strong purgative. It dissolves in alkalies 
to pgec ene Acid, 2 ate (?), which nitric acid converts into Ipomic 
Acid, C,,H,,0, = C,H,,(CO,H 

Jalapin, Msg ee from Convolvulus orizabensis, is very similar to con- 
volvulin, and forms analogous derivatives. 

Myronic Acid, C,,H,,NS,Oj9, occurs as potassium salt in the seeds of black 
mustard. This crystallizes from water in bright needles. On boiling it with 
baryta water, or by the action of the ferment myrosin, present in the seed, the salt 
decomposes into glucose, allyl mustard oil, and primary potassium sulphate : — 


CigH,sK NSO.) = C,H,,0, + C,H,.N:CS + SO,KH. 





BITTER PRINCIPLES. 


Under the head of *‘ bitter principles,’’ or indifferent substances, 
is embraced a class of vegetable bodies whose chemical character is 
but indistinctly indicated. Many of them have already found their 
place in the chemical system. ‘Those yet uninvestigated are :— 


Aloin, C,,H,,0,, found in aloes, the dried sap of many plants of the aloe 
variety. It forms fine needles, Lo a very bitter taste, and acts as a strong 


TOIO ORGANIC CHEMISTRY. 


purgative. If digested with nitric acid it yields aloetic acid, C,,H,(NO,),0,, 
and chrysammic acid (p. 900). It forms a/orcinic acid, C,H,)O, + H,O, when 
fused ‘with caustic potash. This breaks down into orcin and acetic acid. 

Cantharidin, C,,H,,O,, contained in Spanish flies and other insects, crystal- 
lizes in prisms or leaflets, melts at 218°, and sublimes readily. It tastes very bitter 
and produces blisters on the skin. It dissolves when heated with alkalies and 
forms salts of cantharinic acid, CyyQH,,O, = C,H,,0,.CO.CO,H. Hydriodic 
acid converts cantharidin into cantharic acid, C\gH,,0, = C,H,,0.CO.CO,H, 
isomeric with it. 

Picrotoxin, C,,H,,O, + H,O, is found in the grains of cockle, and crys- 
tallizes in fine needles, melting at 201°. It has an extremely bitter taste and is very 
poisonous. 

Santonin, C,,H,,O,, is the active principle of worm-seed, crystallizes in 
shining prisms, and melts at 170°. It dissolves in alkalies to salts of Santonic 
Acid, C,,H,,0,4, which breaks down at 120° into water and santonin. On boil- 
ing with baryta water we have formed salts of isomeric santoic acid, C,,H,,.O,, 
which melts at 171°. Santonin, therefore, bears the same relation to these two 
acids as coumarin to coumarinic and coumaric acids, When santonin is boiled 
with hydriodic acid a- and B-meta santonin, santonid and para santonid (Canni- 
zaro, Berichte, 18, 2746; 22, Ref. 732),—compounds isomeric with santonin—are 
produced. 





The following are unstudied coloring matters; some of them ap- 
pear to have a constitution analogous to the phthaleins (p. 881) :— 


Brasilin, C,,H,,O;, is found in Brazil-wood and red wood; crystallizes in 
white, shining needles, and dissolves in alkalies with a carmine-red color on ex- 
posure to the air. Acids then precipitate dvasz/in, C,,H,,O, + H,O, from the 
solution. The action of iodine upon brasilein also produces this compound. It 
regenerates brasilin by reduction. | When distilled it yields resorcinol (Berichie, 
23, 1428). 

ood te C,,H,,O,, occurs in safflower, the blossoms of Carthamus tinc- 
torium, and is precipitated from its soda solution by acetic acid, as a dark red 
powder, which, on drying, acquires a metallic lustre. It dissolves with a beautiful 
red color in alcohol and the alkalies. It yields para-oxybenzoic acid with caustic 
potash. 

Curcumin, C,,H,,0,, the coloring matter of turmeric, crystallizes in orange- 
yellow prisms, melts at 177°, and dissolves in the alkalies to brownish-red salts. 
Ethyl vanillic acid is obtained on oxidizing diethyl-curcumin with potassium 
permanganate. 

Euxanthinic Acid, C,,H,,O,, (Porrisic acid), occurs as magnesium salt in so- 
called purrée (jaune indien), a yellow coloring matter from India and China, 
(Annalen, 254, 265). It crystallizes from alcohol in yellow prisms with one 
molecule of water.. When boiled with dilute sulphuric acid it splits up into gly- 
curonic acid and euxanthone, C,,H,O, (p. 860). 

Hematoxylin, C,,H,,O,, the coloring matter of logwood (Hzmatoxylon 
Campechianum), is very soluble in water and alcohol, and crystallizes in yellowish 
prisms with 3H,O, It dissolves in alkalies with a violet-blue color. When dis- 
tilled or fused with potassium hydroxide, pyrogallic acid and resorcinol result from 
it. If the ammonium hydroxide solution be allowed to stand exposed to the air 
there results hematein-ammonia, C,,H,,(NH,)O,, from which acetic acid 


BILIARY SUBSTANCES. IOIt 


liberates Heematein, C,,H,,O,, a red-brown powder with metallic lustre, when 
dried, 

Gentisin, C,,H,,O;, contained in the Gentian root, crystallizes in yellow 
needles, and fused with caustic potash yields hydroquinone carboxylic acid (p. 778) 
and phloroglucin. 

Carminic Acid, C,,H,,0,), occurs in the buds of certain plants, and espe- 
cially in cochineal, an insect inhabiting different varieties of cactus. It is an 
amorphous purple-red mass, very readily soluble in water and alcohol, and yields 
red salts with the alkalies. When boiled with dilute sulphuric acid it splits into a 
non-fermentable sugar and carmine-red, C,,H,,0,. When distilled with zinc 
dust it yields the hydrocarbon, C,,H,,. On boiling carminic acid with nitric acid 
we get nitrococcic acid. 

Chlorophyll occurs in the chlorophyll granules in all the green parts of plants. 
Wax and other substances are associated with it. We do not yet know its consti- 
tution. There seems to be an essential quantity of iron in it. 





The following are animal substances the more extended discus- 
sion of which belongs to the province of physiological chemistry. 


BILIARY SUBSTANCES. 


In the bile, the liquid secretion of the liver, essential to the 
digestion of fats, occur (in addition to fats, mucous substances and 
albuminoids) the sodium salts of two peculiar acids, glycocholic 
and taurocholic; also cholesterine and bile pigments (bili- 
rubin, biliverdin). 


Cholesterine, C,,H,,O(C,,H,,O) (Berichte, 21, Ref. 657), occurs in not only 
the bile, but in the blood, in the brain, and in the yolk of eggs, also in the seed 
and sprouts of many plants, in which it is often confounded with the fats. It is 
soluble in alcohol and ether, crystallizes in mother-of-pearl leaflets, containing 
1H,O, and possessing a fatty feel. It parts with its water of crystallization at 
100°, melts at 145°, and distils at 360° with scarcely any decomposition. If sul- 
phuric acid be added to the chloroform solution of cholesterine, the chloroform 
acquires a purple-red color, and on evaporation assumes a blue, then green, and 
finally a violet coloration. Chemically cholesterine behaves like a monovalent 
alcohol, and forms esters with acids. 

Isocholesterine, C,,H,,0, an isomeric body, occurs associated with choles- 
terine in distilled sheeps’ fat, melts at 138°, and does not give any color reactions 
with chloroform and sulphuric acid. Phytosterine, present in plant seeds and 
sprouts, is very similar to cholesterine, and is frequently confounded with the fats. 

Lanoline, obtained from raw sheeps’ wool, contains esters of cholesterine and 
isocholesterine with the higher fatty acids. It is applied as a salve, as it will take 
up water and is absorbed by the skin. 

Glycocholic Acid, C,,H,,NO,, separated in crystalline form from its 
sodium salt (found in bile) by dilute sulphuric acid, is sparingly soluble in water. It 
crystallizes in minute needles, melting at 133°. On adding a sugar solution and 
concentrated sulphuric acid or phosphoric acid to glycocholic acid we obtain a 


Io0i2 ORGANIC CHEMISTRY. 


purple-red color. Boiled with alkalies it decomposes into glycocoll and cholic 
acid. 

Taurocholic Acid, C,,H,,NOS,, is very soluble in water and alcohol, crys- 
tallizes in fine needles, and when boiled with water breaks up into cholic acid and 
taurine. For the separation of glycocholic acid and taurocholic acid from bile see 
Journ. pract. Chem., 19; 305. 

Cholic Acid, Cholalic Acid, C,,H,,0; (Berichte, 19, 2009; 20, 1968) or 
C,,H,,0, (Berichte, 20, 1052), from glyco- and taurocholic acids, crystallizes 
from hot water in small anhydrous prisms, which dissolve with difficulty in water, 
and when anhydrous melt at 195°. It reacts the same as glycocholic acid with 
sugar and sulphuric acid. It is monobasic; its esters are crystalline. It forms a 
blue compound with iodine, quite similar to that given by starch and iodine 
( Berichte, 20, 683). 





GELATINOUS TISSUES AND GELATINES. 


These are mostly nitrogenous, organized substances, which on 
boiling with water are converted into gelatines and are distinguished 
as collagenes and chondrogenes. ‘The former constitute bone cartilage 
and sinews, the connective tissues, the skin and fish-bladder, and 
afford the ordinary true gelatines ; the latter contained in the un- 
hardened cartilage, yield chondrin. As regards composition, both 
are very similar to the albuminoids, but differ from the latter. 
mainly in that they are not precipitated by nitric acid and potas- 
sium ferrocyanide. 


Glutin, gelatine, is precipitated from its aqueous solution by alcohol, and when 
pure is a colorless, solid mass, without odor and taste. In cold water it swells 
up, and on boiling dissolves to a thin solution, which gelatinizes on cooling. By 
the addition of concentrated acetic acid or protracted boiling with a little nitric 
acid, the solution loses the property of gelatinizing (liquid gelatin). Tannic acid 
precipitates from the aqueous solution gelatine tannate, a yellowish, glutinous 
precipitate. The substances yielding gelatine combine also with tannic acid, 
withdrawing the latter completely from its solutions and forming leather. 

Glycocoll and leucine are the principal substances produced on boiling gelatine 
with sulphuric acid or alkalies. Dry distillation produces bases of the fatty and 
pyridine series . 

Alcoholic hydrochloric acid changes gelatine into a compound that nitrous acid 
converts into a substance, C; H,N.O,, very similar to the diazo fatty-acids. It 
may be that it represents diazo-oxyacrylic ester, CN,:C(OH).CO,.C,H, (Ze- 
richte, 19, 850). 

Chondrin, from bone cartilage, is very similar to the preceding, and is distin- 
guished from it by the fact that it is precipitated from its aqueous solution by . 
alum, lead. acetate, and most metallic salts; on the other hand, it is not precipi- 
tated by mercuric chloride, whereas it is otherwise with glutin. It affords leucine 
and not glycocoll if boiled with dilute sulphuric acid. Chitine belongs to the 
class of substances present in bone cartilage. It is the chief component of the 

shells of crabs, lobsters, etc. Boiling acids convert it into glucosamine, 


} C,H; sNO; (Pp. 505). 








: ————— 


ADBUMINOID SUBSTANCES, ALBUMINATES. 1ol3 


ALBUMINOID SUBSTANCES, ALBUMINATES. 


These were formerly known as protein substances, and form 
the principal constituents of the animal organism. They also occur 
in plants (chiefly in the seeds), in which they‘are produced exclu- 
sively. When absorbed into the animal organism as nutritive 
matter they sustain but very slight alteration in the process of 
assimilation. 

They exhibit great conformity in their properties and especially 
in their composition, as seen from the following percentage numbers 
of the three most important varieties of albumen :— 


Albumen. Fibrin. Casein, 
C 53.5 per cent. 52.7 per cent. 53.8 per cent. 
H 7.0 “c &<c 6.9 “ ‘“é 7.2 6s 6“ 
N 15-5 “c “ 15 4 “c “6 15.6 “c “ 
O 22:4 “c “c 23.8 “ “ 22.5 “c 73 
S 1.9 “cc ‘sé I.2 * “ 0.9 73 “é 


Owing to indistinct chemical character and great power of 
reaction, no accurate molecular formulas have been deduced for 
the albuminoids up to the present. The formula of Lieberkiihn, 
C,.Hy,,SN,,0.., affords an approximate representation. Loew thinks 
this should be trebled (Berichte, 23, 43; 22, 3046). 

The decomposition products of the albuminoids give us an idea 
as to their constitution. These they yield when boiled with dilute 
sulphuric or hydrochloric acid, or with baryta water. 

The decomposition products are mainly amido-acids-of the fatty — 
series: glycocoll, leucine, leuceines, C,H;,,O, (unsaturated gly- 
cines), aspartic and glutaminic acids, C;H,NO, (p. 467), as well as 
phenylamidopropionic acid, tyrosine, etc. All albuminoids yield 
the same products, only in relatively different amounts, therefore 
they must be assumed to form from the union of these constituents 
(See Berichte, 18, Ref. 444; 19, Ref. 30, 697). 


Putrefaction causes a similar decomposition, but in addition to amido-acids fatty 
acids and aromatic acids, as well as phenols, indol, skatole and skatole-acetic acid 
are produced (Berichte, 22, Ref. 702). Basic compounds. also result in this de- 
composition. ‘These are the diamines and imines of the paraffin series, and have 
been called Atomaines or toxines (p. 316). ; 

Certain pathogenic micro-organisms, as diphtheria and anthrax bacilli, produce a 
decomposition that is far more extended, and results in the formation of poisonous, 
substances somewhat similar to albumen and peptone, which have been termed 
toxalbumens ; these lose their toxic properties when their aqueous solutions are 
heated (Berichte, 23, Ref. 351). 

Tuberculin is a member of this series. It is the active substance that has been 
extracted by means of aqueous glycerol from tubercular bacilli cultures. The 
percentage content of its solution is not known, its composition is unknown, its 
injurious action has never been determined and yet it has, very recently, been sug- 
gested as a curative for tuberculosis. 











1014 ORGANIC CHEMISTRY. 


Most albuminoids exist in two modifications, one soluble the 
other zzsoluble in water. Alcohol, ether, tannic acid, many mine- 
ral acids and metallic salts reprecipitate them from their aqueous 
solutions. In their coagulated condition they are dry, white, amor- 
phous masses. Most of them dissolve in dilute mineral acids, all, 
however, in concentrated acetic acid and in phosphoric acid on 
application of heat. Ferro- and ferri-cyanide of potassium precipi- 
tate them from their dilute acetic acid solution. They dissolve in 
dilute alkalies, with the separation of sulphur in form of sulphide. 
The substances reprecipitated by dilute acetic acid are very similar 
to the albuminoids employed. 


Reactions.—All albuminoids are colored a violet red on warming with a mer- 
curic nitrate solution containing a little nitrous acid (this is like tyrosine). On 
the addition of sugar and concentrated sulphuric acid they acquire a red colora- 
tion, which on exposure to the air becomes dark violet. If concentrated sul- 
phuric acid be added to the acetic acid solution of albuminoids they receive a 
violet coloration and show a characteristic absorption band in the spectrum. 

Gastric juice, pepsine and dilute hydrochloric acid, and various other ferments 
dissolve the albuminoids at 30-40°, converting them first into anti- and hemi albu. 
minoses, which later become so- called peptones. These dissolve readily in water, 
are not coagulated by heat and are not precipitated by most of the reagents (Be- 
richte, 16, 1152; 17, Ref. 79). 


The manner of distinguishing and classifying the various albumi- 
noids is yet very uncertain. According to the manner in which 
they pass from the soluble into the insoluble state we distinguish 
three principal groups of albuminoids; the a/dumins, fibrins and 
caseins. ‘The first are soluble in pure water, coagulate when heated 
alone or after acidulation with a few drops of nitric acid, and are 
then no longer soluble in dilute potassium hydroxide or acetic acid. 
The fibrins coagulate immediately after their exit from the animal 
organism. ‘The caseins (legumins) are almost insoluble in water, 
dissolve, however, very readily in dilute alkalies and alkaline phos- 
phates, and are again precipitated from these solutions on acidulating 
them. 


1. The albumins exist in the following varieties :— 


Egg Albumin is obtained by precipitating its aqueous solution with basic lead 
acetate, decomposing the precipitate with carbon dioxide and hydrogen sulphide 
and then reducing the filtrate at a temperature below 60°. It is a yellowish, 
gummy mass, which swells up in water and then dissolves. The perfectly neutral 
solution coagulates at 72~—73°; it is levo-rotatory and is precipitated by alcohol, 
by shaking with ether and by dilute acids. 

Serum Albumin occurs in the blood, in the lymph and in the various secre- 
tions. It is obtained from the blood serum diluted with water (subsequent to the 
removal of other albuminoids by a little acetic acid) in the same manner as egg 
albumin. It resembles the latter, but is not precipitated by dilute mineral acids. 

Vegetable Albumin occurs in almost all vegetable juices. It coagulates on 


—e 
ALBUMINOID SUBSTANCES, ALBUMINATES. IOr5 


warming and is very similar to egg fibrin. Vite//in, contained dissolved in the 
yellow of the egg, appears to bea mixture of albumin and casein, 


2. Fibrins. 


Blood fibrin separates from the blood after the latter has been discharged from 
the organism, It seems that it does not exist already formed in the blood, but 
that it results by the union of the so-called fidrinop/astic (contained in the serum) 
and fibrinogen (in the blood corpuscles) széstances. Fibrin is obtained by whip- 
ping the fresh blood, when it separates in long fibres, which are freed from blood 
corpuscles by long-continued kneading under water. It is a whitish, sticky, 
fibrinous mass, which becomes hard and brittle upon drying. It is insoluble in 
water, dilute hydrochloric acid and a solution of common salt. . 

_ Myosin constitutes (with water) the chief constituent of the muscles, in which 
it seems to exist in a dissolved state. It is obtained by dissolving the well washed 
muscles in a moderately dilute sodium chloride solution and precipitating the 
filtrate with salt. Vegetable fibrin occurs in an undissolved state in the grain 
granules, On kneading flour (stirred to a paste) under water, the starch granules 
are washed out, together with the soluble albumin, and there remains a pasty mass 
called gluten, which, according to Ritthausen, consists of g/icidin (vegetable 
gelatine), mucedin and gluten fibrin, The latter is soluble in dilute alcohol and 
acids. When seeds sprout the vegetable fibrin is converted into the soluble fer- 
ment called diastase (Berichte, 23, Ref. 210). The other unformed ferments 
(p. 508) appear also to be modified albuminoids. 


2. Caseins. 


Milk casein occurs dissolved in the milk of all mammalia, and on the addition 
of hydrochloric acid separates as a flocculent precipitate, which is washed out 
with water, alcohol and ether (for the removal of the fats). Pure casein is not 
soluble in pure water, but in water containing a little hydrochloric acid or 
alkali. When the solutions are neutralized it is reprecipitated. The solutions do 
not coagulate until heated to 130-140°. If a few drops of hydrochloric acid or 
rennet be added to milk all the casein will be co-precipitated with the fat globules 
(cheese); in the solution (whey) remain milk, sugar, lactic acid and salts. 

Vegetable Casein, or Legumin, occurs chiefly in the seeds of leguminous plants, 
and is perfectly similar to casein. It is precipitated from the pressed out juice by 
acids or rennet. 





In concluding the albuminates mention may be made of the Aemoglobins and 
lecithin. 

The oxyhemoglobins are found in the arterial blood of animals and may be ob- 
tained in crystalline form from the blood corpuscles by treatment with a solution 
of sodium chloride and ether, and the addition of alcohol. The different oxy- 
hemoglobins, isolated from the blood of various animals, exhibit some variations, 
especially in crystalline form. They are bright red, crystalline powders, very 
soluble in cold water, and are precipitated in crystalline form by alcohol. When 
the aqueous solution of oxyhzmoglobin is placed under the air pump or through 
the agency of reducing agents (ammonium sulphide) it parts with oxygen and be- 
comes hemoglobin. The latter is also present in venous blood and may be sepa- 
rated out ina crystalline form (erichte, 19, 128). Its aqueous solution absorbs 
oyxgen very rapidly from the air, and reverts again to oxyhzmoglobin. Both 
bodies in aqueous solution exhibit characteristic absorption spectra, whereby they 
may be easily distinguished. 


1016 ORGANIC CHEMISTRY. 


If carbon monoxide be conducted into the oxy-hemoglobin solution, oxygen is 
also displaced and hzmoglobin-carbon monoxide formed. This can be obtained 
in large crystals with a bluish color, This explains the poisonous action of carbon 
monoxide. ‘The bluish-red solution of hemoglobin-carbon monoxide shows two 
characteristic absorption spectra. These do not disappear upon the addition of 

ammonium sulphide (distinction from*oxy-hemoglobin). 
On heating to 70°, or through the action of acids or alkalies, oxyhamoglobin 
is split up into albuminoids, fatty acids and the pigment Aemasin, which in a dry 
condition is a dark brown powder. It contains 9 per cent. iron, and, as it appears, 
corresponds to the formula, C,,H,,FeN,O,. 

The addition of a drop of glacial acetic acid and very little salt to oxyhzemo- 
globin (or dried blood) aided by heat, produces microscopic reddish-brown crys- 
tals of hzemin (hematin hydrochloride) (Berichte, 18, Ref. 232); alkalies separate 
hematin again from it. The production of these crystals serves as a delicate 
reaction for the detection of blood. 





Lecithin, C,,.H,,NPO, (Protagon), is widely distributed in the animal organ- 
ism and occurs especially in the brain, in the nerves, the blood corpuscles, anc 
the yellow of egg, from which it is most easily prepared. It is a wax-like mass, 
easily soluble in alcohol and ether, and crystallizes in fine needles. It swells up 
in water and forms an opalescent solution, from which it is reprecipitated by various 
salts. It unites with bases and acids to salts, forming a sparingly soluble double 
salt, (C,,H,,NPO,.HCl),.PtCl,, with platinic chloride. Lecithin decomposes 
into choline, glycerol-phosphoric acid (p. 454), stearic acid and palmitic acid, 
when it is boiled with acids or baryta water. Therefore we assume it to be an 
ethereal:compound of choline with glycero-phosphoric acid, combined as glyceride 
with stearic and palmitic acids :— 


/ O.C, ,H3;0 
C,H,;—O.C,,H,,0 (CH,) 


Vv 
\.0.PO(OH).0.CH, CH, \ N.OH = lecithin, 








A 


Abietic acid, 1008 
Absinthol, 1006 
Acediamine, 294 
Acenaphthene, 909 
Acetal, 305 
Acetaldehyde, 193 
Acetamide, 259 
Acetanilide, 607 
Acetic acid, 219 
anhydride, 249 
esters, 254 
Aceto-acetic acid, 334 
ester, 338 
benzoic acids, 764 
butyric acid, 344 
chlorhydrose, 504 
imido-ether, 292 
lactic acid, 358 
malonic acid, 342, 435 
propionic acid, 340 
succinic acid, 436 
thiénone, 534 
Acetol, 321 
Acetone, 203 
bases, 208 
chloride, 1o1 
chloroform, 202 
dicarboxylic acid, 435 
homologues, 209, 210 
Acetonic acid, 363 
Acetonitrile, 283 
Acetonyl acetone, 328 
urea, 293 
Acetophenone, 341, 727 
acetone, 731 
alcohol, 712 oe 
carboxylic acid, 764 
chloride, 728 
Acetoxime, 205 
Acetoximes, 202 


85 


INDEX. 


Acetoximic acids, 203, 207, 325 
Aceturic acid, 371 
Acetyl acetone, 327 
aldehyde, 323 
bromide, 247 
carbinol, 321 
carboxylic acid, 332 
chloride, 247 
cyanide, 248 
Ss iodide, 247 
oxide, 247 
peroxide, 250 
sulphide, 251 
Acetylene, 86, 88 
bromide, 89 
chloride, 88 - 
di-chloride, 90 
iodide, 89 
dicarboxylic acid, 431 
naphthalene, 910 
series, 88 
tetracarboxylic acid, 481 
. urea, 440 
Acid amides, 255, 365, 214 
anhydrides, 213, 248 
chlorides, 246 ~ é 
cyanides, 247 
haloids, 246 
yellow, 648 
Acidoximes, 292, 735 
Aconic acid, 470 
Aconitic acid, 472 
Acridic acid, 973 
Acridines, 603, 981 
Acrite, 506 
Acrolein, 199 
Acrylaldehyde = acrolein 
Acrylic acid, 233, 236 
derivatives, 237 
Adenine, 449 
Adipic acid, 418 
Esculetin, 822 


IO17 























Ibuminates, 1013 

'. Alcarsine, 173 

Aleoholates, 126 

hols, 112, 124, 708 
ambien 351 

formation of, 119, 120, 121 
primary, 117 

__ Secondary, 118 
_. tertiary, 118 ae 
P de, 186, 187, 714 -s* ** 
sids, 329, 761 ‘ 
alcohols, 320 
ammonia, 189, 193 
green, 868, 874 
ketones, 730 » 
phenols, 715 
bs nae 628, 18 943 


19 7 
aliphatic = ac. al. 912 
ae 








INDEX. ; 


ay 52d 





Allylene, isomeric, 89 _ 


Allylin, 457 
Aloes, 1009 


-Aloin, 1009 


Aloetic acid, 1010 
Alorcinic acid, 1010 
Alphatoluic acid, 753 
Aluminium methyl, 182 
ethyl, 182 
Amalic acid, 444 5 
Amarine, 935 
Amber, 1008 
Amethyst, 990 
Amic acids, 365, 402 
Amide chlorides, 258 
Amides, 255, 366 
Amidines, 258, 293, 620 
Amido-azobenzene, 647 
acetic acid, 369 
acids, 365 
compounds, 591 
dicyanic acid, 290 
formic acid, 382 
glutaric acid, 467 
‘_. phenols, 679 
phenyl-glyoxylic acid, 762 
thiophenols, 681 
Amidoximes, 294, 736 
Amines, 157, 31I 
primary, 162 
secondary, 163 
tertiary, 164. 
Ammelide, 290 — 
Ammeline, 290 
Ammon-chelidonic acid, 948 
-Ammonium bases, 165 
Amygdalin, 717 
Amygdalic acid, 717 
Amy] alcohols, 129 
-. lehydes, 198 
1 zene, 578 


Mmnyleues, 84° 


- Amylum, 512 _ 

- Anethol, 803 

Angelic ‘acid, 240 

_ Anhydrides, ‘of mer 248, 315 
Anhydridic acids, 3 

Anhydro bases, 6 

sn lepd Gace, 953 997 
Anilides, 599, 606 

Anilido acids, 608 


Aniline, 595 


black, 991 
_ blue, 874 


Aniline homologues, 623 


* INDEX. 


substitution products, 506, 597, 


598, 599 
yellow, 648 
Anilpyroracemic acid, 609 
Aniluvitonic acid, 972 
Anisic aldehyde, 724 
acid, 770 
Anisil, 889 
Anisoin, 887 
Anisol, 671 
Anisyl alcohol, 714 
Anol, 803 
Anthracene, 892, 893, 894 
alkylic, goo, 901 
hydrides, 895 
Anthrachrysone, 900 
Anthraflavie acid, 900 
Anthramine, 895 
Anthranil, 749 
Anthranilic acid, 748 
Anthranol, 895 
Anthrapurpurin, 900 
Anthraquinone, 896 
Anthraquinoline, 975 
Anthrarufin, 900 
Anthrol, 895 
Anthroxan aldehyde, 837 
Anthroxanic acid, 837 
Antimony bases, 174 
Antipyrine, 930 
Antitartaric acid, 479 
Apiol, 804 ; 
Apione, 697 
Apocinchene, 995 
Apopyllenic acid, 948 
Apoquinene, 995 
Aposorbic acid, 485 
Arabonic acid, 484 
Arachidic acid, 233 
Arabite, 483, 513 
Arabinose, 483 
Arbutin, 1009 
Archil, 781 
Aromatic acids, 737 
bases, 69 
Arsenic esters, 156 
Arsines, 170 
Arsonium compounds, 171 
Asarone, 804 
Asparagine, 466 
Aspartic acid, 466 ~ 
Asphaltum, 77 
Atroglyceric acid, 782 


- 





Atrolactonic acidjye775. 
Atropic acid, 813 
Atropine, 996 
Atroxindol, 759 
Aurantia, 603 
Aurines, 876, 878 
Australene, 999 
Azelaic acid, 423 
Azines, 953 
Azimidobenzene, 626 
compounds, 626 
Azo-amido bases, 650 
benzene, 646 
benzoic acids, 750 
blue, 846 
coloring substances, 650 
_ compounds, 634 
diphenyl blue, g90 
diphenylene, 986 
dyes, 651. 
imide, 640 
phenols, 647 
phenyl blue, 990 
toluenes, 649 
triple bases, 645 
Azole compounds, 551 
imide, 551, 552 
Azoximes, 737 
Azoxybenzene, 645 
Azulinic acid, 265 
Azylines, 648 


a 


Balsams, 1008 
Barbituric acid, 441 
Bassorin, 513 
Behenic acid, 215 


~Behenolic acid, 245 


Behenoxylic acid, 245 
Belladonine, 996 
Benzal = benzylidene. 
chloride, 584 
malonic acid, 823 
violet, 867 
Benzaldehyde, 716 
amides, 717 
amido-, 720 
meta-, 720 
ortho-, 720 
para, 723 
substitution products, 719 
Benzaldoxime, 718 








Sy Seas Se 


1020 INDEX. ° 


Benzamide, 743 


Benzamine, 710 
Benzamidine, 736 
Benzam oxalic acid, 749 
Benzanilide, 744 ; 


4 Benzaurine, 877 \ 
‘Benzazole compounds, 841 


Benzazurine, 846 
Benzeines, 876 
Benzene, 571 
_ additive products, 567 
~ amido-compounds, 591 
azomethane, 652 
derivatives, 556 
formation of, 565 
diazimide, 639 
disulphoxide, 662 
haloids, 579, 581, 582, 583 
homologues, 557 
hydrides, 571 
hydrocarbons, 568 
isomerides, 559 
Benzene-nitro, 586, 587, 589 
nitroso, 591 
nucleus, 563, 564 
phenols, 557 
sulphonic acid, 661 


: Benzenyl amidines, 735 


amidoximes, 735, 737 

azoxime, 737 
Benzhydrazoine, 650 
Benzhydril-benzoic acid, 863 
Benzhydrol, 857 
Benzhydroxamic acid, 746 
Benzhydroximice acid, 737 


Benzidine, 650, 844 


dyes, 845 
Benzil, 888 
oximes, 888 
Benzilic acid, 862 
Benzimido ethers, 735 
Benzoglyoxalines, 841, 842 
Benzoic acid, 742 
homologues, 753 
substitution products, 746, 747, 
748 
sulphinide, 752 


 Benzoin, 887 


Benzo-nitrile, 733 
Benzo-phenone, 858 
phenoxime, 858 
Benzopyrazole, 841 
Benzoquinone, 704 
Benzoquinolines, 969 








Benzothiazole, 681, 842 
Benzotriazines, 957 
Benzoxazines, 981 
Benzoxazole, 679, 680, 842 
Benzoximido ethers, 736 


Benzoyl acetic acid;*763 


aceto-acetic ester, 763 
carboxylic acid, 764 

acetone, 731 

acetyl, 731 

acrylic acid, 816 

aldehyde, 730 

azimide, 640 “ 

benzoic acids, 863 of 

carbinol, 712 

chloride, 743 

cyanide, 743 

formic acid, 762 

glycollic acid, 745 

hydrazine, 745 

phenols, 860 

propionic acid, 764 


Benzoylene urea, 978 


-Benzpinacone, 889 


Ps =h sans acetone, 730 


alcohol, 709 
amines, 710 
anilines, 711 
_ benzoic acid, 863 
chloride, 584 
cyanide, 734 
glycollic acid 776 
hydroxylamines, 7 FI 
malonic acid, 791 
mercaptan, 710 
- methyl ketone, 779 
sulphide, 710 
sulphydrate, 710 
toluene, 862 
Benzylidene aceto-acetic ester, 816 
acetone, 805 
aniline,-718 
hydrazine, 718 
malonic acid, 823 
Berberine, 949 
Berberonic acid, 949 
Beryllium ethide, 179 
Betaine, 316 
Betaorcinol, 694 
Biazolons, 936 
Bidesyl, 892 
Bieberich scarlets, 651 
Biliary substances, IOI 
Bilineurine — choline 


Bilirubin, 1ort 
Biliverdin, 1011 
Lioses, 507 
Bisdiazo-compounds, 639 
Bismuth ethide, 185 
Bitter almond oil, 746. 
principles, 1009 
Biuret, 393 
Boric esters, 155 
Borneol, 1006 
Bornylamine, 1005 
Boron compounds, 175 
Brasilin, 1010 
Brassylic acid, 423 
Brilliant green, 868, 869 
Bromal, 196 
Bromanil, 701 
Bromoform, 103 
3romopicrin, 113 
Brucine, 995 
Butanes, 74 
chlorides, 94 
nitro-, 108 
Butyl alcohols, 128 
amine, 163 
chloral, 197 
Butylene, 84 
glycols, 309 
Butyraldehydes, 197 
Butyramide, 259 
Butyric anhydride, 249 
acids, 226, 227 
esters, 254 


Butyro-carboxylic acid, 348 


Butyrolactone, 362 
Butyrone, 210 
Butyronitrile, 284 
Butyryl chloride, 247 
cyanide, 248 


C. 


Cacodylic acid, 173 
compounds, 172 
Cadaverine, 313, 316 
Caffeic acid, 821 
Caffeine, 449 
Caffuric acid, 450 
Camphene, 1001 


Camphol — borneol, 1006 


Campholic acid, 1007 





INDEX. 1o21 


Camphor, 1004 
Camphoraldehyde, 1005 
Camphoric acid, 1007 / 
Camphoronic acid, 1007 
Camphoroxime, 1005 
chlorides, 1005 Ff 
Camphylamine, 1005 ’ 
Campo-bello yellow, 916 
Cane sugar, 508 
Cantharidin, 1o1o 
Caoutchouc, 1008 
Capric acid, 231 ; 
r aldehyde, 198 : te 
Caproic acid, 229 
Caprolactone, 364 
Caprone, 210 
Caproyl alcohols, 132 
Capryl alcohol, see Octyl alcohols 
Caprylic acid, 230 
Caprylone, 210 
Caramel, 509 
Carbamic acid, 382 
Carbamides, 386 
Carbanile, 612 
Carbanilamide, 612 
Carbanilic acids 612 
Carbanilide, 611 
Carbazol, 847 
Carbdiamide-imide, 294 
Carbimide, 384 
Carbinol, 130 


Carbizines, phenyl, 935 


Carbodiimide, 288 
Carbodiphenylimide, 620 
Carbohydrates, 497 





- Carbon disulphide, 379 


- oxysulphide, 378 

tetrachloride, wag 10 f 
Carbonic acid, 353, 375 
Carbony! amidophenol, 680. 

chloride, 375 

diacetic acid, 959 

diurea, 394 
Carbopyrotritartaric acid, 528 
Carbopyrrolic acid, 546 
Carbostyril, 755, 968 

carboxylic acid, 973 
Carbostyrilic acid, 745 
Carbothialdine, 385 
Carboxyl, 211 
Carboxy-tartronic acid, 480 
Carbylamines, 287 
Carbyl sulphate, 319 
Carmine, 1011 





pe 
> 
¥ 


1022 


Carminic acid, 1o1l 
Carnine, 449 
Carthamine, 1010 
Carvacrol, 687 
Carvene, IOoI 
Carvol, 688 
Caryophyllin, 1006 
Casein, 1015 
Cassia oil, 805 
Catechin, 780, 785 
Catechu tannin, 785 
Cedriret, 848 
Cellulose, 514 
nitro, 514 
Ceresine, 78 
Cerotene, 86 
Cerotin, 134 
Cerotic acid, 233 
Ceryl alcohol, 134 
Cetene, 86 
Cetyl acetic acid, 233 
alcohol, 133 
malonic acid, 423 
Cevadine, 998 
Chavibetol, 803 
Chavicol, 803 


-Chelidamic acid, 948 


Chelidonic acid, 958 
Chitine, 1012 


- Chloracetol, ror 


i 


methyl, Loz. 
Chloral, 196 > 
Chloralides, 360 
Chloranil, 701 
Chloranilic acid, 701 
Chlorbenzil, 889 
Chlorcarbonic acid, 376 
Chlor-cyanogen, 267 
Chlor-ethyl benzenes, 586. 
Chlorhydrins, 300, 456 
Chlorformic acid, 219 
Chloric acid esters, 155 
Chlorimides, 258 
Chloroform, 102 
Chlorophyll, 1o11 
Chloropicrin, 113 
Chloroxalic ester, 406 
Chlorphenyl mustard oil, 682 
Cholesterine, roi 

iso-, IOII 
Cholestrophane, 439 
Cholalic acid, 1012 
Cholic acid, ro12. 
Choline, 315 


INDEX. 


Chondrin 1012 
Chromic acid mixture, 203, 738 
Chrysamine, 846 
Chrysammic acid, 900 
Chrysaniline, 983 
Chrysanisic acid, 750 
Chrysarobin, 901 
Chrysazin, 900 
Chrysazol, 896 
Chrysene, 928 
perhydride, 929 
Chrysoine, 651 
Chrysoidines, 643, 648 
Chrysoketone, 929 
Chrysolin, 883 
Chrysophanic acid, go1 
Chrysophenol, 983 
Chrysoquinone, 928 
Cinchene, 995 
Cinchomeronic acid, 948 
Cinchonidine, 994. 
Cinchonine, 994 
Cinchoninic acid, 972 
Cinene, 1002 
Cineols, 1006 
‘Cinnamein, 809 
Cinnamic acid, 808 
allo-, 813 
amido-, 811, 812 
brom-, 810 
chlor-, 809 
di-, 813 
9 hydro-, 812 
nitro-, 810, 811 
aldehyde, 805 
Cinnameny]l acrylic acid, 816 - 
Cinnamone, 806 
Cinnamy] alcohol, 804 
formic acid, 816 
Cinnoline, 976 
Citraconic acid, 429 
Citraconanile, 611 
Citramide, 481 
Citramalic acid, 468 
Citrene, IooI 
Citric acid, 480 
Cocaine, 996 
Cochineal, 1011 
Codeine, 992 
Coeroulignone, 848 
Coerulin, 883 
Collidine, 943 . 
dicarboxylic acid, 949 
| Collodion, 514 





Colophene, 1003 
Colophony, 1008 
Comanic acid, 958 


Comenamic acid, 959 
Comenic acid, 95 
Compound ureas, 3 


INDEX. 


Cuminoin, 887 

Cuminol—cumic aldehyde, 722 
Cumylic acid—durylic acid, 760 
Curara, 316 

Curcumin, 1010 

Cyammelide, 271 


Condensation, 88, 195, 208, 335; 566 Cyanalkines, 955 


Congo red, $46 
yellow, 847 
Conhydrine, 952 
Coniferine, 725 
Coniferyl alcohol, 725 
Conine, 952 
benzoyl, 952 
Convolvulin, 1009 
Conylene, 952 
Conyrine, 944 
Corindine, 937 
Cotarnic acid, 993 
Cotarnine, 993 
Cotarnine-hydro-, 993 
Coumalic acid, 958 
Coumaric acid, 818 
Coumarilic acid, 826 
Coumarin, $17, 819 
Coumarinic acid, 819 
Coumarone, 825 
Coumazone. compounds, 778 
Creasote, 669 
Creatine, 398 
Creatinine, 398 
Creosol, 693 
Cresols, 685 
Cresorcin, 693 
Cresotinic acids, 771 
Crocein, 651 
Croconic acid, 521, 703 
Croton aldehyde, 199 
Croton-chloral, 200 
Croton oil, 241 
Crotonic acid derivatives, 239 
Crotonic acids, 233, 238 
Crotonylene, 89 
Crotoyl alcohol, 135 
Cryptidine, 960 
Crystal violet, 875 
Cumene, 575 
Cumenol, 687 
Cumic acids, 760 
aldehyde, 722 
Cumidines, 624 
Cumin alcohol, 711 
oil, 688 
Cuminil, 889 


Cyanamines, 984 

Cyan-acetic acid, 262 
-amide, 288 

' -anilide, 620 

-benzoic acids, 752 
-carbonic acid, 295 
-chloride, 267 - 
-conine, 956 
-ethine, 956 
-etholins, 275 
-formic acid, 262 
-hydrin, 717 
-iodide, 268 
-methine, 956. 
-phenine, 734 
-propionic acid, 263 
-sulphide, 278 
-toluenes, 734 

Cyanic acid, 271 
esters, 273 

Cyanides, metallic, 269 

Cyanine, 966 

Cyanogen, 264 

Cyanuric acid, 272 

amide, 290 

esters, 275 

' Cymenes, 577 

Cystein, 360 

Cystin, 360 


Dahlia, 873 

Daphnetin, 822 
Daphnin, 823, 1008 
Daturin — atropin, 996 
Decane, 76 

Decyl alcohol, 133 
Decylenic acid, 242 
Dehydracetic acid, 337, 957 
Dehydrofichtelite, 927 
Dehydromucic acid, 528 
Desoxalic acid, 485 
Desoxybenzoin, 887 
Dextrine, 513 





1023 






1024 INDEX. 


Dextrose, 503 
Diacetamide, 259 


Diacetic acid. See Aceto-acetic acid. 


Diaceto-acetic ester, 437 
-succinic acid, 437 
_ -analogues, 438 
Diacetonamine, 208 
Diacetone alcohol, 208, 322 
Diacetyl, 326 
Diacetylene, 90 
-dimethy], 90 
-dicarboxylic acids, 432 
Dialdan, 321 
Dialdehydes, 324 
_ Diallyl, 89° 
-acetic acid, 245 
malonic acid, 430 
Dialuramide, 441 
Dialuric acid, 442 
Diamido-benzenes, 625, 648 
Diamido-toluenes, 626 
Diamidotriphenyl methanes, 867 
_ Diamines, 311 
Diamylene, $5 
Diastase, 508 
Diaterebic acid, 469 
Diaterpenylic acid, 470 
Diazimido compounds, 639 
Diazines, 953 
benzo-, 976 
Diazo-acetamide, 374 
acids, 373 
Diazoamidobenzene, 637 
Diazoamido- compounds, 631 
benzene nitrate, 636 
Diazobenzoic acids, 751 
Diazo-compounds, 629 
Dibenzoyl, 888 
acetic acid, 891 
s! methane, 891 
“> » succinic acid, So” 
» Dibenzyl, 884 
carboxylic acids, 889 
_ glycollic acid, 891 
~ Diearbon tetracarboxylic acid, 482 
Dichlorhydrins, 455 
Dicyanogen, 264 
Dicyanamide, 289 
Dicyandiamide, 289 
Dicyandiamidine, 289 
Diethyl, 74 
Digallic acid, 784 
Diglycolamidic acid, 371 
‘Diglycollic acid, 356 





Dihydrobenzene, 717 
Dihydropyrrol, 549 
Di-indogen, 833 
Diisatogen, 834 
Diketones, 325, 327 
Diketo-hexamethylene, 701 
Diketon-monocarboxylic ester, 341 
Dilactic acid, 359 
Dilituric acid, 441 
Dimethyl, 74 
Dimethyl-acrylic acid, 241 
aniline, 601 
fumaric acid, 430 
glyoxim, 207, 326 
-methylene chloride, 1o1 
-phenylene green, 708 
Dinicotinic acid, 948 
Dinitro aceto-nitrile, 286 
Dinitroparaffins, 111 
Dioxindol, 834 
Dioxybenzophenone, 860 
Dioxybutyric acid, 461 
Dioxymalonic acid, 475 
Dioxysuccinic acid, 475 
Dioxytartaric acid, 491 


_Dipentene, 1002 


Diphenacyl, 891 

Diphenic acid, 849 

Diphenine, 650 

Diphenols, 848 

Diphenyl, 843 
acetic acid, 861 
acetylene, 886 
amido-derivatives, S44, 845 
benzene, 852 
carbinol, 857 
carboxylic acids, 849 
di-carboxylic acids, 849, 850 
ethane, 861, 864 
ethylene, 861, 885 
glycollic acid, 862 
guanidine, 619 
imide, 847 
ketone, 858 
methane, 852, 856 

.  phthalide, 880 
succinic acid, 890 
thiohydantoin, 618 
thiurea, 616 
tolyl methanes, 866 
urea, 611 

Diphenylamine, 603 _ 
blue, 603 
dyes, 605 





Dipbensiend acetic acid, 851) 
derivatives, 850 
glycollic acid, 851 
ketone, 851 
carboxylic acids, 852 
oxide, 860 

oxide, 848 

methane, 847. 

Diphenylin, 845 

Diphenylol, 847 

Diphthalyl, 787, 890 
acid, 890 
dicarboxylic acids, 793, 794 

Dipicolinic acid, 948 

Dipiperidyls, 951 

Dipropargyl, 90 

Dipyridine, 942 

Dipyridyl, 942 
carboxylic acid, 950 

Disaccharides, 507 

Disazo-compounds, 645 

Disulphanilic acid, 665 

Disulphoxides, 154 

Dithiényl, 536 

Dithiocarbamic acid, 614 . 

Dithiocarbonic acid, 380 

Dithiourethanes, 385 

Ditolyl, 844 

Ditolylamine, 624 
ethane, 863 
ketone, 863 
methane, 863 

Ditolylin, 845 

Diureides, 736 

Duboisine, 996 

Dulcitol, 488 

Durenes, 576 

Durenol, 760 

Durylic acid, 760 

iso, 760 

Dynamite, 454 


Ecgonine, 997 
benzoyl, 997 
Elaidic acid, 243 
Ellagic acid, 783 
Emerald green, 686 
Emodin, gor 
Emulsin, 508 
Eosin, 883 
Epichlorhydrin, 456 


86 


INDEX. : 1025 





Epicyanhydrin, 456 
Epihydrin carboxylic ee 456 
Erucic acid, 243 
Erythrin, 781 
Erythrite, 474 
Erythritic acid, 474 
Erythro-oxyanthraquinone, 898. 
Esters, 137, 146, 148, 150, 151, 251 - 
anhydrides, 351 
Ethane, 74 
perbromide, 105 
perchloride, 105 
Ethanes, 70 
Ethenyl amidine, 294, 620 
amido-phenol, 683 
tricarboxylic acid, 471 
Ethers, compound, 137 
mixed, 136 
simple, 136 
Ether acids, 146 
Ethereal oils, 998 
Ethidene compounds, 305, 
chloride, 100 ("aga 
dimalonic acid, 481 
lactic acid, 356 
sulphonic acids, 320 
Ethine diphthalyl, 824 
Ethionic acid, 319 
Ethyl. See Dimethyl 
aceto-acetic ester, 338 





a 


aldoxime, 194 
amine, 163 
benzoic acids, 757 
bromide, 94 

~ carbonic acid, 377 
chloride,93 
cyanide, 284 


orange, 651 
sulphide, 143 
sulphonic acid, 153 
4€n 52 





1026 


Ethylene dichlorides, 97 
di-iodides, 97 
glycol, 301 
lactic acid, 361 
oxide, 303 

- sulphide, 303 
sulphonic acids, 317 

Ethylidene chloride, 1oo 
bromide, 100 
iodide, IoI 

Euchroic acid, 799 

Eugenol, 803 

Eupittonic acid, 879 

Eurhodines, 986 

Eurhodols, 988 

Euthiochronic acid, 692 

Euxanthinic acid, 1010 

Euxanthone, 860 

Everninic acid, 782 


Fats, 459 
Fatty acids, 211, 215 
compounds, 68, 69 

Fermentation, 503 
Ferulic acid, 821 

iso, 821 
Fibrin, 1015 
Fichtelite, 927 
Flavaniline, 971 
Flavenol, 971 


_Flavol, 896 


Flavophenine, 846 


- Flavopurpurine, 900 
_ Fluoranthene, 927 


- Fluoranthraquinone, 927 


Fluorbenzene, 583 


~ Fluorbenzoic acid, 747 


Fluorene, 850 
Fluorene alcohol, 851 
Fluorenic acid, 851 
Fluorescein, 882 


= _ Fluorescin, 883 


Fluorindene, 991 
Formal, 301 
Formamide, 259 
Formamidine, 293 
Formanilide, 606 
Forn.ic acid, 216 
aldehyde, 191 





INDEX. 


Formic esters, 253 
Formoimido-ethers, 292 
Formonitrile, 283 
Formose, 499 
Formy] acetic acid, 331 
acetone, 323 
tricarboxylic acid, 471 
Fructose, 505 
Fructose carboxylic acid, 496 
Fruit sugar, 505 
Fuchsine, 872 
Fulminic acid, 285 
Fulminuric acid, 286 
Fumaric acid, 425 
Furfurane, 521, 523 
acids, 526, 527, 528 
alcohols, 524 
alkylic, 523 
amides, 525 


G. 


Gaidinic acid, 242 
Galactose, 506 
Gallacetophenone, 729 
Gallein, 883 
Gallesine, 50 
Gallic acid, 782 
Gallin, 883 
Gallocarboxylic acid, 796 
Gallocyanine, 984 
Gallylgallic.acid, 785 
Garancin, 898 
Gaultheria procumbens, 767 
Gelatines, 1012 © 
Gentisin, IOIT 
Gentisinic acid, 778 
aldehyde, 724 
Germanium ethide, 183 
Gluconie acid, 489 
Glucosamine, 505 
Glucosazone, 501, 504 
Glucose carboxylic acid, 495 
Glucoses, 497, 502, 503 
Glucosides, 502, 1008 
Glucosine, 325 
Glucosone, 505 
Glutaconic acid, 428 
Glutamin, 467 
Glutaminic acid, 467 





Glutaric acid, 417 
Gluten, 1015 
Glutin, 1012 
Glutinic acid, 432 
Glyceric acid, 460 
Glycerides, 458 
Glycerol, 452 
ethers, 454 
Glyceryl bromide, 104 
chloride, 104 
iodide, 104 
Glycide compounds, 456 
Glycidic acid, 457 
Glycine or glycocoll, 369 
Glycocholic acid, Io11 
Glycocoll, 369 
anhydride, 370 
Glycocollamide, 370 
Glycocyamine, 397 
Glycogen, 513 
Glycolide, 356 
Glycollic acid, 354 
derivatives, 354 
alcohol, 355 
anhydride, 356 
Glycol mercaptan, 303 
Glycols, 296, 297 
Glycoluric acid, 392 
Glycolyl, 353 
aldehyde, 321 
-phenyl urea, 612 
urea, 391 
Glycouril, 440 
Glycovanillin, 725 
Glycuronic acid, 491 
Glyoxal, 324 
ethylin, 552 
Glyoxalic acid=Glyoxylic acid, 330 
Glyoxalin, 325, 326, 551, 552 
Glyoxalines, phenylated, 934 
Glyoximes, 324, 325 
Glyoxyl urea, 440 
Glyoxylic acid, 330 
Grape sugar, 503, 504 
Guaiacol, 690 
Guanamines, 296 
Guanidines, 294, 397 
Guanine, 448 
Guanyl urea, 289 
_ Guinea green, 869 
Gum resins, 1008 
Gums, 513 
Gun cotton, 515 
Gutta percha, 1008 


INDEX. 


H. 


Heematin, 1016 
Hematoxylin, 1010 
Heemin, 1016 
Hezemoglobin, 1015 
Halogen esters, 299 
Haloid anhydrides, 213, 246 
Helianthine, 651 
Helicin, 713 
Heliotropine, 804 
Helvetia green, 869 
Hemimellithene, 575 
Hemimellitic acid, 797 
Hemipinic acid, 793 
Heptamethylene, 521 
Heptanes, 75 ~ 
Heptoic acids, 230 
Heptolactone, 365 
Heptoses, 507. 
Heptyl] alcohols, 133 
Heracleum oil, 133 
Herapathite, 994 
Hesperidin, 1001, 1009 
Hesperitic acid, 821 
Hexamethyl benzene, 579 
Hexamethylene, 521 
Hexamethylene amine, 193 
Hexanes, 75 
Hexaoxydiphenyl, 498 
Hexoic acids, 229 
Hexoses, 498 
Hexoylene, 89 
Hexy] alcohols, 132 
Hipparaffin, 745 
Hippuric acid, 744 
Homatropine, 996 
Howeophthalimide, 791 
Homoprotocatechuic acid, 780 
Homopyrocatechin, 693 
Homopyrrols, 542 
Homovanillic acid, 780 
Hyezenic acid, 215 
Hydantoic acid, 392 
Hydantoin, 391, 392 
Hydracrylic acid, 361 
Hydramines, 314 
Hydranthranol, 895 
Hydrazines, 166,653 
alkylized, 657 
Hydrazo-benzene, 649 
-benzoic acid, 751 
Hydrazoic acid, 640 
Hydrazones, 500 





1027 


B 
. 
; ; 
3 “4 
ae 
Pie ; 
‘ ¥ : : 
ae 
| 
~~ : Fr 
ae 
‘ = 
r z “ 
ie = 
ra a 
*. wae 
& Nees 
* 
¥ ; 
Be 


1028 


Hydrazoximes, 326 
Hydrindene, 902, 903 
Hydrindic acid, 773 
ar ~ Hydrindone, 904 
__ Hydrindo-naphthene, go2 
. *: _ Hydroatropic acid, 759 
_ Hydrobenzamide, 717 
_ Hydrobenzoin, 886 
Hydrocaffeic acid, 782. 
Hydrocarbostyril, 755, 758, 968 
Hydrocinnamide, 805 
(~drocinnamic acid, 757 
H ydrocoerouglinone, 844 
Hydrocornicularic acid, 892 
Hiydrocoumaric acid, 782 
Hydrocoumarin, 774 
_ Hydroferulic acid, 782 
_ Hydroflavic acid, 265 
-Hydrojuglones, 918 
iydromellitic acids, 800 
Hydromuconic acid, 430 
i ydronaphthoquinones, 918 
lydronaphthylamines, 911 
ydrophlorol, 694 
drophthalic acids, 778 
ydrophthalide, 772 
ydropicolines, 951 
Hydropiperic acid, 822 
Hydroquinone, 691 
‘lydroquinone carboxylic acid, 778 
drorubianic acid, 265 
Hydrosorbic acid, 245 
_ Hydroterephthalic acid, 790 
__ Hydroumbellic acid, 782 
droxamic acids, 260 
droxylamine derivatives, 166 
droxyurea, 388 
durilic acid, 445 
oscine, 996 
yoscyamine, 996 
pogzeic acid, 242 
lypoxanthine = sarcine, 449 



























is ‘Tmido- carbonic acid, 384 
-ethers, 292, 735 
_ -thio-carbonic acids, 386 


INDEX. 


Imido-thio-ethers, 293 
Indazol, 812, 841 
Indene, 902 
Indican, 839 
Indigo, 837, 839 
carmine, 840 
purpurine, 840 
Indigotin, 837 
white, 840 
Indin, 840 * 
Indirubin, 833, 840 
Indoanilines, 705, 707 
Indoamines, 705, 708 
Indogenides, 833 
Indoin, 334 
Indol, 827 
Indophenin, 835 
Indophenols, 705, 707 
Indoxanthic ester, 833 
Indoxyl, 832 
Indoxylic acid, 832 
Indulines, 648, 990 
Inosite, 697 
Inuline, 512 
Invert sugar, 505 
Todine, green, 874 
Iodoform, §03 
Todol, 541 
Ipomic acid, 1009 
Iridolin, 960 
Isatin, 834 
chloride, 836 
Tsatinic acid, 762 
Isatogenic ester, 834 
Isatoxime, 837 
Isatropic acid, 813 
Isatid, 835 
Isethionic acid, 318 
Isindazole, 841 
Isobenzil, 889 
Isobutyric acid, 227 
Isobutyryl chloride, 247 
Isocaprolactone, 364 
Isocholine, 316 
Isocinchomeronic acid, 948 
Isocyanic acid, 271 
Isocyanides, 287 
Isocyanuric acid, 272 
Isodiphenic acid, 850 
Tsodulcitol, 483 
Isoferulic acid, 821 
Tsoglucosamine, 505 
Isohydrobenzoin, 886 
Tsoindol, 955 








Isonicotine, 953 
Isonicotinic acid, 946 
Isonitroso-acetic acids, 222 
-acetone, 206 
acetophenone, 728 
acids, 214 
compounds, 106 
Iso-orcin, 693 
Isophthalic acid, 788 
Isoprene, 1002 
Isopropyl alcohol, 127 
bromide, 95 j 
chloride, 94 
iodide, 96 
Isopurpuric acid, 678 
Isoquinoline, 975 
Isosaccharic acid, 494 
Isosaccharin, 484. 
Isosafrol, 804 
Isosuccinic acid, 416 
Isothio- acetamide, 260, 608 
-cyanic acid, 277 
-ureas, 617 
Isouvitic acid, 790 
Isovaleramide, 259 
Isovaleryl chloride, 247 
Tsovanillic acid, 780 
Isovanillin, 726 
Isuret, 294, 388 
Itaconic acid, 429 
Itamalic acid, 468 


J 
Jalapin, 1009 
Juglone, 919 
“Oxy, 919 
K 


Kairine, 967 

Kairoline, 966 

Kanarine, 278 

Kerosene, 77 

Ketines, 207, 954, 955 

Ketipic acid, 437 

Ketoamines, 112 

Ketol, 830 

Ketone alcohols, 321 
aldehydes, 323 
decomposition, 337 
dicarboxylic acids, 432 





INDEX. | 1029. 


Ketones, 186, 200, 726 

Ketonic acids, 220. 234, 343» 761, 763 
Ketopentene, 521 

Ketoses, 498 

Ketoximes, 202, 325 

Kino-tannin, 785 

Kynurenic acid, 973 

Kynuric acid, 973 

Kynurine, 969 


Lactams, 755 
Lactamides, 366 
Lactic acids, 356 
Lactides, 351, 358, 359 
Lactimides, 366 
Lactims, 755 
Lactones, 351, 352 
Lactonic acid, 491 
acids, 462 
Lactose, 506, 509 
Lacturic acid, 393 
Lactyl chloride, 358 
urea, 392 
Lzvomannitol, 487 
Lzevulinic acid, 343 i" nee 
Leevulose, 505 . iy 5 nee 
Lanoline, 1o1t Ane 
Lauramide, 259 
Lauric aldehyde, 198 
acid, 232 me 
Laurone, 210 ete 
Lauth’s violet, 604 -s 
Lead compounds, 185 
Lead plaster, 231 
Lecanoric acid, 781 
Lecithin, 1015, 1016 i 
Legumin, I0I5 
Lekene, 79 
Lepargylic acid, 423. 
Lepidine, 968, 969, 970 
Leucaniline, 871 
Leucaurine, 878 
Leucaurolic acids, 110 
Leucic acid, 364 
Leucine, 373 
Leucoline, 960 
Leucomalachite green, 867 
Leuconic acid, 521, 703 
*Leucorosolic acid, 878 
Leucoturic acid, 444 





1030 INDEX. 





Leucoviolet, 875 Melene, 291 
Lichinine, 512 Melezitose, 511 
Ligroine, 77 Melilotic acid, 774 
Limonene, I0oI Melissic acid, 233 
Linoleic acid, 243 Melissyl alcohol, 134 
Litmus, 693 Melitose, 511 
Lophine, 934 Mellimide, 799 
Lupetidines, 951 Mellitic acid, 799 
Luteoline, 780 Mellon 292. 
Lutidines, 943 Mellophanic acid, 799 
Lutidinic acid, 948 Menthene, 1000, 1007 
Lutidones, 945 Menthol, 1006 : 
Lycine, 316 Mercaptans, 140 
Mercaptals, 142 
Mercaptides, 142 
M Mercaptols, 142 
Mercapturic acids, 360 
Maclurin, 780 Mercury allyl iodide, 182 
Magdala red, 990_—C— -ethide, 182 
Magenta, 872 methide, 182 
Magnesium-ethide, 179 Mesaconic acid, 429 
Malachite green, 867 Mesicerine, 714 
Malamide, 466 Mesidic acid, 790 
Maleic acid, 425, 426. Mesidine, 624 
Malic acid, 464 Mesitylene, 208, 574 
Malon-anilic acid, 610 glycerol, 714 
Malonic acid, 408 Mesitylenic acid, 756 
Malonitrile, 409 Mesityl oxide, 208 
Malonyl aldehyde, 325 Mesitylol, 687 
urea, 441 Mesorcin, 694 
Maltose, 510 Mesotartaric acid, 479 
Mandarin yellow, 916 Mesoxalic acid, 434 
Mandelic acid, 772 Mesoxalyl urea, 443 
Mannide, 487 Metadiazines, 955 
Mannitan, 487 -oxy, 956 
Mannitic acid, 489 Metaldehyde, 194 
Mannitol, 487 Metallo-organic compounds, 177 
Mannonic acids, 490 Metasaccharic acid, 494 
Mannononose, 507 Metasaccharin, 484 
Manno-octose, 507.. Methacrylic acid, 193 
Mannose, 503 Methane, 73 
= carboxylic acid, 445 chlor, 105 
-— Margaric acid, 232 iodo, 105 
~. Marsh gas, 73 tetrabrom, 104 
- Mauvaniline, 990 Methionic acid, 317 
Mauvéine, 990 Metheny! amidine, 293 
Meconine, 793 amido-thio-phenol, 614 
Meconic acid, 959 amidoxime, 294 
Meconinic acid, 793 Methose, 499 
Melane, 291 Methronic acid, 528 
Melamine, 290 Methylal, 301 
Melampyrine = Dulcitol, 488 Methyl aldehyde, I91 
Melanurenic acid, 291 { alcohol, 124~ 
Melebiose, 511 Methylamine, 162 





Methyl aniline, 513 
anthracene, goI 
bromide, 94 
chloride, 93 
crotonic acid, 241 
cyanide, 283 
ethyl aceto-acetic ester, 340 
glyoxal, 323 
glyoxime, 207 
indol, 830 
iodide, 95 
ketol, 321, 830 
orange, 651 
quinolinic acid, 949 
sulphurane, 304 
umbelliferon, 821 
violet, 874 

Methylene, 82 
blue, 605 
chloride, 100 
derivatives, 301 
red, 606 

Methylenitan, 499 

Milk sugar, 509 

Mirbane oil, 587 

Mixed azo-compounds, 653 

Morin, 785 

Moringa-tannin, 785 

Morphine, 992 

Morpholine, 315, 957 

Mucedin, 1015 

-Mucic acid, 493 

Mucilages, 513 

Mucobromine acid, 427 

Mucochloric acid, 428 

Mucolactonic acid, 470 

Muconic acid. 432, 470 

Murexan, 441 

Murexide, 445 

Muscarine, 316 

Mustard oil, 280 

Mycose, 511 

Mydatoxime, 316 

| Mydine, 316 

| Myosin, Lors 

| Myricyl alcohol, 134 

Myrisitic acid 232 

Myristamide, 259 

Myristic aldehyde, 198 

Myristicol, 1006 

Myristone, 210 

Myronic acid, 281, 1009 

Myrosine, 281, 1009 

Mytilotoxine, 316 


INDEX. 103h) 


~ 


N 


Naphanthracene, 929 
Naphsultone, 916 
Naphtha, 77 
Naphthalene, 905, 908 
alcohols, 921 
amido-, 910 
azo-, 913 
carboxylic acids, 922 
haloids, 909 
hydrides, 908 
ketones, 921 
nitriles, 921 
nitro-, g1O ' 
phenol derivatives, 915, 916 
red, 990 
sulpho-acids, 914 
yellow, 916 
Naphthalic acid, 923 - 
Naphthalidine — Naphthylamine 
Naphthalizarin, 919 
Naphthazine, 986 
Naphthene, 78 
Naphthindol, 923 
Naphthionic acid, 915 
Naphthofurfurane, 923 
Naphthoic acid, 922 
Naphthol, 915, 917 
blue, 707, 919, 984 
hydrides, 917 
nitroso-, 920 
sulphonic acids, 917 
Naphthoquinone, 918, 919 
chlorimide, 919 
hydrides, 919 
Naphthoquinoximes, 920 
Naphthostyril, 922 
Naphthylamine, 910, 911 
Naphthyl hydrazines, 914 
Narceine, 993 
Narcotine, 993 
Neurine, 316 
Neutral red, 988 
Nicotidene, 953 
Nicotine, 953 
Nigrosine, 990 
Nitranilic acid, 7o1 ; 
petitriles, 282, 732 ; 
Nitroacetonitrile, 285 
Nitro-amines, 106, 594 
Nitrobenzene, 587 
Nitrobutanes, 108 





Nitrochloroform, 113 


1032 INDEX. 


Nitrococcic acid, 771 Organo-metallic compounds, 177 
Nitro-compounds, 105, 586 Orsellinic acid, 781 
Nitroethane, 108 Ortho-carbonic ester 473 
Nitroform, 112 Orthoformic ester, 452 
Nitroglycerol. 454 Osazones, 326, 502 
Nitrolamines, 112, 998 Osones, 501 
Nitrolic acids, 109, 110, 646 Osotetrazones, 326 
Nitromethane, 107 Osotriazones, 326, 553 
Nitroparaffins, 107 Oxalan, 440 
Nitrophenols, 676 Oxalantin, 444 
Nitropropane, 108 Oxalethylin, 552 
Nitropropionic acid, 180 Oxalic acid, 403 
Nitroprussides, 270 Oxalines, 552 
Nitrosates, III Oxalmethylin, 407, 552 
Nitrosites, L111, 999 -| Oxalo-acetic acid, 435 
Nitroso-compounds, 106 | Oxaluric acid, 439 
iso-, 106, 591 Oxalyl urea, 439 

-indoxyl, 833 Oxamethane, 407 

naphthols, 920 Oxamic acid, 407 

phenol, 675 Oxamide, 406 
Nitrotoluenes, 590 Oxamidine, 294 
Nonane, 76 Oxamidines, 294, 736 
Nonoic acid, 230 . Oxanilic acid, 610 
Nonoses, 507 Oxanilide, 610 
Nonylenic acid, 242 Oxanthranol, 896 
Norhydrotropine, 953 Oxatolic acid, 891 


Noropianic acid, 793 Oxazine, 957 
Oximes = aldoximes. 
Oximido-compounds, 106 


esters, 735 
O Oxindol, 831 
Oxyacids, 345, 353 

Octane, 75 anhydrides, 351 
Octodecyl alcohol, 133 primary, 350 
Octoic acid, 230 secondary, 350 
Octoses, 507 Oxyacrylic acids, 365 
Octyl alcohol, 133 Oxyalcohols, 713 
(Enanthol, 198 Oxyangelic acids, 365 
(Enanthone, 210 Oxyanthraquinones, 897 
(Enanthylic alcohol, 133 Oxybenzoic acid, 767 

acid, 230 Oxybenzo-phenones, 860 
Oils, drying, 243, 453 Oxybutyric acids, 362, 363 

fatty, 243, 453 Oxycaproic acids, 364 
Olefiant gas, 82 Oxychrysazine, 900 
Olefines, 79 Oxycinchoninic acid, 973 

formation of; 79, 80 Oxycinnamic acids, 818 

higher, 85, 86 Oxycitric acid, 486 

oxidation, 82 Oxycoumarin, 821 

* polymerization, 82 “© xycrotonic acids, 365 
Oleic acids, 233, 242 Oxycyanides, 190, 202,347. 
_ Opianic acid, 793 Oxydiphenyl, 847 

Opium, 992 Oxyethylene bases, 314 
Orcein, 692 Oxyformic acid, 353 





Orcin, 692 Oxyglutaric acid, 467 


Oxymalonic acid, 463 
Oxymethylbenzoic acids, 772 
Oxymethylene, 192 
Oxyneurine, 316 
Oxyphenic acid, 689 
Oxypheny] acetic acid, 771 
Oxyphthalic acid, 792 
Oxyphthalophenone, 881 
Oxypiperidine, 951 
Oxypropionic acids, 356 
Oxypropylbenzoic acid, 777 
Oxypyrimidines, 736 
Oxyquinolines, 967 
Oxyquinolinic acid, 948 
Oxytetraldine, 321 
Oxytoluic acids, 771 
Oxyuvitic acid, 792 
Oxyvaleric acids, 363, 364 
Ozokerite, 78 


Palmitamide, 259 
Palmitic acids, 232 
aldehyde, 198 
Palmitin, 458 
Palmitolic acid, 245 
Palmitone, 210 
Palmitoxylic acid, 245 
Papaverine, 993 
Para-azoxine, 315 
Parabanic acid, 439 
Paraconine, 953 
Paraconic acid, 468 
Paracyanogen, 265 
Paracymene, 577 
Paradiazines, 954 
Paraffin, 67, 70, 76, 78 
Paraformaldehyde, 192 
Paralactic acid, 360 
Paraldehyde, 194 
Paraldol, 321 
Paraleucaniline, 869, 870 
Param, 289 
Paramide, 799 
Paramylum, 512 
Pararosaniline, 871 
derivatives, 874 
Parietic acid, see Chrysophanic acid 
Parvoline, 937 
Patchouly, 1006 
Pelargonic acid, 230 


INDEX. 





Pentadecatoic acid, 232 
Pentamethyl benzene, 578 
Pentamethylene derivatives, 520 
Pentane, 75 


_Pentaoxyhexane, 483 


Penthiophene derivatives, 537 
Pentinic acid, 345 
Peonine, 878 
Pepsine, 1014 
Peppermint oil, 1006 
Peptones, 1014 
Perbromethane, 105 
Perchlormesole, 105 
Perchlormethane, 105 
Perchlorpyrocoll, 547 
Perseite, 494 

Peru balsam, 742 


Petroleum, 77 


benzine, 77 
ether, 77 
Petrolic acids, 243 
Phaseomannite — inosite, 697 
Phellandrene, 1003 
Phenacetolin, 670 
Phenanthrene, 924 
hydrides, 925 
Phenanthrene carboxylic acids, 926 
Phenanthraquinone, 925 
Phenanthridine, 974 
Phenanthroline, 975 
Phenazine, 629, 980, 984, 986 
tetramido derivatives, 987 
triamido derivatives, 987 
Phenetol, 670 
Phenol, 666, 649 
blue, 707. 
diazo compounds, 683 
ethereal salts, 670 
ethers, 670 
homologues, 685 
phthalein, 382 
sulphonic acids, 684 
sulphuric acids, 685. 
Phenoquinone, 700 
Phenose, 697 
Phenoxazine, 983 
Phenyl] acetaldehyde, 721 
acetic acid, 753 
aceto-carboxylic acid, 790 
acetone, 729 
acetylene, 802 
acrylic acids, 807, 813 
alanine, 758 
amidines, 450 


1033 


1034 


Phenyl benzoic acid, 849 
butyro-lactone, 777 
carbonate, 670 
carbylamine, 613 
crotonic acid, 813 
diacetylene, 803 
dithio-carbamic acid, 614 
ethers, 671 
ethylene, 800 
ethyl sulphone, 662 
glyceric acid, 782 
glycerol, 714 
glycidic acid, 777 
glycocoll, 608 
glycocollic acid, 671, 772 
glyoxyllic acid, 762 
glyoxime, 728 
guanidine, 619 
hydantoin, 608 
hydracrylic acid, 776 
hydrazides, 489 
hydrazine, 655 
hydrazones, 656 


imido butyric acid — phenylimido- 


crotonic ester, 609 

indol, 830, 831 
isocyanates, 634 
isocyanide, 613 
itamalic acid, 793 
lactic acid, 776 
malonic acid, 791 
methyl ketone, 727 
mustard oil, 614 

glycollide, 616 
oxyacrylic acid, 777 
phenazonium, 989 — 
phosphine, 621 
paraconic acid, 793 
phthalide, 863 
propiolic acid, 814 

amido, 815 
nitro, 815 

quinoline, 971 
styceric acid, 782 
succinic acids, 791 
sulphaminic acid, 664 
sulph-hydantoins, 619 
sulphide, 672 
sulphone, 663 
thio-hydantoin, 618 

urea, 616 
thiurethanes, 615 
tolyl, 843 
/ methanes, 862 





INDEX. 


Phenyl urea, 612 
urethanes, 612 
Phenylene blue, 708 
diamines, 625 
methenyl amidine, 628, 842 
ureas, 627 
Phloretic acid, 775 
Phloretin, 1009 
Phloridzin, 1009 
Phloroglucin, 695 
tricarboxylic acid, 797 
Phloron, 704 
Pheenicin-sulphuric acid, 840 
Phorone, 208 
Phosgene, 375 
Phospheny] chloride, 621 
Phosphin, 983 
Phosphines, 168, 317 
Phosphinic acids, 156 
Phospho-benzene, 451 
Phosphonium bases, 170 
Phosphoric aeids, 155 
esters, 155 
Photogene, 78 
Phthalanile, 611 
Phihaleins, 881 
Phthal-green, $83 
Phthalic acid, 786 
aldehydes, 722 
anhydride, 787 
chloride, 787 
Phthalid, 772 
Phthalide, 879 
Phthalideins, 628 
Phthalidins, 772, 882 
Phthalimide, 737 
Phthalimidine, 788 
Phthalins, 882 
Phthalophenone, 864, 880 
Phthalyl acetic acid, 823 
alcohol, 712 
hydroxamic acid, 787 
Phycite, 474 
Phytosterine, Lor! 
Picamar, 696 
Picene, 929 
Picoline, 943 
carboxylic acids, 947, 949 
Picolinic acid, 947 
Picramic acid, 683 
Picramide, 598 
Picric acid, 677 
Picro-cyaminic acid, 678 
Picroerythrin, 781 








INDEX. 1035 
Picrotoxin, Io1o Propionyl chloride, 247 
Picryl chloride, 590 cyanide, 248 
Pimaric acid, 1008 Propiophenone, 729 
Pimelic acid, 421 4 Propio-propionic acid, 225 
Pinacones, 202, 310 Propyl acetylene carbonic acid, 245 
Inavolines, 202, 210 acetylene carbonic acid, iso-, 245 
Pinacoly| alcohol, 131 alcohols, 127 
Pinene, 99.) bromide, 94 
dibromi. > 1000 - chlorides, 93 
dichloride, 15 ~9 iodide, 96 
hydrochloride, roo Propylamine, 163 
_ _ nitroso chloride, 1000 Propylene, 79, 83 
Pinite, 484, 697 a glycols, 308 
Pinol, 1006 } haloids, 98, 102 
E ipecolines, 951 : Propylidene acetic acid, 241 
TR azine, 955 j chloride, 1o1 
Pipeny dronic acid, 822 y diacetic acid, 421 
Piperic aus, 822 Protagon = Lecithin. 
Piperideines, 6% Protein substances, 1013 
Piperidine, 950 S|. 4 Protocatechuic acid, 779 
alkyl-, 951 *. aldehyde, 724 
benzoyl, 951 : | Prussic acid, 265 i: 
urethanes, 951 Pseudoaconitic acidyug73 
Piperine, 951 seudocarbostyril, 968 
Piperonal, 726 .. | Pseudocumene, §74 | 
Piperonyl alcohol, 714 ; _* | Pseudocyanogen sulphide, 275 
Piperonylic acid, 780 ' Pseudoindoxyl, 833 
Piperylene, 951 Pseudoisatin, 834, 837 
Pittical, 879 Pseudoisatoxime, 837 
Pivalic acid = Trimethyl acetic acid Pseudonitrols, 110 
Polyglycerols, 459 Pseudopurpurin, 902 
Polyglycols, 304 Ptomaines, 316, 1013 
Polymerization, 82, 190 Pulvic acid, 892 
Polymethylene compounds, 595 Purpuric acid, 445 
Polyquinoyls, 702 Purpurin, 900 
Polysaccharides, 512 Purpur-oxanthin, 900 
Populin, 713 Putrescine, 313, 316 
Porissic acid — Euxanthinic acid Pyrazine, 954, 980 
Prehnitic acid, 798 Pyrazole, 551 
Propalanine, 372 phenylated, 930 
Propane, 74 phenyl, 932 
Propargyl! alcohol, 135 Pyrazoline, 551 
Propargylic acid, 244 Pyrazolidine, 551 
Propeny]-benzoic acid,778 Pyrazolon, isophenyl, 932 
tricarboxylic acid, 471 phenyl-methyl, 933 
Propidene chloride, 1o1 phenyl-dimethyl, 933 
Propiolic acid, 244 . Pyrene, 928 
Propionamide, Pyrenic acid, 928 
Propione, 209 Pyrenquinone, 928 
Propionic acid, 259 Pyridine, 936, 937,941 
aldehyde, 197 dicarboxylic acids, 947 
anhydride, 222 monocarboxylic acids, 946 
esters, 254 pentacarboxylic acids, 950 
Propionitrile, 284 tetracarboxylic acids, 950 — 





1036 


Pyridine tricarboxylic acids, 949 
fatty acids, 947 
hexahydro-, 950 
homologues, 942, 943, 944 
hydrides, 950 
isomerides, 941 
oxy-derivatives, 944 
phenyl, 944 

Pyridones, 945 

Pyrimidine, 955 
oxy-, 956 

Pyrocatechin, 689 

Pyrocinchonic acid, 430 

Pyrocomenic acid, 958 

Pyrogallol, 694 
carbonic acid, 562 ‘ 

Pyrogallic acid, 694 

Pyroglutaminic acid, 467 

Pyromecazonic acid, 946 

Pyromeconic acid, 958 

Pyromellitic acid, 798 

Pyromucic acid, 526 

Pyrone, 958 
oxy-, 958 wi btes 

. carboxylic acids, 958 

~ Pyroracemic acid, Ce ie 

Pyrotartaric acid, 416 bs 

Pyroterebic acid, 241 

Pyroxylin, 514 

Pyrrocol, 547 

Pyrrol, 521, 539 
alkylic derivatives, 540 
azo-compounds, 544 
carbonyl-, 540 
carboxylic acids, 545, 546, 547 
cyan-, 540 
dicarboxylic acids, 548 
homologues, 542, 543 
hydrides, 549 
ketones, 544 
ketonic acids, 548 
tetraiodo-, 541 

Pyrrolidine, 413 

_ compounds, 550 
_ Pyrollin, §49, 550 

/ Pyruvic acid, 333 
Pyruvil, 341 


Q 


Quercite, 484, 697 
Quercitin, 1009 
Quercitrin, 1009 
- Quinacetophenone, 729 
.- o sr Sas ‘ 


———- 


INDEX. 


Quinaldinic acid, 972 


Quinaldine, 969 
nitro-, 9 
~  Oxy-, 970 


tetrahydro-, 970 
carboxylic acids, 973 
Quinazole, 841 
Quinazoline, 977 
thio-, 978 
Quinhydrone, 700 
Quinic acid, 78% 
Quinene, 075 
Quinine, 994 - 
Quiningic acid, 973 
_ Quinisa tin, 765 
Quinisa.tinic acid, 765 
Quiniz arin, goo 
Quiniz ine compounds, 930 
Quin gens, 320 
Quit oline, 936. 0, 965 
ATi acid, 970 
~~ amido-, 907° 
ine, 966 
carboxylic acids, 972 
chlor-, 966 
dicarboxylic acids, 97 3 
dihydro-, 966 
dioxy-, 969 
homologues, 969 
methyl, 969 
naphtho, 974 
nitro ,966 
oxy-, 967, 968 
phenyl 971 
red, 976 
tetrahydro-, 966 
trioxy-, 969 
yellow, 970 
Quinolinic acid, 947 
Quinolyls, 966 
di-, 966 
Quinone, 326, 699 
carboxylic acid, 796, 798 - 
chlorimides, 705 
phenolimide, 706 
Quinophthalone, 970 
Quinoxalines, 326, 978, 980. 
Quinoxime, 706 








R 


Racemic acid, 478 
Radicals, 45, 70, 177, 213 
Raffinose, 511 








INDEX. 


Resacetophenone, 729 
Resazurin, 691 
Resins, 1008 


Resocyamine == Methyl Umbelliferon,. 


822 ; 
Resorcin, 690 
Resorcinol, 690 

phthalein, 882 
Resorcyl aldehyde, 724 
Resorcylic acids, 778 
Resorufin, 691 
Retene, 926 
Rhamnose, 483 

carboxylic acid, 491 
Rheinic acid = Chrysophanic acid, 9oI 
Rhodamines, 884 
Rhodanic acid, 356 
Rhodanides, 634 
Rhodizonic acid, 702 
Ricinelaidic acid, 244 
Ricinoleic acid, 243 
Roccellic acid, 423 
Rocellin, 652, 917 
Rock oil, 77 
Roman oil of cumin, 240 
Rosaniline, 870, 871 

alkylic, 873, 874, 875, 876 
Rosamines, 877 
Roshydrazine, 876 
Rosindulines, 991 
Rosolic acids, 876, 878 
Ruberythric acid, 898 
‘ Rubidine, 937 
Rubine, 873 
Rue, oil of, 210 
Rufigallic acid, 783, g00 
Rufiopin, goo 
Rufol, 896 


S 


Saccharic acid, 484, 492 
Saccharates, 502 
Saccharin, 484, 752 
Saccharon, 485 
Saccharonic acid, 485 
Saccharose, 508 
Safflower, 1010 
Safranines, 989 


pheno-, 989, 990 
phenyl, 990 
_ tolu-, 990 
Safranol, 990 
Safrol, 804 
Salicin, 713 





Salicylic acid, 767 
aldehyde, 723 

Saligenin, 713 

Saliretin, 713 

Salol, 769 

Santoic acid, 1010 

Santonin, 1010 

Saponin, 1009 

Saponification, 253 

Saprine, 316 

Sarcine, 449 

Sarcolactic acid, 360 

Sarcosine, 370 

Schweinfurt’s green, 221 

Sebacic acid, 423 

Seignette salt, 371 

Selenium compounds, 145 

Serin, 461 

Sesquiterpenes, 1003 

Shellac, 1008 

Skatole, 830 

Silicic acid esters, 156 

Silicon-benzoic acids, 622 

Silicon-ethide, 176 

Silicononyl alcohol, 176 

Silicopropionic acid, 177 

Sinamine — Allylcyanide 

Sinapic acid, 998 

Sinapine, 998 

Sinapoline, 390 

Sincaline — Choline 

Soaps, 231 © 

Solar oil, 78 

Sorbic acid, 245 

Sorbine, 506 

Sorbinose, 506 

Sorbite, 488, 503 

Sparteine, 992 

Spermaceti, 255 

Spermine, 955 

Starch, 512 

Stearamide, 259 

Stearic acid, 232 
aldehyde, 198 

Stearin, 232 

Stearoleic acid, 245 

Stearone, 210 

Stearoxylic acid, 245 

Stibethyl, 175 

Stibines, 174 

Stilbazole, 943 

Stilbene, 885 
carboxylic acid, 890 

Storax, 808 











1038 


Strychnine, 995 

Stycerine, 714 

Styphbnic acid, 678 

Styracine, 808, 809 

Styrene, 804 

Styrolene, 800 
alcohol, 712 

Styryl alcohol, 804 

Suberic acid, 422 

Suberone, 422 

Succinamic acid, 413 

Succinamide, 412 

Succinic acids, 410, 420, 421, 422 
bromo-, 413, 414 

Succino-succinic acid, 795 

Succinyl aldehyde, 325 
aldoxime, 325 

Sugar, 503 

Sulph, see also Thio, 

Sulphamides, 752 

Sulphamin-benzoic acid, 752 

Sulphanilic acid, 664 

Sulphimido-benzenes, 665 

Sulphines, 144 

Sulphinic acids, 154, 659 

Sulphourethanes, 386 

Sulpho-acetic acid, 262 
-acids, 152, 261, 644, 659” 
-benzide, 662 
-benzoic acids, 752. 
-carbamic acid, 386 
-carbamide, 394 
-carbanile, 614 
-carbanilide, 616 
-carbonic acid, 382 
-carboxylic acids, 345 
-cyanacetic acid, 355 
-hydantoins, 396 

Sulphonal, 307. 

Sulphonazurine, 846 

Sulphones, 142 

Sulphonic acids, 152 , 

Sulphonic acid, methyl-, 153 

ethyl-, 153 

Sulphoxides, 142 

Sulphurea, > 394 

Sylvestrine, 1003 

Sylvic acid, 1008 

Synaptase, 508 


di 
Tannin, 784 
Tannic acids, 784 


INDEX. 


Tartaric acid, 475 
Tartramic acid, 477 
Tartramide, 477 
Tartronic acid, 463 
Tartronyl urea, 442 
Taurine, 319 
Tauro-betaine, 319 
cholic acid, 1012 
Tellurium compounds, 145 
Teraconic acid, 431 
Teracrylic acid, 241 
Terebenthene, 999 
Terebic acid, 469 
Terephthalic acid, 789 
Terpenes, 998 
homologues, 1003 
nitroso-, 998 
nitroso- chlorides of, 998 
tetrahydride, 1000 
Terpenylic acid, 470 
Terpine, 1000 
hydrate, 1000 
Terpinenes, 1003 
Terpinolene, 1003 \ 
Tetraacetylene dicarboxylic acid, 4 
Tetradecatyl alcohol, 133 
Tetrahydropyridines, 952 
Tetramethylene derivatives, 519 
imine, 550 
Tetranitromethane, 113 
Tetraoxysuccinic acid, 480 
Tetraphenyl ethane, 891 
ethylene, 891 
Tetrazines, 957 
Tetrazo- compounds, 645 
Tetrazones, 167, 658 
Tetrinic acid, 345 
Tetrolic acid, 245 
Tetrylone, 521 
Thallium diethyl chloride, 182 
Thebaine, 992 
Theine, 449 
Theobromic acid, 233 
Theobromine, 449 
Thiacetic acid, 251 
Thialdin, 197 
Thiazole compounds, 554 
Thienyl. See Thiophene. 
Thio-acetals, 306 
-acetanilide, 607 
-acetic acid, 251 
-acids, 250 
-alcohols, 140 
-aldehydes, 193 





Thio-amides, 260 
-ammeline, 291 
-anhydrides, 250 
-anilines, 684 
-benzaldehyde, 717 
-benzoic acid, 743 
-carbamic acids, 386, 614 
-carbonic acids, 382 
-carbonyl chloride, 376 
-cyanacetic acid, 355 
-cyanic acids, 277 
-cresols, 686 
-diphenylamine, 604 
-ethers, 140 
-formanilides, 260 
-glycollic acid, 355 
-hydantoins, 396 
-lactic acid, 359 
-naphthene, 924 
-naphthols, 918 

Thionine, 605 

Thionuric acid, 442 

Thiophene, 521, 529 
alcohol, 534 
aldehydes and ketones, 534 
amido- derivatives, 533 
carboxylic acids, 535, 536 
condensed derivatives, 537 
halogen derivatives, 532 
homologues, 531 
nitro- derivatives, 532 
phenols, 533 
sulpho- acids, 533 

Thiophenin, 533 

Thiophenol, 672 

Thiophyllin, 449 

Thiophtene, 924 

Thiosinamine, 396 

Thiotolenic acids, 535 
tolene, 531 
urea, 394 
urethanes, 386 

Thioxanthone, 983 

Thioxine, 531 

Thymene, 688 

Thymo-hydroquinone, 694 

Thymoil, 705 

Thymol, 687 

Thymo-quinone, 694 

Tiglic acid, 241 

Tin compounds, 183 

Tolane, 886 

Tolidines, 845 

Tollylene alcohols, 712 


INDEX. 





Tolu anthrazine, 986 
Tolu balsam, 742 
Tolubenzoic acid, 864 
Toluene, 572 
Toluene derivatives, 583, 584, 585 

nitro-derivatives, 590 

nitroso-derivatives, 591 

sulphonic acids, 665 
Tolu-hydroquinone, 694 
Toluic acids, 753 

aldehyde, 721 
Toluidines, 623 
Tolunaphthazine, 986 
Tolunitrile, 734 
Toluphenazine, 986 
Toluquinolines, 969 
Toluquinone, 704 
Toluquinoxaline, 980 
Toluylene, 885 

blue, 708 

diamines, 626 

glycols, 886 

hydrate, 888 

red, 986, 988 
Tolyl alcohols, 711 

lide, 864. 

Trehalose — Mycose. 
Triacetamide, 259 
Triacetonamine, 208 
Triacetonine, 209 
Triazole compounds, 553 
Triazoles, phenylated, 935 sgh 
Tribasic acids (C,H, — Oe)> 471 
Tribenzoyl methane, 891 
Tricarballylic acid, 471 
Trichloracetic acid, 221 
Trichloracetoacrylic acid, 344 
Trichlorhydrin, 455 
Trichlorlactic acid, 359 
Trichlorphenomalic acid, 344 
Tricyanogen chloride, 267 
Tridecylic acid, 232 
Triketones, mixed, 731 
Trimellitic acid, 797 
Trimesic acid, 797 
Trimethyl acetic acid, 229 

amine, 164 

carbinol, 129 
Trimethylene, 83 

bromide, 102 

derivatives, 516 
Trinitroacetonitrile, 286 
Trioxyglutaric acid, 485 
Trioxymethylene, 192 


1039 





| 


1040 ! INDEX. 


Triphenyl acetic acid, 615 
amine, 604 
benzene, 852 
carbinol, 866 
cyanurate, 613 
guanidine, 618 
methane carboxylic acid, 880 
tricyanide, 734 

Trisaccharides, 511 

Trithiocarbonic acid, 379 

Trithiocyanuric acid, 281 
esters of, 281 

Tropzeolines, 644, 651 

Tropeines, 996 

Tropic acid, 776 

Tropidine, 953 

Tropine, 943, 953 

Truxillic acids, 813 

Tuberculin, 1013 

Turpentine oil, 998 

Tyrosine, 775 


Uz. 


Umbellic acid, $21 

Umbelliferon, 821 

Undecolic acid, 245 

Undecylenic acid, 231 

Undecylic acid, 231 

Unsaturated tetracarboxylic acids, 482 
Uracyl, 442, 957 


Uramidobenzoic acid, 750 


Uramil, 441 
Urazole, 553 

Urea, 18, 386 
Urea chloride, 376 _ 
Ureides, 391 : 
Urethanes, 382 
Uric acid, 445 
Uvinic acid, 527 
Uvitic acid, 790 
Uvitonic acid, 949 


V. 


__ Valeraldehydes, 198 
_* Valeric acids, 228 
_ Valeridine, 198 
-Valeritrine, 198 


Valerolactone, 363 
Valeronitrile, 284 
Valerylene, 89 
Valylene, 90° @ 
? 


* 
x 





Vanillin, 725 
alcohol, 714 
Vanillic acid, 780 
Varnishes, 1008 
Vaseline, 78 
Veratric acid, 779 » 
Veratrine, 998 
Veratrol, 690 
Victoria blue, 876 
green, 868 
orange, 686 
Vinaconic acid, 517 
Vinyl, 97 
alcohol, 134 
Vinylamine, 163 
bromide, 97 
chloride, 97 
Vinylether, 140 
ethyl ether, 140 
iodide, 97 
malonic acid, 428, 517 
Violet-aniline, 990 
Hofmann’s, 873 
Violuric acid, 441 
Viridin, 869 
Vitellin, TOTS 


\Vulpic acid, 892 


W. 


Wax, 255 
Wintergreen Oil, 767 


am: 


Xanthic acid, 380 
Xanthine, 448 
Xanthone, 860 
Xanthoquinic acid, 973 
Xeronic acid, 431 
Xylenes, 572, 573 
Xylenols, 687 
Xylic acids, 757 
Xylidic acid, 790 
Xylidines, 624 
Xyloquinone, 704 
Xylose, 483 


Zinc ethide, 180 
methide 136 





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